1
|
Kimenyi KM, Akinyi MY, Mwikali K, Gilmore T, Mwangi S, Omer E, Gichuki B, Wambua J, Njunge J, Obiero G, Bejon P, Langhorne J, Abdi A, Ochola-Oyier LI. Distinct transcriptomic signatures define febrile malaria depending on initial infective states, asymptomatic or uninfected. BMC Infect Dis 2024; 24:140. [PMID: 38287287 PMCID: PMC10823747 DOI: 10.1186/s12879-024-08973-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/01/2024] [Indexed: 01/31/2024] Open
Abstract
BACKGROUND Cumulative malaria parasite exposure in endemic regions often results in the acquisition of partial immunity and asymptomatic infections. There is limited information on how host-parasite interactions mediate the maintenance of chronic symptomless infections that sustain malaria transmission. METHODS Here, we determined the gene expression profiles of the parasite population and the corresponding host peripheral blood mononuclear cells (PBMCs) from 21 children (< 15 years). We compared children who were defined as uninfected, asymptomatic and those with febrile malaria. RESULTS Children with asymptomatic infections had a parasite transcriptional profile characterized by a bias toward trophozoite stage (~ 12 h-post invasion) parasites and low parasite levels, while early ring stage parasites were characteristic of febrile malaria. The host response of asymptomatic children was characterized by downregulated transcription of genes associated with inflammatory responses, compared with children with febrile malaria,. Interestingly, the host responses during febrile infections that followed an asymptomatic infection featured stronger inflammatory responses, whereas the febrile host responses from previously uninfected children featured increased humoral immune responses. CONCLUSIONS The priming effect of prior asymptomatic infection may explain the blunted acquisition of antibody responses seen to malaria antigens following natural exposure or vaccination in malaria endemic areas.
Collapse
Affiliation(s)
- Kelvin M Kimenyi
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biochemistry, University of Nairobi, Nairobi, Kenya
| | | | - Kioko Mwikali
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Shaban Mwangi
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
| | - Elisha Omer
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - James Njunge
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
| | - George Obiero
- Department of Biochemistry, University of Nairobi, Nairobi, Kenya
| | - Philip Bejon
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | | | | | | |
Collapse
|
2
|
Gomes C, Varo R, Duran-Frigola M, Sitoe A, Bila R, Machevo S, Mayor A, Bassat Q, Rodriguez A. Endothelial transcriptomic analysis identifies biomarkers of severe and cerebral malaria. JCI Insight 2023; 8:e172845. [PMID: 37788095 PMCID: PMC10721316 DOI: 10.1172/jci.insight.172845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/28/2023] [Indexed: 10/05/2023] Open
Abstract
Malaria can quickly progress from an uncomplicated infection into a life-threatening severe disease. However, the unspecificity of early symptoms often makes it difficult to identify patients at high risk of developing severe disease. Additionally, one of the most feared malaria complications - cerebral malaria - is challenging to diagnose, often resulting in treatment delays that can lead to adverse outcomes. To identify candidate biomarkers for the prognosis and/or diagnosis of severe and cerebral malaria, we have analyzed the transcriptomic response of human brain microvascular endothelial cells to erythrocytes infected with Plasmodium falciparum. Candidates were validated in plasma samples from a cohort of pediatric patients with malaria from Mozambique, resulting in the identification of several markers with capacity to distinguish uncomplicated from severe malaria, the most potent being the metallopeptidase ADAMTS18. Two other biomarkers, Angiopoietin-like-4 and Inhibin-βE were able to differentiate children with cerebral malaria within the severe malaria group, showing increased sensitivity after combination in a biomarker signature. The validation of the predicted candidate biomarkers in plasma of children with severe and cerebral malaria underscores the power of this transcriptomic approach and indicates that a specific endothelial response to P. falciparum-infected erythrocytes is linked to the pathophysiology of severe malaria.
Collapse
Affiliation(s)
- Cláudia Gomes
- New York University Grossman School of Medicine, New York, USA
| | - Rosauro Varo
- ISGlobal, Hospital Clínic — University of Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | | | - Antonio Sitoe
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Rubão Bila
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Sonia Machevo
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Alfredo Mayor
- ISGlobal, Hospital Clínic — University of Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- Spanish Consortium for Research in Epidemiology and Public Health (CIBERESP), Carlos III Health Institute, Madrid, Spain
- Department of Physiologic Sciences, Faculty of Medicine, Universidade Eduardo Mondlane, Maputo, Mozambique
| | - Quique Bassat
- ISGlobal, Hospital Clínic — University of Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- Spanish Consortium for Research in Epidemiology and Public Health (CIBERESP), Carlos III Health Institute, Madrid, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain
- Pediatrics Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Esplugues, Barcelona, Spain
| | - Ana Rodriguez
- New York University Grossman School of Medicine, New York, USA
| |
Collapse
|
3
|
Mwaba C, Munsaka S, Bvulani B, Mwakazanga D, Chiluba BC, Fitzwanga K, Mpabalwani E. Malaria is the leading cause of acute kidney injury among a Zambian paediatric renal service cohort retrospectively evaluated for aetiologies, predictors of the need for dialysis, and outcomes. PLoS One 2023; 18:e0293037. [PMID: 37878602 PMCID: PMC10599569 DOI: 10.1371/journal.pone.0293037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 10/03/2023] [Indexed: 10/27/2023] Open
Abstract
BACKGROUND Whilst malaria is a prominent aetiology associated with acute kidney injury (AKI) in many parts of Africa, a shift in the traditional AKI aetiologies has been witnessed in sections of the continent. Additionally, limited access to dialysis worsens patient outcomes in these low-resource settings. This retrospective cross-sectional study aimed to determine the associated aetiologies, predictors of need for dialysis and malaria-associated AKI (MAKI), and outcomes of AKI and dialysis among children evaluated by the renal service in Lusaka, Zambia. METHODS The study sampled all children aged 16 years or below, diagnosed with AKI between 2017 and 2021, by the renal unit at the University Teaching Hospitals- Children's Hospital (UTH-CH), and retrospectively abstracted their records for exposures and outcomes. AKI was defined using the Kidney Disease Improving Global Outcomes (KDIGO) 2012 criteria. Frequency and percentage distributions were used to describe the occurrence of AKI aetiologies and treatment outcomes. Predictors of the need for dialysis, MAKI, and poor treatment outcome were identified by using multivariable logistic regression models. RESULTS A total of 126 children diagnosed with AKI were included in this study. Malaria was the most frequent aetiology of AKI(61.1% (77/126, 95% Confidence Interval (CI): 52.0%-69.7%)). Of the 126 children with AKI, 74.6% (94) underwent dialysis. Predictors of the need for dialysis were oliguria (p = 0.0024; Odds ratio (OR) = 7.5, 95% CI: 2.1-27.7) and anuria (p = 0.0211; OR = 6.4, 95% CI = 1.3, 30.7). A fifth (18.3%, 23/126) of the children developed chronic kidney disease (CKD), 5.6% (7/126) died and, a year later, 77% (97/126) were lost to follow-up. CONCLUSION At UTH-CH, malaria is the most frequent aetiology among children with AKI undergoing dialysis and children from low-medium malaria incidence areas are at risk; a considerable proportion of children with AKI need dialysis and Tenchoff catheter use in AKI is advocated.
Collapse
Affiliation(s)
- Chisambo Mwaba
- Department of Paediatrics and Child Health, School of Medicine, University of Zambia, Lusaka, Zambia
- Department of Paediatrics, University Teaching Hospitals-Children’s Hospital, Lusaka, Zambia
| | - Sody Munsaka
- Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka, Zambia
| | - Bruce Bvulani
- Department of Paediatric Surgery, University Teaching Hospitals-Adult Hospital, Lusaka, Zambia
| | - David Mwakazanga
- Department of Public Health, Tropical Diseases Research Centre, 6-7 Floors Ndola Teaching Hospital, Ndola, Zambia
| | - Brian Chanda Chiluba
- Department of Biostatistics and Epidemiology, School of Public Health, University of Zambia, Lusaka, Zambia
| | - Kaiser Fitzwanga
- Department of Paediatrics, Intensive Care Unit, Windhoek Central Hospital, Windhoek, Namibia
| | - Evans Mpabalwani
- Department of Paediatrics and Child Health, School of Medicine, University of Zambia, Lusaka, Zambia
- Department of Paediatrics, University Teaching Hospitals-Children’s Hospital, Lusaka, Zambia
| |
Collapse
|
4
|
Hoffman-Hall A, Puett R, Silva JA, Chen D, Bredder A, Shevade V, Han ZY, Han KT, Aung PP, Plowe CV, Nyunt MM, Loboda TV. Comparison of deforestation and forest land use factors for malaria elimination in Myanmar. IJID REGIONS 2023; 8:75-83. [PMID: 37533552 PMCID: PMC10393544 DOI: 10.1016/j.ijregi.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 08/04/2023]
Abstract
Objectives Within the remote region of Ann Township in Myanmar's Rakhine State, malaria prevalence has remained steady at ∼10% of the population from 2016-2019. Previous studies have linked areas of higher malaria prevalence in the region to heavily forested areas, however, little is known about how people live, work, and move through these areas. This work aims to disentangle landscape from land use in regard to malaria exposure. Methods We investigated the roles of forest cover, forest loss, and land use activities with malaria prevalence through the combined use of land use surveys, malaria surveillance, and satellite earth observations. Results Our results confirm previous research that linked areas of high forest cover with high malaria prevalence. However, areas experiencing high levels of deforestation were not associated with malaria prevalence. The land use factors that contribute most significantly to increased malaria risk remained those which put people in direct contact with forests, including conducting forest chores, having an outdoor job, and having a primary occupation in the logging and/or plantation industry. Conclusion Malaria prevention methods in Myanmar should focus on anyone who lives near forests or engages in land use activities that bring them within proximity of forested landscapes, whether through occupation or chores.
Collapse
Affiliation(s)
| | - Robin Puett
- University of Maryland, School of Public Health, College Park, USA
| | - Julie A. Silva
- University at Buffalo, Department of Geography, Buffalo, USA
| | - Dong Chen
- University of Maryland, Department of Geographical Sciences, College Park, USA
| | - Allison Bredder
- University of Maryland, Department of Geographical Sciences, College Park, USA
| | - Varada Shevade
- University of Maryland, Department of Geographical Sciences, College Park, USA
| | - Zay Yar Han
- Duke University, Global Health Institute, Durham, USA
| | - Kay Thwe Han
- Department of Medical Research, Myanmar Ministry of Health and Sports, Yangon, Myanmar
| | - Poe Poe Aung
- Malaria Consortium, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Tatiana V. Loboda
- University of Maryland, Department of Geographical Sciences, College Park, USA
| |
Collapse
|
5
|
Opi DH, Ndila CM, Uyoga S, Macharia AW, Fennell C, Ochola LB, Nyutu G, Siddondo BR, Ojal J, Shebe M, Awuondo KO, Mturi N, Peshu N, Tsofa B, Band G, Maitland K, Kwiatkowski DP, Rockett KA, Williams TN, Rowe JA. Non-O ABO blood group genotypes differ in their associations with Plasmodium falciparum rosetting and severe malaria. PLoS Genet 2023; 19:e1010910. [PMID: 37708213 PMCID: PMC10522014 DOI: 10.1371/journal.pgen.1010910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 09/26/2023] [Accepted: 08/08/2023] [Indexed: 09/16/2023] Open
Abstract
Blood group O is associated with protection against severe malaria and reduced size and stability of P. falciparum-host red blood cell (RBC) rosettes compared to non-O blood groups. Whether the non-O blood groups encoded by the specific ABO genotypes AO, BO, AA, BB and AB differ in their associations with severe malaria and rosetting is unknown. The A and B antigens are host RBC receptors for rosetting, hence we hypothesized that the higher levels of A and/or B antigen on RBCs from AA, BB and AB genotypes compared to AO/BO genotypes could lead to larger rosettes, increased microvascular obstruction and higher risk of malaria pathology. We used a case-control study of Kenyan children and in vitro adhesion assays to test the hypothesis that "double dose" non-O genotypes (AA, BB, AB) are associated with increased risk of severe malaria and larger rosettes than "single dose" heterozygotes (AO, BO). In the case-control study, compared to OO, the double dose genotypes consistently had higher odds ratios (OR) for severe malaria than single dose genotypes, with AB (OR 1.93) and AO (OR 1.27) showing most marked difference (p = 0.02, Wald test). In vitro experiments with blood group A-preferring P. falciparum parasites showed that significantly larger rosettes were formed with AA and AB host RBCs compared to OO, whereas AO and BO genotypes rosettes were indistinguishable from OO. Overall, the data show that ABO genotype influences P. falciparum rosetting and support the hypothesis that double dose non-O genotypes confer a greater risk of severe malaria than AO/BO heterozygosity.
Collapse
Affiliation(s)
- D. Herbert Opi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Carolyne M. Ndila
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Sophie Uyoga
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Alex W. Macharia
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Clare Fennell
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Lucy B. Ochola
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Gideon Nyutu
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Bethseba R. Siddondo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - John Ojal
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mohammed Shebe
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Kennedy O. Awuondo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Neema Mturi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Norbert Peshu
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Benjamin Tsofa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Gavin Band
- Wellcome Centre for Human Genetics, Oxford, United Kingdom
| | - Kathryn Maitland
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Institute for Global Health Innovation, Department of Surgery and Cancer, Imperial College, London, United Kingdom
| | | | | | - Thomas N. Williams
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Institute for Global Health Innovation, Department of Surgery and Cancer, Imperial College, London, United Kingdom
| | - J. Alexandra Rowe
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
6
|
Sissoko S, Kone A, Dara A, Oboh MA, Fofana B, Sangare CO, Dembele D, Haidara AS, Diallo N, Toure S, Haidara K, Sanogo K, Doumbo OK, Ouattar A, Amambua-Ngwa A, Djimde AA. Complexity of Plasmodium falciparum infection and genetic variations associated with differences in parasite clearance time in two Malian villages. RESEARCH SQUARE 2023:rs.3.rs-3083860. [PMID: 37461533 PMCID: PMC10350111 DOI: 10.21203/rs.3.rs-3083860/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2023]
Abstract
Background Effective approaches to fight against malaria include disease prevention, an early diagnosis of malaria cases, and rapid management of confirmed cases by treatment with effective antimalarials. Artemisinin-based combination therapies are first-line treatments for uncomplicated malaria in endemic areas. However, cases of resistance to artemisinin have already been described in South-East Asia resulting in prolonged parasite clearance time after treatment. In Mali, though mutations in the K13 gene associated with delayed clearance in Asia are absent, a significant difference in parasite clearance time following treatment with artesunate was observed between two malaria endemic sites, Bougoula-Hameau and Faladje. Hypothetically, differences in complexity of Plasmodium falciparum infections may be accounted for this difference. Hence, the aims of this study were to assess the complexity of infection (COI) and genetic diversity of P. falciparum parasites during malaria treatment in Bougoula-Hameau and Faladje in Mali. Methods Thirty (30) patients per village were randomly selected from 221 patients enrolled in a prospective artesunate monotherapy study conducted in Faladje and Bougoula-Hameau in 2016. All parasitemic blood samples of patients from enrollment to last positive slide were retained to assess malaria parasite COI and polymorphisms. DNA were extracted with a Qiagen kit and Pfcsp and Pfama1 encoding gene were amplified by nested PCR and sequenced using the Illumina platform. The parasite clearance time (PCT) was determined using the parasite clearance estimator of Worldwide Antimarial Resistance Network (WWARN). Data were analyzed with R®. Results The median number of genetically distinct parasite clones was similar at enrollment, 7 (IQR of 5-9) in Faladje and 6 (IQR of 4-10) in Bougoula-Hameau (p-value = 0.1). On the first day after treatment initiation, the COI was higher in Faladje (6; CI:4-8) than in Bougoula-Hameau (4; CI:4-6) with a p-value =0. 02. Overall, COI was high with higher PCT. Finally, there was a low genetic diversity between Faladje and Bougoula-Hameau. Conclusion This study demonstrated that the difference in PCT observed between the two villages could be due to differences in the complexity of infection of these two villages.
Collapse
Affiliation(s)
- Sekou Sissoko
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Aminatou Kone
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Antoine Dara
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Mary Aigbiremo Oboh
- Medical Research Council Unit, The Gambia at London School of Hygiene and Tropical
| | - Bakary Fofana
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Cheick O Sangare
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Demba Dembele
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Aboubecrine Sedhigh Haidara
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Nouhoum Diallo
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Sekou Toure
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Kadidia Haidara
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Kassim Sanogo
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | - Ogobara K Doumbo
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| | | | - Alfred Amambua-Ngwa
- Medical Research Council Unit, The Gambia at London School of Hygiene and Tropical
| | - Abdoulaye A Djimde
- Malaria Research and Training Center, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako
| |
Collapse
|
7
|
Abdi AI, Achcar F, Sollelis L, Silva-Filho JL, Mwikali K, Muthui M, Mwangi S, Kimingi HW, Orindi B, Andisi Kivisi C, Alkema M, Chandrasekar A, Bull PC, Bejon P, Modrzynska K, Bousema T, Marti M. Plasmodium falciparum adapts its investment into replication versus transmission according to the host environment. eLife 2023; 12:e85140. [PMID: 36916164 PMCID: PMC10059685 DOI: 10.7554/elife.85140] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/01/2023] [Indexed: 03/14/2023] Open
Abstract
The malaria parasite life cycle includes asexual replication in human blood, with a proportion of parasites differentiating to gametocytes required for transmission to mosquitoes. Commitment to differentiate into gametocytes, which is marked by activation of the parasite transcription factor ap2-g, is known to be influenced by host factors but a comprehensive model remains uncertain. Here, we analyze data from 828 children in Kilifi, Kenya with severe, uncomplicated, and asymptomatic malaria infection over 18 years of falling malaria transmission. We examine markers of host immunity and metabolism, and markers of parasite growth and transmission investment. We find that inflammatory responses associated with reduced plasma lysophosphatidylcholine levels are associated with markers of increased investment in parasite sexual reproduction (i.e. transmission investment) and reduced growth (i.e. asexual replication). This association becomes stronger with falling transmission and suggests that parasites can rapidly respond to the within-host environment, which in turn is subject to changing transmission.
Collapse
Affiliation(s)
- Abdirahman I Abdi
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
- Pwani University Biosciences Research Centre, Pwani UniversityKilifiKenya
| | - Fiona Achcar
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | - Lauriane Sollelis
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | - João Luiz Silva-Filho
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | | | | | | | | | | | - Cheryl Andisi Kivisi
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
- Pwani University Biosciences Research Centre, Pwani UniversityKilifiKenya
| | - Manon Alkema
- Radboud University Nijmegen Medical CentreNijmegenNetherlands
| | - Amrita Chandrasekar
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
| | - Peter C Bull
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
| | - Katarzyna Modrzynska
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
| | - Teun Bousema
- Radboud University Nijmegen Medical CentreNijmegenNetherlands
| | - Matthias Marti
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| |
Collapse
|
8
|
Otiende M, Bauni E, Nyaguara A, Amadi D, Nyundo C, Tsory E, Walumbe D, Kinuthia M, Kihuha N, Kahindi M, Nyutu G, Moisi J, Deribew A, Agweyu A, Marsh K, Tsofa B, Bejon P, Bottomley C, Williams TN, Scott JAG. Mortality in rural coastal Kenya measured using the Kilifi Health and Demographic Surveillance System: a 16-year descriptive analysis. Wellcome Open Res 2023; 6:327. [PMID: 37416502 PMCID: PMC10320326 DOI: 10.12688/wellcomeopenres.17307.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2023] [Indexed: 10/30/2023] Open
Abstract
Background: The Kilifi Health and Demographic Surveillance System (KHDSS) was established in 2000 to define the incidence and prevalence of local diseases and evaluate the impact of community-based interventions. KHDSS morbidity data have been reported comprehensively but mortality has not been described. This analysis describes mortality in the KHDSS over 16 years. Methods: We calculated mortality rates from 2003-2018 in four intervals of equal duration and assessed differences in mortality across these intervals by age and sex. We calculated the period survival function and median survival using the Kaplan-Meier method and mean life expectancies using abridged life tables. We estimated trend and seasonality by decomposing a time series of monthly mortality rates. We used choropleth maps and random-effects Poisson regression to investigate geographical heterogeneity. Results: Mortality declined by 36% overall between 2003-2018 and by 59% in children aged <5 years. Most of the decline occurred between 2003 and 2006. Among adults, the greatest decline (49%) was observed in those aged 15-54 years. Life expectancy at birth increased by 12 years. Females outlived males by 6 years. Seasonality was only evident in the 1-4 year age group in the first four years. Geographical variation in mortality was ±10% of the median value and did not change over time. Conclusions: Between 2003 and 2018, mortality among children and young adults has improved substantially. The steep decline in 2003-2006 followed by a much slower reduction thereafter suggests improvements in health and wellbeing have plateaued in the last 12 years. However, there is substantial inequality in mortality experience by geographical location.
Collapse
Affiliation(s)
- Mark Otiende
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Evasius Bauni
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Amek Nyaguara
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - David Amadi
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Christopher Nyundo
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Emmanuel Tsory
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - David Walumbe
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Michael Kinuthia
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Norbert Kihuha
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Michael Kahindi
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Gideon Nyutu
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Jennifer Moisi
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Amare Deribew
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Ambrose Agweyu
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Kevin Marsh
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Benjamin Tsofa
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Philip Bejon
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Christian Bottomley
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Thomas N. Williams
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - J. Anthony G. Scott
- Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| |
Collapse
|
9
|
Lin Y, Tebulo A, Small D, Seydel K, Taylor T, Zhang B. Using Malarial Retinopathy to Improve the Diagnosis of Pediatric Cerebral Malaria. Am J Trop Med Hyg 2023; 108:69-75. [PMID: 36509055 PMCID: PMC9833082 DOI: 10.4269/ajtmh.22-0547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/03/2022] [Indexed: 12/14/2022] Open
Abstract
In malaria endemic areas, a high proportion of children have detectable parasitemia but show no clinical symptoms. When comatose from a cause other than malaria, this group confounds the cerebral malaria (CM) definition, making accurate diagnosis challenging. One important biomarker of CM is malarial retinopathy, a set of specific features visible in the ocular fundus. In this study, we quantified the contribution of malarial retinopathy in discriminating malaria-caused coma from non-malaria-caused coma. We estimated that 10% of our study cohort of N = 1,192 patients who met the WHO clinical definition of CM in Malawi had non-malarial coma based on a Gaussian mixture model using the parasite protein Plasmodium falciparum histidine-rich protein-2. A classification based on platelets, white blood cells, and retinopathy significantly improved the discriminative power of a previously established model including only platelets plus white blood cells (area under the receiver operating characteristic curve: 0.89 versus 0.75, P value < 0.001). We conclude that malarial retinopathy is highly predictive of malaria-caused versus non-malaria-caused coma and recommend that an ocular funduscopic examination to determine malarial retinopathy status be included in the assessment of parasitemic comatose African children.
Collapse
Affiliation(s)
- Yuzhou Lin
- Department of Statistics, Harvard University, Cambridge, Massachusetts
| | - Andrew Tebulo
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Dylan Small
- Department of Statistics and Data Science, The Wharton School, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Karl Seydel
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
- Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, Michigan
| | - Terrie Taylor
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
- Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, Michigan
| | - Bo Zhang
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington
| |
Collapse
|
10
|
Stresman G, Stratil AS, Gomane S, Armando S, Rodrigues M, Candrinho B, Roca-Feltrer A. Optimizing Routine Malaria Surveillance Data in Urban Environments: A Case Study in Maputo City, Mozambique. Am J Trop Med Hyg 2023; 108:24-31. [PMID: 36191871 PMCID: PMC9904158 DOI: 10.4269/ajtmh.22-0166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/03/2022] [Indexed: 02/04/2023] Open
Abstract
In urban settings in malaria-endemic countries, malaria incidence is not well characterized and assumed to be typically very low and consisting largely of imported infections. In such contexts, surveillance systems should adapt to ensure that data are of sufficient spatial and temporal resolution to inform appropriate programmatic interventions. The aim of this research was to 1) assess spatial and temporal trends in reported malaria cases in Maputo City, Mozambique, using an expanded case notification form and 2) to determine how malaria surveillance can be optimized to characterize the local epidemiological context, which can then be used to inform targeted entomological investigations and guide implementation of localized malaria responses. This study took place in all six health facilities of KaMavota District in Maputo City, Mozambique. A questionnaire was administered to all confirmed cases from November 2019 to August 2021. Households of cases were retrospectively geolocated using local landmarks as reference. Overall, 2,380 malaria cases were reported, with the majority being uncomplicated (97.7%) and a median age of 21 years; 70.8% of cases had reported traveling outside the city in the past month with nine reporting traveling internationally. Maps of the 1,314 malaria cases that were geolocated showed distinct spatial patterns. The expanded case notification form enables a more granular overview of the malaria epidemiology in Maputo City; the geolocation data clearly show the areas where endemic transmission is likely, thus informing where resources should be prioritized. As urbanization is rapidly increasing in malaria endemic areas, identifying systems and key variables to collect ensures an operational way to characterize urban malaria through optimization of routine data to inform decision-making.
Collapse
Affiliation(s)
- Gillian Stresman
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London United Kingdom
| | | | | | | | | | | | - Arantxa Roca-Feltrer
- Malaria Consortium, London, United Kingdom;,Address correspondence to Arantxa Roca-Feltrer, Malaria Control and Elimination Partnership in Africa (MACEPA), 2201 Westlake Avenue, Suite 200, Seattle, WA 98121. E-mail:
| |
Collapse
|
11
|
Cross-sectional prevalence and pattern of non-anaemia severe malaria among 2-10 year olds in Sokoto in Northwestern Nigeria. Front Med 2022; 16:969-974. [PMID: 36245046 DOI: 10.1007/s11684-021-0912-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 11/25/2021] [Indexed: 01/19/2023]
Abstract
Malaria is highly prevalent in Nigeria and accounts for approximately 40% of global malaria mortality. However, most reports on severe malaria in Nigeria are from hospital-based studies without accurate information from communities; thus, malaria-related deaths in the community are left untracked. This study aimed to describe the prevalence and pattern of severe malaria in a community in Northwestern Nigeria. A cross-sectional study was conducted among 2-10-year-old children in Sokoto, in August and December 2016, to determine the endemicity of malaria based on Plasmodium falciparum prevalence rate (PfPR2-10) and to describe the disease pattern. Severe malaria was diagnosed according to the World Health Organisation criteria. Data were described using Stata version 15. The prevalence of non-anaemia severe malaria was higher than expected (2.6%), considering the endemicity pattern which was mesoendemic based on a PfPR2-10 of 34.8%. The mean age of children with severe malaria was 3.73 years, and the male-female ratio was 2:1. However, 54.0% of the patients had hyperparasitaemia. A relatively high prevalence of non-anaemia severe malaria was found in Wamakko. This finding suggests the need to identify and treat cases in the community using modifications of current strategies, particularly seasonal malaria chemoprophylaxis.
Collapse
|
12
|
Lubinda J, Bi Y, Haque U, Lubinda M, Hamainza B, Moore AJ. Spatio-temporal monitoring of health facility-level malaria trends in Zambia and adaptive scaling for operational intervention. COMMUNICATIONS MEDICINE 2022; 2:79. [PMID: 35789566 PMCID: PMC9249860 DOI: 10.1038/s43856-022-00144-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/15/2022] [Indexed: 12/02/2022] Open
Abstract
Background The spatial and temporal variability inherent in malaria transmission within countries implies that targeted interventions for malaria control in high-burden settings and subnational elimination are a practical necessity. Identifying the spatio-temporal incidence, risk, and trends at different administrative geographies within malaria-endemic countries and monitoring them in near real-time as change occurs is crucial for developing and introducing cost-effective, subnational control and elimination intervention strategies. Methods This study developed intelligent data analytics incorporating Bayesian trend and spatio-temporal Integrated Laplace Approximation models to analyse high-burden over 32 million reported malaria cases from 1743 health facilities in Zambia between 2009 and 2015. Results The results show that at least 5.4 million people live in catchment areas with increasing trends of malaria, covering over 47% of all health facilities, while 5.7 million people live in areas with a declining trend (95% CI), covering 27% of health facilities. A two-scale spatio-temporal trend comparison identified significant differences between health facilities and higher-level districts, and the pattern observed in the southeastern region of Zambia provides the first evidence of the impact of recently implemented localised interventions. Conclusions The results support our recommendation for an adaptive scaling approach when implementing national malaria monitoring, control and elimination strategies and a particular need for stratified subnational approaches targeting high-burden regions with increasing disease trends. Strong clusters along borders with highly endemic countries in the north and south of Zambia underscore the need for coordinated cross-border malaria initiatives and strategies. Malaria is an infectious disease that is widespread in many African countries. Malaria transmission within a country can vary between regions, so tailored interventions for malaria control and elimination targeted to different regions are necessary. To achieve this, it is important to measure and monitor the frequency of malaria infections, its risk, and trends at different geographic administrative scales. This study analysed over 32 million reported malaria cases from 1743 health facilities in Zambia between 2009 and 2015. The results showed an increasing national trend in malaria risk and malaria infection frequency and identified differences between health facility and district trends. These findings support a flexible approach when implementing and expanding national malaria monitoring, control and elimination strategies, especially in areas bordering countries where malaria is widespread, cross-border movement is common, and cross-border initiatives could be beneficial. Lubinda et al. analyse over 32 million health-facility reported malaria cases in Zambia (2009–15) to examine spatially-structured temporal trends. They observe overall increasing trends in risk and rates and highlight the potential benefits of using an adaptive scaling approach in national malaria strategies, and a need for cross-border initiatives.
Collapse
|
13
|
Mwai K, Nkumama I, Thairu A, Mburu J, Odera D, Kimathi R, Nyamako L, Tuju J, Kinyanjui S, Musenge E, Osier F. Malaria attributable fractions with changing transmission intensity: Bayesian latent class vs logistic models. Malar J 2022; 21:326. [DOI: 10.1186/s12936-022-04346-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 10/27/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Asymptomatic carriage of malaria parasites is common in high transmission intensity areas and confounds clinical case definitions for research studies. This is important for investigations that aim to identify immune correlates of protection from clinical malaria. The proportion of fevers attributable to malaria parasites is widely used to define different thresholds of parasite density associated with febrile episodes. The varying intensity of malaria transmission was investigated to check whether it had a significant impact on the parasite density thresholds. The same dataset was used to explore an alternative statistical approach, using the probability of developing fevers as a choice over threshold cut-offs. The former has been reported to increase predictive power.
Methods
Data from children monitored longitudinally between 2005 and 2017 from Junju and Chonyi in Kilifi, Kenya were used. Performance comparison of Bayesian-latent class and logistic power models in estimating malaria attributable fractions and probabilities of having fever given a parasite density with changing malaria transmission intensity was done using Junju cohort. Zero-inflated beta regressions were used to assess the impact of using probabilities to evaluate anti-merozoite antibodies as correlates of protection, compared with multilevel binary regression using data from Chonyi and Junju.
Results
Malaria transmission intensity declined from over 49% to 5% between 2006 and 2017, respectively. During this period, malaria attributable fraction varied between 27–59% using logistic regression compared to 10–36% with the Bayesian latent class approach. Both models estimated similar patterns of fevers attributable to malaria with changing transmission intensities. The Bayesian latent class model performed well in estimating the probabilities of having fever, while the latter was efficient in determining the parasite density threshold. However, compared to the logistic power model, the Bayesian algorithm yielded lower estimates for both attributable fractions and probabilities of fever. In modelling the association of merozoite antibodies and clinical malaria, both approaches resulted in comparable estimates, but the utilization of probabilities had a better statistical fit.
Conclusions
Malaria attributable fractions, varied with an overall decline in the malaria transmission intensity in this setting but did not significantly impact the outcomes of analyses aimed at identifying immune correlates of protection. These data confirm the statistical advantage of using probabilities over binary data.
Collapse
|
14
|
Guinovart C, Sigaúque B, Bassat Q, Loscertales MP, Nhampossa T, Acácio S, Machevo S, Maculuve S, Bambo G, Mucavele H, Soriano-Gabarró M, Saifodine A, Nhacolo A, Nhalungo D, Sacoor C, Saúte F, Aponte JJ, Menéndez C, Macete E, Alonso PL. The epidemiology of severe malaria at Manhiça District Hospital, Mozambique: a retrospective analysis of 20 years of malaria admissions surveillance data. THE LANCET GLOBAL HEALTH 2022; 10:e873-e881. [DOI: 10.1016/s2214-109x(22)00125-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 03/03/2022] [Accepted: 03/17/2022] [Indexed: 11/28/2022] Open
|
15
|
Addy JW, Bediako Y, Ndungu FM, Valetta JJ, Reid AJ, Mwacharo J, Ngoi JM, Wambua J, Otieno E, Musyoki J, Said K, Berriman M, Marsh K, Bejon P, Recker M, Langhorne J. 10-year longitudinal study of malaria in children: Insights into acquisition and maintenance of naturally acquired immunity. Wellcome Open Res 2022; 6:79. [PMID: 35141425 PMCID: PMC8822141 DOI: 10.12688/wellcomeopenres.16562.3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2022] [Indexed: 01/26/2023] Open
Abstract
Background: Studies of long-term malaria cohorts have provided essential insights into how Plasmodium falciparum interacts with humans, and influences the development of antimalarial immunity. Immunity to malaria is acquired gradually after multiple infections, some of which present with clinical symptoms. However, there is considerable variation in the number of clinical episodes experienced by children of the same age within the same cohort. Understanding this variation in clinical symptoms and how it relates to the development of naturally acquired immunity is crucial in identifying how and when some children stop experiencing further malaria episodes. Where variability in clinical episodes may result from different rates of acquisition of immunity, or from variable exposure to the parasite. Methods: Using data from a longitudinal cohort of children residing in an area of moderate P. falciparum transmission in Kilifi district, Kenya, we fitted cumulative episode curves as monotonic-increasing splines, to 56 children under surveillance for malaria from the age of 5 to 15. Results: There was large variability in the accumulation of numbers of clinical malaria episodes experienced by the children, despite being of similar age and living in the same general location. One group of children from a particular sub-region of the cohort stopped accumulating clinical malaria episodes earlier than other children in the study. Despite lack of further clinical episodes of malaria, these children had higher asymptomatic parasite densities and higher antibody titres to a panel of P. falciparum blood-stage antigens. Conclusions: This suggests development of clinical immunity rather than lack of exposure to the parasite, and supports the view that this immunity to malaria disease is maintained by a greater exposure to P. falciparum, and thus higher parasite burdens. Our study illustrates the complexity of anti-malaria immunity and underscores the need for analyses which can sufficiently reflect the heterogeneity within endemic populations.
Collapse
Affiliation(s)
- John W.G. Addy
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
| | - Yaw Bediako
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | | | - John Joseph Valetta
- School of Mathematics and Statistics, University of St Andrews, St Andrews, UK
| | - Adam J. Reid
- Parasite Genomics, Wellcome Sanger Institute, Hixton, UK
| | | | | | - Joshua Wambua
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | - Edward Otieno
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Khadija Said
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Kevin Marsh
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Philip Bejon
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mario Recker
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | - Jean Langhorne
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
| |
Collapse
|
16
|
Yaro JB, Tiono AB, Ouedraogo A, Lambert B, Ouedraogo ZA, Diarra A, Traore A, Lankouande M, Soulama I, Sanou A, Worrall E, Agboraw E, Sagnon N, Ranson H, Churcher TS, Lindsay SW, Wilson AL. Risk of Plasmodium falciparum infection in south-west Burkina Faso: potential impact of expanding eligibility for seasonal malaria chemoprevention. Sci Rep 2022; 12:1402. [PMID: 35082312 PMCID: PMC8791962 DOI: 10.1038/s41598-022-05056-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/10/2021] [Indexed: 11/10/2022] Open
Abstract
Burkina Faso has one of the highest malaria burdens in sub-Saharan Africa despite the mass deployment of insecticide-treated nets (ITNs) and use of seasonal malaria chemoprevention (SMC) in children aged up to 5 years. Identification of risk factors for Plasmodium falciparum infection in rural Burkina Faso could help to identify and target malaria control measures. A cross-sectional survey of 1,199 children and adults was conducted during the peak malaria transmission season in the Cascades Region of south-west Burkina Faso in 2017. Logistic regression was used to identify risk factors for microscopically confirmed P. falciparum infection. A malaria transmission dynamic model was used to determine the impact on malaria cases averted of administering SMC to children aged 5-15 year old. P. falciparum prevalence was 32.8% in the study population. Children aged 5 to < 10 years old were at 3.74 times the odds (95% CI = 2.68-5.22, P < 0.001) and children aged 10 to 15 years old at 3.14 times the odds (95% CI = 1.20-8.21, P = 0.02) of P. falciparum infection compared to children aged less than 5 years old. Administration of SMC to children aged up to 10 years is predicted to avert an additional 57 malaria cases per 1000 population per year (9.4% reduction) and administration to children aged up to 15 years would avert an additional 89 malaria cases per 1000 population per year (14.6% reduction) in the Cascades Region, assuming current coverage of pyrethroid-piperonyl butoxide ITNs. Malaria infections were high in all age strata, although highest in children aged 5 to 15 years, despite roll out of core malaria control interventions. Given the burden of infection in school-age children, extension of the eligibility criteria for SMC could help reduce the burden of malaria in Burkina Faso and other countries in the region.
Collapse
Affiliation(s)
- Jean Baptiste Yaro
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
- Department of Biosciences, Durham University, Durham, UK
| | - Alfred B Tiono
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Alphonse Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Ben Lambert
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Faculty of Medicine, Imperial College London, London, UK
| | - Z Amidou Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Amidou Diarra
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Adama Traore
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Malik Lankouande
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issiaka Soulama
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
- Institut de Recherche en Sciences de la Santé, Ouagadougou, Burkina Faso
| | - Antoine Sanou
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
- Institute of Biodiversity, Animal Health & Comparative Medicine, Glasgow University, Glasgow, UK
| | - Eve Worrall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Efundem Agboraw
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - N'Fale Sagnon
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Hilary Ranson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Thomas S Churcher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Faculty of Medicine, Imperial College London, London, UK
| | | | - Anne L Wilson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| |
Collapse
|
17
|
Lisbôa PGS, Medeiros JMR, de Souza AV, dos Santos BFB, Sanches HOC, da Rocha JLG, Correa Junior WDJP, Costa GG, Chaves TDSS, da Silva Ventura AMR, Libonati RMF. Analysis of malaria clinical-epidemiological predictors in individuals from Brazilian Amazon. Parasitology 2022; 149:10-14. [PMID: 34218833 PMCID: PMC11010514 DOI: 10.1017/s0031182021001165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/26/2021] [Accepted: 06/27/2021] [Indexed: 11/06/2022]
Abstract
This research aims to determine whether the combination of epidemiological and clinical features can predict malaria. Diagnostic investigation detected 22.3% of individuals with Plasmodium vivax (P. vivax) malaria, with significant predominance of the male gender. The malaria triad (fever, chills and headache) had a more expressive frequency (81.1%) in individuals with positive thick blood than those with negative thick blood smear (65.1%), although there was no statistical significance. Among the variables analysed as predictive for positive thick blood smear, it was observed that personal history of travel to an endemic malaria area and past malaria infection (PMI) were significantly associated with malaria, even in multiple logistic regression. Fever had the higher sensitivity (94.6%) and past malaria history had the greater specificity (68.2%), with accuracy of 23.5% and 67.5%, respectively. In combined analysis, fever with chills had the highest sensitivity (91.9%), but low accuracy (38.5%). High specificity (91.5%) was found in the association of malaria triad, PMI and history of travel to endemic malaria area (which along with anorexia, was higher 94.6%), with good accuracy (80.7%), suggesting that the screening of patients for performing thick blood smear can be based on these data. The epidemiological features and the malaria triad (fever, chills and headache) can be predictors for identification of malaria patients, concurring to precocious diagnosis and immediate treatment of individuals with malaria.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Gabriela Góes Costa
- Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém, Pará, Brazil
| | | | | | | |
Collapse
|
18
|
Addy JW, Bediako Y, Ndungu FM, Valetta JJ, Reid AJ, Mwacharo J, Ngoi JM, Wambua J, Otieno E, Musyoki J, Said K, Berriman M, Marsh K, Bejon P, Recker M, Langhorne J. 10-year longitudinal study of malaria in children: Insights into acquisition and maintenance of naturally acquired immunity. Wellcome Open Res 2021; 6:79. [PMID: 35141425 PMCID: PMC8822141 DOI: 10.12688/wellcomeopenres.16562.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2021] [Indexed: 01/26/2023] Open
Abstract
Background: Studies of long-term malaria cohorts have provided essential insights into how Plasmodium falciparum interacts with humans, and influences the development of antimalarial immunity. Immunity to malaria is acquired gradually after multiple infections, some of which present with clinical symptoms. However, there is considerable variation in the number of clinical episodes experienced by children of the same age within the same cohort. Understanding this variation in clinical symptoms and how it relates to the development of naturally acquired immunity is crucial in identifying how and when some children stop experiencing further malaria episodes. Where variability in clinical episodes may result from different rates of acquisition of immunity, or from variable exposure to the parasite. Methods: Using data from a longitudinal cohort of children residing in an area of moderate P. falciparum transmission in Kilifi district, Kenya, we fitted cumulative episode curves as monotonic-increasing splines, to 56 children under surveillance for malaria from the age of 5 to 15. Results: There was large variability in the accumulation of numbers of clinical malaria episodes experienced by the children, despite being of similar age and living in the same general location. One group of children from a particular sub-region of the cohort stopped accumulating clinical malaria episodes earlier than other children in the study. Despite lack of further clinical episodes of malaria, these children had higher asymptomatic parasite densities and higher antibody titres to a panel of P. falciparum blood-stage antigens. Conclusions: This suggests development of clinical immunity rather than lack of exposure to the parasite, and supports the view that this immunity to malaria disease is maintained by a greater exposure to P. falciparum, and thus higher parasite burdens. Our study illustrates the complexity of anti-malaria immunity and underscores the need for analyses which can sufficiently reflect the heterogeneity within endemic populations.
Collapse
Affiliation(s)
- John W.G. Addy
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
| | - Yaw Bediako
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | | | - John Joseph Valetta
- School of Mathematics and Statistics, University of St Andrews, St Andrews, UK
| | - Adam J. Reid
- Parasite Genomics, Wellcome Sanger Institute, Hixton, UK
| | | | | | - Joshua Wambua
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | - Edward Otieno
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Khadija Said
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Kevin Marsh
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Philip Bejon
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mario Recker
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | - Jean Langhorne
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
| |
Collapse
|
19
|
Otiende M, Bauni E, Nyaguara A, Amadi D, Nyundo C, Tsory E, Walumbe D, Kinuthia M, Kihuha N, Kahindi M, Nyutu G, Moisi J, Deribew A, Agweyu A, Marsh K, Tsofa B, Bejon P, Bottomley C, Williams TN, Scott JAG. Mortality in rural coastal Kenya measured using the Kilifi Health and Demographic Surveillance System: a 16-year descriptive analysis. Wellcome Open Res 2021. [DOI: 10.12688/wellcomeopenres.17307.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Background: The Kilifi Health and Demographic Surveillance System (KHDSS) was established in 2000 to define the incidence and prevalence of local diseases and evaluate the impact of community-based interventions. KHDSS morbidity data have been reported comprehensively but mortality has not been described. This analysis describes mortality in the KHDSS over 16 years. Methods: We calculated mortality rates from 2003–2018 in four intervals of equal duration and assessed differences in mortality across these intervals by age and sex. We calculated the period survival function and median survival using the Kaplan–Meier method and mean life expectancies using abridged life tables. We estimated trend and seasonality by decomposing a time series of monthly mortality rates. We used choropleth maps and random-effects Poisson regression to investigate geographical heterogeneity. Results: Mortality declined by 36% overall between 2003–2018 and by 59% in children aged <5 years. Most of the decline occurred between 2003 and 2006. Among adults, the greatest decline (49%) was observed in those aged 15–54 years. Life expectancy at birth increased by 12 years. Females outlived males by 6 years. Seasonality was only evident in the 1–4 year age group in the first four years. Geographical variation in mortality was ±10% of the median value and did not change over time. Conclusions: Between 2003 and 2018, mortality among children and young adults has improved substantially. The steep decline in 2003–2006 followed by a much slower reduction thereafter suggests improvements in health and wellbeing have plateaued in the last 12 years. However, there is substantial inequality in mortality experience by geographical location.
Collapse
|
20
|
Rubach MP, Mukemba JP, Florence SM, Lopansri BK, Hyland K, Simmons RA, Langelier C, Nakielny S, DeRisi JL, Yeo TW, Anstey NM, Weinberg JB, Mwaikambo ED, Granger DL. Cerebrospinal Fluid Pterins, Pterin-Dependent Neurotransmitters, and Mortality in Pediatric Cerebral Malaria. J Infect Dis 2021; 224:1432-1441. [PMID: 33617646 PMCID: PMC8682765 DOI: 10.1093/infdis/jiab086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/10/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Cerebral malaria (CM) pathogenesis remains incompletely understood. Having shown low systemic levels of tetrahydrobiopterin (BH4), an enzymatic cofactor for neurotransmitter synthesis, we hypothesized that BH4 and BH4-dependent neurotransmitters would likewise be low in cerebrospinal fluid (CSF) in CM. METHODS We prospectively enrolled Tanzanian children with CM and children with nonmalaria central nervous system conditions (NMCs). We measured CSF levels of BH4, neopterin, and BH4-dependent neurotransmitter metabolites, 3-O-methyldopa, homovanillic acid, and 5-hydroxyindoleacetate, and we derived age-adjusted z-scores using published reference ranges. RESULTS Cerebrospinal fluid BH4 was elevated in CM (n = 49) compared with NMC (n = 51) (z-score 0.75 vs -0.08; P < .001). Neopterin was increased in CM (z-score 4.05 vs 0.09; P < .001), and a cutoff at the upper limit of normal (60 nmol/L) was 100% sensitive for CM. Neurotransmitter metabolite levels were overall preserved. A higher CSF BH4/BH2 ratio was associated with increased odds of survival (odds ratio, 2.94; 95% confidence interval, 1.03-8.33; P = .043). CONCLUSION Despite low systemic BH4, CSF BH4 was elevated and associated with increased odds of survival in CM. Coma in malaria is not explained by deficiency of BH4-dependent neurotransmitters. Elevated CSF neopterin was 100% sensitive for CM diagnosis and warrants further assessment of its clinical utility for ruling out CM in malaria-endemic areas.
Collapse
Affiliation(s)
- Matthew P Rubach
- Department of Medicine, Division of Infectious Diseases, Duke University, Durham, North Carolina, USA
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA
| | - Jackson P Mukemba
- Department of Pediatrics, Hubert Kairuki Memorial University, Dar es Salaam, United Republic of Tanzania
| | - Salvatore M Florence
- Department of Pediatrics, Hubert Kairuki Memorial University, Dar es Salaam, United Republic of Tanzania
| | - Bert K Lopansri
- Department of Medicine, Intermountain Healthcare, Salt Lake City, Utah, USA
- Department of Medicine, University of Utah School of Medicine and VA Medical Center, Salt Lake City, Utah, USA
| | - Keith Hyland
- Medical Neurogenetics Laboratories, Atlanta, Georgia, USA
| | - Ryan A Simmons
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA
- Department of Biostatistics, Duke University, Durham, North Carolina, USA
| | - Charles Langelier
- Department of Medicine, Division of Infectious Diseases, University of California San Francisco, San Francisco, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
| | - Sara Nakielny
- Chan Zuckerberg Biohub, San Francisco, California, USA
| | - Joseph L DeRisi
- Chan Zuckerberg Biohub, San Francisco, California, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Tsin W Yeo
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia
- Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Nicholas M Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia
- Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - J Brice Weinberg
- Department of Medicine, Duke University and VA Medical Centers, Durham, North Carolina, USA
| | - Esther D Mwaikambo
- Department of Pediatrics, Hubert Kairuki Memorial University, Dar es Salaam, United Republic of Tanzania
| | - Donald L Granger
- Department of Medicine, University of Utah School of Medicine and VA Medical Center, Salt Lake City, Utah, USA
| |
Collapse
|
21
|
Ajogbasile FV, Kayode AT, Oluniyi PE, Akano KO, Uwanibe JN, Adegboyega BB, Philip C, John OG, Eromon PJ, Emechebe G, Finimo F, Ogbulafor N, Jiya N, Okafor U, Ambe J, Wammanda RD, Oguche S, Mokuolu OA, Sowunmi A, Folarin OA, Happi CT. Genetic diversity and population structure of Plasmodium falciparum in Nigeria: insights from microsatellite loci analysis. Malar J 2021; 20:236. [PMID: 34039364 PMCID: PMC8152046 DOI: 10.1186/s12936-021-03734-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 04/13/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria remains a public health burden especially in Nigeria. To develop new malaria control and elimination strategies or refine existing ones, understanding parasite population diversity and transmission patterns is crucial. METHODS In this study, characterization of the parasite diversity and structure of Plasmodium falciparum isolates from 633 dried blood spot samples in Nigeria was carried out using 12 microsatellite loci of P. falciparum. These microsatellite loci were amplified via semi-nested polymerase chain reaction (PCR) and fragments were analysed using population genetic tools. RESULTS Estimates of parasite genetic diversity, such as mean number of different alleles (13.52), effective alleles (7.13), allelic richness (11.15) and expected heterozygosity (0.804), were high. Overall linkage disequilibrium was weak (0.006, P < 0.001). Parasite population structure was low (Fst: 0.008-0.105, AMOVA: 0.039). CONCLUSION The high level of parasite genetic diversity and low population structuring in this study suggests that parasite populations circulating in Nigeria are homogenous. However, higher resolution methods, such as the 24 SNP barcode and whole genome sequencing, may capture more specific parasite genetic signatures circulating in the country. The results obtained can be used as a baseline for parasite genetic diversity and structure, aiding in the formulation of appropriate therapeutic and control strategies in Nigeria.
Collapse
Affiliation(s)
- Fehintola V Ajogbasile
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Adeyemi T Kayode
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Paul E Oluniyi
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Kazeem O Akano
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Jessica N Uwanibe
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Benjamin B Adegboyega
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria
| | - Courage Philip
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria
| | | | - Philomena J Eromon
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria
| | - George Emechebe
- Department of Paediatrics, Imo State University Teaching Hospital, Orlu, Nigeria
| | - Finimo Finimo
- Department of Paediatrics, Federal Medical Centre, Yenagoa, Nigeria
| | - Nnenna Ogbulafor
- Case Management Unit, National Malaria Elimination Programme, Federal Ministry of Health, Abuja, Nigeria
| | - Nma Jiya
- Department of Paediatrics, Uthman Dan Fodio University, Sokoto, Nigeria
| | - Uche Okafor
- Department of Paediatrics, University of Nigeria Teaching Hospital, University of Nigeria, Nsukka, Nigeria
| | - Jose Ambe
- Department of Paediatrics, University of Maiduguri, Maiduguri, Nigeria
| | | | - Stephen Oguche
- Department of Paediatrics, University of Jos Teaching Hospital, University of Jos, Jos, Nigeria
| | - Olugbenga A Mokuolu
- Department of Paediatrics and Child Health, University of Ilorin, Ilorin, Nigeria
| | - Akintunde Sowunmi
- Institute of Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria.,Department of Pharmacology and Therapeutics, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Onikepe A Folarin
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Christian T Happi
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria. .,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria.
| |
Collapse
|
22
|
Addy JW, Bediako Y, Ndungu FM, Valetta JJ, Reid AJ, Mwacharo J, Ngoi JM, Wambua J, Otieno E, Musyoki J, Said K, Berriman M, Marsh K, Bejon P, Recker M, Langhorne J. 10-year longitudinal study of malaria in children: Insights into acquisition and maintenance of naturally acquired immunity. Wellcome Open Res 2021; 6:79. [PMID: 35141425 PMCID: PMC8822141 DOI: 10.12688/wellcomeopenres.16562.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2021] [Indexed: 01/26/2023] Open
Abstract
Background: Studies of long-term malaria cohorts have provided essential insights into how Plasmodium falciparum interacts with humans, and influences the development of antimalarial immunity. Immunity to malaria is acquired gradually after multiple infections, some of which present with clinical symptoms. However, there is considerable variation in the number of clinical episodes experienced by children of the same age within the same cohort. Understanding this variation in clinical symptoms and how it relates to the development of naturally acquired immunity is crucial in identifying how and when some children stop experiencing further malaria episodes. Where variability in clinical episodes may result from different rates of acquisition of immunity, or from variable exposure to the parasite. Methods: Using data from a longitudinal cohort of children residing in an area of moderate P. falciparum transmission in Kilifi district, Kenya, we fitted cumulative episode curves as monotonic-increasing splines, to 56 children under surveillance for malaria from the age of 5 to 15. Results: There was large variability in the accumulation of numbers of clinical malaria episodes experienced by the children, despite being of similar age and living in the same general location. One group of children from a particular sub-region of the cohort stopped accumulating clinical malaria episodes earlier than other children in the study. Despite lack of further clinical episodes of malaria, these children had higher asymptomatic parasite densities and higher antibody titres to a panel of P. falciparum blood-stage antigens. Conclusions: This suggests development of clinical immunity rather than lack of exposure to the parasite, and supports the view that this immunity to malaria disease is maintained by a greater exposure to P. falciparum, and thus higher parasite burdens. Our study illustrates the complexity of anti-malaria immunity and underscores the need for analyses which can sufficiently reflect the heterogeneity within endemic populations.
Collapse
Affiliation(s)
- John W.G. Addy
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
| | - Yaw Bediako
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | | | - John Joseph Valetta
- School of Mathematics and Statistics, University of St Andrews, St Andrews, UK
| | - Adam J. Reid
- Parasite Genomics, Wellcome Sanger Institute, Hixton, UK
| | | | | | - Joshua Wambua
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | - Edward Otieno
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Khadija Said
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Kevin Marsh
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Philip Bejon
- KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mario Recker
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, UK
| | - Jean Langhorne
- Malaria Immunology Laboratory, Francis Crick Institute, London, UK
| |
Collapse
|
23
|
McGregor D, Texeira da Silva E, Grignard L, Goncalves A, Vasileva H, Mabey D, Last A. The Epidemiology of Plasmodium falciparum Malaria in the Bijagos Islands of Guinea-Bissau. Am J Trop Med Hyg 2021; 104:2117-2122. [PMID: 33782209 PMCID: PMC8176492 DOI: 10.4269/ajtmh.20-1029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/15/2020] [Indexed: 11/07/2022] Open
Abstract
Distribution of long-lasting insecticide-treated nets (LLINs), passive detection and treatment with artemisinin-based combination therapy (ACT), and intermittent preventive treatment in pregnancy (IPTp) are the mainstay malaria control measures of Guinea-Bissau’s national control programme. This study aimed to estimate the prevalence of Plasmodium falciparum on Bubaque, the most populous island of the country’s remote Bijagos archipelago. A cross-sectional survey was performed at the start of the rainy season in August 2017. Participants were recruited using systematic random sampling in a two-stage stratified cluster design. Malaria parasitemia was detected using rapid diagnostic tests (RDTs) and quantitative PCR (qPCR). Data on housing, education, larval source management, socioeconomic status, anemia, and malaria preventive measures were collected. Multivariable logistic regression models were constructed to identify associations with P. falciparum infection. Four hundred four persons (aged 6 months–79 years, median 17 years) were enrolled in the study. The prevalence of P. falciparum parasitemia was 5.8% by RDT (95% CI: 3.55–9.33) and 16.9% by qPCR (95% CI: 13.09–21.71). The prevalence of anemia was 74.3% (95% CI: 69.04–78.85) as defined by the WHO criteria. All sampled houses were found to have open eaves; 99.5% of the surveyed population reported sleeping under a bednet (95% CI: 97.8–99.9). Although reported LLIN use is high, there remains an appreciable prevalence of malaria, suggesting that transmission is ongoing and further tools are required to reduce the burden of the disease.
Collapse
Affiliation(s)
- David McGregor
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Eunice Texeira da Silva
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom.,2Region Sanitaria Bolama-Bijagós, Bubaque, Guinea-Bissau
| | - Lynn Grignard
- 3Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Adriana Goncalves
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Hristina Vasileva
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David Mabey
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Anna Last
- 1Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| |
Collapse
|
24
|
Connolly JB, Mumford JD, Fuchs S, Turner G, Beech C, North AR, Burt A. Systematic identification of plausible pathways to potential harm via problem formulation for investigational releases of a population suppression gene drive to control the human malaria vector Anopheles gambiae in West Africa. Malar J 2021; 20:170. [PMID: 33781254 PMCID: PMC8006393 DOI: 10.1186/s12936-021-03674-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Population suppression gene drive has been proposed as a strategy for malaria vector control. A CRISPR-Cas9-based transgene homing at the doublesex locus (dsxFCRISPRh) has recently been shown to increase rapidly in frequency in, and suppress, caged laboratory populations of the malaria mosquito vector Anopheles gambiae. Here, problem formulation, an initial step in environmental risk assessment (ERA), was performed for simulated field releases of the dsxFCRISPRh transgene in West Africa. METHODS Building on consultative workshops in Africa that previously identified relevant environmental and health protection goals for ERA of gene drive in malaria vector control, 8 potentially harmful effects from these simulated releases were identified. These were stratified into 46 plausible pathways describing the causal chain of events that would be required for potential harms to occur. Risk hypotheses to interrogate critical steps in each pathway, and an analysis plan involving experiments, modelling and literature review to test each of those risk hypotheses, were developed. RESULTS Most potential harms involved increased human (n = 13) or animal (n = 13) disease transmission, emphasizing the importance to subsequent stages of ERA of data on vectorial capacity comparing transgenics to non-transgenics. Although some of the pathways (n = 14) were based on known anatomical alterations in dsxFCRISPRh homozygotes, many could also be applicable to field releases of a range of other transgenic strains of mosquito (n = 18). In addition to population suppression of target organisms being an accepted outcome for existing vector control programmes, these investigations also revealed that the efficacy of population suppression caused by the dsxFCRISPRh transgene should itself directly affect most pathways (n = 35). CONCLUSIONS Modelling will play an essential role in subsequent stages of ERA by clarifying the dynamics of this relationship between population suppression and reduction in exposure to specific potential harms. This analysis represents a comprehensive identification of plausible pathways to potential harm using problem formulation for a specific gene drive transgene and organism, and a transparent communication tool that could inform future regulatory studies, guide subsequent stages of ERA, and stimulate further, broader engagement on the use of population suppression gene drive to control malaria vectors in West Africa.
Collapse
Affiliation(s)
- John B Connolly
- Department of Life Sciences, Imperial College London, London, UK.
| | - John D Mumford
- Centre for Environmental Policy, Imperial College London, London, UK
| | - Silke Fuchs
- Department of Life Sciences, Imperial College London, London, UK
| | - Geoff Turner
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Ace R North
- Department of Zoology, University of Oxford, Oxford, UK
| | - Austin Burt
- Department of Life Sciences, Imperial College London, London, UK
| |
Collapse
|
25
|
Epstein A, Namuganga JF, Kamya EV, Nankabirwa JI, Bhatt S, Rodriguez-Barraquer I, Staedke SG, Kamya MR, Dorsey G, Greenhouse B. Estimating malaria incidence from routine health facility-based surveillance data in Uganda. Malar J 2020; 19:445. [PMID: 33267886 PMCID: PMC7709253 DOI: 10.1186/s12936-020-03514-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/19/2020] [Indexed: 12/03/2022] Open
Abstract
Background Accurate measures of malaria incidence are essential to track progress and target high-risk populations. While health management information system (HMIS) data provide counts of malaria cases, quantifying the denominator for incidence using these data is challenging because catchment areas and care-seeking behaviours are not well defined. This study’s aim was to estimate malaria incidence using HMIS data by adjusting the population denominator accounting for travel time to the health facility. Methods Outpatient data from two public health facilities in Uganda (Kihihi and Nagongera) over a 3-year period (2011–2014) were used to model the relationship between travel time from patient village of residence (available for each individual) to the facility and the relative probability of attendance using Poisson generalized additive models. Outputs from the model were used to generate a weighted population denominator for each health facility and estimate malaria incidence. Among children aged 6 months to 11 years, monthly HMIS-derived incidence estimates, with and without population denominators weighted by probability of attendance, were compared with gold standard measures of malaria incidence measured in prospective cohorts. Results A total of 48,898 outpatient visits were recorded across the two sites over the study period. HMIS incidence correlated with cohort incidence over time at both study sites (correlation in Kihihi = 0.64, p < 0.001; correlation in Nagongera = 0.34, p = 0.045). HMIS incidence measures with denominators unweighted by probability of attendance underestimated cohort incidence aggregated over the 3 years in Kihihi (0.5 cases per person-year (PPY) vs 1.7 cases PPY) and Nagongera (0.3 cases PPY vs 3.0 cases PPY). HMIS incidence measures with denominators weighted by probability of attendance were closer to cohort incidence, but remained underestimates (1.1 cases PPY in Kihihi and 1.4 cases PPY in Nagongera). Conclusions Although malaria incidence measured using HMIS underestimated incidence measured in cohorts, even when adjusting for probability of attendance, HMIS surveillance data are a promising and scalable source for tracking relative changes in malaria incidence over time, particularly when the population denominator can be estimated by incorporating information on village of residence.
Collapse
Affiliation(s)
- Adrienne Epstein
- Department of Medicine, University of California, San Francisco, 550 16th Street, San Francisco, CA, 94158, USA.
| | | | | | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Internal Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Samir Bhatt
- Department of Infectious Disease Epidemiology, St Marys Hospital, Imperial College, London, UK
| | - Isabel Rodriguez-Barraquer
- Department of Medicine, University of California, San Francisco, 550 16th Street, San Francisco, CA, 94158, USA
| | | | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Internal Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, 550 16th Street, San Francisco, CA, 94158, USA
| | - Bryan Greenhouse
- Department of Medicine, University of California, San Francisco, 550 16th Street, San Francisco, CA, 94158, USA.,Chan Zuckerberg Biohub, San Francisco, CA, USA
| |
Collapse
|
26
|
Cohee LM, Opondo C, Clarke SE, Halliday KE, Cano J, Shipper AG, Barger-Kamate B, Djimde A, Diarra S, Dokras A, Kamya MR, Lutumba P, Ly AB, Nankabirwa JI, Njagi JK, Maiga H, Maiteki-Sebuguzi C, Matangila J, Okello G, Rohner F, Roschnik N, Rouhani S, Sissoko MS, Staedke SG, Thera MA, Turner EL, Van Geertruyden JP, Zimmerman MB, Jukes MCH, Brooker SJ, Allen E, Laufer MK, Chico RM. Preventive malaria treatment among school-aged children in sub-Saharan Africa: a systematic review and meta-analyses. Lancet Glob Health 2020; 8:e1499-e1511. [PMID: 33222799 PMCID: PMC7721819 DOI: 10.1016/s2214-109x(20)30325-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 05/09/2020] [Accepted: 07/02/2020] [Indexed: 01/19/2023]
Abstract
BACKGROUND The burden of malaria infection in sub-Saharan Africa among school-aged children aged 5-15 years is underappreciated and represents an important source of human-to-mosquito transmission of Plasmodium falciparum. Additional interventions are needed to control and eliminate malaria. We aimed to assess whether preventive treatment of malaria might be an effective means of reducing P falciparum infection and anaemia in school-aged children and lowering parasite transmission. METHODS In this systematic review and two meta-analyses, we searched the online databases PubMed, Embase, Cochrane CENTRAL, and Clinicaltrials.gov for intervention studies published between Jan 1, 1990, and Dec 14, 2018. We included randomised studies that assessed the effect of antimalarial treatment among asymptomatic school-aged children aged 5-15 years in sub-Saharan Africa on prevalence of P falciparum infection and anaemia, clinical malaria, and cognitive function. We first extracted data for a study-level meta-analysis, then contacted research groups to request data for an individual participant data meta-analysis. Outcomes of interest included prevalence of P falciparum infection detected by microscopy, anaemia (study defined values or haemoglobin less than age-adjusted and sex-adjusted values), clinical malaria (infection and symptoms on the basis of study-specific definitions) during follow-up, and code transmission test scores. We assessed effects by treatment type and duration of time protected, and explored effect modification by transmission setting. For study-level meta-analysis, we calculated risk ratios for binary outcomes and standardised mean differences for continuous outcomes and pooled outcomes using fixed-effect and random-effects models. We used a hierarchical generalised linear model for meta-analysis of individual participant data. This study is registered with PROSPERO, CRD42016030197. FINDINGS Of 628 studies identified, 13 were eligible for the study-level meta-analysis (n=16 309). Researchers from 11 studies contributed data on at least one outcome (n=15 658) for an individual participant data meta-analysis. Interventions and study designs were highly heterogeneous; overall risk of bias was low. In the study-level meta-analysis, treatment was associated with reductions in P falciparum prevalence (risk ratio [RR] 0·27, 95% CI 0·17-0·44), anaemia (0·77, 0·65-0·91), and clinical malaria (0·40, 0·28-0·56); results for cognitive outcomes are not presented because data were only available for three trials. In our individual participant data meta-analysis, we found treatment significantly decreased P falciparum prevalence (adjusted RR [ARR] 0·46, 95% CI 0·40-0·53; p<0·0001; 15 648 individuals; 11 studies), anaemia (ARR 0·85, 0·77-0·92; p<0·0001; 15 026 individuals; 11 studies), and subsequent clinical malaria (ARR 0·50, 0·39-0·60; p<0·0001; 1815 individuals; four studies) across transmission settings. We detected a marginal effect on cognitive function in children older than 10 years (adjusted mean difference in standardised test scores 0·36, 0·01-0·71; p=0·044; 3962 individuals; five studies) although we found no significant effect when combined across all ages. INTERPRETATION Preventive treatment of malaria among school-aged children significantly decreases P falciparum prevalence, anaemia, and risk of subsequent clinical malaria across transmission settings. Policy makers and programme managers should consider preventive treatment of malaria to protect this age group and advance the goal of malaria elimination, while weighing these benefits against potential risks of chemoprevention. FUNDING US National Institutes of Health and Burroughs Wellcome Fund/ASTMH Fellowship.
Collapse
Affiliation(s)
- Lauren M Cohee
- Center for Vaccine Development and Global Health, University of Maryland, Baltimore, MA, USA
| | - Charles Opondo
- Department of Medical Statistics, Faculty of Epidemiology and Population Health, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Siân E Clarke
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Katherine E Halliday
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Jorge Cano
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Andrea G Shipper
- University of Maryland School of Medicine, and Health Sciences and Human Services Library, University of Maryland, Baltimore, MA, USA
| | | | - Abdoulaye Djimde
- Faculty of Medicine, Pharmacy, and Odnonto-Stomatology, Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Mali
| | | | - Aditi Dokras
- Department of Pediatrics, University of Maryland, Baltimore, MA, USA
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Pascal Lutumba
- Tropical Medicine Department, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | | | - Joaniter I Nankabirwa
- School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda; Infectious Diseases Research Collaboration, Kampala, Uganda
| | - J Kiambo Njagi
- National Malaria Control Programme, Ministry of Health, Nairobi, Kenya
| | - Hamma Maiga
- Faculty of Medicine, Pharmacy, and Odnonto-Stomatology, Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Mali
| | | | - Junior Matangila
- Tropical Medicine Department, University of Kinshasa, Kinshasa, Democratic Republic of Congo; Global Health Institute, University of Antwerp, Antwerp, Belgium
| | - George Okello
- Health Systems and Social Science Research Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Saba Rouhani
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK; Save the Children, Bamako, Mali
| | - Mahamadou S Sissoko
- Faculty of Medicine, Pharmacy, and Odnonto-Stomatology, Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Sarah G Staedke
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Mahamadou A Thera
- Faculty of Medicine, Pharmacy, and Odnonto-Stomatology, Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Mali
| | - Elizabeth L Turner
- Department of Biostatistics & Bioinformatics and Duke Global Health Institute, Duke University, Durham, NC, USA
| | | | - Michael B Zimmerman
- Institute of Food, Nutrition, and Health, Swiss Federal Institute of Technology, Zurich, Switzerland
| | | | | | - Elizabeth Allen
- Department of Medical Statistics, Faculty of Epidemiology and Population Health, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Miriam K Laufer
- Center for Vaccine Development and Global Health, University of Maryland, Baltimore, MA, USA
| | - R Matthew Chico
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| |
Collapse
|
27
|
Stresman G, Sepúlveda N, Fornace K, Grignard L, Mwesigwa J, Achan J, Miller J, Bridges DJ, Eisele TP, Mosha J, Lorenzo PJ, Macalinao ML, Espino FE, Tadesse F, Stevenson JC, Quispe AM, Siqueira A, Lacerda M, Yeung S, Sovannaroth S, Pothin E, Gallay J, Hamre KE, Young A, Lemoine JF, Chang MA, Phommasone K, Mayxay M, Landier J, Parker DM, Von Seidlein L, Nosten F, Delmas G, Dondorp A, Cameron E, Battle K, Bousema T, Gething P, D'Alessandro U, Drakeley C. Association between the proportion of Plasmodium falciparum and Plasmodium vivax infections detected by passive surveillance and the magnitude of the asymptomatic reservoir in the community: a pooled analysis of paired health facility and community data. THE LANCET. INFECTIOUS DISEASES 2020; 20:953-963. [PMID: 32277908 PMCID: PMC7391005 DOI: 10.1016/s1473-3099(20)30059-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/23/2020] [Accepted: 01/28/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Passively collected malaria case data are the foundation for public health decision making. However, because of population-level immunity, infections might not always be sufficiently symptomatic to prompt individuals to seek care. Understanding the proportion of all Plasmodium spp infections expected to be detected by the health system becomes particularly paramount in elimination settings. The aim of this study was to determine the association between the proportion of infections detected and transmission intensity for Plasmodium falciparum and Plasmodium vivax in several global endemic settings. METHODS The proportion of infections detected in routine malaria data, P(Detect), was derived from paired household cross-sectional survey and routinely collected malaria data within health facilities. P(Detect) was estimated using a Bayesian model in 431 clusters spanning the Americas, Africa, and Asia. The association between P(Detect) and malaria prevalence was assessed using log-linear regression models. Changes in P(Detect) over time were evaluated using data from 13 timepoints over 2 years from The Gambia. FINDINGS The median estimated P(Detect) across all clusters was 12·5% (IQR 5·3-25·0) for P falciparum and 10·1% (5·0-18·3) for P vivax and decreased as the estimated log-PCR community prevalence increased (adjusted odds ratio [OR] for P falciparum 0·63, 95% CI 0·57-0·69; adjusted OR for P vivax 0·52, 0·47-0·57). Factors associated with increasing P(Detect) included smaller catchment population size, high transmission season, improved care-seeking behaviour by infected individuals, and recent increases (within the previous year) in transmission intensity. INTERPRETATION The proportion of all infections detected within health systems increases once transmission intensity is sufficiently low. The likely explanation for P falciparum is that reduced exposure to infection leads to lower levels of protective immunity in the population, increasing the likelihood that infected individuals will become symptomatic and seek care. These factors might also be true for P vivax but a better understanding of the transmission biology is needed to attribute likely reasons for the observed trend. In low transmission and pre-elimination settings, enhancing access to care and improvements in care-seeking behaviour of infected individuals will lead to an increased proportion of infections detected in the community and might contribute to accelerating the interruption of transmission. FUNDING Wellcome Trust.
Collapse
Affiliation(s)
- Gillian Stresman
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK.
| | - Nuno Sepúlveda
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK; Centre of Statistics and Its Applications, University of Lisbon, Lisbon, Portugal
| | - Kimberly Fornace
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Lynn Grignard
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Julia Mwesigwa
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia; Department of Global Health, University of Antwerp, Antwerp, Belgium
| | - Jane Achan
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - John Miller
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds Lusaka, Zambia
| | - Daniel J Bridges
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds Lusaka, Zambia
| | - Thomas P Eisele
- Center for Applied Malaria Research and Evaluation, Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Jacklin Mosha
- National Institute for Medical Research, Mwanza Medical Research Centre, Mwanza, Tanzania
| | - Pauline Joy Lorenzo
- Department of Parasitology, Research Institute for Tropical Medicine, Research Drive, Alabang, Muntinlupa, Metro Manila, Philippines
| | - Maria Lourdes Macalinao
- Department of Parasitology, Research Institute for Tropical Medicine, Research Drive, Alabang, Muntinlupa, Metro Manila, Philippines
| | - Fe Esperanza Espino
- Department of Parasitology, Research Institute for Tropical Medicine, Research Drive, Alabang, Muntinlupa, Metro Manila, Philippines
| | - Fitsum Tadesse
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jennifer C Stevenson
- Macha Research Trust, Choma District, Zambia; Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - André Siqueira
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, Brazil; Programa de Pós-graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil; Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Marcus Lacerda
- Fundacao de Medicine Tropical Dr. Heitor Viera Dourado, Manaus, Brazil; Institutos Nacionais de Ciencia e Technologia (INCT), Instituto Elimina, Manaus, Brazil
| | - Shunmay Yeung
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Siv Sovannaroth
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Emilie Pothin
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; Clinton Health Access Initiative, Boston, MA, USA
| | - Joanna Gallay
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Karen E Hamre
- Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, USA; CDC Foundation, Atlanta, GA, USA
| | - Alyssa Young
- Clinton Health Access Initiative, Port-au-Prince, Haiti
| | - Jean Frantz Lemoine
- Programme National de Contrôle de la Malaria, Ministère de la Santé Publique et de la Population (MSPP), Port-au-Prince, Haiti
| | - Michelle A Chang
- Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, USA
| | - Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Institute of Research and Education Development, University of Health Sciences, Vientiane, Laos
| | - Jordi Landier
- Aix Marseille Univ, IRD, INSERM, SESSTIM, Marseille, France
| | - Daniel M Parker
- Department of Population Health and Disease Prevention and Department of Epidemiology, University of California, Irvine, CA, USA
| | - Lorenz Von Seidlein
- Oxford Tropical Medicine Research Unit, Mahidol University Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Francois Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Gilles Delmas
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Arjen Dondorp
- Oxford Tropical Medicine Research Unit, Mahidol University Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ewan Cameron
- Telethon Kids Institute, Perth Children's Hospital, Nedlands, WA, Australia; Curtin University, Bentley, WA, Australia
| | | | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Peter Gething
- Telethon Kids Institute, Perth Children's Hospital, Nedlands, WA, Australia; Curtin University, Bentley, WA, Australia
| | - Umberto D'Alessandro
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK; Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| |
Collapse
|
28
|
Akech S, Chepkirui M, Ogero M, Agweyu A, Irimu G, English M, Snow RW. The Clinical Profile of Severe Pediatric Malaria in an Area Targeted for Routine RTS,S/AS01 Malaria Vaccination in Western Kenya. Clin Infect Dis 2020; 71:372-380. [PMID: 31504308 PMCID: PMC7353324 DOI: 10.1093/cid/ciz844] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 08/23/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The malaria prevalence has declined in western Kenya, resulting in the risk of neurological phenotypes in older children. This study investigates the clinical profile of pediatric malaria admissions ahead of the introduction of the RTS,S/AS01 vaccine. METHODS Malaria admissions in children aged 1 month to 15 years were identified from routine, standardized, inpatient clinical surveillance data collected between 2015 and 2018 from 4 hospitals in western Kenya. Malaria phenotypes were defined based on available data. RESULTS There were 5766 malaria admissions documented. The median age was 36 months (interquartile range, 18-60): 15% were aged between 1-11 months of age, 33% were aged 1-23 months of age, and 70% were aged 1 month to 5 years. At admission, 2340 (40.6%) children had severe malaria: 421/2208 (19.1%) had impaired consciousness, 665/2240 (29.7%) had an inability to drink or breastfeed, 317/2340 (13.6%) had experienced 2 or more convulsions, 1057/2340 (45.2%) had severe anemia, and 441/2239 (19.7%) had severe respiratory distress. Overall, 211 (3.7%) children admitted with malaria died; 163/211 (77% deaths, case fatality rate 7.0%) and 48/211 (23% deaths, case fatality rate 1.4%) met the criteria for severe malaria and nonsevere malaria at admission, respectively. The median age for fatal cases was 33 months (interquartile range, 12-72) and the case fatality rate was highest in those unconscious (44.4%). CONCLUSIONS Severe malaria in western Kenya is still predominantly seen among the younger pediatric age group and current interventions targeted for those <5 years are appropriate. However, there are increasing numbers of children older than 5 years admitted with malaria, and ongoing hospital surveillance would identify when interventions should target older children.
Collapse
Affiliation(s)
- Samuel Akech
- Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya
| | - Mercy Chepkirui
- Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya
| | - Morris Ogero
- Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya
| | - Ambrose Agweyu
- Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya
| | - Grace Irimu
- Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya
- Department of Paediatrics and Child Health, University of Nairobi, Nairobi, Kenya
| | - Mike English
- Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Robert W Snow
- Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
29
|
Gilchrist JJ, Uyoga S, Pirinen M, Rautanen A, Mwarumba S, Njuguna P, Mturi N, Hill AVS, Scott JAG, Williams TN. Risk of pneumococcal bacteremia in Kenyan children with glucose-6-phosphate dehydrogenase deficiency. BMC Med 2020; 18:148. [PMID: 32536341 PMCID: PMC7294654 DOI: 10.1186/s12916-020-01604-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/23/2020] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency state in humans. The clinical phenotype is variable and includes asymptomatic individuals, episodic hemolysis induced by oxidative stress, and chronic hemolysis. G6PD deficiency is common in malaria-endemic regions, an observation hypothesized to be due to balancing selection at the G6PD locus driven by malaria. G6PD deficiency increases risk of severe malarial anemia, a key determinant of invasive bacterial disease in malaria-endemic settings. The pneumococcus is a leading cause of invasive bacterial infection and death in African children. The effect of G6PD deficiency on risk of pneumococcal disease is undefined. We hypothesized that G6PD deficiency increases pneumococcal disease risk and that this effect is dependent upon malaria. METHODS We performed a genetic case-control study of pneumococcal bacteremia in Kenyan children stratified across a period of falling malaria transmission between 1998 and 2010. RESULTS Four hundred twenty-nine Kenyan children with pneumococcal bacteremia and 2677 control children were included in the study. Among control children, G6PD deficiency, secondary to the rs1050828 G>A mutation, was common, with 11.2% (n = 301 of 2677) being hemi- or homozygotes and 33.3% (n = 442 of 1329) of girls being heterozygotes. We found that G6PD deficiency increased the risk of pneumococcal bacteremia, but only during a period of high malaria transmission (P = 0.014; OR 2.33, 95% CI 1.19-4.57). We estimate that the population attributable fraction of G6PD deficiency on risk of pneumococcal bacteremia in areas under high malaria transmission is 0.129. CONCLUSIONS Our data demonstrate that G6PD deficiency increases risk of pneumococcal bacteremia in a manner dependent on malaria. At the population level, the impact of G6PD deficiency on invasive pneumococcal disease risk in malaria-endemic regions is substantial. Our study highlights the infection-associated morbidity and mortality conferred by G6PD deficiency in malaria-endemic settings and adds to our understanding of the potential indirect health benefits of improved malaria control.
Collapse
Affiliation(s)
- James J Gilchrist
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK. .,Department of Paediatrics, University of Oxford, Oxford, OX3 9DU, UK.
| | - Sophie Uyoga
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Matti Pirinen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 00014, Helsinki, Finland
| | - Anna Rautanen
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Salim Mwarumba
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | | | - Neema Mturi
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | | | - Adrian V S Hill
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.,The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
| | - J Anthony G Scott
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya.,Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya. .,Department of Medicine, Imperial College, Norfolk Place, London, W2 1PG, UK.
| |
Collapse
|
30
|
Kigozi SP, Kigozi RN, Epstein A, Mpimbaza A, Sserwanga A, Yeka A, Nankabirwa JI, Halliday K, Pullan RL, Rutazaana D, Sebuguzi CM, Opigo J, Kamya MR, Staedke SG, Dorsey G, Greenhouse B, Rodriguez-Barraquer I. Rapid shifts in the age-specific burden of malaria following successful control interventions in four regions of Uganda. Malar J 2020; 19:128. [PMID: 32228584 PMCID: PMC7106889 DOI: 10.1186/s12936-020-03196-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/20/2020] [Indexed: 12/17/2022] Open
Abstract
Background Malaria control using long-lasting insecticidal nets (LLINs) and indoor residual spraying of insecticide (IRS) has been associated with reduced transmission throughout Africa. However, the impact of transmission reduction on the age distribution of malaria cases remains unclear. Methods Over a 10-year period (January 2009 to July 2018), outpatient surveillance data from four health facilities in Uganda were used to estimate the impact of control interventions on temporal changes in the age distribution of malaria cases using multinomial regression. Interventions included mass distribution of LLINs at all sites and IRS at two sites. Results Overall, 896,550 patient visits were included in the study; 211,632 aged < 5 years, 171,166 aged 5–15 years and 513,752 > 15 years. Over time, the age distribution of patients not suspected of malaria and those malaria negative either declined or remained the same across all sites. In contrast, the age distribution of suspected and confirmed malaria cases increased across all four sites. In the two LLINs-only sites, the proportion of malaria cases in < 5 years decreased from 31 to 16% and 35 to 25%, respectively. In the two sites receiving LLINs plus IRS, these proportions decreased from 58 to 30% and 64 to 47%, respectively. Similarly, in the LLINs-only sites, the proportion of malaria cases > 15 years increased from 40 to 61% and 29 to 39%, respectively. In the sites receiving LLINs plus IRS, these proportions increased from 19 to 44% and 18 to 31%, respectively. Conclusions These findings demonstrate a shift in the burden of malaria from younger to older individuals following implementation of successful control interventions, which has important implications for malaria prevention, surveillance, case management and control strategies.
Collapse
Affiliation(s)
- Simon P Kigozi
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. .,Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.
| | - Ruth N Kigozi
- USAID's Malaria Action Program for Districts, PO Box 8045, Kampala, Uganda
| | - Adrienne Epstein
- Department of Epidemiology & Biostatistics, University of California, San Francisco, 550 16th Street, San Francisco, CA, 94158, USA
| | - Arthur Mpimbaza
- Child Health and Development Centre, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Asadu Sserwanga
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda
| | - Adoke Yeka
- School of Public Health, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Katherine Halliday
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Rachel L Pullan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Damian Rutazaana
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Catherine M Sebuguzi
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Jimmy Opigo
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Sarah G Staedke
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Grant Dorsey
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,Department of Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH Building 30, San Francisco, CA, 94110, USA
| | - Bryan Greenhouse
- Division of HIV, ID, and Global Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH, Building 3, San Francisco, CA, 94110, USA.,Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Isabel Rodriguez-Barraquer
- Division of HIV, ID, and Global Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH, Building 3, San Francisco, CA, 94110, USA
| |
Collapse
|
31
|
Bridges DJ, Chishimba S, Mwenda M, Winters AM, Slawsky E, Mambwe B, Mulube C, Searle KM, Hakalima A, Mwenechanya R, Larsen DA. The use of spatial and genetic tools to assess Plasmodium falciparum transmission in Lusaka, Zambia between 2011 and 2015. Malar J 2020; 19:20. [PMID: 31941493 PMCID: PMC6964105 DOI: 10.1186/s12936-020-3101-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Zambia has set itself the ambitious target of eliminating malaria by 2021. To continue tracking transmission to zero, new interventions, tools and approaches are required. METHODS Urban reactive case detection (RCD) was performed in Lusaka city from 2011 to 2015 to better understand the location and drivers of malaria transmission. Briefly, index cases were followed to their home and all consenting individuals living in the index house and nine proximal houses were tested with a malaria rapid diagnostic test and treated if positive. A brief survey was performed and for certain responses, a dried blood spot sample collected for genetic analysis. Aggregate health facility data, individual RCD response data and genetic results were analysed spatially and against environmental correlates. RESULTS Total number of malaria cases remained relatively constant, while the average age of incident cases and the proportion of incident cases reporting recent travel both increased. The estimated R0 in Lusaka was < 1 throughout the study period. RCD responses performed within 250 m of uninhabited/vacant land were associated with a higher probability of identifying additional infections. CONCLUSIONS Evidence suggests that the majority of malaria infections are imported from outside Lusaka. However there remains some level of local transmission occurring on the periphery of urban settlements, namely in the wet season. Unfortunately, due to the higher-than-expected complexity of infections and the small number of samples tested, genetic analysis was unable to identify any meaningful trends in the data.
Collapse
Affiliation(s)
- Daniel J Bridges
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia. .,Akros, 45A Roan Road, Lusaka, Zambia.
| | - Sandra Chishimba
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia.,Akros, 45A Roan Road, Lusaka, Zambia
| | - Mulenga Mwenda
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia.,Akros, 45A Roan Road, Lusaka, Zambia
| | - Anna M Winters
- Akros, 45A Roan Road, Lusaka, Zambia.,School of Public and Community Health Sciences, University of Montana, Missoula, MT, USA
| | - Erik Slawsky
- Department of Public Health, Syracuse University, Syracuse, NY, USA
| | - Brenda Mambwe
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia
| | - Conceptor Mulube
- PATH MACEPA, National Malaria Elimination Centre, Gt East Rd, Lusaka, Zambia
| | - Kelly M Searle
- School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Aves Hakalima
- Lusaka District Health Management Team, Ministry of Health, Lusaka, Zambia
| | - Roy Mwenechanya
- Akros, 45A Roan Road, Lusaka, Zambia.,Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - David A Larsen
- Akros, 45A Roan Road, Lusaka, Zambia.,Department of Public Health, Syracuse University, Syracuse, NY, USA
| |
Collapse
|
32
|
Nikolaeva D, Illingworth JJ, Miura K, Alanine DGW, Brian IJ, Li Y, Fyfe AJ, Da DF, Cohuet A, Long CA, Draper SJ, Biswas S. Functional Characterization and Comparison of Plasmodium falciparum Proteins as Targets of Transmission-blocking Antibodies. Mol Cell Proteomics 2020; 19:155-166. [PMID: 29089373 PMCID: PMC6944241 DOI: 10.1074/mcp.ra117.000036] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/26/2017] [Indexed: 12/13/2022] Open
Abstract
Plasmodium falciparum malaria continues to evade control efforts, utilizing highly specialized sexual-stages to transmit infection between the human host and mosquito vector. In a vaccination model, antibodies directed to sexual-stage antigens, when ingested in the mosquito blood meal, can inhibit parasite growth in the midgut and consequently arrest transmission. Despite multiple datasets for the Plasmodium sexual-stage transcriptome and proteome, there have been no rational screens to identify candidate antigens for transmission-blocking vaccine (TBV) development. This study characterizes 12 proteins from across the P. falciparum sexual-stages as possible TBV targets. Recombinant proteins are heterologously expressed as full-length ectodomains in a mammalian HEK293 cell system. The proteins recapitulate native parasite epitopes as assessed by indirect fluorescence assay and a proportion exhibits immunoreactivity when tested against sera from individuals living in malaria-endemic Burkina Faso and Mali. Purified IgG generated to the mosquito-stage parasite antigen enolase demonstrates moderate inhibition of parasite development in the mosquito midgut by the ex vivo standard membrane feeding assay. The findings support the use of rational screens and comparative functional assessments in identifying proteins of the P. falciparum transmission pathway and establishing a robust pre-clinical TBV pipeline.
Collapse
Affiliation(s)
- Daria Nikolaeva
- The Jenner Institute, University of Oxford, Oxford UK; Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious DiseaseNational Institutes of Health, Rockville, Maryland
| | | | - Kazutoyo Miura
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious DiseaseNational Institutes of Health, Rockville, Maryland
| | | | - Iona J Brian
- The Jenner Institute, University of Oxford, Oxford UK
| | - Yuanyuan Li
- The Jenner Institute, University of Oxford, Oxford UK
| | - Alex J Fyfe
- The Jenner Institute, University of Oxford, Oxford UK
| | - Dari F Da
- Institut de Recherche en Sciences de la Santé, Bobo Dioulasso, Burkina Faso
| | - Anna Cohuet
- Institut de Recherche pour le Développement, Montpellier Cedex, France
| | - Carole A Long
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious DiseaseNational Institutes of Health, Rockville, Maryland
| | | | - Sumi Biswas
- The Jenner Institute, University of Oxford, Oxford UK.
| |
Collapse
|
33
|
Umunnakwe FA, Idowu ET, Ajibaye O, Etoketim B, Akindele S, Shokunbi AO, Otubanjo OA, Awandare GA, Amambua-Ngwa A, Oyebola KM. High cases of submicroscopic Plasmodium falciparum infections in a suburban population of Lagos, Nigeria. Malar J 2019; 18:433. [PMID: 31856852 PMCID: PMC6924037 DOI: 10.1186/s12936-019-3073-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/13/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Asymptomatic malaria parasites are significant sources of infections for onward malaria transmission. Conventional tools for malaria diagnosis such as microscopy and rapid diagnostic test kits (RDT) have relatively low sensitivity, hence the need for alternative tools for active screening of such low-density infections. METHODS This study tested var acidic terminal sequence-based (varATS) quantitative polymerase chain reaction (qPCR) for screening asymptomatic Plasmodium falciparum infections among dwellers of a sub-urban community in Lagos, Nigeria. Clinically healthy participants were screened for malaria using microscopy, RDT and varATS qPCR techniques. Participants were stratified into three age groups: 1-5, 6-14 and > 14 years old. RESULTS Of the 316 participants screened for asymptomatic malaria infection, 78 (24.68%) were positive by microscopy, 99 (31.33%) were positive by RDT and 112 (35.44%) by varATS qPCR. Participants aged 6-14 years had the highest prevalence of asymptomatic malaria, with geometric means of ~ 116 parasites/µL and ~ 6689 parasites/µL as detected by microscopy and varATS, respectively. CONCLUSION This study has revealed high prevalence of asymptomatic malaria in the study population, with varATS detecting additional sub-microscopic infections. The highest concentration of asymptomatic malaria was observed among school-age children between 6 and 14 years old. A large-scale screening to identify other potential hotspots of asymptomatic parasites in the country is recommended.
Collapse
Affiliation(s)
- Florence A Umunnakwe
- Parasitology and Bioinformatics Unit, Department of Zoology, Faculty of Science, University of Lagos, Akoka, Lagos, Nigeria
| | - Emmanuel T Idowu
- Parasitology and Bioinformatics Unit, Department of Zoology, Faculty of Science, University of Lagos, Akoka, Lagos, Nigeria
| | - Olusola Ajibaye
- Nigerian Institute of Medical Research, Yaba, Lagos, Nigeria
| | - Blessed Etoketim
- Medical Research Council at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Samuel Akindele
- Nigerian Institute of Medical Research, Yaba, Lagos, Nigeria
| | - Aminat O Shokunbi
- Parasitology and Bioinformatics Unit, Department of Zoology, Faculty of Science, University of Lagos, Akoka, Lagos, Nigeria
| | - Olubunmi A Otubanjo
- Parasitology and Bioinformatics Unit, Department of Zoology, Faculty of Science, University of Lagos, Akoka, Lagos, Nigeria
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Accra, Ghana
| | - Alfred Amambua-Ngwa
- Medical Research Council at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Kolapo M Oyebola
- Parasitology and Bioinformatics Unit, Department of Zoology, Faculty of Science, University of Lagos, Akoka, Lagos, Nigeria. .,Nigerian Institute of Medical Research, Yaba, Lagos, Nigeria. .,Medical Research Council at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia. .,West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Accra, Ghana.
| |
Collapse
|
34
|
Malinga J, Mogeni P, Omedo I, Rockett K, Hubbart C, Jeffreys A, Williams TN, Kwiatkowski D, Bejon P, Ross A. Investigating the drivers of the spatio-temporal patterns of genetic differences between Plasmodium falciparum malaria infections in Kilifi County, Kenya. Sci Rep 2019; 9:19018. [PMID: 31836742 PMCID: PMC6911066 DOI: 10.1038/s41598-019-54348-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 11/12/2019] [Indexed: 01/17/2023] Open
Abstract
Knowledge of how malaria infections spread locally is important both for the design of targeted interventions aiming to interrupt malaria transmission and the design of trials to assess the interventions. A previous analysis of 1602 genotyped Plasmodium falciparum parasites in Kilifi, Kenya collected over 12 years found an interaction between time and geographic distance: the mean number of single nucleotide polymorphism (SNP) differences was lower for pairs of infections which were both a shorter time interval and shorter geographic distance apart. We determine whether the empiric pattern could be reproduced by a simple model, and what mean geographic distances between parent and offspring infections and hypotheses about genotype-specific immunity or a limit on the number of infections would be consistent with the data. We developed an individual-based stochastic simulation model of households, people and infections. We parameterized the model for the total number of infections, and population and household density observed in Kilifi. The acquisition of new infections, mutation, recombination, geographic location and clearance were included. We fit the model to the observed numbers of SNP differences between pairs of parasite genotypes. The patterns observed in the empiric data could be reproduced. Although we cannot rule out genotype-specific immunity or a limit on the number of infections per individual, they are not necessary to account for the observed patterns. The mean geographic distance between parent and offspring malaria infections for the base model was 0.5 km (95% CI 0.3-1.5), for a distribution with 68% of distances shorter than the mean. Very short mean distances did not fit well, but mixtures of distributions were also consistent with the data. For a pathogen which undergoes meiosis in a setting with moderate transmission and a low coverage of infections, analytic methods are limited but an individual-based model can be used with genotyping data to estimate parameter values and investigate hypotheses about underlying processes.
Collapse
Affiliation(s)
- Josephine Malinga
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Polycarp Mogeni
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Irene Omedo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Kirk Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Christina Hubbart
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Anne Jeffreys
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Thomas N Williams
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Medicine, South Kensington Campus, Imperial College London, London, UK
| | - Dominic Kwiatkowski
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Philip Bejon
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine & Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Amanda Ross
- Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
| |
Collapse
|
35
|
Ndong IC, Okyere D, Enos JY, Mensah BA, Nyarko A, Abuaku B, Amambua-Ngwa A, Merle CSC, Koram KA, Ahorlu CS. Prevalence of asymptomatic malaria parasitaemia following mass testing and treatment in Pakro sub-district of Ghana. BMC Public Health 2019; 19:1622. [PMID: 31795981 PMCID: PMC6889629 DOI: 10.1186/s12889-019-7986-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 11/21/2019] [Indexed: 11/22/2022] Open
Abstract
Background Global efforts to scale-up malaria control interventions are gaining steam. These include the use of Long-Lasting Insecticide Nets, Indoor Residual Spraying, Intermittent Preventive Treatment and Test, Treat and Track. Despite these, the drive for malaria elimination is far from being realistic in endemic communities in Africa. This is partly due to the fact that asymptomatic parasite carriage, not specifically targeted by most interventions, remains the bedrock that fuels transmission. This has led to mass testing, treatment and tracking (MTTT) as an alternative strategy to target asymptomatic individuals. We report the impact of MTTT on the prevalence of asymptomatic malaria parasitaemia over a one-year period in Ghana, hypothesizing that implementing MTTT could reduce the rate of asymptomatic parasitaemia. Methods A population of about 5000 individuals in seven communities in the Pakro sub-district of Ghana participated in this study. A register was developed for each community following a census. MTTT engaged trained community-based health volunteers who conducted house-to-house testing using RDTs every 4 months and treated positive cases with Artemisinin–based Combination Therapy. Between interventions, community-based management of malaria was implemented for symptomatic cases. Results MTTT Coverage was 98.8% in July 2017 and 79.3% in July 2018. Of those tested, asymptomatic infection with malaria parasites reduced from 36.3% (1795/4941) in July 2017 to 32.9% (1303/3966) in July 2018 (p = 0.001). Prevalence of asymptomatic parasitaemia among children under 15 years declined from 52.6% (1043/1984) in July 2017 to 47.5% (820/1728) in July 2018 (p = 0.002). Implementing MTTT significantly reduced asymptomatic parasitaemia by 24% from July 2017 to July 2018 after adjusting for age, ITN use and axillary temperature (OR = 0.76, CI = 0.67, 0.85 p ≤ 0.001). Conclusion This study has demonstrated that implementing MTTT is feasible and could reduce the prevalence of asymptomatic malaria parasitaemia in children under 15 years of age. Furthermore, the use of community-based health volunteers could ensure high coverage at lower cost of implementation. Trial registration NCT04167566, Date 14/11/2019. Retrospective registration.
Collapse
Affiliation(s)
- Ignatius Cheng Ndong
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana. .,Department of Biochemistry, Faculty of Science, Catholic University of Cameroon, Bamenda, Cameroon.
| | - Daniel Okyere
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Juliana Yartey Enos
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Benedicta A Mensah
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Alexander Nyarko
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Benjamin Abuaku
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit, The Gambia at London School of Hygiene and Tropical Medicine, Serrekunda, Gambia
| | - Corinne Simone C Merle
- Special Programme for Research & Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - Kwadwo Ansah Koram
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Collins Stephen Ahorlu
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| |
Collapse
|
36
|
Uyoga S, Macharia AW, Mochamah G, Ndila CM, Nyutu G, Makale J, Tendwa M, Nyatichi E, Ojal J, Otiende M, Shebe M, Awuondo KO, Mturi N, Peshu N, Tsofa B, Maitland K, Scott JAG, Williams TN. The epidemiology of sickle cell disease in children recruited in infancy in Kilifi, Kenya: a prospective cohort study. Lancet Glob Health 2019; 7:e1458-e1466. [PMID: 31451441 PMCID: PMC7024980 DOI: 10.1016/s2214-109x(19)30328-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 07/02/2019] [Accepted: 07/05/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Sickle cell disease is the most common severe monogenic disorder in humans. In Africa, 50-90% of children born with sickle cell disease die before they reach their fifth birthday. In this study, we aimed to describe the comparative incidence of specific clinical outcomes among children aged between birth and 5 years with and without sickle cell disease, who were resident within the Kilifi area of Kenya. METHODS This prospective cohort study was done on members of the Kilifi Genetic Birth Cohort Study (KGBCS) on the Indian Ocean coast of Kenya. Recruitment to the study was facilitated through the Kilifi Health and Demographic Surveillance System (KHDSS), which covers a resident population of 260 000 people, and was undertaken between Jan 1, 2006, and April 30, 2011. All children who were born within the KHDSS area and who were aged 3-12 months during the recruitment period were eligible for inclusion. Participants were tested for sickle cell disease and followed up for survival status and disease-specific admission to Kilifi County Hospital by passive surveillance until their fifth birthday. Children with sickle cell disease were offered confirmatory testing and care at a dedicated outpatient clinic. FINDINGS 15 737 infants were recruited successfully to the KGBCS, and 128 (0·8%) of these infants had sickle cell disease, of whom 70 (54·7%) enrolled at the outpatient clinic within 12 months of recruitment. Mortality was higher in children with sickle cell disease (58 per 1000 person-years of observation, 95% CI 40-86) than in those without sickle cell disease (2·4 per 1000 person-years of observation, 2·0-2·8; adjusted incidence rate ratio [IRR] 23·1, 95% CI 15·1-35·3). Among children with sickle cell disease, mortality was lower in those who enrolled at the clinic (adjusted IRR 0·26, 95% CI 0·11-0·62) and in those with higher levels of haemoglobin F (HbF; adjusted IRR 0·40, 0·17-0·94). The incidence of admission to hospital was also higher in children with sickle cell disease than in children without sickle cell disease (210 per 1000 person-years of observation, 95% CI 174-253, vs 43 per 1000 person-years of observation, 42-45; adjusted IRR 4·80, 95% CI 3·84-6·15). The most common reason for admission to hospital among those with sickle cell disease was severe anaemia (incidence 48 per 1000 person-years of observation, 95% CI 32-71). Admission to hospital was lower in those with a recruitment HbF level above the median (IRR 0·43, 95% CI 0·24-0·78; p=0·005) and those who were homozygous for α-thalassaemia (0·07, 0·01-0·83; p=0·035). INTERPRETATION Although morbidity and mortality were high in young children with sickle cell disease in this Kenyan cohort, both were reduced by early diagnosis and supportive care. The emphasis must now move towards early detection and prevention of long-term complications of sickle cell disease. FUNDING Wellcome Trust.
Collapse
Affiliation(s)
- Sophie Uyoga
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | - Gideon Nyutu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | - John Ojal
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mark Otiende
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Neema Mturi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Norbert Peshu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Kathryn Maitland
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; Faculty of Medicine, Imperial College, St Mary's Hospital, London, UK
| | - J Anthony G Scott
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; London School of Hygiene & Tropical Medicine, London, UK; INDEPTH Network, Accra, Ghana
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; London School of Hygiene & Tropical Medicine, London, UK; INDEPTH Network, Accra, Ghana.
| |
Collapse
|
37
|
Cohee LM, Laufer MK. The unanticipated benefits of protecting young children from malaria. THE LANCET. INFECTIOUS DISEASES 2019; 19:918-919. [PMID: 31307884 PMCID: PMC10369479 DOI: 10.1016/s1473-3099(19)30285-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 05/24/2019] [Indexed: 06/10/2023]
Affiliation(s)
- Lauren M Cohee
- Center for Vaccine Development and Global Health, School of Medicine, University of Maryland, Baltimore, MD 21201, USA.
| | - Miriam K Laufer
- Center for Vaccine Development and Global Health, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| |
Collapse
|
38
|
Maitland K, Ohuma EO, Mpoya A, Uyoga S, Hassall O, Williams TN. Informing thresholds for paediatric transfusion in Africa: the need for a trial. Wellcome Open Res 2019; 4:27. [PMID: 31633055 PMCID: PMC6784792 DOI: 10.12688/wellcomeopenres.15003.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2019] [Indexed: 01/29/2023] Open
Abstract
Background: Owing to inadequate supplies of donor blood for transfusion in sub-Saharan Africa (sSA) World Health Organization paediatric guidelines recommend restrictive transfusion practices, based on expert opinion. We examined whether survival amongst hospitalised children by admission haemoglobin and whether this was influenced by malaria infection and/or transfusion. Methods: A retrospective analysis of standardised clinical digital records in an unselected population of children admitted to a rural hospital in Kenya over an 8-year period. We describe baseline parameters with respect to categories of anaemia and outcome (in-hospital death) by haemoglobin (Hb), malaria and transfusion status. Results: Among 29,226 children, 1,143 (3.9%) had profound anaemia (Hb <4g/dl) and 3,469 (11.9%) had severe anaemia (Hb 4-6g/d). In-hospital mortality rate was 97/1,143 (8.5%) if Hb<4g/dl or 164/2,326 (7.1%) in those with severe anaemia (Hb ≥4.0-<6g/dl). Admission Hb <3g/dl was associated with higher risk of death versus those with higher Hbs (OR=2.41 (95%CI: 1.8 - 3.24; P<0.001), increasing to OR=6.36, (95%CI: 4.21-9.62; P<0.001) in malaria positive children. Conversely, mortality in non-malaria admissions was unrelated to Hb level. Transfusion was associated with a non-significant improvement in outcome if Hb<3g/dl (malaria-only) OR 0.72 (95%CI 0.29 - 1.78), albeit the number of cases were too few to show a statistical difference. For those with Hb levels above 4g/dl, mortality was significantly higher in those receiving a transfusion compared to the non-transfused group. For non-malarial cases, transfusion did not affect survival-status, irrespective of baseline Hb level compared to children who were not transfused at higher Hb levels. Conclusion: Although severe anaemia is common among children admitted to hospital in sSA (~16%), our data do not indicate that outcome is improved by transfusion irrespective of malaria status. Given the limitations of observational studies, clinical trials investigating the role of transfusion in outcomes in children with severe anaemia are warranted.
Collapse
Affiliation(s)
- Kathryn Maitland
- Department of Medicine, Imperial College London, London, W2 1PG, UK
- Clinical Trials Facility, KEMRI-Wellcome Trust Research Programme, Kilifi, PO Box 230, Kenya
| | - Eric O. Ohuma
- Nuffield Department of Medicine, Oxford University, Oxford, OX3 7BN, UK
| | - Ayub Mpoya
- Clinical Trials Facility, KEMRI-Wellcome Trust Research Programme, Kilifi, PO Box 230, Kenya
| | - Sophie Uyoga
- Epidemiology and Demographic Surveillance, KEMRI Wellcome Trust Research Programme, Kilifi, PO Box 230, Kenya
| | - Oliver Hassall
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Thomas N. Williams
- Department of Medicine, Imperial College London, London, W2 1PG, UK
- Epidemiology and Demographic Surveillance, KEMRI Wellcome Trust Research Programme, Kilifi, PO Box 230, Kenya
| |
Collapse
|
39
|
Khagayi S, Desai M, Amek N, Were V, Onyango ED, Odero C, Otieno K, Bigogo G, Munga S, Odhiambo F, Hamel MJ, Kariuki S, Samuels AM, Slutsker L, Gimnig J, Vounatsou P. Modelling the relationship between malaria prevalence as a measure of transmission and mortality across age groups. Malar J 2019; 18:247. [PMID: 31337411 PMCID: PMC6651924 DOI: 10.1186/s12936-019-2869-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 07/05/2019] [Indexed: 11/24/2022] Open
Abstract
Background Parasite prevalence has been used widely as a measure of malaria transmission, especially in malaria endemic areas. However, its contribution and relationship to malaria mortality across different age groups has not been well investigated. Previous studies in a health and demographic surveillance systems (HDSS) platform in western Kenya quantified the contribution of incidence and entomological inoculation rates (EIR) to mortality. The study assessed the relationship between outcomes of malaria parasitaemia surveys and mortality across age groups. Methods Parasitological data from annual cross-sectional surveys from the Kisumu HDSS between 2007 and 2015 were used to determine malaria parasite prevalence (PP) and clinical malaria (parasites plus reported fever within 24 h or temperature above 37.5 °C). Household surveys and verbal autopsy (VA) were used to obtain data on all-cause and malaria-specific mortality. Bayesian negative binomial geo-statistical regression models were used to investigate the association of PP/clinical malaria with mortality across different age groups. Estimates based on yearly data were compared with those from aggregated data over 4 to 5-year periods, which is the typical period that mortality data are available from national demographic and health surveys. Results Using 5-year aggregated data, associations were established between parasite prevalence and malaria-specific mortality in the whole population (RRmalaria = 1.66; 95% Bayesian Credible Intervals: 1.07–2.54) and children 1–4 years (RRmalaria = 2.29; 1.17–4.29). While clinical malaria was associated with both all-cause and malaria-specific mortality in combined ages (RRall-cause = 1.32; 1.01–1.74); (RRmalaria = 2.50; 1.27–4.81), children 1–4 years (RRall-cause = 1.89; 1.00–3.51); (RRmalaria = 3.37; 1.23–8.93) and in older children 5–14 years (RRall-cause = 3.94; 1.34–11.10); (RRmalaria = 7.56; 1.20–39.54), no association was found among neonates, adults (15–59 years) and the elderly (60+ years). Distance to health facilities, socioeconomic status, elevation and survey year were important factors for all-cause and malaria-specific mortality. Conclusion Malaria parasitaemia from cross-sectional surveys was associated with mortality across age groups over 4 to 5 year periods with clinical malaria more strongly associated with mortality than parasite prevalence. This effect was stronger in children 5–14 years compared to other age-groups. Further analyses of data from other HDSS sites or similar platforms would be useful in investigating the relationship between malaria and mortality across different endemicity levels. Electronic supplementary material The online version of this article (10.1186/s12936-019-2869-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Sammy Khagayi
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Meghna Desai
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Nyaguara Amek
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Vincent Were
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Eric Donald Onyango
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Christopher Odero
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Kephas Otieno
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Godfrey Bigogo
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Stephen Munga
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Frank Odhiambo
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Mary J Hamel
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Simon Kariuki
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Aaron M Samuels
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Laurence Slutsker
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - John Gimnig
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| |
Collapse
|
40
|
Njuguna P, Maitland K, Nyaguara A, Mwanga D, Mogeni P, Mturi N, Mohammed S, Mwambingu G, Ngetsa C, Awuondo K, Lowe B, Adetifa I, Scott JAG, Williams TN, Atkinson S, Osier F, Snow RW, Marsh K, Tsofa B, Peshu N, Hamaluba M, Berkley JA, Newton CRJ, Fondo J, Omar A, Bejon P. Observational study: 27 years of severe malaria surveillance in Kilifi, Kenya. BMC Med 2019; 17:124. [PMID: 31280724 PMCID: PMC6613255 DOI: 10.1186/s12916-019-1359-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 06/04/2019] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Many parts of Africa have witnessed reductions in Plasmodium falciparum transmission over the last 15 years. Since immunity to malaria is acquired more rapidly at higher transmission, the slower acquisition of immunity at lower transmission may partially offset the benefits of reductions in transmission. We examined the clinical spectrum of disease and predictors of mortality after sustained changes in transmission intensity, using data collected from 1989 to 2016. METHODS We conducted a temporal observational analysis of 18,000 children, aged 14 days to 14 years old, who were admitted to Kilifi County Hospital, Kenya, from 1989 to 2016 with malaria. We describe the trends over time of the clinical and laboratory criteria for severe malaria and associated risk of mortality. RESULTS During the time periods 1989-2003, 2004-2008, and 2009-2016, Kilifi County Hospital admitted averages of 657, 310, and 174 cases of severe malaria per year including averages of 48, 14, and 12 malaria-associated deaths per year, respectively. The median ages in years of children admitted with cerebral malaria, severe anaemia, and malaria-associated mortality were 3.0 (95% confidence interval (CI) 2.2-3.9), 1.1 (95% CI 0.9-1.4), and 1.1 (95% CI 0.3-2.2) in the year 1989, rising to 4.9 (95% CI 3.9-5.9), 3.8 (95% CI 2.5-7.1), and 5 (95% CI 3.3-6.3) in the year 2016. The ratio of children with cerebral malaria to severe anaemia rose from 1:2 before 2004 to 3:2 after 2009. Hyperparasitaemia was a risk factor for death after 2009 but not in earlier time periods. CONCLUSION Despite the evidence of slower acquisition of immunity, continued reductions in the numbers of cases of severe malaria resulted in lower overall mortality. Our temporal data are limited to a single site, albeit potentially applicable to a secular trend present in many parts of Africa.
Collapse
Affiliation(s)
- Patricia Njuguna
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Kathryn Maitland
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,Department of Paediatrics, Faculty of Medicine, Imperial College, London, UK
| | - Amek Nyaguara
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Daniel Mwanga
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Polycarp Mogeni
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Neema Mturi
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Shebe Mohammed
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Gabriel Mwambingu
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Caroline Ngetsa
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Kenedy Awuondo
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Brett Lowe
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ifedayo Adetifa
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,London School of Hygiene and Tropical Medicine, London, UK
| | - J Anthony G Scott
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,London School of Hygiene and Tropical Medicine, London, UK
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,Department of Paediatrics, Faculty of Medicine, Imperial College, London, UK
| | - Sarah Atkinson
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,Department of Paediatrics, University of Oxford, Oxford, UK
| | - Faith Osier
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Robert W Snow
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Benjamin Tsofa
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Norbert Peshu
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - Mainga Hamaluba
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya
| | - James A Berkley
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Charles R J Newton
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.,Department of Psychiatry, University of Oxford, Oxford, UK
| | - John Fondo
- Kilifi County Department of Health, Kilifi, Kenya
| | - Anisa Omar
- Kilifi County Department of Health, Kilifi, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, CGMR-C, KEMRI, PO Box 230, Kilifi, Kenya.
| |
Collapse
|
41
|
Kibe LW, Habluetzel A, Gachigi JK, Kamau AW, Mbogo CM. Exploring communities' and health workers' perceptions of indicators and drivers of malaria decline in Malindi, Kenya. MALARIAWORLD JOURNAL 2019; 8:21. [PMID: 31338302 PMCID: PMC6650290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND Since 2000, a decrease in malaria burden has been observed in most endemic countries. Declining infection rates and disease burden and reduction in asymptomatic carriers are the outcome of improved quality of care and related health system factors. These include improved case management through better diagnosis, implementation of highly effective antimalarial drugs and increased use of bednets. We studied communities' and health workers' perceptions of indicators and drivers in the context of decreasing malaria transmission in Malindi, Kenya. MATERIALS AND METHODS A variety of qualitative methods that included participatory rural appraisal (PRA) tools such as community river of life and trend lines, focus group discussions (FGDs) and key informant interviews were used. Studies took place between November 2013 and April 2014. RESULTS Providing residents with bednets contributed to malaria reduction, and increasing community awareness on the causes and symptoms of malaria and improved malaria treatment were also perceived to contribute to the decline of malaria. The study identified three perceived drivers to the reported decline in malaria: a) community health workers' enhanced awareness creation towards household owners regarding malaria-related activities through visitations and awareness sessions, b) Women involvement in Savings Internal Lending Community was perceived to have increased their financial base, thereby improving their decision-making power towards the care of their sick child(ren), c) Non Governmental Organizations (NGOs) and partners played a promoter part in health and general economic development initiatives. CONCLUSIONS To achieve the goal of malaria elimination, collaboration between governmental and NGOs will be crucial when improving the financial base of women and enhancing participation of community health workers.
Collapse
Affiliation(s)
- Lydiah W. Kibe
- Vector Biology Unit, KEMRI - Wellcome Trust Research Program, Kilifi, Kenya
| | | | - John K. Gachigi
- Social Protection Secretariat, Ministry of East African Community, Labour and Social Protection, Nairobi, Kenya
| | - Anne W. Kamau
- Institute for Development Studies, University of Nairobi, Nairobi, Kenya
| | - Charles M. Mbogo
- Vector Biology Unit, KEMRI - Wellcome Trust Research Program, Kilifi, Kenya
| |
Collapse
|
42
|
Hercik C, Cosmas L, Mogeni OD, Kohi W, Mfinanga S, Loffredo C, Montgomery JM. Health Beliefs and Patient Perspectives of Febrile Illness in Kilombero, Tanzania. Am J Trop Med Hyg 2019; 101:263-270. [PMID: 31115309 PMCID: PMC6609178 DOI: 10.4269/ajtmh.17-0862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 03/16/2019] [Indexed: 01/18/2023] Open
Abstract
This qualitative study assessed the knowledge and beliefs surrounding fever syndrome among adult febrile patients seeking health care in Kilombero, Tanzania. From June 11 to July 13, 2014, 10% of all adult (≥ 15 years) febrile patients enrolled in the larger syndromic study, who presented with an axillary temperature ≥ 37.5°C and symptom onset ≤ 5 days prior, were randomly selected to participate in an in-depth physician-patient interview, informed by Health Belief Model constructs. Interviews were audio recorded, translated, and transcribed. Transcripts were coded using NVivo Version 11.1, and the thematic content was analyzed by two separate researchers. Blood and nasopharyngeal/oralpharyngeal specimens were collected and analyzed using both acute febrile illness and respiratory TaqMan Array Cards for multipathogen detection of 56 potential causative agents. A total of 18 participants provided 188 discrete comments. When asked to speculate the causative agent of febrile illness, 33.3% cited malaria and the other 66.6% offered nonbiomedical responses, such as "mosquitoes" and "weather." Major themes emerging related to severity and susceptibility to health hazards included lack of bed net use, misconceptions about bed nets, and mosquito infestation. Certain barriers to treatment were cited, including dependence on traditional healers, high cost of drugs, and poor dispensary services. Overall, we demonstrate low concurrence in speculations of fever etiology according to patients, clinicians, and laboratory testing. Our findings contribute to the important, yet limited, base of knowledge surrounding patient risk perceptions of febrile illness and underscore the potential utility of community-based participatory research to inform disease control programs.
Collapse
Affiliation(s)
| | - Leonard Cosmas
- Division of Global Health Protection, Center for Global Health, US Centers for Disease Control and Prevention (US CDC), Nairobi, Kenya
| | - Ondari D. Mogeni
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Wanze Kohi
- Muhimbili Research Centre, National Institute of Medical Research, Dar es Salaam, Tanzania
| | - Sayoki Mfinanga
- Muhimbili Research Centre, National Institute of Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Science, Dar es Salaam, Tanzania
| | - Christopher Loffredo
- Georgetown Lombardi Comprehensive Cancer Center, Georgetown University, Washington, District of Columbia
| | - Joel M. Montgomery
- Division of Global Health Protection, Center for Global Health, US Centers for Disease Control and Prevention (US CDC), Nairobi, Kenya
| |
Collapse
|
43
|
Lindsay SW, Jawara M, Mwesigwa J, Achan J, Bayoh N, Bradley J, Kandeh B, Kirby MJ, Knudsen J, Macdonald M, Pinder M, Tusting LS, Weiss DJ, Wilson AL, D'Alessandro U. Reduced mosquito survival in metal-roof houses may contribute to a decline in malaria transmission in sub-Saharan Africa. Sci Rep 2019; 9:7770. [PMID: 31123317 PMCID: PMC6533302 DOI: 10.1038/s41598-019-43816-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 04/27/2019] [Indexed: 11/09/2022] Open
Abstract
In The Gambia, metal-roof houses were hotter during the day than thatched-roof houses. After 24 h, the mortality of Anopheles gambiae, the principal African malaria vector, was 38% higher in metal-roof houses than thatched ones. During the day, mosquitoes in metal-roof houses moved from the hot roof to cooler places near the floor, where the temperature was still high, reaching 35 °C. In laboratory studies, at 35 °C few mosquitoes survived 10 days, the minimum period required for malaria parasite development. Analysis of epidemiological data showed there was less malaria and lower vector survival rates in Gambian villages with a higher proportion of metal roofs. Our findings are consistent with the hypothesis that the indoor climate of metal-roof houses, with higher temperatures and lower humidity, reduces survivorship of indoor-resting mosquitoes and may have contributed to the observed reduction in malaria burden in parts of sub-Saharan Africa.
Collapse
Affiliation(s)
- Steve W Lindsay
- Department of Biosciences, Durham University, Durham, DH13LE, UK. .,London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
| | - Musa Jawara
- Medical Research Council Unit Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Julia Mwesigwa
- Medical Research Council Unit Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Jane Achan
- Medical Research Council Unit Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Nabie Bayoh
- Department of Biosciences, Durham University, Durham, DH13LE, UK.,Adaptive Management and Research Consultants, Kisumu, Kenya
| | - John Bradley
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Balla Kandeh
- National Malaria Control Programme, Banjul, The Gambia
| | - Matthew J Kirby
- Department of Biosciences, Durham University, Durham, DH13LE, UK.,London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Jakob Knudsen
- The Royal Danish Academy of Fine Arts, School of Architecture, Design and Conservation, The School of Architecture, Copenhagen, Denmark
| | | | - Margaret Pinder
- Department of Biosciences, Durham University, Durham, DH13LE, UK.,Medical Research Council Unit Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Lucy S Tusting
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Dan J Weiss
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Anne L Wilson
- Department of Biosciences, Durham University, Durham, DH13LE, UK.,Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Umberto D'Alessandro
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,Medical Research Council Unit Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| |
Collapse
|
44
|
Guerra Mendoza Y, Garric E, Leach A, Lievens M, Ofori-Anyinam O, Pirçon JY, Stegmann JU, Vandoolaeghe P, Otieno L, Otieno W, Owusu-Agyei S, Sacarlal J, Masoud NS, Sorgho H, Tanner M, Tinto H, Valea I, Mtoro AT, Njuguna P, Oneko M, Otieno GA, Otieno K, Gesase S, Hamel MJ, Hoffman I, Kaali S, Kamthunzi P, Kremsner P, Lanaspa M, Lell B, Lusingu J, Malabeja A, Aide P, Akoo P, Ansong D, Asante KP, Berkley JA, Adjei S, Agbenyega T, Agnandji ST, Schuerman L. Safety profile of the RTS,S/AS01 malaria vaccine in infants and children: additional data from a phase III randomized controlled trial in sub-Saharan Africa. Hum Vaccin Immunother 2019; 15:2386-2398. [PMID: 31012786 PMCID: PMC6816384 DOI: 10.1080/21645515.2019.1586040] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A phase III, double-blind, randomized, controlled trial (NCT00866619) in sub-Saharan Africa showed RTS,S/AS01 vaccine efficacy against malaria. We now present in-depth safety results from this study. 8922 children (enrolled at 5–17 months) and 6537 infants (enrolled at 6–12 weeks) were 1:1:1-randomized to receive 4 doses of RTS,S/AS01 (R3R) or non-malaria control vaccine (C3C), or 3 RTS,S/AS01 doses plus control (R3C). Aggregate safety data were reviewed by a multi-functional team. Severe malaria with Blantyre Coma Score ≤2 (cerebral malaria [CM]) and gender-specific mortality were assessed post-hoc. Serious adverse event (SAE) and fatal SAE incidences throughout the study were 24.2%–28.4% and 1.5%–2.5%, respectively across groups; 0.0%–0.3% of participants reported vaccination-related SAEs. The incidence of febrile convulsions in children was higher during the first 2–3 days post-vaccination with RTS,S/AS01 than with control vaccine, consistent with the time window of post-vaccination febrile reactions in this study (mostly the day after vaccination). A statistically significant numerical imbalance was observed for meningitis cases in children (R3R: 11, R3C: 10, C3C: 1) but not in infants. CM cases were more frequent in RTS,S/AS01-vaccinated children (R3R: 19, R3C: 24, C3C: 10) but not in infants. All-cause mortality was higher in RTS,S/AS01-vaccinated versus control girls (2.4% vs 1.3%, all ages) in our setting with low overall mortality. The observed meningitis and CM signals are considered likely chance findings, that – given their severity – warrant further evaluation in phase IV studies and WHO-led pilot implementation programs to establish the RTS,S/AS01 benefit-risk profile in real-life settings.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Seth Owusu-Agyei
- Kintampo Health Research Center , Kintampo , Ghana.,Diseases Control Department, London School of Hygiene and Tropical Medicine , London , UK
| | - Jahit Sacarlal
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,Faculdade de Medicina, Universidade Eduardo Mondlane (UEM) , Maputo , Mozambique
| | - Nahya Salim Masoud
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania
| | - Hermann Sorgho
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Marcel Tanner
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania.,Swiss Tropical and Public Health Institute , Basel , Switzerland.,Epidemiology and Medical Parasitology department, University of Basel , Basel , Switzerland
| | - Halidou Tinto
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Innocent Valea
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Ali Takadir Mtoro
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania
| | - Patricia Njuguna
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya.,Pwani University , Kilifi , Kenya.,University of Oxford , Oxford , UK
| | - Martina Oneko
- Kenya Medical Research Institute, Centre for Global Health Research , Kisumu , Kenya
| | | | - Kephas Otieno
- Kenya Medical Research Institute, Centre for Global Health Research , Kisumu , Kenya
| | - Samwel Gesase
- National Institute for Medical Research , Korogwe , Tanzania
| | - Mary J Hamel
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention , Atlanta , GA , USA
| | - Irving Hoffman
- University of North Carolina Project , Lilongwe , Malawi
| | - Seyram Kaali
- Kintampo Health Research Center , Kintampo , Ghana
| | | | - Peter Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
| | - Miguel Lanaspa
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona , Barcelona , Spain
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
| | - John Lusingu
- National Institute for Medical Research , Korogwe , Tanzania
| | | | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,National Institute of Health, Ministry of Health , Maputo , Mozambique
| | - Pauline Akoo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya
| | - Daniel Ansong
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | | | - James A Berkley
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya.,University of Oxford , Oxford , UK
| | - Samuel Adjei
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | - Tsiri Agbenyega
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
| | | |
Collapse
|
45
|
Etyang AO, Kapesa S, Odipo E, Bauni E, Kyobutungi C, Abdalla M, Muntner P, Musani SK, Macharia A, Williams TN, Cruickshank JK, Smeeth L, Scott JAG. Effect of Previous Exposure to Malaria on Blood Pressure in Kilifi, Kenya: A Mendelian Randomization Study. J Am Heart Assoc 2019; 8:e011771. [PMID: 30879408 PMCID: PMC6475058 DOI: 10.1161/jaha.118.011771] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 02/05/2019] [Indexed: 12/31/2022]
Abstract
Background Malaria exposure in childhood may contribute to high blood pressure ( BP ) in adults. We used sickle cell trait ( SCT ) and α+thalassemia, genetic variants conferring partial protection against malaria, as tools to test this hypothesis. Methods and Results Study sites were Kilifi, Kenya, which has malaria transmission, and Nairobi, Kenya, and Jackson, Mississippi, where there is no malaria transmission. The primary outcome was 24-hour systolic BP. Prevalent hypertension, diagnosed using European Society of Hypertension thresholds was a secondary outcome. We performed regression analyses adjusting for age, sex, and estimated glomerular filtration rate. We studied 1127 participants in Kilifi, 516 in Nairobi, and 651 in Jackson. SCT frequency was 21% in Kilifi, 16% in Nairobi, and 9% in Jackson. SCT was associated with -2.4 (95% CI , -4.7 to -0.2) mm Hg lower 24-hour systolic BP in Kilifi but had no effect in Nairobi/Jackson. The effect of SCT in Kilifi was limited to 30- to 59-year-old participants, among whom it was associated with -6.1 mm Hg ( CI , -10.5 to -1.8) lower 24-hour systolic BP. In pooled analysis allowing interaction by site, the effect of SCT on 24-hour systolic BP in Kilifi was -3.5 mm Hg ( CI , -6.9 to -0.1), increasing to -5.2 mm Hg ( CI , -9.5 to -0.9) when replacing estimated glomerular filtration rate with urine albumin to creatinine ratio as a covariate. In Kilifi, the prevalence ratio for hypertension was 0.86 ( CI , 0.76-0.98) for SCT and 0.89 ( CI , 0.80-0.99) for α+thalassemia. Conclusions Lifelong malaria protection is associated with lower BP in Kilifi. Confirmation of this finding at other sites and elucidating the mechanisms involved may yield new preventive and therapeutic targets.
Collapse
Affiliation(s)
- Anthony O. Etyang
- KEMRI‐Wellcome Trust Research ProgrammeKilifiKenya
- London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | | | - Emily Odipo
- KEMRI‐Wellcome Trust Research ProgrammeKilifiKenya
| | | | | | | | | | | | | | - Thomas N. Williams
- KEMRI‐Wellcome Trust Research ProgrammeKilifiKenya
- Imperial CollegeLondonUnited Kingdom
| | | | - Liam Smeeth
- London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | - J. Anthony G. Scott
- KEMRI‐Wellcome Trust Research ProgrammeKilifiKenya
- London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| |
Collapse
|
46
|
Maitland K, Ohuma EO, Mpoya A, Uyoga S, Hassall O, Williams TN. Informing thresholds for paediatric transfusion in Africa: the need for a trial. Wellcome Open Res 2019; 4:27. [PMID: 31633055 PMCID: PMC6784792 DOI: 10.12688/wellcomeopenres.15003.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2019] [Indexed: 10/15/2023] Open
Abstract
Background: Provision of adequate supplies of donor blood for paediatric transfusion remains a challenge. Guidelines recommend restrictive transfusion practices, based on expert opinion. We examined whether survival among children admitted to hospital varied by admission haemoglobin status and whether this was influenced by malaria infection and/or transfusion. Methods: A retrospective analysis in an unselected population of children admitted to a rural district hospital in Kenya over an 8-year period. We describe baseline parameters with respect to categories of anaemia and outcome (in-hospital death) with respect to haemoglobin, malaria and transfusion status. Results: Among 29,226 admitted children, 1,143 (3.9%) had profound anaemia (Hb <4g/dl) and 3,469 (11.9%) had severe anaemia (Hb 4-6g/d). In-hospital mortality was; 97/1,143 (8.5%) in those with Hb<4g/dl and 164/2,326 (7.1%) in those with severe anaemia (Hb ≥4.0-<6g/dl). Admission Hb <3g/dl was associated with higher risk of death versus those with higher Hbs (OR=2.41 (95%CI: 1.8 - 3.24; P<0.001), increasing to OR=6.36, (95%CI: 4.21-9.62; P<0.001) in malaria positive children. Conversely, mortality in non-malaria admissions was unrelated to Hb level. Transfusion was associated with a non-significant improvement in outcome if Hb<3g/dl (malaria-only) OR 0.72 (95%CI 0.29 - 1.78), albeit the number of cases were too few to show a statistical difference. For those with Hb levels above 4g/dl, mortality was significantly higher in those receiving a transfusion compared to the non-transfused group. For non-malarial cases, transfusion did not affect survival-status, irrespective of baseline Hb level compared to children who were not transfused at higher Hb levels. Conclusion: Although severe and complicated anaemia is common among children admitted to hospital in sSA (~16%), our data do not indicate that outcome is improved by transfusion irrespective of malaria status. Given the limitations of observational studies, clinical trials investigating the role of transfusion in outcomes in children with severe anaemia are warranted.
Collapse
Affiliation(s)
- Kathryn Maitland
- Department of Medicine, Imperial College London, London, W2 1PG, UK
- Clinical Trials Facility, KEMRI-Wellcome Trust Research Programme, Kilifi, PO Box 230, Kenya
| | - Eric O. Ohuma
- Nuffield Department of Medicine, Oxford University, Oxford, OX3 7BN, UK
| | - Ayub Mpoya
- Clinical Trials Facility, KEMRI-Wellcome Trust Research Programme, Kilifi, PO Box 230, Kenya
| | - Sophie Uyoga
- Epidemiology and Demographic Surveillance, KEMRI Wellcome Trust Research Programme, Kilifi, PO Box 230, Kenya
| | - Oliver Hassall
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Thomas N. Williams
- Department of Medicine, Imperial College London, London, W2 1PG, UK
- Epidemiology and Demographic Surveillance, KEMRI Wellcome Trust Research Programme, Kilifi, PO Box 230, Kenya
| |
Collapse
|
47
|
Bonko MDA, Kiemde F, Tahita MC, Lompo P, Some AM, Tinto H, van Hensbroek MB, Mens PF, Schallig HDFH. The effect of malaria rapid diagnostic tests results on antimicrobial prescription practices of health care workers in Burkina Faso. Ann Clin Microbiol Antimicrob 2019; 18:5. [PMID: 30691506 PMCID: PMC6348635 DOI: 10.1186/s12941-019-0304-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 01/20/2019] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Malaria rapid diagnostic tests (RDT) are widely used in endemic areas in order to comply with the recommendation that malaria treatment should only be given after the clinical diagnosis has been confirmed by RDT or microscopy. However, the overestimation of malaria infection with the use of PfHRP2 based RDT, makes the management of febrile illnesses more challenging. This study aimed to assess the effect of the use of malaria RDT on antimicrobial prescription practices. METHODS A prospective study was conducted among febrile children under-5 years of age attending four health facilities and the referral hospital in the Nanoro Health District (Burkina Faso). To assess the effect of malaria RDT testing on the prescriptions of antimicrobials in febrile children, the initial diagnosis and antimicrobial prescriptions following a malaria RDT testing were recorded. The necessity of these prescriptions was subsequently checked by assessing the actual cause of fever by expert malaria microscopy and a microbiology analysis of blood, urine, stool and nasopharynx swabs that were collected from febrile cases to determine the actual cause of the fever episode. RESULTS Malaria was diagnosed by nurses, who are the primary health care providers, with a malaria RDT in 72.7% (798/1098) of febrile children, but only 53.7% (589/1097) cases could be confirmed by expert microscopy. Health care workers were likely to prescribe antimalarials to malaria positive RDT compared to malaria negative RDT (RR = 7.74, p = 0.00001). Malaria negative RDT result had a significant influence on the antibiotic prescriptions (RR = 3.57, p = 0.0001). The risk of prescribing antimicrobials was higher in health facility level compared to referral hospital. By cross-checking of laboratory findings to antimicrobial prescriptions, an important part of children with positive bacterial infection have received antibiotic prescriptions although the majority without any infection have also received antibiotics. CONCLUSION Despite the good attitude of health care workers to adhere to diagnostic test results, antimalarials and antibiotics remain inappropriate prescribed to febrile children. The low specificity of malaria RDT used could be an important cause of these practices.
Collapse
Affiliation(s)
- Massa dit Achille Bonko
- Institut de Recherche en Science de la Sante-Unite de Recherche Clinique de Nanoro, Nanoro, Burkina Faso
- Parasitology Unit, Department of Medical Microbiology, Amsterdam University Medical Centers, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Francois Kiemde
- Institut de Recherche en Science de la Sante-Unite de Recherche Clinique de Nanoro, Nanoro, Burkina Faso
- Parasitology Unit, Department of Medical Microbiology, Amsterdam University Medical Centers, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Global Child Health Group, Amsterdam University Medical Centers, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Marc Christian Tahita
- Institut de Recherche en Science de la Sante-Unite de Recherche Clinique de Nanoro, Nanoro, Burkina Faso
| | - Palpouguini Lompo
- Institut de Recherche en Science de la Sante-Unite de Recherche Clinique de Nanoro, Nanoro, Burkina Faso
| | - Athanase M. Some
- Institut de Recherche en Science de la Sante-Unite de Recherche Clinique de Nanoro, Nanoro, Burkina Faso
| | - Halidou Tinto
- Institut de Recherche en Science de la Sante-Unite de Recherche Clinique de Nanoro, Nanoro, Burkina Faso
| | - Michael Boele van Hensbroek
- Global Child Health Group, Amsterdam University Medical Centers, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Petra F. Mens
- Parasitology Unit, Department of Medical Microbiology, Amsterdam University Medical Centers, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Henk D. F. H. Schallig
- Parasitology Unit, Department of Medical Microbiology, Amsterdam University Medical Centers, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| |
Collapse
|
48
|
Kamau A, Mwangangi JM, Rono MK, Mogeni P, Omedo I, Midega J, Scott JAG, Bejon P. Variation in the effectiveness of insecticide treated nets against malaria and outdoor biting by vectors in Kilifi, Kenya. Wellcome Open Res 2019; 2:22. [PMID: 30542660 DOI: 10.12688/wellcomeopenres.11073.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2017] [Indexed: 11/20/2022] Open
Abstract
Background: Insecticide treated nets (ITNs) protect humans against bites from the Anopheles mosquito vectors that transmit malaria, thereby reducing malaria morbidity and mortality. It has been noted that ITN use leads to a switch from indoor to outdoor feeding among these vectors. It might be expected that outdoor feeding would undermine the effectiveness of ITNs that target indoors vectors, but data are limited. Methods: We linked homestead level geospatial data to clinical surveillance data at a primary healthcare facility in Kilifi County in order to map geographical heterogeneity in ITN effectiveness and observed vector feeding behaviour using landing catches and CDC light traps in six selected areas of varying ITN effectiveness. We quantified the interaction between mosquitoes and humans to evaluate whether outdoor vector biting is a potential explanation for the variation in ITN effectiveness. Results: We observed 37% and 46% visits associated with positive malaria slides among ITN users and non-ITN-users, respectively; ITN use was associated with 32% protection from malaria (crude OR = 0.68, 95% CI: 0.64, 0.73). We obtained modification of ITN effectiveness by geographical area (p=0.016), and identified 6 hotspots using the spatial scan statistic. Majority of mosquitoes were caught outdoor (60%) and were of the An. funestus group (75%). The overall propensity to feed at times when most people were asleep was high; the vast majority of the Anopheles mosquitoes were caught at times when most people are indoors asleep. Estimates for the proportion of human-mosquito contact between the first and last hour when most humans were asleep was consistently high across all locations, ranging from 0.83 to 1.00. Conclusion: Our data do not provide evidence of an epidemiological association between microgeographical variations in ITN effectiveness and variations in the microgeographical distribution of outdoor biting.
Collapse
Affiliation(s)
- Alice Kamau
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Joseph M Mwangangi
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Integrated Vector and Disease Management Cluster, International Centre of Insect Physiology and Ecology, Nairobi, Kenya.,Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya
| | - Martin K Rono
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya
| | - Polycarp Mogeni
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Irene Omedo
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Janet Midega
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Centre for Genomics and Global Health, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - J Anthony G Scott
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| |
Collapse
|
49
|
Adetifa IMO, Karia B, Mutuku A, Bwanaali T, Makumi A, Wafula J, Chome M, Mwatsuma P, Bauni E, Hammitt LL, Mataza C, Tabu C, Kamau T, Williams TN, Scott JAG. Coverage and timeliness of vaccination and the validity of routine estimates: Insights from a vaccine registry in Kenya. Vaccine 2018; 36:7965-7974. [PMID: 30416017 PMCID: PMC6288063 DOI: 10.1016/j.vaccine.2018.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 11/02/2022]
Abstract
BACKGROUND The benefits of childhood vaccines are critically dependent on vaccination coverage. We used a vaccine registry (as gold standard) in Kenya to quantify errors in routine coverage methods (surveys and administrative reports), to estimate the magnitude of survivor bias, contrast coverage with timeliness and use both measures to estimate population immunity. METHODS Vaccination records of children in the Kilifi Health and Demographic Surveillance System (KHDSS), Kenya were combined with births, deaths, migration and residence data from 2010 to 17. Using inverse survival curves, we estimated up-to-date and age-appropriate vaccination coverage, calculated mean vaccination coverage in infancy as the area under the inverse survival curves, and estimated the proportion of fully immunised children (FIC). Results were compared with published coverage estimates. Risk factors for vaccination were assessed using Cox regression models. RESULTS We analysed data for 49,090 infants and 48,025 children aged 12-23 months in 6 birth cohorts and 6 cross-sectional surveys respectively, and found 2nd year of life surveys overestimated coverage by 2% compared to birth cohorts. Compared to mean coverage in infants, static coverage at 12 months was exaggerated by 7-8% for third doses of oral polio, pentavalent (Penta3) and pneumococcal conjugate vaccines, and by 24% for the measles vaccine. Surveys and administrative coverage also underestimated the proportion of the fully immunised child by 10-14%. For BCG, Penta3 and measles, timeliness was 23-44% higher in children born in a health facility but 20-37% lower in those who first attended during vaccine stock outs. CONCLUSIONS Standard coverage surveys in 12-23 month old children overestimate protection by ignoring timeliness, and survivor and recall biases. Where delayed vaccination is common, up-to-date coverage will give biased estimates of population immunity. Surveys and administrative methods also underestimate FIC prevalence. Better measurement of coverage and more sophisticated analyses are required to control vaccine preventable diseases.
Collapse
Affiliation(s)
- Ifedayo M O Adetifa
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya; Infectious Diseases Epidemiology, London School of Hygiene and Tropical Medicine, WC1E 7HT London, UK.
| | - Boniface Karia
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya.
| | - Alex Mutuku
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya
| | - Tahreni Bwanaali
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya
| | - Anne Makumi
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya
| | - Jackline Wafula
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya.
| | - Martina Chome
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya.
| | - Pauline Mwatsuma
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya
| | - Evasius Bauni
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya
| | - Laura L Hammitt
- Centre for International Health, Johns Hopkins University, Baltimore, MD, United States.
| | - Christine Mataza
- County Department of Health, Kilifi County Hospital, PO Box 491-80108, Kilifi, Kenya.
| | - Collins Tabu
- National Vaccines and Immunisations Programme, Ministry of Health, Kenya
| | - Tatu Kamau
- Vector Borne Diseases Control Unit, Ministry of Health, Kenya
| | - Thomas N Williams
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya; Department of Medicine, Imperial College, St Mary's Hospital, Praed Street, London, United Kingdom; INDEPTH Network, Accra, Ghana.
| | - J Anthony G Scott
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, PO Box 230-80108, Kilifi, Kenya; Infectious Diseases Epidemiology, London School of Hygiene and Tropical Medicine, WC1E 7HT London, UK; INDEPTH Network, Accra, Ghana.
| |
Collapse
|
50
|
Adetifa IMO, Bwanaali T, Wafula J, Mutuku A, Karia B, Makumi A, Mwatsuma P, Bauni E, Hammitt LL, Nokes DJ, Maree E, Tabu C, Kamau T, Mataza C, Williams TN, Scott JAG. Cohort Profile: The Kilifi Vaccine Monitoring Study. Int J Epidemiol 2018; 46:792-792h. [PMID: 27789669 PMCID: PMC5654374 DOI: 10.1093/ije/dyw202] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2016] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ifedayo M O Adetifa
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Infectious Diseases Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Tahreni Bwanaali
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Infectious Diseases Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Jackline Wafula
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Alex Mutuku
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Boniface Karia
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Anne Makumi
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Pauline Mwatsuma
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Evasius Bauni
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Laura L Hammitt
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - D James Nokes
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,School of Life Sciences and WIDER, University of Warwick, Coventry, UK
| | | | | | - Tatu Kamau
- Vector Borne Diseases Control Unit, Ministry of Health, Nairobi, Kenya
| | | | - Thomas N Williams
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Medicine, Imperial College, St Mary's Hospital, London, UK.,INDEPTH Network, Accra, Ghana
| | - J Anthony G Scott
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Infectious Diseases Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.,INDEPTH Network, Accra, Ghana
| |
Collapse
|