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Nyawanda BO, Murunga N, Otieno NA, Bigogo G, Nyiro JU, Vodicka E, Bulterys M, Nokes DJ, Munywoki PK, Emukule GO. Estimates of the national burden of respiratory syncytial virus in Kenyan children aged under 5 years, 2010-2018. BMC Med 2023; 21:122. [PMID: 37004034 PMCID: PMC10067313 DOI: 10.1186/s12916-023-02787-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 02/15/2023] [Indexed: 04/03/2023] Open
Abstract
BACKGROUND Respiratory syncytial virus (RSV) is among the leading childhood causes of viral pneumonia worldwide. Establishing RSV-associated morbidity and mortality is important in informing the development, delivery strategies, and evaluation of interventions. METHODS Using data collected during 2010-2018 from base regions (population-based surveillance studies in western Kenya and the Kilifi Health and Demographic Surveillance Study), we estimated age-specific rates of acute respiratory illness (ARI), severe acute respiratory illness (SARI-defined as hospitalization with cough or difficulty breathing with onset within the past 10 days), and SARI-associated deaths. We extrapolated the rates from the base regions to other regions of Kenya, while adjusting for risk factors of ARI and healthcare seeking behavior, and finally applied the proportions of RSV-positive cases identified from various sentinel and study facilities to the rates to obtain regional age-specific rates of RSV-associated outpatient and non-medically attended ARI and hospitalized SARI and severe ARI that was not hospitalized (non-hospitalized SARI). We applied age-specific RSV case fatality ratios to SARI to obtain estimates of RSV-associated in- and out-of-hospital deaths. RESULTS Among Kenyan children aged < 5 years, the estimated annual incidence of outpatient and non-medically attended RSV-associated ARI was 206 (95% credible interval, CI; 186-229) and 226 (95% CI; 204-252) per 1000 children, respectively. The estimated annual rates of hospitalized and non-hospitalized RSV-associated SARI were 349 (95% CI; 303-404) and 1077 (95% CI; 934-1247) per 100,000 children respectively. The estimated annual number of in- and out-of-hospital deaths associated with RSV infection in Kenya were 539 (95% CI; 420-779) and 1921 (95% CI; 1495-2774), respectively. Children aged < 6 months had the highest burden of RSV-associated severe disease: 2075 (95% CI; 1818-2394) and 44 (95% CI 25-71) cases per 100,000 children for hospitalized SARI and in-hospital deaths, respectively. CONCLUSIONS Our findings suggest a substantial disease burden due to RSV infection, particularly among younger children. Prioritizing development and use of maternal vaccines and affordable long-lasting monoclonal antibodies could help reduce this burden.
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Affiliation(s)
- Bryan O Nyawanda
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya.
| | - Nickson Murunga
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Nancy A Otieno
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Godfrey Bigogo
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Joyce U Nyiro
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Marc Bulterys
- US Centers for Disease Control and Prevention, Nairobi, Kenya
| | - D James Nokes
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
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Nyawanda BO, Beloconi A, Khagayi S, Bigogo G, Obor D, Otieno NA, Lange S, Franke J, Sauerborn R, Utzinger J, Kariuki S, Munga S, Vounatsou P. The relative effect of climate variability on malaria incidence after scale-up of interventions in western Kenya: A time-series analysis of monthly incidence data from 2008 to 2019. Parasite Epidemiol Control 2023; 21:e00297. [PMID: 37021322 PMCID: PMC10068258 DOI: 10.1016/j.parepi.2023.e00297] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 03/07/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023] Open
Abstract
Background Despite considerable progress made over the past 20 years in reducing the global burden of malaria, the disease remains a major public health problem and there is concern that climate change might expand suitable areas for transmission. This study investigated the relative effect of climate variability on malaria incidence after scale-up of interventions in western Kenya. Methods Bayesian negative binomial models were fitted to monthly malaria incidence data, extracted from records of patients with febrile illnesses visiting the Lwak Mission Hospital between 2008 and 2019. Data pertaining to bed net use and socio-economic status (SES) were obtained from household surveys. Climatic proxy variables obtained from remote sensing were included as covariates in the models. Bayesian variable selection was used to determine the elapsing time between climate suitability and malaria incidence. Results Malaria incidence increased by 50% from 2008 to 2010, then declined by 73% until 2015. There was a resurgence of cases after 2016, despite high bed net use. Increase in daytime land surface temperature was associated with a decline in malaria incidence (incidence rate ratio [IRR] = 0.70, 95% Bayesian credible interval [BCI]: 0.59-0.82), while rainfall was associated with increased incidence (IRR = 1.27, 95% BCI: 1.10-1.44). Bed net use was associated with a decline in malaria incidence in children aged 6-59 months (IRR = 0.78, 95% BCI: 0.70-0.87) but not in older age groups, whereas SES was not associated with malaria incidence in this population. Conclusions Variability in climatic factors showed a stronger effect on malaria incidence than bed net use. Bed net use was, however, associated with a reduction in malaria incidence, especially among children aged 6-59 months after adjusting for climate effects. To sustain the downward trend in malaria incidence, this study recommends continued distribution and use of bed nets and consideration of climate-based malaria early warning systems when planning for future control interventions.
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Hollowell T, Sewe MO, Rocklöv J, Obor D, Odhiambo F, Ahlm C. Public health determinants of child malaria mortality: a surveillance study within Siaya County, Western Kenya. Malar J 2023; 22:65. [PMID: 36823600 PMCID: PMC9948786 DOI: 10.1186/s12936-023-04502-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/18/2023] [Indexed: 02/25/2023] Open
Abstract
BACKGROUND Malaria deaths among children have been declining worldwide during the last two decades. Despite preventive, epidemiologic and therapy-development work, mortality rate decline has stagnated in western Kenya resulting in persistently high child malaria morbidity and mortality. The aim of this study was to identify public health determinants influencing the high burden of malaria deaths among children in this region. METHODS A total of 221,929 children, 111,488 females and 110,441 males, under the age of 5 years were enrolled in the Kenya Medical Research Institute/Center for Disease Control Health and Demographic Surveillance System (KEMRI/CDC HDSS) study area in Siaya County during the period 2003-2013. Cause of death was determined by use of verbal autopsy. Age-specific mortality rates were computed, and cox proportional hazard regression was used to model time to malaria death controlling for the socio-demographic factors. A variety of demographic, social and epidemiologic factors were examined. RESULTS In total 8,696 (3.9%) children died during the study period. Malaria was the most prevalent cause of death and constituted 33.2% of all causes of death, followed by acute respiratory infections (26.7%) and HIV/AIDS related deaths (18.6%). There was a marked decrease in overall mortality rate from 2003 to 2013, except for a spike in the rates in 2008. The hazard of death differed between age groups with the youngest having the highest hazard of death HR 6.07 (95% CI 5.10-7.22). Overall, the risk attenuated with age and mortality risks were limited beyond 4 years of age. Longer distance to healthcare HR of 1.44 (95% CI 1.29-1.60), l ow maternal education HR 3.91 (95% CI 1.86-8.22), and low socioeconomic status HR 1.44 (95% CI 1.26-1.64) were all significantly associated with increased hazard of malaria death among children. CONCLUSIONS While child mortality due to malaria in the study area in Western Kenya, has been decreasing, a final step toward significant risk reduction is yet to be accomplished. This study highlights residual proximal determinants of risk which can further inform preventive actions.
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Affiliation(s)
- Thomas Hollowell
- Department of Clinical Microbiology, Infection and Immunology, Umeå University, Umeå, Sweden. .,Department of Infectious Diseases, Karlstad Central Hospital, Region Värmland, Karlstad, Sweden.
| | - Maquins Odhiambo Sewe
- grid.33058.3d0000 0001 0155 5938KEMRI Centre for Global Health Research, Kisumu, Kenya ,grid.12650.300000 0001 1034 3451Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden
| | - Joacim Rocklöv
- grid.12650.300000 0001 1034 3451Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden ,grid.7700.00000 0001 2190 4373Heidelberg Institute of Global Health and Interdisciplinary Center for Scientific Computing, University of Heidelberg, Heidelberg, Germany
| | - David Obor
- grid.33058.3d0000 0001 0155 5938KEMRI Centre for Global Health Research, Kisumu, Kenya
| | - Frank Odhiambo
- grid.33058.3d0000 0001 0155 5938KEMRI Centre for Global Health Research, Kisumu, Kenya
| | - Clas Ahlm
- grid.12650.300000 0001 1034 3451Department of Clinical Microbiology, Infection and Immunology, Umeå University, Umeå, Sweden
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Nyanchoka M, Mulaku M, Nyagol B, Owino EJ, Kariuki S, Ochodo E. Implementing essential diagnostics-learning from essential medicines: A scoping review. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000827. [PMID: 36962808 PMCID: PMC10121180 DOI: 10.1371/journal.pgph.0000827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 11/17/2022] [Indexed: 12/24/2022]
Abstract
The World Health Organization (WHO) model list of Essential In vitro Diagnostic (EDL) introduced in 2018 complements the established Essential Medicines List (EML) and improves its impact on advancing universal health coverage and better health outcomes. We conducted a scoping review of the literature on implementing the WHO essential lists in Africa to inform the implementation of the recently introduced EDL. We searched eight electronic databases for studies reporting on implementing the WHO EDL and EML in Africa. Two authors independently conducted study selection and data extraction, with disagreements resolved through discussion. We used the Supporting the Use of Research Evidence (SURE) framework to extract themes and synthesised findings using thematic content analysis. We used the Mixed Method Appraisal Tool (MMAT) version 2018 to assess the quality of included studies. We included 172 studies reporting on EDL and EML after screening 3,813 articles titles and abstracts and 1,545 full-text papers. Most (75%, n = 129) studies were purely quantitative in design, comprising descriptive cross-sectional designs (60%, n = 104), 15% (n = 26) were purely qualitative, and 10% (n = 17) had mixed-methods approaches. There were no qualitative or randomised experimental studies about EDL. The main barrier facing the EML and EDL was poorly equipped health facilities-including unavailability or stock-outs of essential in vitro diagnostics and medicines. Financial and non-financial incentives to health facilities and workers were key enablers in implementing the EML; however, their impact differed from one context to another. Only fifty-six (33%) of the included studies were of high quality. Poorly equipped and stocked health facilities remain an implementation barrier to essential diagnostics and medicines. Health system interventions such as financial and non-financial incentives to improve their availability can be applied in different contexts. More implementation study designs, such as experimental and qualitative studies, are required to evaluate the effectiveness of essential lists.
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Affiliation(s)
- Moriasi Nyanchoka
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Mercy Mulaku
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
- Centre for Evidence-based Health Care, Division of Epidemiology and Biostatistics, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
- Department of Pharmacology, Clinical Pharmacy, and Pharmacy Practice, Faculty of Health Sciences, University of Nairobi, Nairobi, Kenya
| | - Bruce Nyagol
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Eddy Johnson Owino
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Eleanor Ochodo
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
- Centre for Evidence-based Health Care, Division of Epidemiology and Biostatistics, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
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Dulacha D, Were V, Oyugi E, Kiptui R, Owiny M, Boru W, Gura Z, Perry RT. Reduction in malaria burden following the introduction of indoor residual spraying in areas protected by long-lasting insecticidal nets in Western Kenya, 2016-2018. PLoS One 2022; 17:e0266736. [PMID: 35442999 PMCID: PMC9020686 DOI: 10.1371/journal.pone.0266736] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 03/25/2022] [Indexed: 11/19/2022] Open
Abstract
Background Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the main malaria vector control measures deployed in Kenya. Widespread pyrethroid resistance among the primary vectors in Western Kenya has necessitated the re-introduction of IRS using an organophosphate insecticide, pirimiphos-methyl (Actellic® 300CS), as a pyrethroid resistance management strategy. Evaluation of the effectiveness of the combined use of non-pyrethroid IRS and LLINs has yielded varied results. We aimed to evaluate the effect of non-pyrethroid IRS and LLINs on malaria indicators in a high malaria transmission area. Methods We reviewed records and tallied monthly aggregate of outpatient department (OPD) attendance, suspected malaria cases, those tested for malaria and those testing positive for malaria at two health facilities, one from Nyatike, an intervention sub-county, and one from Suba, a comparison sub-county, both located in Western Kenya, from February 1, 2016, through March 31, 2018. The first round of IRS was conducted in February–March 2017 in Nyatike sub-county and the second round one year later in both Nyatike and Suba sub-counties. The mass distribution of LLINs has been conducted in both locations. We performed descriptive analysis and estimated the effect of the interventions and temporal changes of malaria indicators using Poisson regression for a period before and after the first round of IRS. Results A higher reduction in the intervention area in total OPD, the proportion of OPD visits due to suspected malaria, testing positivity rate and annual malaria incidences were observed except for the total OPD visits among the under 5 children (59% decrease observed in the comparison area vs 33% decrease in the intervention area, net change -27%, P <0.001). The percentage decline in annual malaria incidence observed in the intervention area was more than twice the observed percentage decline in the comparison area across all the age groups. A marked decline in the monthly testing positivity rate (TPR) was noticed in the intervention area, while no major changes were observed in the comparison area. The monthly TPR reduced from 46% in February 2016 to 11% in February 2018, representing a 76% absolute decrease in TPR among all ages (RR = 0.24, 95% CI 0.12–0.46). In the comparison area, TPR was 16% in both February 2016 and February 2018 (RR = 1.0, 95% CI 0.52–2.09). A month-by-month comparison revealed lower TPR in Year 2 compared to Year 1 in the intervention area for most of the one year after the introduction of the IRS. Conclusions Our findings demonstrated a reduced malaria burden among populations protected by both non-pyrethroid IRS and LLINs implying a possible additional benefit afforded by the combined intervention in the malaria-endemic zone.
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Affiliation(s)
- Diba Dulacha
- Field Epidemiology and Laboratory Training Program, Ministry of Health, Nairobi, Kenya
- * E-mail:
| | - Vincent Were
- The U.S. Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Elvis Oyugi
- Field Epidemiology and Laboratory Training Program, Ministry of Health, Nairobi, Kenya
| | - Rebecca Kiptui
- National Malaria Control Program, Ministry of Health, Nairobi, Kenya
| | - Maurice Owiny
- Field Epidemiology and Laboratory Training Program, Ministry of Health, Nairobi, Kenya
| | - Waqo Boru
- Field Epidemiology and Laboratory Training Program, Ministry of Health, Nairobi, Kenya
| | - Zeinab Gura
- Field Epidemiology and Laboratory Training Program, Ministry of Health, Nairobi, Kenya
| | - Robert T. Perry
- The U.S. President’s Malaria Initiative-Kenya, Malaria Branch, Division of Parasitic Diseases and Malaria, Centre for Global Health, US Centers for Disease Control and Prevention, Atlanta, GA, United States of America
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Oruko K, Maixenchs M, Phillips-Howard P, Ondire M, Akelo C, Sanz A, Ordi J, Menéndez C, Bassat Q, Odhiambo FO, Munguambe K. Conceptual frameworks for understanding the acceptability and feasibility of the minimally invasive autopsy to determine cause of death: Findings from the CADMIA Study in western Kenya. PLoS One 2020; 15:e0242574. [PMID: 33315918 PMCID: PMC7735626 DOI: 10.1371/journal.pone.0242574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 11/04/2020] [Indexed: 11/17/2022] Open
Abstract
Establishing the cause of death (CoD) is critical to better understanding health and prioritizing health investments, however the use of full post-mortem examination is rare in most low and middle-income counties for multiple reasons. The use of minimally invasive autopsy (MIA) approaches, such as needle biopsies, presents an alternate means to assess CoD. In order to understand the feasibility and acceptability of MIA among communities in western Kenya, we conducted focus groups and in-depth interviews with next-of-kin of recently deceased persons, community leaders and health care workers in Siaya and Kisumu counties. Results suggest two conceptual framework can be drawn, one with facilitating factors for acceptance of MIA due to the ability to satisfy immediate needs related to interest in learning CoD or protecting social status and honoring the deceased), and one framework covering barriers to acceptance of MIA, for reasons relating to the failure to serve an existing need, and/or the exacerbation of an already difficult time.
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Affiliation(s)
- Kelvin Oruko
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya.,Kenya Medical Training College, Nairobi, Kenya
| | - Maria Maixenchs
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | | | - Maureen Ondire
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Clarah Akelo
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Ariadna Sanz
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Jaume Ordi
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Department of Pathology, Hospital Clinic - Universitat de Barcelona, Barcelona, Spain
| | - Clara Menéndez
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Quique Bassat
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain.,Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain
| | - Frank O Odhiambo
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Khatia Munguambe
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,Faculty of Medicine, Universidade Eduardo Mondlane (UEM), Maputo, Mozambique
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Kigozi SP, Kigozi RN, Sebuguzi CM, Cano J, Rutazaana D, Opigo J, Bousema T, Yeka A, Gasasira A, Sartorius B, Pullan RL. Spatial-temporal patterns of malaria incidence in Uganda using HMIS data from 2015 to 2019. BMC Public Health 2020; 20:1913. [PMID: 33317487 PMCID: PMC7737387 DOI: 10.1186/s12889-020-10007-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/04/2020] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND As global progress to reduce malaria transmission continues, it is increasingly important to track changes in malaria incidence rather than prevalence. Risk estimates for Africa have largely underutilized available health management information systems (HMIS) data to monitor trends. This study uses national HMIS data, together with environmental and geographical data, to assess spatial-temporal patterns of malaria incidence at facility catchment level in Uganda, over a recent 5-year period. METHODS Data reported by 3446 health facilities in Uganda, between July 2015 and September 2019, was analysed. To assess the geographic accessibility of the health facilities network, AccessMod was employed to determine a three-hour cost-distance catchment around each facility. Using confirmed malaria cases and total catchment population by facility, an ecological Bayesian conditional autoregressive spatial-temporal Poisson model was fitted to generate monthly posterior incidence rate estimates, adjusted for caregiver education, rainfall, land surface temperature, night-time light (an indicator of urbanicity), and vegetation index. RESULTS An estimated 38.8 million (95% Credible Interval [CI]: 37.9-40.9) confirmed cases of malaria occurred over the period, with a national mean monthly incidence rate of 20.4 (95% CI: 19.9-21.5) cases per 1000, ranging from 8.9 (95% CI: 8.7-9.4) to 36.6 (95% CI: 35.7-38.5) across the study period. Strong seasonality was observed, with June-July experiencing highest peaks and February-March the lowest peaks. There was also considerable geographic heterogeneity in incidence, with health facility catchment relative risk during peak transmission months ranging from 0 to 50.5 (95% CI: 49.0-50.8) times higher than national average. Both districts and health facility catchments showed significant positive spatial autocorrelation; health facility catchments had global Moran's I = 0.3 (p < 0.001) and districts Moran's I = 0.4 (p < 0.001). Notably, significant clusters of high-risk health facility catchments were concentrated in Acholi, West Nile, Karamoja, and East Central - Busoga regions. CONCLUSION Findings showed clear countrywide spatial-temporal patterns with clustering of malaria risk across districts and health facility catchments within high risk regions, which can facilitate targeting of interventions to those areas at highest risk. Moreover, despite high and perennial transmission, seasonality for malaria incidence highlights the potential for optimal and timely implementation of targeted interventions.
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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
| | - Catherine M Sebuguzi
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Jorge Cano
- 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
| | - Jimmy Opigo
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University, Nijmegen, Netherlands
| | - Adoke Yeka
- Department of Disease Control and Environmental Health, College of Health Sciences, School of Public Health, Makerere University, PO Box 7072, Kampala, Uganda
| | - Anne Gasasira
- African Leaders Malaria Alliance (ALMA), Kampala, Uganda
| | - Benn Sartorius
- 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
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Sokadjo YM, Atchadé MN, Kossou HD. Carbon dioxide emissions from transport and anemia influence on under-five mortality in Benin. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:40277-40285. [PMID: 32661976 DOI: 10.1007/s11356-020-09800-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 06/18/2020] [Indexed: 06/11/2023]
Abstract
This work is the first study about the joint effect (influence) of carbon dioxide emissions (CO2) from transport and anemia influence on under-five mortality in the Republic of Benin. We focused on that interaction effect and provide scientific pieces of evidence through multiple linear and multinomial regression models. Therefore, the World Bank yearly data about Benin has been used. Time series analysis and co-integration checking were done to deepen the study. The interaction of anemia and CO2 emissions from transport influences positively under-five mortality (U5M) rate (p = 0.00). Findings reveal that when CO2 emissions from transport and anemia increase of 1 unit in a given year, Benin is likely to have 10 deaths over 1000 live births higher on the under-five mortality rate the following year.
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Affiliation(s)
- Yves Morel Sokadjo
- Université d'Abomey-Calavi/ International Chair in Mathematical Physics and Applications (ICMPA : UNESCO-Chair), 072 BP 50, Cotonou, Republic of Benin.
| | - Mintodê Nicodème Atchadé
- National Higher School of Mathematics Genius and Modelization, National University of Sciences, Technologies, Engineering and Mathematics, Abomey, Republic of Benin
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Wotodjo AN, Doucoure S, Diagne N, Sarr FD, Parola P, Gaudart J, Sokhna C. The Impact of Renewing Long-Lasting Insecticide-Treated Nets in the Event of Malaria Resurgence: Lessons from 10 Years of Net Use in Dielmo, Senegal. Am J Trop Med Hyg 2020; 104:255-262. [PMID: 33078700 DOI: 10.4269/ajtmh.20-0127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The occurrence of malaria resurgences could threaten progress toward elimination of the disease. This study investigated the impact of repeated renewal of long-lasting insecticide-treated net (LLIN) universal coverage on malaria resurgence over a period of 10 years of net implementation in Dielmo (Senegal). A longitudinal study was carried out in Dielmo between August 2007 and July 2018. In July 2008, LLINs were offered to all villagers through universal campaign distribution which was renewed in July 2011, August 2014, and May 2016. Malaria cases were treated with artemisinin-based combination therapy. Two resurgences of malaria occurred during the 10 years in which LLINs have been in use. Since the third renewal of the nets, malaria decreased significantly compared with the first year the nets were implemented (adjusted incidence rate ratio) (95% CI) = 0.35 (0.15-0.85), during the ninth year after net implementation). During the tenth year of net implementation, no cases of malaria were observed among the study population. The use of nets increased significantly after the third time the nets were renewed when compared with the year after the first and the second times the nets were renewed (P < 0.001). The third renewal of nets, which took place after 2 years instead of 3 years together with a higher use of LLINs especially among the young, probably prevented the occurrence of a third malaria upsurge in this village.
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Affiliation(s)
| | | | | | - Fatoumata Diene Sarr
- 2Unité d'Épidémiologie des Maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal
| | - Philippe Parola
- 3IRD, AP-HM, SSA, IHU-Méditerranée Infection, VITROME, Aix-Marseille University, Marseille, France
| | - Jean Gaudart
- 4APHM, INSERM, IRD, SESSTIM, Hop Timone, BioSTIC, Biostatistic and ICT, Aix Marseille University, Marseille, France.,5Malaria Research and Training Center - Ogobara K Doumbo (MRTC-OKD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Cheikh Sokhna
- 1VITROME, UMR 257 IRD, Campus UCAD-IRD, Dakar, Senegal
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10
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Nyawanda BO, Otieno NA, Otieno MO, Emukule GO, Bigogo G, Onyango CO, Lidechi S, Nyaundi J, Langley GE, Widdowson MA, Chaves SS. The impact of maternal HIV infection on the burden of respiratory syncytial virus among pregnant women and their infants, western Kenya. J Infect Dis 2020; 225:2097-2105. [PMID: 32777041 PMCID: PMC9200157 DOI: 10.1093/infdis/jiaa490] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/31/2020] [Indexed: 02/07/2023] Open
Abstract
Background Respiratory syncytial virus (RSV) is an important cause of respiratory illness worldwide; however, burden data on mother–infant pairs remain sparse in sub-Saharan Africa, where human immunodeficiency virus (HIV) is prevalent. We evaluated the impact of maternal HIV infection on the burden of RSV among mothers and their infants in western Kenya. Methods We enrolled pregnant women (≤20 weeks’ gestation) and followed them and their newborns weekly for up to 3–6 months postpartum, to document cases of acute respiratory illness (ARI). Nasal/oropharyngeal swabs were collected and tested for RSV using polymerase chain reaction. Analyses were stratified by maternal HIV status and incidence was computed per 1000 person-months. Results Compared to RSV-negative ARI cases, RSV-positive cases were associated with cough, apnea, and hospitalization among infants. RSV incidence per 1000 person-months among mothers was 4.0 (95% confidence interval [CI], 3.2–4.4), and was twice that among the HIV-infected mothers (8.4 [95% CI, 5.7–12.0]) compared to the HIV-uninfected mothers (3.1 [95% CI, 2.3–4.0]). Among infants, incidence per 1000 person-months was 15.4 (95% CI, 12.5–18.8); incidence did not differ by HIV exposure or prematurity. Conclusions HIV infection may increase the risk of RSV illness among pregnant women. Future maternal RSV vaccines may have added benefit in areas with high HIV prevalence.
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Affiliation(s)
- Bryan O Nyawanda
- Kenya Medical Research Institute - Center for Global Health Research
| | - Nancy A Otieno
- Kenya Medical Research Institute - Center for Global Health Research
| | - Michael O Otieno
- Kenya Medical Research Institute - Center for Global Health Research
| | | | - Godfrey Bigogo
- Kenya Medical Research Institute - Center for Global Health Research
| | | | - Shirley Lidechi
- Kenya Medical Research Institute - Center for Global Health Research
| | - Jeremiah Nyaundi
- Kenya Medical Research Institute - Center for Global Health Research
| | - Gayle E Langley
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Marc-Alain Widdowson
- Centers for Disease Control and Prevention, Nairobi, Kenya.,Division of Global Health Protection, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Sandra S Chaves
- Centers for Disease Control and Prevention, Nairobi, Kenya.,Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
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11
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Kamau A, Mogeni P, Okiro EA, Snow RW, Bejon P. A systematic review of changing malaria disease burden in sub-Saharan Africa since 2000: comparing model predictions and empirical observations. BMC Med 2020; 18:94. [PMID: 32345315 PMCID: PMC7189714 DOI: 10.1186/s12916-020-01559-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/16/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The most widely used measures of declining burden of malaria across sub-Saharan Africa are predictions from geospatial models. These models apply spatiotemporal autocorrelations and covariates to parasite prevalence data and then use a function of parasite prevalence to predict clinical malaria incidence. We attempted to assess whether trends in malaria cases, based on local surveillance, were similar to those captured by Malaria Atlas Project (MAP) incidence surfaces. METHODS We undertook a systematic review (PROSPERO International Prospective Register of Systematic Reviews; ID = CRD42019116834) to identify empirical data on clinical malaria in Africa since 2000, where reports covered at least 5 continuous years. The trends in empirical data were then compared with the trends of time-space matched clinical malaria incidence from MAP using the Spearman rank correlation. The correlations (rho) between changes in empirically observed and modelled estimates of clinical malaria were displayed by forest plots and examined by meta-regression. RESULTS Sixty-seven articles met our inclusion criteria representing 124 sites from 24 African countries. The single most important factor explaining the correlation between empirical observations and modelled predictions was the slope of empirically observed data over time (rho = - 0.989; 95% CI - 0.998, - 0.939; p < 0.001), i.e. steeper declines were associated with a stronger correlation between empirical observations and modelled predictions. Factors such as quality of study, reported measure of malaria and endemicity were only slightly predictive of such correlations. CONCLUSIONS In many locations, both local surveillance data and modelled estimates showed declines in malaria burden and hence similar trends. However, there was a weak association between individual surveillance datasets and the modelled predictions where stalling in progress or resurgence of malaria burden was empirically observed. Surveillance data were patchy, indicating a need for improved surveillance to strengthen both empiric reporting and modelled predictions.
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Affiliation(s)
- Alice Kamau
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | | | | | - Robert W Snow
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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12
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Machani MG, Ochomo E, Amimo F, Kosgei J, Munga S, Zhou G, Githeko AK, Yan G, Afrane YA. Resting behaviour of malaria vectors in highland and lowland sites of western Kenya: Implication on malaria vector control measures. PLoS One 2020; 15:e0224718. [PMID: 32097407 PMCID: PMC7041793 DOI: 10.1371/journal.pone.0224718] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/04/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Understanding the interactions between increased insecticide resistance and resting behaviour patterns of malaria mosquitoes is important for planning of adequate vector control. This study was designed to investigate the resting behavior, host preference and rates of Plasmodium falciparum infection in relation to insecticide resistance of malaria vectors in different ecologies of western Kenya. METHODS Anopheles mosquito collections were carried out during the dry and rainy seasons in Kisian (lowland site) and Bungoma (highland site), both in western Kenya using pyrethrum spray catches (PSC), mechanical aspiration (Prokopack) for indoor collections, clay pots, pit shelter and Prokopack for outdoor collections. WHO tube bioassay was used to determine levels of phenotypic resistance of indoor and outdoor collected mosquitoes to deltamethrin. PCR-based molecular diagnostics were used for mosquito speciation, genotype for knockdown resistance mutations (1014S and 1014F) and to determine specific host blood meal origins. Enzyme-linked Immunosorbent Assay (ELISA) was used to determine mosquito sporozoite infections. RESULTS Anopheles gambiae s.l. was the most predominant species (75%, n = 2706) followed by An. funestus s.l. (25%, n = 860). An. gambiae s.s hereafter (An. gambiae) accounted for 91% (95% CI: 89-93) and An. arabiensis 8% (95% CI: 6-9) in Bungoma, while in Kisian, An. arabiensis composition was 60% (95% CI: 55-66) and An. gambiae 39% (95% CI: 34-44). The resting densities of An. gambiae s.l and An. funestus were higher indoors than outdoor in both sites (An. gambiae s.l; F1, 655 = 41.928, p < 0.0001, An. funestus; F1, 655 = 36.555, p < 0.0001). The mortality rate for indoor and outdoor resting An. gambiae s.l F1 progeny was 37% (95% CI: 34-39) vs 67% (95% CI: 62-69) respectively in Bungoma. In Kisian, the mortality rate was 67% (95% CI: 61-73) vs 76% (95% CI: 71-80) respectively. The mortality rate for F1 progeny of An. funestus resting indoors in Bungoma was 32% (95% CI: 28-35). The 1014S mutation was only detected in indoor resitng An. arabiensis. Similarly, the 1014F mutation was present only in indoor resting An. gambiae. The sporozoite rates were highest in An. funestus followed by An. gambiae, and An. arabiensis resting indoors at 11% (34/311), 8% (47/618) and 4% (1/27) respectively in Bungoma. Overall, in Bungoma, the sporozoite rate for indoor resting mosquitoes was 9% (82/956) and 4% (8/190) for outdoors. In Kisian, the sporozoite rate was 1% (1/112) for indoor resting An. gambiae. None of the outdoor collected mosquitoes in Kisian tested positive for sporozoite infections (n = 73). CONCLUSION The study reports high indoor resting densities of An. gambiae and An. funestus, insecticide resistance, and persistence of malaria transmission indoors regardless of the use of long-lasting insecticidal nets (LLINs). These findings underline the difficulties of controlling malaria vectors resting and biting indoors using the current interventions. Supplemental vector control tools and implementation of sustainable insecticide resistance management strategies are needed in western Kenya.
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Affiliation(s)
- Maxwell G. Machani
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- School of Health Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya
| | - Eric Ochomo
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Fred Amimo
- School of Health Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya
| | - Jackline Kosgei
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California, Irvine, California, United States of America
| | - Andrew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California, Irvine, California, United States of America
| | - Yaw A. Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Accra, Ghana
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13
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Association between Malaria Infection and Early Childhood Development Mediated by Anemia in Rural Kenya. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17030902. [PMID: 32024214 PMCID: PMC7037381 DOI: 10.3390/ijerph17030902] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/24/2020] [Accepted: 01/24/2020] [Indexed: 02/08/2023]
Abstract
Malaria is a leading cause of morbidity and mortality among children under five years of age, with most cases occurring in Sub-Saharan Africa. Children in this age group in Africa are at greatest risk worldwide for developmental deficits. There are research gaps in quantifying the risks of mild malaria cases, understanding the pathways linking malaria infection and poor child development, and evaluating the impact of malaria on the development of children under five years. We analyzed the association between malaria infection and gross motor, communication, and personal social development in 592 children age 24 months in rural, western Kenya as part of the WASH Benefits environmental enteric dysfunction sub-study. Eighteen percent of children had malaria, 20% were at risk for gross motor delay, 21% were at risk for communication delay, and 23% were at risk for personal social delay. Having a positive malaria test was associated with increased risk for gross motor, communication, and personal social delay while adjusting for child characteristics, household demographics, study cluster, and intervention treatment arm. Mediation analyses suggested that anemia was a significant mediator in the pathway between malaria infection and risk for gross motor, communication, and personal social development delays. The proportion of the total effect of malaria on the risk of developmental delay that is mediated by anemia across the subscales was small (ranging from 9% of the effect on gross motor development to 16% of the effect on communication development mediated by anemia). Overall, malaria may be associated with short-term developmental delays during a vulnerable period of early life. Therefore, preventative malaria measures and immediate treatment are imperative for children’s optimal development, particularly in light of projections of continued high malaria transmission in Kenya and Africa.
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14
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Were V, Buff AM, Desai M, Kariuki S, Samuels AM, Phillips-Howard P, Ter Kuile FO, Kachur SP, Niessen LW. Trends in malaria prevalence and health related socioeconomic inequality in rural western Kenya: results from repeated household malaria cross-sectional surveys from 2006 to 2013. BMJ Open 2019; 9:e033883. [PMID: 31542772 PMCID: PMC6756336 DOI: 10.1136/bmjopen-2019-033883] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE The objective of this analysis was to examine trends in malaria parasite prevalence and related socioeconomic inequalities in malaria indicators from 2006 to 2013 during a period of intensification of malaria control interventions in Siaya County, western Kenya. METHODS Data were analysed from eight independent annual cross-sectional surveys from a combined sample of 19 315 individuals selected from 7253 households. Study setting was a health and demographic surveillance area of western Kenya. Data collected included demographic factors, household assets, fever and medication use, malaria parasitaemia by microscopy, insecticide-treated bed net (ITN) use and care-seeking behaviour. Households were classified into five socioeconomic status and dichotomised into poorest households (poorest 60%) and less poor households (richest 40%). Adjusted prevalence ratios (aPR) were calculated using a multivariate generalised linear model accounting for clustering and cox proportional hazard for pooled data assuming constant follow-up time. RESULTS Overall, malaria infection prevalence was 36.5% and was significantly higher among poorest individuals compared with the less poor (39.9% vs 33.5%, aPR=1.17; 95% CI 1.11 to 1.23) but no change in prevalence over time (trend p value <0.256). Care-seeking (61.1% vs 62.5%, aPR=0.99; 95% CI 0.95 to 1.03) and use of any medication were similar among the poorest and less poor. Poorest individuals were less likely to use Artemether-Lumefantrine or quinine for malaria treatment (18.8% vs 22.1%, aPR=0.81, 95% CI 0.72 to 0.91) while use of ITNs was lower among the poorest individuals compared with less poor (54.8% vs 57.9%; aPR=0.95; 95% CI 0.91 to 0.99), but the difference was negligible. CONCLUSIONS Despite attainment of equity in ITN use over time, socioeconomic inequalities still existed in the distribution of malaria. This might be due to a lower likelihood of treatment with an effective antimalarial and lower use of ITNs by poorest individuals. Additional strategies are necessary to reduce socioeconomic inequities in prevention and control of malaria in endemic areas in order to achieve universal health coverage and sustainable development goals.
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Affiliation(s)
- Vincent Were
- Center for Global Health, Kenya Medical Research Institute, Kisumu, Kenya
- Health Economics, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Ann M Buff
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Meghna Desai
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - A M Samuels
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - Feiko O Ter Kuile
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - S P Kachur
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Louis Wilhelmus Niessen
- Health Economics, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Health Sciences, University of Warwick, Coventry, UK
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15
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Nyawanda BO, Njuguna HN, Onyango CO, Makokha C, Lidechi S, Fields B, Winchell JM, Katieno JS, Nyaundi J, Ade F, Emukule GO, Mott JA, Otieno N, Widdowson MA, Chaves SS. Comparison of respiratory pathogen yields from Nasopharyngeal/Oropharyngeal swabs and sputum specimens collected from hospitalized adults in rural Western Kenya. Sci Rep 2019; 9:11237. [PMID: 31375774 PMCID: PMC6677726 DOI: 10.1038/s41598-019-47713-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/16/2019] [Indexed: 11/13/2022] Open
Abstract
Molecular diagnostic methods are becoming increasingly available for assessment of acute lower respiratory illnesses (ALRI). However, nasopharyngeal/oropharyngeal (NP/OP) swabs may not accurately reflect etiologic agents from the lower respiratory tract where sputum specimens are considered as a more representative sample. The pathogen yields from NP/OP against sputum specimens have not been extensively explored, especially in tropical countries. We compared pathogen yields from NP/OP swabs and sputum specimens from patients ≥18 years hospitalized with ALRI in rural Western Kenya. Specimens were tested for 30 pathogens using TaqMan Array Cards (TAC) and results compared using McNemar's test. The agreement for pathogen detection between NP/OP and sputum specimens ranged between 85-100%. More viruses were detected from NP/OP specimens whereas Klebsiella pneumoniae and Mycobacterium tuberculosis were more common in sputum specimens. There was no clear advantage in using sputum over NP/OP specimens to detect pathogens of ALRI in adults using TAC in the context of this tropical setting.
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Affiliation(s)
- Bryan O Nyawanda
- Kenya Medical Research Institute - Center for Global Health Research, Kisumu, Kenya.
| | - Henry N Njuguna
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Clayton O Onyango
- Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Caroline Makokha
- Kenya Medical Research Institute - Center for Global Health Research, Kisumu, Kenya
| | - Shirley Lidechi
- Kenya Medical Research Institute - Center for Global Health Research, Kisumu, Kenya
| | - Barry Fields
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Jim S Katieno
- Kenya Medical Research Institute - Center for Global Health Research, Kisumu, Kenya
| | - Jeremiah Nyaundi
- Kenya Medical Research Institute - Center for Global Health Research, Kisumu, Kenya
| | - Fredrick Ade
- Kenya Medical Research Institute - Center for Global Health Research, Kisumu, Kenya
| | - Gideon O Emukule
- Influenza Program, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Joshua A Mott
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Nancy Otieno
- Kenya Medical Research Institute - Center for Global Health Research, Kisumu, Kenya
| | - Marc-Alain Widdowson
- Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Sandra S Chaves
- Centers for Disease Control and Prevention, Atlanta, GA, USA
- Influenza Program, Centers for Disease Control and Prevention, Nairobi, Kenya
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16
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Starnes JR, Chamberlain L, Sutermaster S, Owuor M, Okoth V, Edman W, Moon TD. Under-five mortality in the Rongo Sub-County of Migori County, Kenya: Experience of the Lwala Community Alliance 2007-2017 with evidence from a cross-sectional survey. PLoS One 2018; 13:e0203690. [PMID: 30192880 PMCID: PMC6128651 DOI: 10.1371/journal.pone.0203690] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 08/24/2018] [Indexed: 01/27/2023] Open
Abstract
Introduction Childhood mortality remains a pressing problem in rural Kenya, and reducing under-five deaths is a key target of the Sustainable Development Goals. We aim to describe the reduction in under-five mortality in a rural Kenyan community served by the Lwala Community Alliance and factors associated with under-five mortality in this community. Methods A cross-sectional survey containing a complete birth history was administered to a representative sample of the catchment area of the Lwala Community Alliance. Survival analysis techniques were used to describe temporal trends and risk factors related to under-five mortality. Results 1,362 children were included in the study, and 91 children died before the fifth birthday. The most common causes of death among children under five were malaria (19%), respiratory infection (13%), and anemia (11%). The under-five mortality rate was 104.8 per 1,000 live births from 1999 to 2006 and 53.0 per 1,000 after the founding of the Lwala Community Alliance in 2007. Factors associated with under-five mortality included year of birth (HR 0.931; 95% CI: 0.877, 0.988; p = 0.019), multiple-gestation pregnancy (HR 6.201; 95% CI: 2.073, 18.555; p < 0.001), and birth in the long rain season (HR 1.981; 95% CI: 1.350, 2.907; p < 0.001). Birth spacing greater than 18 months was negatively associated with under-five mortality (HR 0.345; 95% CI: 0.203, 0.587; p < 0.001). Conclusions There was a significant decrease in under-five mortality before and after the presence of the Lwala Community Alliance. Multiple-gestation pregnancies, birth season, and short birth spacing were associated with under-five mortality and provide possible targets to further reduce mortality in the region. This provides both hyper-local data necessary for implementation efforts and generalizable data and sampling methods that may be useful for other implementing organizations in sub-Saharan Africa.
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Affiliation(s)
- Joseph R. Starnes
- School of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America
- Lwala Community Alliance, Lwala, Migori County, Kenya
- * E-mail:
| | | | | | - Mercy Owuor
- Lwala Community Alliance, Lwala, Migori County, Kenya
| | - Vincent Okoth
- Lwala Community Alliance, Lwala, Migori County, Kenya
| | - William Edman
- Lwala Community Alliance, Lwala, Migori County, Kenya
| | - Troy D. Moon
- Vanderbilt Institute for Global Health, Vanderbilt University, Nashville, Tennessee, United States of America
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Asymptomatic Plasmodium Parasites among Adults in Eastern Uganda: A Case of Donor Blood Screening at Mbale Regional Blood Bank. J Trop Med 2018; 2018:6359079. [PMID: 30112007 PMCID: PMC6077612 DOI: 10.1155/2018/6359079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/25/2018] [Indexed: 12/13/2022] Open
Abstract
Background There is a paucity of data on asymptomatic carriage of Plasmodium parasite among adult population in Eastern Uganda, an area of perennial high transmission of malaria. In this study, we estimated the prevalence of Plasmodium parasites in donor blood units at Mbale Regional Blood Bank (Mbale RBB), a satellite centre of the Uganda Blood Transfusion Service (UBTS). Method This was a cross-sectional descriptive study in which 380 screened donor blood units were examined for the presence of Plasmodium parasites. A systematic random sampling technique using the interval of 7 was used in selecting the screened blood units for testing. Two experienced malaria slide microscopists (MC1 and MC2) independently examined each thick and thin blood slide under high power magnification of X400 and then X1000 as stated on the study standard operation procedure (SOP). Each slide was examined for 100 oil immersion fields before the examiner declared them negative for Plasmodium parasites. The results by each microscopist's examination were tallied separately, and finally, the two tallies were compared. The third independent microscopist (MC3) was blinded to the results from MC1 and MC2, but whose role was to perform quality control on the slides randomly sampled and read 38 (10%) of all the slides and was available to examine any slides with inconsistent findings by MC1 or MC2. Results All the microscopists were unanimous in all the slide readings. Five of the thick smears (1.3%) confirmed the presence of Plasmodium parasites among donor blood units. Of these, 4/5 were from male donors. Plasmodium falciparum was identified in 4 positive samples, while Plasmodium malariae was identified in one of the donor units. Conclusion The 1.3% prevalence of Plasmodium malaria parasites in screened donor blood units represents risk of malaria blood transfusion transmitted infection and a pool of community transmittable malaria infections, respectively.
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18
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McCann RS, Gimnig JE, Bayoh MN, Ombok M, Walker ED. Microdam Impoundments Provide Suitable Habitat for Larvae of Malaria Vectors: An Observational Study in Western Kenya. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:723-730. [PMID: 29462354 PMCID: PMC7296561 DOI: 10.1093/jme/tjy007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Indexed: 06/08/2023]
Abstract
Impoundments formed by microdams in rural areas of Africa are important sources of water for people, but they provide potential larval habitats for Anopheles (Diptera: Culicidae) mosquitoes that are vectors of malaria. To study this association, the perimeters of 31 microdam impoundments in western Kenya were sampled for Anopheles larvae in three zones (patches of floating and emergent vegetation, shorelines of open water, and aggregations of cattle hoofprints) across dry and rainy seasons. Of 3,169 larvae collected, most (86.8%) were collected in the rainy season. Of 2,403 larvae successfully reared to fourth instar or adult, nine species were identified; most (80.2%) were Anopheles arabiensis Patton, sampled from hoofprint zones in the rainy season. Other species collected were Anopheles coustani Laveran, Anopheles gambiae s.s. Giles, Anopheles funestus Giles, and Anopheles rivulorum Leeson, Anopheles pharoensis Theobald, Anopheles squamosus Theobald, Anopheles rufipes (Gough), and Anopheles ardensis (Theobald). Larvae of An. funestus were uncommon (1.5%) in both dry and rainy seasons and were confined to vegetated zones, suggesting that microdam impoundments are not primary habitats for this important vector species, although microdams may provide a dry season refuge habitat for malaria vectors, contributing to population persistence through the dry season. In this study, microdam impoundments clearly provided habitat for the malaria vector An. arabiensis in the rainy season, most of which was within the shallow apron side of the impoundments where people brought cattle for watering, resulting in compacted soil with aggregations of water-filled hoofprints. This observation suggests a potential conflict between public health concerns about malaria and people's need for stable and reliable sources of water.
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Affiliation(s)
- Robert S. McCann
- Department of Entomology, Michigan State University, East
Lansing, MI
- Current address: Laboratory of Entomology Wageningen,
University and Research Centre, PO Box 8031 6700 EH Wageningen, The
Netherlands
| | - John E. Gimnig
- Division of Parasitic Diseases and Malaria, Centers for
Disease Control and Prevention, Atlanta, Georgia
| | - M. Nabie Bayoh
- Centre for Global Health Research, Kenya Medical Research
Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Maurice Ombok
- Centre for Global Health Research, Kenya Medical Research
Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Edward D. Walker
- Department of Entomology, Michigan State University, East
Lansing, MI
- Department of Microbiology and Molecular Genetics, Michigan
State University, East Lansing, MI
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19
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Were V, Buff AM, Desai M, Kariuki S, Samuels A, Ter Kuile FO, Phillips-Howard PA, Patrick Kachur S, Niessen L. Socioeconomic health inequality in malaria indicators in rural western Kenya: evidence from a household malaria survey on burden and care-seeking behaviour. Malar J 2018; 17:166. [PMID: 29661245 PMCID: PMC5902919 DOI: 10.1186/s12936-018-2319-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 04/11/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Health inequality is a recognized barrier to achieving health-related development goals. Health-equality data are essential for evidence-based planning and assessing the effectiveness of initiatives to promote equity. Such data have been captured but have not always been analysed or used to manage programming. Health data were examined for microeconomic differences in malaria indices and associated malaria control initiatives in western Kenya. METHODS Data was analysed from a malaria cross-sectional survey conducted in July 2012 among 2719 people in 1063 households in Siaya County, Kenya. Demographic factors, history of fever, malaria parasitaemia, malaria medication usage, insecticide-treated net (ITN) use and expenditure on malaria medications were collected. A composite socioeconomic status score was created using multiple correspondence analyses (MCA) of household assets; households were classified into wealth quintiles and dichotomized into poorest (lowest 3 quintiles; 60%) or less-poor (highest 2 quintiles; 40%). Prevalence rates were calculated using generalized linear modelling. RESULTS Overall prevalence of malaria infection was 34.1%, with significantly higher prevalence in the poorest compared to less-poor households (37.5% versus 29.2%, adjusted prevalence ratio [aPR] 1.23; 95% CI = 1.08-1.41, p = 0.002). Care seeking (aPR = 0.95; 95% CI 0.87-1.04, p = 0.229), medication use (aPR = 0.94; 95% CI 0.87-1.00, p = 0.087) and ITN use (aPR = 0.96; 95% CI = 0.87-1.05, p = 0.397) were similar between households. Among all persons surveyed, 36.4% reported taking malaria medicines in the prior 2 weeks; 92% took artemether-lumefantrine, the recommended first-line malaria medication. In the poorest households, 4.9% used non-recommended medicines compared to 3.5% in less-poor (p = 0.332). Mean and standard deviation [SD] for expenditure on all malaria medications per person was US$0.38 [US$0.50]; the mean was US$0.35 [US$0.52] amongst the poorest households and US$0.40 [US$0.55] in less-poor households (p = 0.076). Expenditure on non-recommended malaria medicine was significantly higher in the poorest (mean US$1.36 [US$0.91]) compared to less-poor households (mean US$0.98 [US$0.80]; p = 0.039). CONCLUSIONS Inequalities in malaria infection and expenditures on potentially ineffective malaria medication between the poorest and less-poor households were evident in rural western Kenya. Findings highlight the benefits of using MCA to assess and monitor the health-equity impact of malaria prevention and control efforts at the microeconomic level.
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Affiliation(s)
- Vincent Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya. .,Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Ann M Buff
- Malaria Branch, Division of Parasitic Diseases and Malaria,Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA.,U.S. President's Malaria Initiative, Nairobi, Kenya
| | - Meghna Desai
- Malaria Branch, Division of Parasitic Diseases and Malaria,Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Aaron Samuels
- Malaria Branch, Division of Parasitic Diseases and Malaria,Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | | | | | - S Patrick Kachur
- Malaria Branch, Division of Parasitic Diseases and Malaria,Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Louis Niessen
- Liverpool School of Tropical Medicine, Liverpool, UK
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20
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Amek NO, Van Eijk A, Lindblade KA, Hamel M, Bayoh N, Gimnig J, Laserson KF, Slutsker L, Smith T, Vounatsou P. Infant and child mortality in relation to malaria transmission in KEMRI/CDC HDSS, Western Kenya: validation of verbal autopsy. Malar J 2018; 17:37. [PMID: 29347942 PMCID: PMC5774157 DOI: 10.1186/s12936-018-2184-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 01/10/2018] [Indexed: 12/02/2022] Open
Abstract
Background Malaria transmission reduction is a goal of many malaria control programmes. Little is known of how much mortality can be reduced by specific reductions in transmission. Verbal autopsy (VA) is widely used for estimating malaria specific mortality rates, but does not reliably distinguish malaria from other febrile illnesses. Overall malaria attributable mortality includes both direct and indirect deaths. It is unclear what proportion of the deaths averted by reducing malaria transmission are classified as malaria in VA. Methods Both all-cause, and cause-specific mortality reported by VA for children under 5 years of age, were assembled from the KEMRI/CDC health and demographic surveillance system in Siaya county, rural Western Kenya for the years 2002–2004. These were linked to household-specific estimates of the Plasmodium falciparum entomological inoculation rate (EIR) based on high resolution spatio-temporal geostatistical modelling of entomological data. All-cause and malaria specific mortality (by VA), were analysed in relation to EIR, insecticide-treated net use (ITN), socioeconomic status (SES) and parameters describing space–time correlation. Time at risk for each child was analysed using Bayesian geostatistical Cox proportional hazard models, with time-dependent covariates. The outputs were used to estimate the diagnostic performance of VA in measuring mortality that can be attributed to malaria exposure. Results The overall under-five mortality rate was 80 per 1000 person-years during the study period. Eighty-one percent of the total deaths were assigned causes of death by VA, with malaria assigned as the main cause of death except in the neonatal period. Although no trend was observed in malaria-specific mortality assessed by VA, ITN use was associated with reduced all-cause mortality in infants (hazard ratio 0.15, 95% CI 0.02, 0.63) and the EIR was strongly associated with both all-cause and malaria-specific mortality. 48.2% of the deaths could be attributed to malaria by analysing the exposure–response relationship, though only 20.5% of VAs assigned malaria as the cause and the sensitivity of VAs was estimated to be only 26%. Although VAs assigned some deaths to malaria even in areas where there was estimated to be no exposure, the specificity of the VAs was estimated to be 85%. Conclusion Interventions that reduce P. falciparum transmission intensity will not only significantly reduce malaria-diagnosed mortality, but also mortality assigned to other causes in under-5 year old children in endemic areas. In this setting, the VA tool based on clinician review substantially underestimates the number of deaths that could be averted by reducing malaria exposure in childhood, but has a reasonably high specificity. This suggests that malaria transmission-reducing interventions such as ITNs can potentially reduce overall child mortality by as much as twice the total direct malaria burden estimated from VAs. Electronic supplementary material The online version of this article (10.1186/s12936-018-2184-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nyaguara O Amek
- Kenya Medical Research Institute, Centre for Global Health Research, P.O. Box 1578, Kisumu, Kenya. .,Swiss Tropical and Public Health Institute, Socinstr. 57, P.O. Box, 4002, Basel, Switzerland. .,University of Basel, Petersplatz 1, P.O. Box, 4003, Basel, Switzerland.
| | - Annemieke Van Eijk
- Kenya Medical Research Institute, Centre for Global Health Research, P.O. Box 1578, Kisumu, Kenya
| | - Kim A Lindblade
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Mary Hamel
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Nabie Bayoh
- Kenya Medical Research Institute, Centre for Global Health Research, P.O. Box 1578, Kisumu, Kenya
| | - John Gimnig
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Kayla F Laserson
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Laurence Slutsker
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Thomas Smith
- Swiss Tropical and Public Health Institute, Socinstr. 57, P.O. Box, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, P.O. Box, 4003, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Socinstr. 57, P.O. Box, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, P.O. Box, 4003, Basel, Switzerland
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21
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Herrera S, Enuameh Y, Adjei G, Ae-Ngibise KA, Asante KP, Sankoh O, Owusu-Agyei S, Yé Y. A systematic review and synthesis of the strengths and limitations of measuring malaria mortality through verbal autopsy. Malar J 2017; 16:421. [PMID: 29058621 PMCID: PMC5651608 DOI: 10.1186/s12936-017-2071-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/16/2017] [Indexed: 01/08/2023] Open
Abstract
Background Lack of valid and reliable data on malaria deaths continues to be a problem that plagues the global health community. To address this gap, the verbal autopsy (VA) method was developed to ascertain cause of death at the population level. Despite the adoption and wide use of VA, there are many recognized limitations of VA tools and methods, especially for measuring malaria mortality. This study synthesizes the strengths and limitations of existing VA tools and methods for measuring malaria mortality (MM) in low- and middle-income countries through a systematic literature review. Methods The authors searched PubMed, Cochrane Library, Popline, WHOLIS, Google Scholar, and INDEPTH Network Health and Demographic Surveillance System sites’ websites from 1 January 1990 to 15 January 2016 for articles and reports on MM measurement through VA. Inclusion criteria: article presented results from a VA study where malaria was a cause of death; article discussed limitations/challenges related to measurement of MM through VA. Two authors independently searched the databases and websites and conducted a synthesis of articles using a standard matrix. Results The authors identified 828 publications; 88 were included in the final review. Most publications were VA studies; others were systematic reviews discussing VA tools or methods; editorials or commentaries; and studies using VA data to develop MM estimates. The main limitation were low sensitivity and specificity of VA tools for measuring MM. Other limitations included lack of standardized VA tools and methods, lack of a ‘true’ gold standard to assess accuracy of VA malaria mortality. Conclusions Existing VA tools and methods for measuring MM have limitations. Given the need for data to measure progress toward the World Health Organization’s Global Technical Strategy for Malaria 2016–2030 goals, the malaria community should define strategies for improving MM estimates, including exploring whether VA tools and methods could be further improved. Longer term strategies should focus on improving countries’ vital registration systems for more robust and timely cause of death data. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-2071-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samantha Herrera
- MEASURE Evaluation, ICF, 530 Gaither Road, Suite 500, Rockville, MD, 20850, USA.
| | - Yeetey Enuameh
- Kintampo Health Research Centre, Kintampo, Ghana.,School of Public Health, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - George Adjei
- Kintampo Health Research Centre, Kintampo, Ghana
| | | | | | - Osman Sankoh
- INDEPTH Network, 38 & 40 Mensah Wood Street, East Legon, Accra, Ghana.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Mathematics and Statistics, Njala University, Njala, Sierra Leone
| | - Seth Owusu-Agyei
- Kintampo Health Research Centre, Kintampo, Ghana.,Institute of Health Research, University of Health and Allied Sciences, Ho, Ghana
| | - Yazoume Yé
- MEASURE Evaluation, ICF, 530 Gaither Road, Suite 500, Rockville, MD, 20850, USA
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McCann RS, Messina JP, MacFarlane DW, Bayoh MN, Gimnig JE, Giorgi E, Walker ED. Explaining variation in adult Anopheles indoor resting abundance: the relative effects of larval habitat proximity and insecticide-treated bed net use. Malar J 2017; 16:288. [PMID: 28716087 PMCID: PMC5514485 DOI: 10.1186/s12936-017-1938-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 07/13/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Spatial determinants of malaria risk within communities are associated with heterogeneity of exposure to vector mosquitoes. The abundance of adult malaria vectors inside people's houses, where most transmission takes place, should be associated with several factors: proximity of houses to larval habitats, structural characteristics of houses, indoor use of vector control tools containing insecticides, and human behavioural and environmental factors in and near houses. While most previous studies have assessed the association of larval habitat proximity in landscapes with relatively low densities of larval habitats, in this study these relationships were analysed in a region of rural, lowland western Kenya with high larval habitat density. METHODS 525 houses were sampled for indoor-resting mosquitoes across an 8 by 8 km study area using the pyrethrum spray catch method. A predictive model of larval habitat location in this landscape, previously verified, provided derivations of indices of larval habitat proximity to houses. Using geostatistical regression models, the association of larval habitat proximity, long-lasting insecticidal nets (LLIN) use, house structural characteristics (wall type, roof type), and peridomestic variables (cooking in the house, cattle near the house, number of people sleeping in the house) with mosquito abundance in houses was quantified. RESULTS Vector abundance was low (mean, 1.1 adult Anopheles per house). Proximity of larval habitats was a strong predictor of Anopheles abundance. Houses without an LLIN had more female Anopheles gambiae s.s., Anopheles arabiensis and Anopheles funestus than houses where some people used an LLIN (rate ratios, 95% CI 0.87, 0.85-0.89; 0.84, 0.82-0.86; 0.38, 0.37-0.40) and houses where everyone used an LLIN (RR, 95% CI 0.49, 0.48-0.50; 0.39, 0.39-0.40; 0.60, 0.58-0.61). Cooking in the house also reduced Anopheles abundance across all species. The number of people sleeping in the house, presence of cattle near the house, and house structure modulated Anopheles abundance, but the effect varied with Anopheles species and sex. CONCLUSIONS Variation in the abundance of indoor-resting Anopheles in rural houses of western Kenya varies with clearly identifiable factors. Results suggest that LLIN use continues to function in reducing vector abundance, and that larval source management in this region could lead to further reductions in malaria risk by reducing the amount of an obligatory resource for mosquitoes near people's homes.
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Affiliation(s)
- Robert S. McCann
- Department of Entomology, Michigan State University, East Lansing, MI USA
| | - Joseph P. Messina
- Department of Geography, Environment, and Spatial Sciences, Michigan State University, East Lansing, MI USA
| | | | - M. Nabie Bayoh
- Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - John E. Gimnig
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA USA
| | - Emanuele Giorgi
- Lancaster Medical School, Lancaster University, Lancaster, UK
| | - Edward D. Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, 567 Wilson Road, 2215 Biomedical Physical Sciences Building, East Lansing, MI 48824-4320 USA
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Khagayi S, Amek N, Bigogo G, Odhiambo F, Vounatsou P. Bayesian spatio-temporal modeling of mortality in relation to malaria incidence in Western Kenya. PLoS One 2017; 12:e0180516. [PMID: 28704417 PMCID: PMC5509217 DOI: 10.1371/journal.pone.0180516] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 06/17/2017] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION The effect of malaria exposure on mortality using health facility incidence data as a measure of transmission has not been well investigated. Health and demographic surveillance systems (HDSS) routinely capture data on mortality, interventions and other household related indicators, offering a unique platform for estimating and monitoring the incidence-mortality relationship in space and time. METHODS Mortality data from the HDSS located in Western Kenya collected from 2007 to 2012 and linked to health facility incidence data were analysed using Bayesian spatio-temporal survival models to investigate the relation between mortality (all-cause/malaria-specific) and malaria incidence across all age groups. The analysis adjusted for insecticide-treated net (ITN) ownership, socio-economic status (SES), distance to health facilities and altitude. The estimates obtained were used to quantify excess mortality due to malaria exposure. RESULTS Our models identified a strong positive relationship between slide positivity rate (SPR) and all-cause mortality in young children 1-4 years (HR = 4.29; 95% CI: 2.78-13.29) and all ages combined (HR = 1.55; 1.04-2.80). SPR had a strong positive association with malaria-specific mortality in young children (HR = 9.48; 5.11-37.94), however, in older children (5-14 years), it was associated with a reduction in malaria specific mortality (HR = 0.02; 0.003-0.33). CONCLUSION SPR as a measure of transmission captures well the association between malaria transmission intensity and all-cause/malaria mortality. This offers a quick and efficient way to monitor malaria burden. Excess mortality estimates indicate that small changes in malaria incidence substantially reduce overall and malaria specific mortality.
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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
| | - Nyaguara Amek
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Godfrey Bigogo
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Frank Odhiambo
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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24
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Emukule GO, Spreeuwenberg P, Chaves SS, Mott JA, Tempia S, Bigogo G, Nyawanda B, Nyaguara A, Widdowson MA, van der Velden K, Paget JW. Estimating influenza and respiratory syncytial virus-associated mortality in Western Kenya using health and demographic surveillance system data, 2007-2013. PLoS One 2017; 12:e0180890. [PMID: 28686692 PMCID: PMC5501643 DOI: 10.1371/journal.pone.0180890] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 06/05/2017] [Indexed: 11/18/2022] Open
Abstract
Background Influenza and respiratory syncytial virus (RSV) associated mortality has not been well-established in tropical Africa. Methods We used the negative binomial regression method and the rate-difference method (i.e. deaths during low and high influenza/RSV activity months), to estimate excess mortality attributable to influenza and RSV using verbal autopsy data collected through a health and demographic surveillance system in Western Kenya, 2007–2013. Excess mortality rates were calculated for a) all-cause mortality, b) respiratory deaths (including pneumonia), c) HIV-related deaths, and d) pulmonary tuberculosis (TB) related deaths. Results Using the negative binomial regression method, the mean annual all-cause excess mortality rate associated with influenza and RSV was 14.1 (95% confidence interval [CI] 0.0–93.3) and 17.1 (95% CI 0.0–111.5) per 100,000 person-years (PY) respectively; and 10.5 (95% CI 0.0–28.5) and 7.3 (95% CI 0.0–27.3) per 100,000 PY for respiratory deaths, respectively. Highest mortality rates associated with influenza were among ≥50 years, particularly among persons with TB (41.6[95% CI 0.0–122.7]); and with RSV were among <5 years. Using the rate-difference method, the excess mortality rate for influenza and RSV was 44.8 (95% CI 36.8–54.4) and 19.7 (95% CI 14.7–26.5) per 100,000 PY, respectively, for all-cause deaths; and 9.6 (95% CI 6.3–14.7) and 6.6 (95% CI 3.9–11.0) per 100,000 PY, respectively, for respiratory deaths. Conclusions Our study shows a substantial excess mortality associated with influenza and RSV in Western Kenya, especially among children <5 years and older persons with TB, supporting recommendations for influenza vaccination and efforts to develop RSV vaccines.
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Affiliation(s)
- Gideon O. Emukule
- Centers for Disease Control and Prevention - Kenya Country Office, Nairobi, Kenya
- Radboud University Medical Center, Department of Primary and Community care, Nijmegen, The Netherlands
- * E-mail:
| | - Peter Spreeuwenberg
- Netherlands Institute for Health Services research (NIVEL), Utrecht, The Netherlands
| | - Sandra S. Chaves
- Centers for Disease Control and Prevention - Kenya Country Office, Nairobi, Kenya
- Influenza Division, National Center for Immunization and Respiratory Diseases, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States
| | - Joshua A. Mott
- Centers for Disease Control and Prevention - Kenya Country Office, Nairobi, Kenya
- Influenza Division, National Center for Immunization and Respiratory Diseases, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States
- US Public Health Service, Rockville, Maryland, United States of America
| | - Stefano Tempia
- Influenza Division, National Center for Immunization and Respiratory Diseases, US Centers for Disease Control and Prevention, Atlanta, Georgia, United States
- Center for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | | | | | | | - Marc-Alain Widdowson
- Centers for Disease Control and Prevention - Kenya Country Office, Nairobi, Kenya
| | - Koos van der Velden
- Radboud University Medical Center, Department of Primary and Community care, Nijmegen, The Netherlands
| | - John W. Paget
- Radboud University Medical Center, Department of Primary and Community care, Nijmegen, The Netherlands
- Netherlands Institute for Health Services research (NIVEL), Utrecht, The Netherlands
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Wotodjo AN, Doucoure S, Gaudart J, Diagne N, Diene Sarr F, Faye N, Tall A, Raoult D, Sokhna C. Malaria in Dielmo, a Senegal village: Is its elimination possible after seven years of implementation of long-lasting insecticide-treated nets? PLoS One 2017; 12:e0179528. [PMID: 28678846 PMCID: PMC5497975 DOI: 10.1371/journal.pone.0179528] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 05/31/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The malaria burden has decreased significantly in recent years in Africa through the widespread use of artemisinin-based combination therapy (ACT) and long-lasting insecticide-treated nets (LLINs). However, the occurrence of malaria resurgences, the loss of immunity of exposed populations constitute among other factors, serious concerns about the future of malaria elimination efforts. This study investigated the evolution of malaria morbidity in Dielmo (Senegal) before and after the implementation of LLINs. METHODS A longitudinal study was carried out in Dielmo over eight years, from July 2007 to July 2015. In July 2008, LLINs were offered to all villagers, and in July 2011 and August 2014 the LLINs were renewed. A survey on LLINs use was done each quarter of the year. Thick smears stained with Giemsa, a rapid diagnostic test (RDT) and quantitative polymerase chain reaction (PCR) methods were performed for all cases of fever to assess malaria clinical attacks. Malaria cases were treated with ACT since June 2006. RESULTS Malaria morbidity has decreased significantly since the implementation of LLINs in Dielmo, together with ACT. However, malaria resurgences have occurred twice during the seven years of LLINs use. These resurgences occurred the first time during the third year after the introduction of LLINs (aIRR (adjusted incidence-rate ratio) [95%CI] = 5.90 [3.53; 9.88] p< 0.001) and a second time during the third year after the renewal of LLINs (aIRR [95%CI] = 5.60 [3.34; 9.39] p< 0.001). Sixty-nine percent (69%) of the nets tested for their long-lasting insecticidal activity remained effective after 3 years of use. CONCLUSION Good management of malaria cases by the use of ACT as first-line treatment against malaria in addition to the use of LLINs has significantly reduced malaria in Dielmo and allowed to reach the phase of pre-elimination of the disease. However, the occurrence of malaria resurgences raised serious concerns about malaria elimination, which would require additional tools in this village.
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Affiliation(s)
- Amélé Nyedzie Wotodjo
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP, CP Dakar, Senegal,Université Cheikh Anta Diop de Dakar, Faculté des Sciences et Techniques/ Laboratoire de Parasitologie, Dakar, Senegal
| | - Souleymane Doucoure
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP, CP Dakar, Senegal
| | - Jean Gaudart
- Aix Marseille Univ, IER, INSERM, SESSTIM UMR912, Marseille, France
| | - Nafissatou Diagne
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP, CP Dakar, Senegal
| | - Fatoumata Diene Sarr
- Institut Pasteur de Dakar, Unité d'Épidémiologie des maladies infectieuses, Dakar, Senegal
| | - Ngor Faye
- Université Cheikh Anta Diop de Dakar, Faculté des Sciences et Techniques/ Laboratoire de Parasitologie, Dakar, Senegal
| | - Adama Tall
- Institut Pasteur de Dakar, Unité d'Épidémiologie des maladies infectieuses, Dakar, Senegal
| | - Didier Raoult
- Institut Hospitalo Universitaire Méditerranée-Infection, Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes, IRD198, UM63, CNRS7278, INSERMU1095, Marseille, France
| | - Cheikh Sokhna
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP, CP Dakar, Senegal,* E-mail:
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Ochomo E, Chahilu M, Cook J, Kinyari T, Bayoh NM, West P, Kamau L, Osangale A, Ombok M, Njagi K, Mathenge E, Muthami L, Subramaniam K, Knox T, Mnavaza A, Donnelly MJ, Kleinschmidt I, Mbogo C. Insecticide-Treated Nets and Protection against Insecticide-Resistant Malaria Vectors in Western Kenya. Emerg Infect Dis 2017; 23:758-764. [PMID: 28418293 PMCID: PMC5403037 DOI: 10.3201/eid2305.161315] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Insecticide resistance might reduce the efficacy of malaria vector control. In 2013 and 2014, malaria vectors from 50 villages, of varying pyrethroid resistance, in western Kenya were assayed for resistance to deltamethrin. Long-lasting insecticide-treated nets (LLIN) were distributed to households at universal coverage. Children were recruited into 2 cohorts, cleared of malaria-causing parasites, and tested every 2 weeks for reinfection. Infection incidence rates for the 2 cohorts were 2.2 (95% CI 1.9–2.5) infections/person-year and 2.8 (95% CI 2.5–3.0) infections/person-year. LLIN users had lower infection rates than non-LLIN users in both low-resistance (rate ratio 0.61, 95% CI 0.42–0.88) and high-resistance (rate ratio 0.55, 95% CI 0.35–0.87) villages (p = 0.63). The association between insecticide resistance and infection incidence was not significant (p = 0.99). Although the incidence of infection was high among net users, LLINs provided significant protection (p = 0.01) against infection with malaria parasite regardless of vector insecticide resistance.
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Samuels AM, Awino N, Odongo W, Abong'o B, Gimnig J, Otieno K, Shi YP, Were V, Allen DR, Were F, Sang T, Obor D, Williamson J, Hamel MJ, Patrick Kachur S, Slutsker L, Lindblade KA, Kariuki S, Desai M. Community-based intermittent mass testing and treatment for malaria in an area of high transmission intensity, western Kenya: study design and methodology for a cluster randomized controlled trial. Malar J 2017; 16:240. [PMID: 28592250 PMCID: PMC5463392 DOI: 10.1186/s12936-017-1883-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 05/29/2017] [Indexed: 01/13/2023] Open
Abstract
Most human Plasmodium infections in western Kenya are asymptomatic and are believed to contribute importantly to malaria transmission. Elimination of asymptomatic infections requires active treatment approaches, such as mass testing and treatment (MTaT) or mass drug administration (MDA), as infected persons do not seek care for their infection. Evaluations of community-based approaches that are designed to reduce malaria transmission require careful attention to study design to ensure that important effects can be measured accurately. This manuscript describes the study design and methodology of a cluster-randomized controlled trial to evaluate a MTaT approach for malaria transmission reduction in an area of high malaria transmission. Ten health facilities in western Kenya were purposively selected for inclusion. The communities within 3 km of each health facility were divided into three clusters of approximately equal population size. Two clusters around each health facility were randomly assigned to the control arm, and one to the intervention arm. Three times per year for 2 years, after the long and short rains, and again before the long rains, teams of community health volunteers visited every household within the intervention arm, tested all consenting individuals with malaria rapid diagnostic tests, and treated all positive individuals with an effective anti-malarial. The effect of mass testing and treatment on malaria transmission was measured through population-based longitudinal cohorts, outpatient visits for clinical malaria, periodic population-based cross-sectional surveys, and entomological indices.
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Affiliation(s)
- Aaron M Samuels
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA. .,Centers for Disease Control and Prevention, Kisian Campus, Off Busia Road, P O Box 1578, Kisumu, 40100, Kenya.
| | - Nobert Awino
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Wycliffe Odongo
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Benard Abong'o
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Gimnig
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Kephas Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ya Ping Shi
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Vincent Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Denise Roth Allen
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Florence Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Tony Sang
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - David Obor
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Williamson
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Mary J Hamel
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - S Patrick Kachur
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Laurence Slutsker
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Kim A Lindblade
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Meghna Desai
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
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Wanja E, Achilla R, Obare P, Adeny R, Moseti C, Otieno V, Morang'a C, Murigi E, Nyamuni J, Monthei DR, Ogutu B, Buff AM. Evaluation of a laboratory quality assurance pilot programme for malaria diagnostics in low-transmission areas of Kenya, 2013. Malar J 2017; 16:221. [PMID: 28545579 PMCID: PMC5445328 DOI: 10.1186/s12936-017-1856-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 05/12/2017] [Indexed: 11/21/2022] Open
Abstract
Background One objective of the Kenya National Malaria Strategy 2009–2017 is scaling access to prompt diagnosis and effective treatment. In 2013, a quality assurance (QA) pilot was implemented to improve accuracy of malaria diagnostics at selected health facilities in low-transmission counties of Kenya. Trends in malaria diagnostic and QA indicator performance during the pilot are described. Methods From June to December 2013, 28 QA officers provided on-the-job training and mentoring for malaria microscopy, malaria rapid diagnostic tests and laboratory QA/quality control (QC) practices over four 1-day visits at 83 health facilities. QA officers observed and recorded laboratory conditions and practices and cross-checked blood slides for malaria parasite presence, and a portion of cross-checked slides were confirmed by reference laboratories. Results Eighty (96%) facilities completed the pilot. Among 315 personnel at pilot initiation, 13% (n = 40) reported malaria diagnostics training within the previous 12 months. Slide positivity ranged from 3 to 7%. Compared to the reference laboratory, microscopy sensitivity ranged from 53 to 96% and positive predictive value from 39 to 53% for facility staff and from 60 to 96% and 52 to 80%, respectively, for QA officers. Compared to reference, specificity ranged from 88 to 98% and negative predictive value from 98 to 99% for health-facility personnel and from 93 to 99% and 99%, respectively, for QA officers. The kappa value ranged from 0.48–0.66 for facility staff and 0.57–0.84 for QA officers compared to reference. The only significant test performance improvement observed for facility staff was for specificity from 88% (95% CI 85–90%) to 98% (95% CI 97–99%). QA/QC practices, including use of positive-control slides, internal and external slide cross-checking and recording of QA/QC activities, all increased significantly across the pilot (p < 0.001). Reference material availability also increased significantly; availability of six microscopy job aids and seven microscopy standard operating procedures increased by a mean of 32 percentage points (p < 0.001) and 38 percentage points (p < 0.001), respectively. Conclusions Significant gains were observed in malaria QA/QC practices over the pilot. However, these advances did not translate into improved accuracy of malaria diagnostic performance perhaps because of the limited duration of the QA pilot implementation. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1856-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elizabeth Wanja
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya
| | - Rachel Achilla
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya.,Malaria Diagnostics Center, Kenya Medical Research Institute, Box 54, Kisumu, 40100, Kenya
| | - Peter Obare
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya.,Malaria Diagnostics Center, Kenya Medical Research Institute, Box 54, Kisumu, 40100, Kenya
| | - Rose Adeny
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya.,Malaria Diagnostics Center, Kenya Medical Research Institute, Box 54, Kisumu, 40100, Kenya
| | - Caroline Moseti
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya.,Malaria Diagnostics Center, Kenya Medical Research Institute, Box 54, Kisumu, 40100, Kenya
| | - Victor Otieno
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya.,Malaria Diagnostics Center, Kenya Medical Research Institute, Box 54, Kisumu, 40100, Kenya
| | - Collins Morang'a
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya.,Malaria Diagnostics Center, Kenya Medical Research Institute, Box 54, Kisumu, 40100, Kenya
| | - Ephantus Murigi
- National Malaria Control Programme, Ministry of Health, P.O. Box 19982, Nairobi, 00200, Kenya
| | - John Nyamuni
- National Malaria Control Programme, Ministry of Health, P.O. Box 19982, Nairobi, 00200, Kenya
| | - Derek R Monthei
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya
| | - Bernhards Ogutu
- Malaria Diagnostics Center, U.S. Army Medical Research Directorate-Kenya, Box 54, Kisumu, 40100, Kenya.,Malaria Diagnostics Center, Kenya Medical Research Institute, Box 54, Kisumu, 40100, Kenya
| | - Ann M Buff
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, MS A-06, Atlanta, GA, 30333, USA. .,U.S. President's Malaria Initiative, United Nations Avenue, Village Market, P. O. Box 606, Nairobi, 00621, Kenya.
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A Weather-Based Prediction Model of Malaria Prevalence in Amenfi West District, Ghana. Malar Res Treat 2017; 2017:7820454. [PMID: 28255497 PMCID: PMC5307250 DOI: 10.1155/2017/7820454] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/15/2017] [Indexed: 01/07/2023] Open
Abstract
This study investigated the effects of climatic variables, particularly, rainfall and temperature, on malaria incidence using time series analysis. Our preliminary analysis revealed that malaria incidence in the study area decreased at about 0.35% annually. Also, the month of November recorded approximately 21% more malaria cases than the other months while September had a decreased effect of about 14%. The forecast model developed for this investigation indicated that mean minimum (P = 0.01928) and maximum (P = 0.00321) monthly temperatures lagged at three months were significant predictors of malaria incidence while rainfall was not. Diagnostic tests using Ljung-Box and ARCH-LM tests revealed that the model developed was adequate for forecasting. Forecast values for 2016 to 2020 generated by our model suggest a possible future decline in malaria incidence. This goes to suggest that intervention strategies put in place by some nongovernmental and governmental agencies to combat the disease are effective and thus should be encouraged and routinely monitored to yield more desirable outcomes.
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Mangeni JN, Menya D, Obala A, Platt A, O'Meara WP. Development and validation of a rapid assessment tool for malaria prevention. Malar J 2016; 15:544. [PMID: 27825350 PMCID: PMC5101824 DOI: 10.1186/s12936-016-1575-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 10/27/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Insecticide-treated bed nets (ITN) have been shown to be efficacious in reducing malaria morbidity and mortality in many regions. Unfortunately in some areas, malaria has persisted despite the scale up of ITNs. Recent reports indicate that human behaviour and mosquito behaviour are potential threats to the efficacy of ITNs. However, these concerns are likely highly heterogeneous even at very small scales. This study aimed at developing, testing and validating a rapid assessment tool to collect actionable information at local levels for a quick evaluation of potential barriers to malaria prevention. METHODS The study was conducted at the Webuye Health and Demographic Surveillance Site in Bungoma East Sub-County, Kenya. Based on the findings from the case-control study, 12 primary surveillance components that encompass the major impediments to successful prevention were identified and used to develop a rapid assessment tool. Twenty community health volunteers were trained to identify patients with laboratory-confirmed malaria in six peripheral health facilities located within six sub locations and subsequently followed them up to their homes to conduct a rapid assessment. Sampling and analysis of the results of the survey are based on Lot Quality Assurance. RESULTS The tool was able to detect local heterogeneity in bed net coverage, bed net use and larval site abundance in the six health facility catchment areas. Nearly all the catchment areas met the action threshold for incomplete household coverage (i.e. not all household members not using a net the previous night) except the peri-urban area. Although the threshold for nets not in good condition was set very high (≥50%), only two catchment areas failed to meet the action threshold. On the indicator for "Net not used every day last week", half of the areas failed, while for net ownership, only two areas met the action threshold. CONCLUSION The rapid assessment tool was able to detect marked heterogeneity in key indicators for malaria prevention between patients attending health facilities, and can distinguish between priority areas for intervention. There is need to validate it for use in other contexts.
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Affiliation(s)
| | - Diana Menya
- College of Health Sciences, Moi University, Eldoret, Kenya
| | - Andrew Obala
- College of Health Sciences, Moi University, Eldoret, Kenya
| | | | - Wendy Prudhomme O'Meara
- Duke Global Health Institute, Durham, NC, USA.,Academic Model Providing Access to Healthcare, Eldoret, Kenya.,Department of Medicine, Duke University, Durham, NC, USA
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Genetically Determined Response to Artemisinin Treatment in Western Kenyan Plasmodium falciparum Parasites. PLoS One 2016; 11:e0162524. [PMID: 27611315 PMCID: PMC5017781 DOI: 10.1371/journal.pone.0162524] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/24/2016] [Indexed: 12/16/2022] Open
Abstract
Genetically determined artemisinin resistance in Plasmodium falciparum has been described in Southeast Asia. The relevance of recently described Kelch 13-propeller mutations for artemisinin resistance in Sub-Saharan Africa parasites is still unknown. Southeast Asia parasites have low genetic diversity compared to Sub-Saharan Africa, where parasites are highly genetically diverse. This study attempted to elucidate whether genetics provides a basis for discovering molecular markers in response to artemisinin drug treatment in P. falciparum in Kenya. The genetic diversity of parasites collected pre- and post- introduction of artemisinin combination therapy (ACT) in western Kenya was determined. A panel of 12 microsatellites and 91 single nucleotide polymorphisms (SNPs) distributed across the P. falciparum genome were genotyped. Parasite clearance rates were obtained for the post-ACT parasites. The 12 microsatellites were highly polymorphic with post-ACT parasites being significantly more diverse compared to pre-ACT (p < 0.0001). The median clearance half-life was 2.55 hours for the post-ACT parasites. Based on SNP analysis, 15 of 90 post-ACT parasites were single-clone infections. Analysis revealed 3 SNPs that might have some causal association with parasite clearance rates. Further, genetic analysis using Bayesian tree revealed parasites with similar clearance phenotypes were more closely genetically related. With further studies, SNPs described here and genetically determined response to artemisinin treatment might be useful in tracking artemisinin resistance in Kenya.
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32
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Zhou Z, Mitchell RM, Kariuki S, Odero C, Otieno P, Otieno K, Onyona P, Were V, Wiegand RE, Gimnig JE, Walker ED, Desai M, Shi YP. Assessment of submicroscopic infections and gametocyte carriage of Plasmodium falciparum during peak malaria transmission season in a community-based cross-sectional survey in western Kenya, 2012. Malar J 2016; 15:421. [PMID: 27543112 PMCID: PMC4992329 DOI: 10.1186/s12936-016-1482-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/10/2016] [Indexed: 11/10/2022] Open
Abstract
Background Although malaria control intervention has greatly decreased malaria morbidity and mortality in many African countries, further decline in parasite prevalence has stagnated in western Kenya. In order to assess if malaria transmission reservoir is associated with this stagnation, submicroscopic infection and gametocyte carriage was estimated. Risk factors and associations between malaria control interventions and gametocyte carriage were further investigated in this study. Methods A total of 996 dried blood spot samples were used from two strata, all smear-positives (516 samples) and randomly selected smear-negatives (480 samples), from a community cross-sectional survey conducted at peak transmission season in 2012 in Siaya County, western Kenya. Plasmodium falciparum parasite presence and density were determined by stained blood smear and by 18S mRNA transcripts using nucleic acid sequence-based amplification assay (NASBA), gametocyte presence and density were determined by blood smear and by Pfs25 mRNA-NASBA, and gametocyte diversity by Pfg377 mRNA RT-PCR and RT-qPCR. Results Of the randomly selected smear-negative samples, 69.6 % (334/480) were positive by 18S-NASBA while 18S-NASBA detected 99.6 % (514/516) smear positive samples. Overall, 80.2 % of the weighted population was parasite positive by 18S-NASBA vs 30.6 % by smear diagnosis and 44.0 % of the weighted population was gametocyte positive by Pfs25-NASBA vs 2.6 % by smear diagnosis. Children 5–15 years old were more likely to be parasitaemic and gametocytaemic by NASBA than individuals >15 years old or children <5 years old while gametocyte density decreased with age. Anaemia and self-reported fever within the past 24 h were associated with increased odds of gametocytaemia. Fever was also positively associated with parasite density, but not with gametocyte density. Anti-malarial use within the past 2 weeks decreased the odds of gametocytaemia, but not the odds of parasitaemia. In contrast, recent anti-malarial use was associated with lowered parasite density, but not the gametocyte density. Use of ITNs was associated with lower odds for parasitaemia in part of the study area with a longer history of ITN interventions. In the same part of study area, the odds of having multiple gametocyte alleles were also lower in individuals using ITNs than in those not using ITNs and parasite density was positively associated with gametocyte diversity. Conclusion A large proportion of submicroscopic parasites and gametocytes in western Kenya might contribute to the stagnation in malaria prevalence, suggesting that additional interventions targeting the infectious reservoir are needed. As school aged children and persons with anaemia and fever were major sources for gametocyte reservoir, these groups should be targeted for intervention and prevention to reduce malaria transmission. Anti-malarial use was associated with lower parasite density and odds of gametocytaemia, but not the gametocyte density, indicating a limitation of anti-malarial impact on the transmission reservoir. ITN use had a protective role against parasitaemia and gametocyte diversity in western Kenya. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1482-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhiyong Zhou
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Rebecca M Mitchell
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Christopher Odero
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Peter Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Kephas Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Philip Onyona
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Vincent Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ryan E Wiegand
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - John E Gimnig
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Meghna Desai
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ya Ping Shi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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A cross-sectional study of the availability and price of anti-malarial medicines and malaria rapid diagnostic tests in private sector retail drug outlets in rural Western Kenya, 2013. Malar J 2016; 15:359. [PMID: 27406179 PMCID: PMC4942924 DOI: 10.1186/s12936-016-1404-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 06/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although anti-malarial medicines are free in Kenyan public health facilities, patients often seek treatment from private sector retail drug outlets. In mid-2010, the Affordable Medicines Facility-malaria (AMFm) was introduced to make quality-assured artemisinin-based combination therapy (ACT) accessible and affordable in private and public sectors. METHODS Private sector retail drug outlets stocking anti-malarial medications within a surveillance area of approximately 220,000 people in a malaria perennial high-transmission area in rural western Kenya were identified via a census in September 2013. A cross-sectional study was conducted in September-October 2013 to determine availability and price of anti-malarial medicines and malaria rapid diagnostic tests (RDTs) in drug outlets. A standardized questionnaire was administered to collect drug outlet and personnel characteristics and availability and price of anti-malarials and RDTs. RESULTS Of 181 drug outlets identified, 179 (99 %) participated in the survey. Thirteen percent were registered pharmacies, 25 % informal drug shops, 46 % general shops, 13 % homesteads and 2 % other. One hundred sixty-five (92 %) had at least one ACT type: 162 (91 %) had recommended first-line artemether-lumefantrine (AL), 22 (12 %) had recommended second-line dihydroartemisinin-piperaquine (DHA-PPQ), 85 (48 %) had sulfadoxine-pyrimethamine (SP), 60 (34 %) had any quinine (QN) formulation, and 14 (8 %) had amodiaquine (AQ) monotherapy. The mean price (range) of an adult treatment course for AL was $1.01 ($0.35-4.71); DHA-PPQ was $4.39 ($0.71-7.06); QN tablets were $2.24 ($0.12-4.71); SP was $0.62 ($0.24-2.35); AQ monotherapy was $0.42 ($0.24-1.06). The mean AL price with or without the AMFm logo did not differ significantly ($1.01 and 1.07, respectively; p = 0.45). Only 17 (10 %) drug outlets had RDTs; 149 (84 %) never stocked RDTs. The mean RDT price was $0.92 ($0.24-2.35). CONCLUSIONS Most outlets never stocked RDTs; therefore, testing prior to treatment was unlikely for customers seeking treatment in the private retail sector. The recommended first-line treatment, AL, was widely available. Although SP and AQ monotherapy are not recommended for treatment, both were less expensive than AL, which might have caused preferential use by customers. Interventions that create community demand for malaria diagnostic testing prior to treatment and that increase RDT availability should be encouraged.
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Makokha C, Mott J, Njuguna HN, Khagayi S, Verani JR, Nyawanda B, Otieno N, Katz MA. Comparison of severe acute respiratory illness (sari) and clinical pneumonia case definitions for the detection of influenza virus infections among hospitalized patients, western Kenya, 2009-2013. Influenza Other Respir Viruses 2016; 10:333-9. [PMID: 27219455 PMCID: PMC4910169 DOI: 10.1111/irv.12382] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2016] [Indexed: 12/13/2022] Open
Abstract
Although the severe acute respiratory illness (SARI) case definition is increasingly used for inpatient influenza surveillance, pneumonia is a more familiar term to clinicians and policymakers. We evaluated WHO case definitions for severe acute respiratory illness (SARI) and pneumonia (Integrated Management of Childhood Illnesses (IMCI) for children aged <5 years and Integrated Management of Adolescent and Adult Illnesses (IMAI) for patients aged ≥13 years) for detecting laboratory-confirmed influenza among hospitalized ARI patients. Sensitivities were 84% for SARI and 69% for IMCI pneumonia in children aged <5 years and 60% for SARI and 57% for IMAI pneumonia in patients aged ≥13 years. Clinical pneumonia case definitions may be a useful complement to SARI for inpatient influenza surveillance.
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Affiliation(s)
| | - Joshua Mott
- Centers for Disease Control and PreventionNairobiKenya
- Centers for Disease Control and Prevention (CDC)AtlantaGAUSA
| | | | | | - Jennifer R. Verani
- Centers for Disease Control and PreventionNairobiKenya
- Centers for Disease Control and Prevention (CDC)AtlantaGAUSA
| | | | - Nancy Otieno
- Kenya Medical Research Institute (KEMRI)KisumuKenya
| | - Mark A. Katz
- Centers for Disease Control and Prevention (CDC)AtlantaGAUSA
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Pegha Moukandja I, Biteghe Bi Essone JC, Sagara I, Kassa Kassa RF, Ondzaga J, Lékana Douki JB, Bouyou Akotet M, Nkoghe Mba D, Touré Ndouo FS. Marked Rise in the Prevalence of Asymptomatic Plasmodium falciparum Infection in Rural Gabon. PLoS One 2016; 11:e0153899. [PMID: 27228058 PMCID: PMC4881998 DOI: 10.1371/journal.pone.0153899] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/05/2016] [Indexed: 11/29/2022] Open
Abstract
Control strategies implemented a decade ago led to a marked reduction in the prevalence of malaria in many countries. In Dienga, southeastern Gabon, the prevalence of microscopic P. falciparum infection was 7% in 2003, close to the pre-elimination threshold of 5%. The aim of this work was to determine the prevalence of P. falciparum infection in the same community a decade later. A cohort of 370 individuals aged from 3 to 85 years living in Dienga was investigated for P. falciparum infection; during six passages (P) in 15-month period. Demographic data were collected, along with behaviors and attitudes towards malaria. Plasmodium infection was diagnosed by microscopy (ME), followed by PCR to detect submicroscopic infection. The prevalence of P. falciparum infection in P1, P2, P3, P4, P5 and P6 was respectively 43.5% (25.1% ME+, 18.4% PCR+); 40.9% (27.0% ME+, 13.9% PCR+), 52.7% (26.1% ME+, 26.6% PCR+); 34.1% (14.1% ME+, 20% PCR+), 57.7% (25.4.% ME+, 32.3% PCR+); and 46.2% (21.4% ME+, 24.8% PCR+) with an overall average of 45.9% (95%CI [37.0–54.7], 23.2% ME+ and 22.7% PCR+). P4 and P5 prevalences were statically different throughout the six passages. Microscopic prevalence was significantly higher than that observed ten years ago (23% [n = 370] vs 7% [n = 323], p < 0.001). Asymptomatic infections were the most frequent (96%). Gametocytes were detected in levels ranging from 5.9% to 13.9%. Insecticide-treated nets, indoor residual insecticides, and self-medication were used by respectively 33.2% (95%CI [29.0–37.4]), 17.7% (95%CI [15.5–19.9]) and 12.1% (95%CI [10.6–13.6]) of the study population. A near-threefold increase in P. falciparum infection has been observed in a rural area of southeastern Gabon during a 10-year period. Most infections were asymptomatic, but these subjects likely represent a parasite reservoir. These findings call for urgent reinforcement of preventive measures.
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Affiliation(s)
- Irène Pegha Moukandja
- Centre International de Recherches Médicales de Franceville (CIRMF) B.P. 769 Franceville, Gabon
- Ecole Doctorale Régionale (EDR) en Infectiologie Tropicale, BP: 876 Franceville, Gabon
| | - Jean Claude Biteghe Bi Essone
- Centre International de Recherches Médicales de Franceville (CIRMF) B.P. 769 Franceville, Gabon
- Ecole Doctorale Régionale (EDR) en Infectiologie Tropicale, BP: 876 Franceville, Gabon
| | - Issaka Sagara
- Département d'Epidémiologie et des Affections Parasitaires, MRTC, Faculté de Médecine et d'Odontostomatologie, Université de Bamako, BP 1805 Bamako, Mali
| | | | - Julien Ondzaga
- Centre International de Recherches Médicales de Franceville (CIRMF) B.P. 769 Franceville, Gabon
| | - Jean-Bernard Lékana Douki
- Centre International de Recherches Médicales de Franceville (CIRMF) B.P. 769 Franceville, Gabon
- Ecole Doctorale Régionale (EDR) en Infectiologie Tropicale, BP: 876 Franceville, Gabon
- Département de Parasitologie-Mycologie Médecine Tropicale, Faculté de Médecine, Université des Sciences de la Santé, B.P. 4009 Libreville, Gabon
| | - Marielle Bouyou Akotet
- Département de Parasitologie-Mycologie Médecine Tropicale, Faculté de Médecine, Université des Sciences de la Santé, B.P. 4009 Libreville, Gabon
| | - Dieudonne Nkoghe Mba
- Centre International de Recherches Médicales de Franceville (CIRMF) B.P. 769 Franceville, Gabon
| | - Fousseyni S. Touré Ndouo
- Centre International de Recherches Médicales de Franceville (CIRMF) B.P. 769 Franceville, Gabon
- * E-mail:
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Nyawanda BO, Mott JA, Njuguna HN, Mayieka L, Khagayi S, Onkoba R, Makokha C, Otieno NA, Bigogo GM, Katz MA, Feikin DR, Verani JR. Evaluation of case definitions to detect respiratory syncytial virus infection in hospitalized children below 5 years in Rural Western Kenya, 2009-2013. BMC Infect Dis 2016; 16:218. [PMID: 27207342 PMCID: PMC4875667 DOI: 10.1186/s12879-016-1532-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 05/02/2016] [Indexed: 11/20/2022] Open
Abstract
Background In order to better understand respiratory syncytial virus (RSV) epidemiology and burden in tropical Africa, optimal case definitions for detection of RSV cases need to be identified. Methods We used data collected between September 2009 - August 2013 from children aged <5 years hospitalized with acute respiratory Illness at Siaya County Referral Hospital. We evaluated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of individual signs, symptoms and standard respiratory disease case definitions (severe acute respiratory illness [SARI]; hospitalized influenza-like illness [hILI]; integrated management of childhood illness [IMCI] pneumonia) to detect laboratory-confirmed RSV infection. We also evaluated an alternative case definition of cough or difficulty breathing plus hypoxia, in-drawing, or wheeze. Results Among 4714 children hospitalized with ARI, 3810 (81 %) were tested for RSV; and 470 (12 %) were positive. Among individual signs and symptoms, cough alone had the highest sensitivity to detect laboratory-confirmed RSV [96 %, 95 % CI (95–98)]. Hypoxia, wheezing, stridor, nasal flaring and chest wall in-drawing had sensitivities ranging from 8 to 31 %, but had specificities >75 %. Of the standard respiratory case definitions, SARI had the highest sensitivity [83 %, 95 % CI (79–86)] whereas IMCI severe pneumonia had the highest specificity [91 %, 95 % CI (90–92)]. The alternative case definition (cough or difficulty breathing plus hypoxia, in-drawing, or wheeze) had a sensitivity of [55 %, 95 % CI (50–59)] and a specificity of [60 %, 95 % CI (59–62)]. The PPV for all case definitions and individual signs/symptoms ranged from 11 to 20 % while the negative predictive values were >87 %. When we stratified by age <1 year and 1- < 5 years, difficulty breathing, severe pneumonia and the alternative case definition were more sensitive in children aged <1 year [70 % vs. 54 %, p < 0.01], [19 % vs. 11 %, p = 0.01] and [66 % vs. 43 %, p < 0.01] respectively, while non-severe pneumonia was more sensitive [14 % vs. 26 %, p < 0.01] among children aged 1- < 5 years. Conclusion The sensitivity and specificity of different commonly used case definitions for detecting laboratory-confirmed RSV cases varied widely, while the positive predictive value was consistently low. Optimal choice of case definition will depend upon study context and research objectives.
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Affiliation(s)
- Bryan O Nyawanda
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | - Joshua A Mott
- Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya.,Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Henry N Njuguna
- Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Lilian Mayieka
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Sammy Khagayi
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Reuben Onkoba
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Caroline Makokha
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Nancy A Otieno
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Godfrey M Bigogo
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Mark A Katz
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Daniel R Feikin
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jennifer R Verani
- Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya.,Centers for Disease Control and Prevention, Atlanta, GA, USA
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Gibson DG, Kagucia EW, Ochieng B, Hariharan N, Obor D, Moulton LH, Winch PJ, Levine OS, Odhiambo F, O'Brien KL, Feikin DR. The Mobile Solutions for Immunization (M-SIMU) Trial: A Protocol for a Cluster Randomized Controlled Trial That Assesses the Impact of Mobile Phone Delivered Reminders and Travel Subsidies to Improve Childhood Immunization Coverage Rates and Timeliness in Western Kenya. JMIR Res Protoc 2016; 5:e72. [PMID: 27189422 PMCID: PMC4887657 DOI: 10.2196/resprot.5030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 01/22/2016] [Accepted: 01/22/2016] [Indexed: 01/15/2023] Open
Abstract
Background Text message (short message service, SMS) reminders and incentives are two demand-side interventions that have been shown to improve health care–seeking behaviors by targeting participant characteristics such as forgetfulness, lack of knowledge, and transport costs. Applying these interventions to routine pediatric immunizations may improve vaccination coverage and timeliness. Objective The Mobile Solutions for Immunization (M-SIMU) trial aims to determine if text message reminders, either with or without mobile phone–based incentives, sent to infant’s parents can improve immunization coverage and timeliness of routine pediatric vaccines in rural western Kenya. Methods This is a four-arm, cluster, randomized controlled trial. Villages are randomized to one of four study arms prior to enrollment of participants. The study arms are: (1) no intervention (a general health-related text message will be texted to this group at the time of enrollment), (2) text message reminders only, (3) text message reminders and a 75 Kenyan Shilling (KES) incentive, or (4) text message reminders and a KES200 incentive. Participants assigned to study arms 2-4 will receive two text message reminders; sent 3 days before and one day before the scheduled immunization visit at 6, 10, and 14 weeks for polio and pentavalent (containing diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenza type b antigens) type b antigens) vaccines, and at 9 months for measles vaccine. Participants in incentive arms will, in addition to text message reminders as above, receive mobile phone–based incentives after each timely vaccination, where timely is defined as vaccination within 2 weeks of the scheduled date for each of the four routine expanded program immunization (EPI) vaccination visits. Mother-infant pairs will be followed to 12 months of age where the primary outcome, a fully immunized child, will be ascertained. A fully immunized child is defined as a child receiving vaccines for bacille Calmette-Guerin, three doses of pentavalent and polio, and measles by 12 months of age. General estimating equation (GEE) models that account for clustering will be employed for primary outcome analyses. Results Enrollment was completed in October 2014. Twelve month follow-up visits to ascertain immunization status from the maternal and child health booklet were completed in February 2016. Conclusions This is one of the first studies to examine the effect of text message reminders on immunization coverage and timeliness in a lower income country and is the first study to assess the effect of mobile money-based incentives to improve immunization coverage. Trial Registration Clinicaltrials.gov NCT01878435; https://clinicaltrials.gov/ct2/show/NCT01878435 (Archived by WebCite at http://www.webcitation.org/6hQlwGYJR)
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Affiliation(s)
- Dustin G Gibson
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.
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Genetic diversity of Plasmodium falciparum parasite by microsatellite markers after scale-up of insecticide-treated bed nets in western Kenya. Malar J 2015; 13 Suppl 1:495. [PMID: 26651480 PMCID: PMC4675068 DOI: 10.1186/s12936-015-1003-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 11/19/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND An initial study of genetic diversity of Plasmodium falciparum in Asembo, western Kenya showed that the parasite maintained overall genetic stability 5 years after insecticide-treated bed net (ITN) introduction in 1997. This study investigates further the genetic diversity of P. falciparum 10 years after initial ITN introduction in the same study area and compares this with two other neighbouring areas, where ITNs were introduced in 1998 (Gem) and 2004 (Karemo). METHODS From a cross-sectional survey conducted in 2007, 235 smear-positive blood samples collected from children ≤15-year-old in the original study area and two comparison areas were genotyped employing eight neutral microsatellites. Differences in multiple infections, allele frequency, parasite genetic diversity and parasite population structure between the three areas were assessed. Further, molecular data reported previously (1996 and 2001) were compared to the 2007 results in the original study area Asembo. RESULTS Overall proportion of multiple infections (MA) declined with time in the original study area Asembo (from 95.9 %-2001 to 87.7 %-2007). In the neighbouring areas, MA was lower in the site where ITNs were introduced in 1998 (Gem 83.7 %) compared to where they were introduced in 2004 (Karemo 96.7 %) in 2007. Overall mean allele count (MAC ~ 2.65) and overall unbiased heterozygosity (H e ~ 0.77) remained unchanged in 1996, 2001 and 2007 in Asembo and was the same level across the two neighbouring areas in 2007. Overall parasite population differentiation remained low over time and in the three areas at FST < 0.04. Both pairwise and multilocus linkage disequilibrium showed limited to no significant association between alleles in Asembo (1996, 2001 and 2007) and between three areas. CONCLUSIONS This study showed the P. falciparum high genetic diversity and parasite population resilience on samples collected 10 years apart and in different areas in western Kenya. The results highlight the need for long-term molecular monitoring after implementation and use of combined and intensive prevention and intervention measures in the region.
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Obala AA, Mangeni JN, Platt A, Aswa D, Abel L, Namae J, Prudhomme O'Meara W. What Is Threatening the Effectiveness of Insecticide-Treated Bednets? A Case-Control Study of Environmental, Behavioral, and Physical Factors Associated with Prevention Failure. PLoS One 2015; 10:e0132778. [PMID: 26171962 PMCID: PMC4501815 DOI: 10.1371/journal.pone.0132778] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 06/19/2015] [Indexed: 11/24/2022] Open
Abstract
Background Insecticide-treated nets are the cornerstone of global malaria control and have been shown to reduce malaria morbidity by 50–60%. However, some areas are experiencing a resurgence in malaria following successful control. We describe an efficacy decay framework to understand why high malaria burden persists even under high ITN coverage in a community in western Kenya. Methods We enrolled 442 children hospitalized with malaria and paired them with age, time, village and gender-matched controls. We completed comprehensive household and neighborhood assessments including entomological surveillance. The indicators are grouped into five domains in an efficacy decay framework: ITN ownership, compliance, physical integrity, vector susceptibility and facilitating factors. After variable selection, case-control data were analyzed using conditional logistic regression models and mosquito data were analyzed using negative binomial regression. Predictive margins were calculated from logistic regression models. Results Measures of ITN coverage and physical integrity were not correlated with hospitalized malaria in our study. However, consistent ITN use (Adjusted Odds Ratio (AOR) = 0.23, 95%CI: 0.12–0.43), presence of nearby larval sites (AOR = 1.137, 95%CI: 1.02–1.27), and specific types of crops (AOR (grains) = 0.446, 95%CI: 0.24–0.82) were significantly correlated with malaria amongst children who owned an ITN. The odds of hospitalization for febrile malaria nearly tripled when one other household member had symptomatic malaria infection (AOR–2.76, 95%CI:1.83–4.18). Overall, perfect household adherence could reduce the probability of hospitalization for malaria to less than 30% (95%CI:0.12–0.46) and adjusting environmental factors such as elimination of larval sites and growing grains nearby could reduce the probability of hospitalization for malaria to less than 20% (95%CI:0.04–0.31). Conclusion Availability of ITNs is not the bottleneck for malaria prevention in this community. Behavior change interventions to improve compliance and environmental management of mosquito breeding habitats may greatly enhance ITN efficacy. A better understanding of the relationship between agriculture and mosquito survival and feeding success is needed.
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Affiliation(s)
| | | | - Alyssa Platt
- Duke Global Health Institute, Durham, North Carolina, United States of America
| | - Daniel Aswa
- Academic Model Providing Access to Healthcare, Eldoret, Kenya
| | - Lucy Abel
- Academic Model Providing Access to Healthcare, Eldoret, Kenya
| | - Jane Namae
- Webuye Health and Demographic Surveillance System, Moi University, Eldoret, Kenya
| | - Wendy Prudhomme O'Meara
- College of Health Sciences, Moi University, Eldoret, Kenya
- Duke Global Health Institute, Durham, North Carolina, United States of America
- Department of Medicine, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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The implication of long-lasting insecticide-treated net use in the resurgence of malaria morbidity in a Senegal malaria endemic village in 2010-2011. Parasit Vectors 2015; 8:267. [PMID: 25963402 PMCID: PMC4489109 DOI: 10.1186/s13071-015-0871-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 04/23/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although the burden of malaria has significantly declined in recent years in sub-Saharan Africa through the widespread use of long-lasting insecticide treated bed-nets (LLINs) and artemisinin-based combination therapy, resurgence of malaria is observed in some settings after several years of LLINs use. This study aimed to assess if LLINs use remains protective against malaria during a period of resurgence of malaria morbidity in Dielmo, a rural village of Senegal. METHODS In July 2008, LLINs were offered to all villagers and lately in July 2011, LLINs were renewed. A longitudinal study was conducted between July, 2010 and December, 2011 among inhabitants of the village of Dielmo to identify all episodes of fever. Thick smears stained with Giemsa were done for every febrile villager and malaria attacks were treated with combination of Artesunate plus Amodiaquine. Cross-sectional surveys were also conducted at the end of the rainy season (October 2010 and November 2011) to assess asymptomatic carriage. A survey on LLINs use was done every quarter of the year. A random-effect logistic regression was used to assess the effect of LLINs use on the risk of having a malaria attack after adjusting for the main risk factors. RESULTS The study population included 449 individuals corresponding to a total of 2140 observations. One hundred and fifteen (115) clinical malaria attacks attributed to P. falciparum (cases) have been recorded over the study period. Most of the malaria cases occurred in October-December 2010 (49/115 i.e. 43%) and among adults aged 15 years and over (50/115, i.e. 43%). During the study period, the use of LLINs was 61% among non-malaria cases and only 42% among malaria clinical cases but differenced according to age group. After adjusting on gender, age, rainfall and LLINs replacement, we found that LLINs use (AOR [95%CI] = 0.40 [0.25; 0.62], p < 0.001) remained a protective factor against malaria attacks during the study period. CONCLUSION LLINs use remains effective to reduce malaria burden. These results highlight the need to pursue LLINs implementation in the current context of malaria elimination and to provide positive incentives to increase its use in the population.
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Abstract
Over 90% of the world's severe and fatal Plasmodium falciparum malaria is estimated to affect young children in sub-Sahara Africa, where it remains a common cause of hospital admission and inpatient mortality. Few children will ever be managed on high dependency or intensive care units and, therefore, rely on simple supportive treatments and parenteral anti-malarials. There has been some progress on defining best practice for antimalarial treatment with the publication of the AQUAMAT trial in 2010, involving 5,425 children at 11 centres across 9 African countries, showing that in artesunate-treated children, the relative risk of death was 22.5% (95% confidence interval (CI) 8.1 to 36.9) lower than in those receiving quinine. Human trials of supportive therapies carried out on the basis of pathophysiology studies, have so far made little progress on reducing mortality; despite appearing to reduce morbidity endpoints, more often than not they have led to an excess of adverse outcomes. This review highlights the spectrum of complications in African children with severe malaria, the therapeutic challenges of managing these in resource-poor settings and examines in-depth the results from clinical trials with a view to identifying the treatment priorities and a future research agenda.
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Shah M, Omosun Y, Lal A, Odero C, Gatei W, Otieno K, Gimnig JE, ter Kuile F, Hawley WA, Nahlen B, Kariuki S, Walker E, Slutsker L, Hamel M, Shi YP. Assessment of molecular markers for anti-malarial drug resistance after the introduction and scale-up of malaria control interventions in western Kenya. Malar J 2015; 14:75. [PMID: 25889220 PMCID: PMC4331436 DOI: 10.1186/s12936-015-0588-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/27/2015] [Indexed: 12/29/2022] Open
Abstract
Background Although it is well known that drug pressure selects for drug-resistant parasites, the role of transmission reduction by insecticide-treated bed nets (ITNs) on drug resistance remains unclear. In this study, the drug resistance profile of current and previous first-line anti-malarials in Kenya was assessed within the context of drug policy change and scale-up of ITNs. National first-line treatment changed from chloroquine (CQ) to sulphadoxine-pyrimethamine (SP) in 1998 and to artemether-lumefantrine (AL) in 2004. ITN use was scaled-up in the Asembo, Gem and Karemo areas of western Kenya in 1997, 1999 and 2006, respectively. Methods Smear-positive samples (N = 253) collected from a 2007 cross-sectional survey among children in Asembo, Gem and Karemo were genotyped for mutations in pfcrt and pfmdr1 (CQ), dhfr and dhps (SP), and at pfmdr-N86 and the gene copy number in pfmdr1 (lumefantrine). Results were compared among the three geographic areas in 2007 and to retrospective molecular data from children in Asembo in 2001. Results In 2007, 69 and 85% of samples harboured the pfmdr1-86Y mutation and dhfr/dhps quintuple mutant, respectively, with no significant differences by study area. However, the prevalence of the pfcrt-76T mutation differed significantly among areas (p <0.02), between 76 and 94%, with the highest prevalence in Asembo. Several 2007 samples carried mutations at dhfr-164L, dhps-436A, or dhps-613T. From 2001 to 2007, there were significant increases in the pfcrt-76T mutation from 82 to 94% (p <0.03), dhfr/dhps quintuple mutant from 62 to 82% (p <0.03), and an increase in the septuple CQ and SP combined mutant haplotype, K76Y86I51R59N108G437E540, from 28 to 39%. The prevalence of the pfmdr1-86Y mutation remained unchanged. All samples were single copy for pfmdr1. Conclusions Molecular markers associated with lumefantrine resistance were not detected in 2007. More recent samples will be needed to detect any selective effects by AL. The prevalence of CQ and SP resistance markers increased from 2001 to 2007 in the absence of changes in transmission intensity. In 2007, only the prevalence of pfcrt-76T mutation differed among study areas of varying transmission intensity. Resistant parasites were most likely selected by sustained drug pressure from the continued use of CQ, SP, and mechanistically similar drugs, such as amodiaquine and cotrimoxazole. There was no clear evidence that differences in transmission intensity, as a result of ITN scale-up, influenced the prevalence of drug resistance molecular markers. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0588-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Monica Shah
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA. .,Atlanta Research and Education Foundation, Atlanta, GA, USA.
| | - Yusuf Omosun
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA. .,Atlanta Research and Education Foundation, Atlanta, GA, USA.
| | - Ashima Lal
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA. .,Atlanta Research and Education Foundation, Atlanta, GA, USA.
| | - Christopher Odero
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | - Wangeci Gatei
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Kephas Otieno
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | - John E Gimnig
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | | | - William A Hawley
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA. .,UNICEF, Child Survival and Development Cluster, Jakarta, Indonesia.
| | | | - Simon Kariuki
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | | | - Laurence Slutsker
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Mary Hamel
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA. .,Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | - Ya Ping Shi
- Malaria Branch and Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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The association of weather variability and under five malaria mortality in KEMRI/CDC HDSS in Western Kenya 2003 to 2008: a time series analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:1983-97. [PMID: 25674784 PMCID: PMC4344705 DOI: 10.3390/ijerph120201983] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/30/2015] [Indexed: 11/17/2022]
Abstract
Malaria is among the leading causes of mortality in the younger under-five group of children zero to four years of age. This study aims at describing the relationship between rainfall and temperature on under-five malaria or anaemia mortality in Kenya Medical Research Institute and United States Centers for Disease Control (KEMRI/CDC) Health and Demographic Surveillance System (HDSS). This study was conducted through the ongoing KEMRI and CDC collaboration. A general additive model with a Poisson link function was fit to model the weekly association of lagged cumulative rainfall and average temperature on malaria/anemia mortality in KEMRI/CDC HDSS for the period 2003 to 2008. A trend function was included in the model to control for time trends and seasonality not explained by weather fluctuations. 95% confidence intervals was presented with estimates. Malaria or anemia mortality was found to be associated with changes in temperature and rainfall in the KEMRI HDSS, with a delay up to 16 weeks. The empirical estimates of associations describe established biological relationships well. This information, and particularly, the strength of the relationships over longer lead times can highlight the possibility of developing a predictive forecast with lead times up to 16 weeks in order to enhance preparedness to high transmission episodes.
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Shretta R, Johnson B, Smith L, Doumbia S, de Savigny D, Anupindi R, Yadav P. Costing the supply chain for delivery of ACT and RDTs in the public sector in Benin and Kenya. Malar J 2015; 14:57. [PMID: 25652315 PMCID: PMC4341244 DOI: 10.1186/s12936-014-0530-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 12/21/2014] [Indexed: 11/10/2022] Open
Abstract
Background Studies have shown that supply chain costs are a significant proportion of total programme costs. Nevertheless, the costs of delivering specific products are poorly understood and ballpark estimates are often used to inadequately plan for the budgetary implications of supply chain expenses. The purpose of this research was to estimate the country level costs of the public sector supply chain for artemisinin-based combination therapy (ACT) and rapid diagnostic tests (RDTs) from the central to the peripheral levels in Benin and Kenya. Methods A micro-costing approach was used and primary data on the various cost components of the supply chain was collected at the central, intermediate, and facility levels between September and November 2013. Information sources included central warehouse databases, health facility records, transport schedules, and expenditure reports. Data from document reviews and semi-structured interviews were used to identify cost inputs and estimate actual costs. Sampling was purposive to isolate key variables of interest. Survey guides were developed and administered electronically. Data were extracted into Microsoft Excel®, and the supply chain cost per unit of ACT and RDT distributed by function and level of system was calculated. Results In Benin, supply chain costs added USD 0.2011 to the initial acquisition cost of ACT and USD 0.3375 to RDTs (normalized to USD 1). In Kenya, they added USD 0.2443 to the acquisition cost of ACT and USD 0.1895 to RDTs (normalized to USD 1). Total supply chain costs accounted for more than 30% of the initial acquisition cost of the products in some cases and these costs were highly sensitive to product volumes. The major cost drivers were found to be labour, transport, and utilities with health facilities carrying the majority of the cost per unit of product. Conclusions Accurate cost estimates are needed to ensure adequate resources are available for supply chain activities. Product volumes should be considered when costing supply chain functions rather than dollar value. Further work is needed to develop extrapolative costing models that can be applied at country level without extensive micro-costing exercises. This will allow other countries to generate more accurate estimates in the future. Electronic supplementary material The online version of this article (doi:10.1186/s12936-014-0530-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rima Shretta
- Systems for Improved Access to Pharmaceuticals and Services (SIAPS), Management Sciences for Health (MSH), 4301 North Fairfax Drive, Suite 400, Arlington, VA, 22203, USA. .,Global Health Group, University of California, San Francisco, 550 16th Street, 3rd Floor, San Francisco, CA, 94158, USA. .,Swiss Tropical and Public Health Institute, Socinstrasse 57, PO Box 4002, Basel, Switzerland. .,University of Basel, Petersplatz 1, 4001, Basel, Switzerland.
| | - Brittany Johnson
- William Davidson Institute (WDI), University of Michigan, 724 East University Avenue, Ann Arbor, MI, 48109, USA.
| | - Lisa Smith
- William Davidson Institute (WDI), University of Michigan, 724 East University Avenue, Ann Arbor, MI, 48109, USA.
| | - Seydou Doumbia
- Systems for Improved Access to Pharmaceuticals and Services (SIAPS), Management Sciences for Health (MSH), 4301 North Fairfax Drive, Suite 400, Arlington, VA, 22203, USA.
| | - Don de Savigny
- Swiss Tropical and Public Health Institute, Socinstrasse 57, PO Box 4002, Basel, Switzerland. .,University of Basel, Petersplatz 1, 4001, Basel, Switzerland.
| | - Ravi Anupindi
- Ross School of Business, University of Michigan, 701 Tappan Street, Ann Arbor, MI, 48109, USA.
| | - Prashant Yadav
- William Davidson Institute (WDI), University of Michigan, 724 East University Avenue, Ann Arbor, MI, 48109, USA. .,Ross School of Business, University of Michigan, 701 Tappan Street, Ann Arbor, MI, 48109, USA. .,School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA.
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Global malaria eradication and the importance of Plasmodium falciparum epidemiology in Africa. BMC Med 2015; 13:23. [PMID: 25644195 PMCID: PMC4314741 DOI: 10.1186/s12916-014-0254-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 12/11/2014] [Indexed: 11/20/2022] Open
Abstract
The global agenda for malaria has, once again, embraced the possibility of eradication. As history has shown, there will be no single magic bullet that can be applied to every epidemiological setting. Africa has a diverse malaria ecology, lending itself to some of the highest disease burden areas of the world and a wide range of clinical epidemiological patterns making control with our current tools challenging. This commentary highlights why the epidemiology of Plasmodium falciparum malaria in Africa should not be forgotten when planning an eradication strategy, and why forgetting Africa will, once again, be the single largest threat to any hope for global eradication.
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Phillips-Howard PA, Laserson KF, Amek N, Beynon CM, Angell SY, Khagayi S, Byass P, Hamel MJ, van Eijk AM, Zielinski-Gutierrez E, Slutsker L, De Cock KM, Vulule J, Odhiambo FO. Deaths ascribed to non-communicable diseases among rural Kenyan adults are proportionately increasing: evidence from a health and demographic surveillance system, 2003-2010. PLoS One 2014; 9:e114010. [PMID: 25426945 PMCID: PMC4245262 DOI: 10.1371/journal.pone.0114010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 10/31/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Non-communicable diseases (NCDs) result in more deaths globally than other causes. Monitoring systems require strengthening to attribute the NCD burden and deaths in low and middle-income countries (LMICs). Data from health and demographic surveillance systems (HDSS) can contribute towards this goal. METHODS AND FINDINGS Between 2003 and 2010, 15,228 deaths in adults aged 15 years (y) and older were identified retrospectively using the HDSS census and verbal autopsy in rural western Kenya, attributed into broad categories using InterVA-4 computer algorithms; 37% were ascribed to NCDs, 60% to communicable diseases (CDs), 3% to injuries, and <1% maternal causes. Median age at death for NCDs was 66y and 71y for females and males, respectively, with 43% (39% male, 48% female) of NCD deaths occurring prematurely among adults aged below 65y. NCD deaths were mainly attributed to cancers (35%) and cardio-vascular diseases (CVDs; 29%). The proportionate mortality from NCDs rose from 35% in 2003 to 45% in 2010 (χ2 linear trend 93.4; p<0.001). While overall annual mortality rates (MRs) for NCDs fell, cancer-specific MRs rose from 200 to 262 per 100,000 population, mainly due to increasing deaths in adults aged 65y and older, and to respiratory neoplasms in all age groups. The substantial fall in CD MRs resulted in similar MRs for CDs and NCDs among all adult females by 2010. NCD MRs for adults aged 15y to <65y fell from 409 to 183 per 100,000 among females and from 517 to 283 per 100,000 population among males. NCD MRs were higher among males than females aged both below, and at or above, 65y. CONCLUSIONS NCDs constitute a significant proportion of deaths in rural western Kenya. Evidence of the increasing contribution of NCDs to overall mortality supports international recommendations to introduce or enhance prevention, screening, diagnosis and treatment programmes in LMICs.
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Affiliation(s)
- Penelope A. Phillips-Howard
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Kayla F. Laserson
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Nyaguara Amek
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Caryl M. Beynon
- Center for Public Health, Liverpool John Moores University, Liverpool, United Kingdom
| | - Sonia Y. Angell
- Department of Non-Communicable Diseases, Division of Global Health Protection, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Sammy Khagayi
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Peter Byass
- Umeå Centre for Global Health Research, Umeå University, Umeå, Sweden
| | - Mary J. Hamel
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Anne M. van Eijk
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Emily Zielinski-Gutierrez
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- Division of Global HIV and AIDS, Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Laurence Slutsker
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Kevin M. De Cock
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
- Center for Global Health, Centers for Disease Control and Prevention-Kenya, Nairobi, Kenya
| | - John Vulule
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Frank O. Odhiambo
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
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Wong J, Hamel MJ, Drakeley CJ, Kariuki S, Shi YP, Lal AA, Nahlen BL, Bloland PB, Lindblade KA, Were V, Otieno K, Otieno P, Odero C, Slutsker L, Vulule JM, Gimnig JE. Serological markers for monitoring historical changes in malaria transmission intensity in a highly endemic region of Western Kenya, 1994-2009. Malar J 2014; 13:451. [PMID: 25416454 PMCID: PMC4258276 DOI: 10.1186/1475-2875-13-451] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 11/11/2014] [Indexed: 11/25/2022] Open
Abstract
Background Monitoring local malaria transmission intensity is essential for planning evidence-based control strategies and evaluating their impact over time. Anti-malarial antibodies provide information on cumulative exposure and have proven useful, in areas where transmission has dropped to low sustained levels, for retrospectively reconstructing the timing and magnitude of transmission reduction. It is unclear whether serological markers are also informative in high transmission settings, where interventions may reduce transmission, but to a level where considerable exposure continues. Methods This study was conducted through ongoing KEMRI and CDC collaboration. Asembo, in Western Kenya, is an area where intense malaria transmission was drastically reduced during a 1997–1999 community-randomized, controlled insecticide-treated net (ITN) trial. Two approaches were taken to reconstruct malaria transmission history during the period from 1994 to 2009. First, point measurements were calculated for seroprevalence, mean antibody titre, and seroconversion rate (SCR) against three Plasmodium falciparum antigens (AMA-1, MSP-119, and CSP) at five time points for comparison against traditional malaria indices (parasite prevalence and entomological inoculation rate). Second, within individual post-ITN years, age-stratified seroprevalence data were analysed retrospectively for an abrupt drop in SCR by fitting alternative reversible catalytic conversion models that allowed for change in SCR. Results Generally, point measurements of seroprevalence, antibody titres and SCR produced consistent patterns indicating that a gradual but substantial drop in malaria transmission (46-70%) occurred from 1994 to 2007, followed by a marginal increase beginning in 2008 or 2009. In particular, proportionate changes in seroprevalence and SCR point estimates (relative to 1994 baseline values) for AMA-1 and CSP, but not MSP-119, correlated closely with trends in parasite prevalence throughout the entire 15-year study period. However, retrospective analyses using datasets from 2007, 2008 and 2009 failed to detect any abrupt drop in transmission coinciding with the timing of the 1997–1999 ITN trial. Conclusions In this highly endemic area, serological markers were useful for generating accurate point estimates of malaria transmission intensity, but not for retrospective analysis of historical changes. Further investigation, including exploration of different malaria antigens and/or alternative models of population seroconversion, may yield serological tools that are more informative in high transmission settings. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-13-451) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jacklyn Wong
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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Amek NO, Odhiambo FO, Khagayi S, Moige H, Orwa G, Hamel MJ, Van Eijk A, Vulule J, Slutsker L, Laserson KF. Childhood cause-specific mortality in rural Western Kenya: application of the InterVA-4 model. Glob Health Action 2014; 7:25581. [PMID: 25377340 PMCID: PMC4221497 DOI: 10.3402/gha.v7.25581] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 08/22/2014] [Accepted: 08/26/2014] [Indexed: 11/23/2022] Open
Abstract
Background Assessing the progress in achieving the United Nation's Millennium Development Goals in terms of population health requires consistent and reliable information on cause-specific mortality, which is often rare in resource-constrained countries. Health and demographic surveillance systems (HDSS) have largely used medical personnel to review and assign likely causes of death based on the information gathered from standardized verbal autopsy (VA) forms. However, this approach is expensive and time consuming, and it may lead to biased results based on the knowledge and experience of individual clinicians. We assessed the cause-specific mortality for children under 5 years old (under-5 deaths) in Siaya County, obtained from a computer-based probabilistic model (InterVA-4). Design Successfully completed VA interviews for under-5 deaths conducted between January 2003 and December 2010 in the Kenya Medical Research Institute/US Centers for Disease Control and Prevention HDSS were extracted from the VA database and processed using the InterVA-4 (version 4.02) model for interpretation. Cause-specific mortality fractions were then generated from the causes of death produced by the model. Results A total of 84.33% (6,621) childhood deaths had completed VA data during the study period. Children aged 1–4 years constituted 48.53% of all cases, and 42.50% were from infants. A single cause of death was assigned to 89.18% (5,940) of cases, 8.35% (556) of cases were assigned two causes, and 2.10% (140) were assigned ‘indeterminate’ as cause of death by the InterVA-4 model. Overall, malaria (28.20%) was the leading cause of death, followed by acute respiratory infection including pneumonia (25.10%), in under-5 children over the study period. But in the first 5 years of the study period, acute respiratory infection including pneumonia was the main cause of death, followed by malaria. Similar trends were also reported in infants (29 days–11 months) and children aged 1–4 years. Conclusions Under-5 cause-specific mortality obtained using the InterVA-4 model is consistent with existing knowledge on the burden of childhood diseases in rural western Kenya.
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Affiliation(s)
- Nyaguara O Amek
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;
| | - Frank O Odhiambo
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Sammy Khagayi
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Hellen Moige
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Gordon Orwa
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Mary J Hamel
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Annemieke Van Eijk
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Vulule
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Laurence Slutsker
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Kayla F Laserson
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya; Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Ndila C, Bauni E, Mochamah G, Nyirongo V, Makazi A, Kosgei P, Tsofa B, Nyutu G, Etyang A, Byass P, Williams TN. Causes of death among persons of all ages within the Kilifi Health and Demographic Surveillance System, Kenya, determined from verbal autopsies interpreted using the InterVA-4 model. Glob Health Action 2014; 7:25593. [PMID: 25377342 PMCID: PMC4220144 DOI: 10.3402/gha.v7.25593] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 01/18/2023] Open
Abstract
Background The vast majority of deaths in the Kilifi study area are not recorded through official systems of vital registration. As a result, few data are available regarding causes of death in this population. Objective To describe the causes of death (CODs) among residents of all ages within the Kilifi Health and Demographic Surveillance System (KHDSS) on the coast of Kenya. Design Verbal autopsies (VAs) were conducted using the 2007 World Health Organization (WHO) standard VA questionnaires, and VA data further transformed to align with the 2012 WHO VA instrument. CODs were then determined using the InterVA-4 computer-based probabilistic model. Results Five thousand one hundred and eighty seven deaths were recorded between January 2008 and December 2011. VA interviews were completed for 4,460 (86%) deaths. Neonatal pneumonia and birth asphyxia were the main CODs in neonates; pneumonia and malaria were the main CODs among infants and children aged 1–4, respectively, while HIV/AIDS was the main COD for adult women of reproductive age. Road traffic accidents were more commonly observed among men than women. Stroke and neoplasms were common CODs among the elderly over the age of 65. Conclusions We have established the main CODs among people of all ages within the area served by the KHDSS on the coast of Kenya using the 2007 WHO VA questionnaire coded using InterVA-4. We hope that our data will allow local health planners to estimate the burden of various diseases and to allocate their limited resources more appropriately.
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Affiliation(s)
- Carolyne Ndila
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; INDEPTH Network of Demographic Surveillance Sites, Accra, Ghana;
| | - Evasius Bauni
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; INDEPTH Network of Demographic Surveillance Sites, Accra, Ghana
| | - George Mochamah
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; INDEPTH Network of Demographic Surveillance Sites, Accra, Ghana
| | | | - Alex Makazi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Gideon Nyutu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; INDEPTH Network of Demographic Surveillance Sites, Accra, Ghana
| | | | - Peter Byass
- Umeå Centre for Global Health Research, Department of Public Health and Clinical Medicine, Umea University, Umeå, Sweden
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; INDEPTH Network of Demographic Surveillance Sites, Accra, Ghana; Department of Medicine, Imperial College, London, UK
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