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Powell-Romero F, Wells K, Clark NJ. A systematic review and guide for using multi-response statistical models in co-infection research. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231589. [PMID: 39371046 PMCID: PMC11451405 DOI: 10.1098/rsos.231589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 05/17/2024] [Accepted: 08/05/2024] [Indexed: 10/08/2024]
Abstract
The simultaneous infection of organisms with two or more co-occurring pathogens, otherwise known as co-infections, concomitant infections or multiple infections, plays a significant role in the dynamics and consequences of infectious diseases in both humans and animals. To understand co-infections, ecologists and epidemiologists rely on models capable of accommodating multiple response variables. However, given the diversity of available approaches, choosing a model that is suitable for drawing meaningful conclusions from observational data is not a straightforward task. To provide clearer guidance for statistical model use in co-infection research, we conducted a systematic review to (i) understand the breadth of study goals and host-pathogen systems being pursued with multi-response models and (ii) determine the degree of crossover of knowledge among disciplines. In total, we identified 69 peer-reviewed primary studies that jointly measured infection patterns with two or more pathogens of humans or animals in natural environments. We found stark divisions in research objectives and methods among different disciplines, suggesting that cross-disciplinary insights into co-infection patterns and processes for different human and animal contexts are currently limited. Citation network analysis also revealed limited knowledge exchange between ecology and epidemiology. These findings collectively highlight the need for greater interdisciplinary collaboration for improving disease management.
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Affiliation(s)
- Francisca Powell-Romero
- School of Veterinary Science, The University of Queensland, 5391 Warrego Hwy, Gatton, Queensland4343, Australia
| | - Konstans Wells
- Department of Biosciences, Swansea University, Singleton Park, SwanseaSA2 8PP, UK
| | - Nicholas J. Clark
- School of Veterinary Science, The University of Queensland, 5391 Warrego Hwy, Gatton, Queensland4343, Australia
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Halle S, Hirshberg O, Manzi F, Wolinska J, Ben-Ami F. Coinfection frequency in water flea populations is a mere reflection of parasite diversity. Commun Biol 2024; 7:559. [PMID: 38734859 PMCID: PMC11088698 DOI: 10.1038/s42003-024-06176-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/10/2024] [Indexed: 05/13/2024] Open
Abstract
In nature, parasite species often coinfect the same host. Yet, it is not clear what drives the natural dynamics of coinfection prevalence. The prevalence of coinfections might be affected by interactions among coinfecting species, or simply derive from parasite diversity. Identifying the relative impact of these parameters is crucial for understanding patterns of coinfections. We studied the occurrence and likelihood of coinfections in natural populations of water fleas (Daphnia magna). Coinfection prevalence was within the bounds expected by chance and parasite diversity had a strong positive effect on the likelihood of coinfections. Additionally, coinfection prevalence increased over the season and became as common as a single infection. Our results demonstrate how patterns of coinfection, and particularly their temporal variation, are affected by overlapping epidemics of different parasites. We suggest that monitoring parasite diversity can help predict where and when coinfection prevalence will be high, potentially leading to increased health risks to their hosts.
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Affiliation(s)
- Snir Halle
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel.
| | - Ofir Hirshberg
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Florent Manzi
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - Justyna Wolinska
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
- Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
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Hamidu BA, Tettevi EJ, Larbi JA, Idun BK, Asuming-Brempong EK, Osei-Atweneboana MY. The effectiveness of albendazole against hookworm infections and the impact of bi-annual treatment on anaemia and body mass index of school children in the Kpandai district of northern Ghana. PLoS One 2024; 19:e0294977. [PMID: 38427660 PMCID: PMC10906822 DOI: 10.1371/journal.pone.0294977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/14/2023] [Indexed: 03/03/2024] Open
Abstract
The impact of the Global Programme to Eliminate Lymphatic Filariasis (GPELF) (initiated in 2000 in Ghana and ran for 12 years) in mitigating soil-transmitted helminth (STH) infections in LF-endemic areas is unknown. During a 1-year hiatus which ensued between 2011 and 2012, a longitudinal study was conducted to determine GPELF effect on hookworm infections in selected communities involved in the programme since its inception, while measuring the effectiveness of biannual ALB treatments on schoolchildren living in such communities. A total of 399 school children aged 3 to 18 years were randomly selected from four communities in the Kpandai district of northern Ghana. Each presented a single stool sample at baseline, 21 days post-treatment, at the 3rd and 6th months, 21 days post-second intervention (i.e. following sample collection and treatment with ALB in the 6th month), and in the ninth month of the study period. Haemoglobin (hb) levels were also measured at all time points using finger prick blood samples and a URIT digital test kit. Each participant submitting a sample, was treated with a single-dose ALB (400mg) at baseline and in the sixth month. Stool samples were processed by preparing duplicate Kato-Katz slides per sample, and examined by microscopy. The Body Mass Index-for-age z-scores (BAZ) of participants were assessed following the determination of BMIs at each time point by measuring their height and weight with a stadiometer and weighing scale. Overall hookworm prevalences were 25.68% (95% CI = 20.51-31.75) at baseline, 11.18% (95% CI = 7.87-15.41) 21 days post-treatment, 11.78% (95% CI = 8.38-16.11) and 6.95% (95% CI = 4.41-10.43) in the 3rd and 6th months, 0.91% (95% CI = 0.19-2.65) 21 days post-second intervention, and 8.46% (95% CI = 5.62-12.23) in the ninth month. Observed overall faecal egg count reduction rates (ERRs) were 94.21% (95% CI = 81.50%- 100.00%) 21 days after baseline treatment, 97.70% (95% CI = 85.08-100.00) and 96.95% (95% CI = 84.18%- 100.00%) in the 3rd and 6th months, 99.98% (95% CI = 86.42%- 100.00%) 21 days post-second intervention, and 17.18% (95% CI = 14.07%- 20.67%) in the 9th month. Respective cure rates (CRs) were 62.35% (95% CI = 46.71-81.56%), 85.88% (95% CI = 67.32-100.00%), 87.06% (95% CI = 68.36%- 100.00%), 98.82% (95% CI = 78.83%- 100.00%), and 36.36% (95% CI = 9.91%- 93.11%). Additionally, increases in the percent frequency of 'normal hb' (p < 0.01) were observed across the study time points, whilst 'normal BAZ' cases remained high (from 94.87% to 98.87%) throughout the study period. These findings primarily indicate satisfactory effectiveness of ALB which may be maintainable in mass drug administration programmes by the modification of treatment strategies from annual to bi-annual regimes. This could minimize the likelihood of emerging poorly-responding hookworm phenotypes in Ghana. Additionally, a positive impact of bi-annual treatment on participant anaemia status is herein indicated with particular regard to the school children in our cohort.
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Affiliation(s)
- Buhari A Hamidu
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Accra, Ghana
| | - Edward J Tettevi
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Accra, Ghana
| | - John A Larbi
- Department of Theoretical and Applied Biology, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Bright K Idun
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Accra, Ghana
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Appiah-Twum F, Akorli J, Okyere L, Sagoe K, Osabutey D, Cappello M, Wilson MD. The effect of single dose albendazole (400 mg) treatment on the human gut microbiome of hookworm-infected Ghanaian individuals. Sci Rep 2023; 13:11302. [PMID: 37438457 PMCID: PMC10338455 DOI: 10.1038/s41598-023-38376-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 07/07/2023] [Indexed: 07/14/2023] Open
Abstract
Microbes play a key role in human gut homeostasis, metabolic, immunologic and physiopathology of the body. A longitudinal study conducted during 2018-2021 in the Kintampo North Municipality in Ghana demonstrated low hookworm infection cure rates following treatment with a single dose of 400 mg albendazole in some communities. To investigate associations between hookworm infection and the gut microbiome, we examined stool samples from consented participants who were either cured or remained infected after treatment. At each time point, stool was collected prior to and 10-14 days after albendazole treatment. We used 16S rRNA amplicon sequencing of DNA extracted from stool samples to investigate the composition and diversity of the gut microbiota and to identify potential microbial biomarkers associated with treatment outcomes. Hookworm infection was associated with increased species richness (p = 0.0093). Among treated individuals, there was also a significant variation in microbiota composition at 10-14 days following single-dose albendazole treatment. Individuals cured of hookworm infection after treatment showed a significant reduction in microbiota composition when compared to their pre-treatment state (ANOSIM; p = 0.02), whilst individuals who failed to clear the infection showed no change in microbiota composition (ANOSIM; p = 0.35). Uninfected individuals and those who were successfully treated were similar in their microbial composition and structure. We also found that the abundance of Clostridia spp. was increased in infected individuals pre- or post-treatment. Predictive functional profiling revealed the enrichment of two pyruvate ferredoxin oxidoreductase subunit pathways in individuals who remained infected after treatment (p < 0.05), alluding to an upturn of strictly anaerobic commensal bacteria such as Clostridia spp. This study suggests a relationship between human gut microbiome dysbiosis and albendazole therapy outcomes of hookworm infection. Future studies will further characterize specific biomarkers identified within this study to establish their potential for assessment of pharmacological responses to anthelminthic therapies, as well as explore the possibility of using probiotic supplementation as an adjunct treatment to increase albendazole effectiveness against hookworm.
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Affiliation(s)
- Francis Appiah-Twum
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana
| | - Jewelna Akorli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana
| | - Lydia Okyere
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana
- Department of Pathobiology, University of Illinois, Urbana-Champaign, 2522 Vet Med Basic Sciences Bldg., 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
| | - Kate Sagoe
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana
- Pan African University Institute for Basic Sciences, Technology, and Innovation (PAUSTI), P. O. Box 62000 00200, Nairobi, Kenya
| | - Dickson Osabutey
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana
| | - Michael Cappello
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, 60 College St, New Haven, CT, 06520, USA
| | - Michael D Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana.
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Macharia PM, Ray N, Gitonga CW, Snow RW, Giorgi E. Combining school-catchment area models with geostatistical models for analysing school survey data from low-resource settings: Inferential benefits and limitations. SPATIAL STATISTICS 2022; 51:100679. [PMID: 35880005 PMCID: PMC7613137 DOI: 10.1016/j.spasta.2022.100679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
School-based sampling has been used to inform targeted responses for malaria and neglected tropical diseases. Standard geostatistical methods for mapping disease prevalence use the school location to model spatial correlation, which is questionable since exposure to the disease is more likely to occur in the residential location. In this paper, we propose to overcome the limitations of standard geostatistical methods by introducing a modelling framework that accounts for the uncertainty in the location of the residence of the students. By using cost distance and cost allocation models to define spatial accessibility and in absence of any information on the travel mode of students to school, we consider three school catchment area models that assume walking only, walking and bicycling and, walking and motorized transport. We illustrate the use of this approach using two case studies of malaria in Kenya and compare it with the standard approach that uses the school locations to build geostatistical models. We argue that the proposed modelling framework presents several inferential benefits, such as the ability to combine data from multiple surveys some of which may also record the residence location, and to deal with ecological bias when estimating the effects of malaria risk factors. However, our results show that invalid assumptions on the modes of travel to school can worsen the predictive performance of geostatistical models. Future research in this area should focus on collecting information on the modes of transportation to school which can then be used to better parametrize the catchment area models.
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Affiliation(s)
- Peter M. Macharia
- Centre for Health Informatics, Computing, and Statistics, Lancaster Medical School, Lancaster University, Lancaster, LA1 4YW, UK
- Population Health Unit, Kenya Medical Research Institute-Wellcome Trust Research Programme, PO, Box 43640, Nairobi, Kenya
| | - Nicolas Ray
- GeoHealth group, Institute of Global Health, University of Geneva, Geneva, Switzerland
- Institute for Environmental Sciences, University of Geneva, Geneva, Switzerland
| | - Caroline W. Gitonga
- Population Health Unit, Kenya Medical Research Institute-Wellcome Trust Research Programme, PO, Box 43640, Nairobi, Kenya
| | - Robert W. Snow
- Population Health Unit, Kenya Medical Research Institute-Wellcome Trust Research Programme, PO, Box 43640, Nairobi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LG, UK
| | - Emanuele Giorgi
- Centre for Health Informatics, Computing, and Statistics, Lancaster Medical School, Lancaster University, Lancaster, LA1 4YW, UK
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Alzain AA, Elbadwi FA. De Novo Design of Cathepsin B1 Inhibitors as Potential Anti-Schistosomal Agents Using Computational Studies. ADVANCES AND APPLICATIONS IN BIOINFORMATICS AND CHEMISTRY 2022; 15:29-41. [PMID: 35935393 PMCID: PMC9355347 DOI: 10.2147/aabc.s361626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 07/21/2022] [Indexed: 11/23/2022]
Abstract
Background Schistosomiasis is the world’s second most devastating disease after malaria and the leading cause of disease and mortality for more than 200 million people in developing countries. Cysteine proteases, in particular SmCB1, are the most well-researched biological targets for this disorder. Objective To apply computational techniques to design new antischistosomal agents against SmCB1 protein with favorable pharmacokinetic properties. Methods The smCB1 receptor-based pharmacophore model was created and used to screen 567,000 fragments from the Enamine library. The best scoring fragments have been linked to build novel compounds that were subjected to molecular docking, MM-GBSA free energy estimation, ADME prediction, and molecular dynamics. Results A seven-point pharmacophore hypothesis ADDDRRR was created. The developed hypothesis was used to screen 1.3 M fragment conformations. Among them, 23,732 fragments matched the hypothesis and screened against the protein. The top 50 fragments were used to design new 7745 compounds using the Breed ligand panel which were subjected to docking and MMGBSA binding energy. This led to the identification of 10 compounds with better docking scores (−8.033– −7.483 kcal/mol) and lower-bound free energies (−58.49 – −40.02 kcal/mol) compared to the reference bound ligand. Most of the designed compounds demonstrated good drug-like properties. Concerning Molecular dynamics (MD) simulation results, a low root mean square deviation (RMSD) range (0.25–1.2 Å) was found for the top 3 complexes which indicated their stability. Conclusion We identified compounds that could be potential candidates in the search for novel Schistosoma mansoni inhibitors by targeting SmCB1 utilizing various computational tools. Three newly designed compounds namely breed 1, 2, and 3 showed promising affinity to the target as well as favorable drug-like properties which might be considered potential anti-schistosomal agents.
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Affiliation(s)
- Abdulrahim A Alzain
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Gezira, Gezira, Sudan
- Correspondence: Abdulrahim A Alzain, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Gezira, Gezira, Sudan, Tel +249-511854501, Fax +249-511861180, Email
| | - Fatima A Elbadwi
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Gezira, Gezira, Sudan
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A simple new screening tool for diagnosing imported schistosomiasis. PUBLIC HEALTH IN PRACTICE 2022; 3:100245. [PMID: 36101771 PMCID: PMC9461506 DOI: 10.1016/j.puhip.2022.100245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 03/08/2022] [Accepted: 03/15/2022] [Indexed: 11/22/2022] Open
Abstract
Objectives We sought to test the sensitivity and feasibility of a Schistosoma infection screening process consisting of a scored patient consultation questionnaire and a serological diagnostic test. Study design Prospective cross-sectional study. Methods We collected from Schistosoma-exposed individuals a 14-point check list of clinical and laboratory data related to Schistosoma infection, alongside a serological test to detect Schistosoma spp infection. A check list score was created and compared with the risk of infection and clinical recovery through an agreement analysis. Results Two-hundred and fifty individuals were enrolled, of whom 220 (88%) were male and 30 (12%) female. The median age was 39 (range 18–78). One hundred-fifty (60%, 95% CI 54.9%–65.1%) had a check-list score ≥2. Serology test results were positive for 142 (56.8%, 95% CI 51.6%–62%). Chronic complications compatible with long-term Schistosoma infection were detected in 29 out of these 142 (20.4%, 95% CI 13.8%–27%).,. The median score value was 3, the area under the receiver operating characteristic (ROC) curve against serology results was 0.85 and the estimated intercept check-list questionnaire score value was 1.72 (95%, CI: 1.3–2.2). Participants with a positive serological test had a substantially higher check-list score (Cohen's kappa coefficient: 0.62, 95% CI: 0.54–0.70). Ninety four percent patients empirically treated showed a subsequent improvement in clinical and laboratory parameters. Conclusions A two-component process consisting of a scored patient consultation questionnaire followed by serological assay can be a suitable strategy for screening populations at high risk of schistosomiasis infection.
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Alene KA, Elagali A, Barth DD, Rumisha SF, Amratia P, Weiss DJ, Atalell KA, Erena AK, Gething PW, Clements ACA. Spatial codistribution of HIV, tuberculosis and malaria in Ethiopia. BMJ Glob Health 2022; 7:bmjgh-2021-007599. [PMID: 35217531 PMCID: PMC8867247 DOI: 10.1136/bmjgh-2021-007599] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 01/20/2022] [Indexed: 12/15/2022] Open
Abstract
Background HIV, tuberculosis (TB) and malaria are the three most important infectious diseases in Ethiopia, and sub-Saharan Africa. Understanding the spatial codistribution of these diseases is critical for designing geographically targeted and integrated disease control programmes. This study investigated the spatial overlap and drivers of HIV, TB and malaria prevalence in Ethiopia. Methods HIV, TB and malaria data were obtained from different nationwide prevalence surveys, and geospatial covariates were obtained from publicly available sources. A Bayesian model-based geostatistical framework was applied to each survey leveraging the strength of high-resolution spatial covariates to predict continuous disease-specific prevalence surfaces and their codistribution. Results The national prevalence was 1.54% (95% CI 1.40 to 1.70) for HIV, 0.39% (95% CI 0.34 to 0.45) for TB and 1.1% (95%CI 0.95 to 1.32) for malaria. Substantial subnational variation was predicted with the highest HIV prevalence estimated in Gambela (4.52%), Addis Ababa (3.52%) and Dire Dawa (2.67%) regions. TB prevalence was highest in Dire Dawa (0.96%) and Gambela (0.88%), while malaria was highest in Gambela (6.1%) and Benishangul-Gumuz (3.8%). Spatial overlap of their prevalence was observed in some parts of the country, mainly Gambela region. Spatial distribution of the diseases was significantly associated with healthcare access, demographic, and climatic factors. Conclusions The national distribution of HIV, TB and malaria was highly focal in Ethiopia, with substantial variation at subnational and local levels. Spatial distribution of the diseases was significantly associated with healthcare access, demographic and climatic factors. Spatial overlap of HIV, TB and malaria prevalence was observed in some parts of the country. Integrated control programmes for these diseases should be targeted to these areas with high levels of co-endemicity.
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Affiliation(s)
- Kefyalew Addis Alene
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia .,Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Ahmed Elagali
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Dylan D Barth
- University of Western Australia, Perth, Western Australia, Australia.,Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Susan F Rumisha
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia.,National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Punam Amratia
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Daniel J Weiss
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia.,Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Kendalem Asmare Atalell
- School of Nursing, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | | | - Peter W Gething
- Geospatial Health and Development, Telethon Kids Institute, Nedlands, Western Australia, Australia.,Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Archie C A Clements
- Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
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Akosah-Brempong G, Attah SK, Hinne IA, Abdulai A, Addo-Osafo K, Appiah EL, Osei MM, Afrane YA. Infection of Plasmodium falciparum and helminths among school children in communities in Southern and Northern Ghana. BMC Infect Dis 2021; 21:1259. [PMID: 34920721 PMCID: PMC8680042 DOI: 10.1186/s12879-021-06972-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 12/07/2021] [Indexed: 11/17/2022] Open
Abstract
Background Infections of Plasmodium species, Schistosoma species and soil-transmitted helminths (STH) inflict a significant burden on children mostly in deprived communities in Ghana. Despite the deployment of malaria vector control and the annual Mass Drug Administration by National Control Programmes, these infections still pose major public health concerns in Ghana. Some remote communities which are hard-to-reach are not covered by MDA campaigns which is a major challenge to meeting elimination targets. Adequate data is necessary for formulating policies and strengthening interventions to mitigate transmission. This study assessed the infection burden of Plasmodium, Schistosoma species and STH infections among school children in communities in Southern and Northern Ghana. Method School children living in communities in Southern (Ada Foah, Pediatorkope, Tuanikope) and Northern (Kpalsogu) Ghana were enrolled in a cross-sectional study. A total of 493 (241 males and 252 females) school children aged (2–15 years) were enrolled in the study. Stool samples were collected to screen for Schistosoma mansoni and STH infections using the formol-ether concentration technique and urine samples were also collected to screen for S. haematobium using the routine urine examination method. Plasmodium parasitaemia was determined from thick and thin finger-prick blood samples. Results Overall, the prevalence of P. falciparum, S. mansoni, S. haematobium, Trichuris trichiura and hookworm infections were 17.2% (95%CI 12.8–19.7), 22.6% (95%CI 25.2–32.7), 1.6% (95%CI 0.89–5.2), 1.2% (95%CI 0.78–4.8) and 1.2% (95%CI 0.78–4.8) respectively. Plasmodium falciparum infection was generally widespread in all the study sites with Ada Foah recording the highest prevalence (35.3%) and Kpalsogu recording the lowest (5.8%). Schistosoma mansoni was present in only two Southern communities with Tuanikope recording the highest prevalence of 70.3% as against 51.5% recorded in Pediatorkope. A total of 4.5% (95% CI 2.82–10.8) of the children were co-infected with P. falciparum, Schistosoma species and STHs. This occurred only in the Southern communities; of which combination of P. falciparum and S. mansoni were predominant (1.4%). Conclusion A relatively low burden of parasites co-infection among children only in the Southern communities was detected. However, there were a high prevalence of single infections of P. falciparum and S. mansoni in those communities. Control measures for the helminths needs to be restarted in the island communities with a high burden of S. mansoni infections and that of Plasmodium needs to be scaled up in Ada Foah where P. falciparum infections were high.
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Affiliation(s)
- G Akosah-Brempong
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - S K Attah
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - I A Hinne
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - A Abdulai
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - K Addo-Osafo
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - E L Appiah
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - M-M Osei
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - Y A Afrane
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana.
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Gender-related differences in prevalence, intensity and associated risk factors of Schistosoma infections in Africa: A systematic review and meta-analysis. PLoS Negl Trop Dis 2021; 15:e0009083. [PMID: 34788280 PMCID: PMC8635327 DOI: 10.1371/journal.pntd.0009083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 12/01/2021] [Accepted: 09/29/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Schistosomiasis remains a global-health problem with over 90% of its burden concentrated in Africa. Field studies reflect the complex ways in which socio-cultural and socio-economic variables, affect the distribution of Schistosoma infections across different populations. This review set out to systematically investigate and quantify the differences in Schistosoma infection burdens between males and females in Africa for two of the most prevalent Schistosoma species-Schistosoma mansoni and Schistosoma haematobium. METHODOLOGY We searched (from inception to 11th March 2020) Embase, MEDLINE, PubMed, and Web of Science for relevant studies on schistosomiasis. We included studies that report S. mansoni and/or S. haematobium prevalence and/or intensity data distributed between males and females. We conducted meta-analyses on the male to female (M:F) prevalence of infection ratios. Subgroup analyses were performed according to study baseline prevalence, sample size and the lower and upper age limit of study participants. We also present a descriptive analysis of differential risk and intensity of infection across males and females. Evidence for differences in the prevalence of schistosomiasis infection between males and females is presented, stratified by Schistosoma species. RESULT We identified 128 relevant studies, with over 200,000 participants across 23 countries. Of all the reported differences in the prevalence of infection between males and females, only 41% and 34% were statistically significant for S. mansoni and S. haematobium, respectively. Similar proportions of studies (27% and 34% for for S. haematobium and S. mansoni, respectively) of the reported differences in intensity of infection between males and females were statistically significant. The meta-analyses summarized a higher prevalence of infection in males; pooled random-effects weighted M:F prevalence of infection ratios were 1.20 (95% CI 1.11-1.29) for S. haematobium and 1.15 (95% CI 1.08-1.22) for S. mansoni. However, females are underrespresented in some of the studies. Additionally, there was significant heterogeneity across studies (Higgins I2 statistic (p-values < 0.001, I2values>95%)). Results of the subgroup analysis showed that the baseline prevalence influenced the M:F prevalence ratios for S. haematobium and S. mansoni, with higher M:F prevalence of infection ratios in settings with a lower baseline prevalence of infection. Across the studies, we identified four major risk factors associated with infection rates: occupational and recreational water contact, knowledge, socio-economic factors and demographic factors. The effect of these risk factors on the burden of infection in males and females varied across studies. CONCLUSIONS We find evidence of differences in prevalence of infection between males and females which may reflect differences in gender norms and water contact activities, suggesting that policy changes at the regional level may help ameliorate gender-related disparities in schistosomiasis infection burden. Collecting, robustly analysing, and reporting, sex-disaggregated epidemiological data, is currently lacking, but would be highly informative for planning effective treatment programmes and establishing those most at risk of schistosomiasis infections.
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Suwannatrai AT, Thinkhamrop K, Suwannatrai K, Pratumchart K, Wangdi K, Kelly M, Restrepo AMC, Gray DJ, Clements ACA, Tangkawattana S, Sripa B. Opisthorchis viverrini and Strongyloides stercoralis mono- and co-infections: Bayesian geostatistical analysis in an endemic area, Thailand. Acta Trop 2021; 223:106079. [PMID: 34363777 DOI: 10.1016/j.actatropica.2021.106079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/25/2021] [Accepted: 07/27/2021] [Indexed: 12/19/2022]
Abstract
Parasitic infections caused by Opisthorchis viverrini and Strongyloides stercoralis remain a major public health threat in the Greater Mekong Sub-region. An understanding of climate and other environmental influences on the geographical distribution and emergence of parasitic diseases is a crucial step to guide targeted control and prevention programs. A parasitological survey was conducted from 2008 to 2013 and included 12,554 individuals (age between 20 and 60 years) from 142 villages in five districts in Khon Kaen Province, Thailand. Geographical information systems, remote sensing technologies and a Bayesian geostatistical framework were used to develop models for O. viverrini and S. stercoralis mono- and co-infections in areas where both parasites are known to co-occur. The results indicate that male sex, increased age, altitude, precipitation, and land surface temperature have influenced the infection rate and geographical distribution of mono- and co-infections of O. viverrini and S. stercoralis in this area. Males were 6.69 times (95% CrI: 5.26-8.58) more likely to have O. viverrini - S. stercoralis co-infection. We observed that O. viverrini and S. stercoralis mono-infections display distinct spatial pattern, while co-infection is predicted in the center and southeast of the study area. The observed spatial clustering of O. viverrini and S. stercoralis provides valuable information for the spatial targeting of prevention interventions in this area.
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Affiliation(s)
- Apiporn T Suwannatrai
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Health and Epidemiology Geoinformatics Research (HEGER), Faculty of Public Health, Khon Kaen University, Khon Kaen, Thailand.
| | - Kavin Thinkhamrop
- Health and Epidemiology Geoinformatics Research (HEGER), Faculty of Public Health, Khon Kaen University, Khon Kaen, Thailand; Cholangiocarcinoma Screening and Care Program (CASCAP), Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Data Management and Statistical Analysis Center (DAMASAC), Faculty of Public Health, Khon Kaen University, Khon Kaen, Thailand
| | - Kulwadee Suwannatrai
- Department of Biology, Faculty of Science and Technology, Sakon Nakhon Rajabhat University, Sakon Nakhon, Thailand
| | - Khanittha Pratumchart
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Health and Epidemiology Geoinformatics Research (HEGER), Faculty of Public Health, Khon Kaen University, Khon Kaen, Thailand
| | - Kinley Wangdi
- Department of Global Health, Research School of Population Health, College of Medicine, Biology and Environment, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Matthew Kelly
- Department of Global Health, Research School of Population Health, College of Medicine, Biology and Environment, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Angela M Cadavid Restrepo
- School of Public Health, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Darren J Gray
- Department of Global Health, Research School of Population Health, College of Medicine, Biology and Environment, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Archie C A Clements
- Faculty of Health Sciences, Curtin University, Bentley, Western Australia, Australia; Telethon Kids Institute, Nedlands, WA, Australia
| | | | - Banchob Sripa
- WHO Collaborating Centre for Research and Control of opisthorchiasis, Tropical Disease Research Center, Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
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Kretchy JP, Dzodzomenyo M, Ayi I, Dwomoh D, Agyabeng K, Konradsen F, Dalsgaard A. The Incidence, Intensity, and Risk Factors for Soil Transmissible Helminthes Infections among Waste Handlers in a Large Coastal Periurban Settlement in Southern Ghana. JOURNAL OF ENVIRONMENTAL AND PUBLIC HEALTH 2021; 2021:5205793. [PMID: 33777151 PMCID: PMC7949191 DOI: 10.1155/2021/5205793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 01/15/2021] [Accepted: 02/04/2021] [Indexed: 11/18/2022]
Abstract
Soil-transmissible helminthes (STH) infections are among the most common sanitation-related public health problems in poor periurban settlements of tropical regions of low- and middle-income countries. In Ghana, research studies documenting the incidence rate, intensity, and occupational risk factors of STH infections among adults are scanty. A prospective cohort study of 261 waste handlers was conducted to investigate this. Stool samples were collected after 90 and 180 days of treatment with albendazole (400 mg per dose). The geometric mean intensity of STH among waste handlers after 180 days of treatment was 2.8 eggs/gram (light intensity), with an incidence rate of 1.5%. The proportion of waste handlers with light intensity STH infections was 4.8%. The odds of STH infection among female waste handlers were 80% lower when compared with male waste handlers (aOR = 0.2; 95% CI: 0.0-0.8). Waste handlers who used rubber gloves when working were 80% (aOR = 0.2: 95% CI: 0.2-1.9) protected from STH infections compared with those who did not use gloves. Infections with STH among the 261 waste handlers significantly correlated with the type of waste handling activities (LR χ 2 = 15.3; p=0.033) with the highest proportion of infection found among transporters, 2 (40%). Waste handlers should receive periodic antihelminthic treatment, at least once every six months, practice adequate hand hygiene, and use suitable personal protective equipment during work.
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Affiliation(s)
- James-Paul Kretchy
- Department of Physician Assistantship Studies, School of Medicine and Health Sciences, Central University, Miotso, Accra, Ghana
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Mawuli Dzodzomenyo
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Irene Ayi
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Duah Dwomoh
- Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Kofi Agyabeng
- Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Flemming Konradsen
- Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anders Dalsgaard
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
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Prevalence, Intensity, and Associated Factors of Schistosoma mansoni among School Children in Northwest Ethiopia. J Parasitol Res 2020; 2020:8820222. [PMID: 33274074 PMCID: PMC7676956 DOI: 10.1155/2020/8820222] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/30/2020] [Accepted: 11/04/2020] [Indexed: 11/18/2022] Open
Abstract
Background Schistosomiasis is one of the Neglected Tropical Diseases in Ethiopia, and its burden may show variations from time to time across different regions. Thus, this study was aimed at determining the prevalence, intensity, and associated risk factors of Schistosoma mansoni (S. mansoni) among schoolchildren in Northwest Ethiopia. Methods A school-based cross-sectional study was conducted. A multistage sampling technique was used to select the study participants. Stool specimens were collected and examined using two-slide Kato-Katz method. Data were analyzed using SPSS version 20 software. Multivariate logistic regression analysis was used to identify risk factors. p values less than 0.05 were taken as statistically significant. Result A total of 786 schoolchildren were participated in this study. The prevalence of S. mansoni was 33.5%. The mean egg count of the parasite among the infected study participants was 523.665 eggs per gram (epg) of stool. Thirty-seven, 42, and 21 percent of the study participant's infection were due to light, moderate, and heavy infection intensities, respectively. Age of 8-11 years old (AOR = 1,687, 95%CI = 1.163, 2.892), 5th-8th grade level (AOR = 2.280, 95%CI = 1.348, 3.856), residing in Chuahit District (AOR = 95.559, 95%CI = 12.945, 705.419), and using untreated water for domestic supply (AOR = 1.724, 95%CI = 1.457, 2.148) were found to be risk factors for S. mansoni infection. Conclusion High prevalence of S. mansoni and relatively higher proportion of moderate intensity of infection in this study imply that schistosomiasis is still one of the major public health problems in Northwest Ethiopia. It is also highlighted that study sites, provision of water supply, age, and grade level of the schoolchildren were identified as a risk factors for the disease.
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Schistosoma haematobium infection and environmental factors in Southwestern Tanzania: A cross-sectional, population-based study. PLoS Negl Trop Dis 2020; 14:e0008508. [PMID: 32833959 PMCID: PMC7446842 DOI: 10.1371/journal.pntd.0008508] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 06/22/2020] [Indexed: 12/30/2022] Open
Abstract
Schistosomiasis is a leading cause of morbidity in Africa. Understanding the disease ecology and environmental factors that influence its distribution is important to guide control efforts. Geographic information systems have increasingly been used in the field of schistosomiasis environmental epidemiology. This study reports prevalences of Schistosoma haematobium infection and uses remotely sensed and questionnaire data from over 17000 participants to identify environmental and socio-demographic factors that are associated with this parasitic infection. Data regarding socio-demographic status and S. haematobium infection were obtained between May 2006 and May 2007 from 17280 participants (53% females, median age = 17 years) in the Mbeya Region, Tanzania. Combined with remotely sensed environmental data (vegetation cover, altitude, rainfall etc.) this data was analyzed to identify environmental and socio-demographic factors associated with S. haematobium infection, using mixed effects logistic regression and geostatistical modelling. The overall prevalence of S. haematobium infection was 5.3% (95% confidence interval (CI): 5.0-5.6%). Multivariable analysis revealed increased odds of infection for school-aged children (5-15 years, odds ratio (OR) = 7.8, CI: 5.9-10.4) and the age groups 15-25 and 25-35 years (15-25 years: OR = 5.8, CI: 4.3-8.0, 25-35 years: OR = 1.6, CI: 1.1-2.4) compared to persons above 35 years of age, for increasing distance to water courses (OR = 1.4, CI: 1.2-1.6 per km) and for proximity to Lake Nyasa (<1 km, OR = 4.5, CI: 1.8-11.4; 1-2 km, OR = 3.5, CI: 1.7-7.5; 2-4 km; OR = 3.3, CI: 1.7-6.6), when compared to distances >4 km. Odds of infection decreased with higher altitude (OR = 0.7, CI: 0.6-0.8 per 100 m increase) and with increasing enhanced vegetation index EVI (OR = 0.2, CI: 0.1-0.4 per 0.1 units). When additionally adjusting for spatial correlation population density became a significant predictor of schistosomiasis infection (OR = 1.3, CI: 1.1-1.5 per 1000 persons/km2) and altitude turned non-significant. We found highly focal geographical patterns of S. haematobium infection in Mbeya Region in Southwestern Tanzania. Despite low overall prevalence our spatially heterogeneous results show that some of the study sites suffer from a considerable burden of S. haematobium infection, which is related to various socio-demographic and environmental factors. Our results could help to design more effective control strategies in the future, especially targeting school-aged children living in low altitude sites and/or crowded areas as the persons at highest need for preventive chemotherapy.
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Current status and future prospects of protein vaccine candidates against Schistosoma mansoni infection. Parasite Epidemiol Control 2020; 11:e00176. [PMID: 32923703 PMCID: PMC7475110 DOI: 10.1016/j.parepi.2020.e00176] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 06/04/2020] [Accepted: 08/16/2020] [Indexed: 12/30/2022] Open
Abstract
Schistosomiasis is an acute and chronic tropical parasitic disease caused by blood dwelling worm of the genus Schistosoma. It is the most destructive disease globally and is a major cause of morbidity and mortality for developing countries. Three main species of schistosomes infect human beings from which S. mansoni is the most common and widespread. Over the last several decades, chemotherapy using praziquantel has been a commonly used strategy for the treatment and control of schistosomiasis. However, control programs focused exclusively on chemotherapy have been challenging because of the frequency and rapidity of reinfection and these programs were expensive. Thus, new schistosomiasis control strategies will be needed. Vaccination strategy would be an ideal tool for a significant and sustainable reduction in the transmission and disease burden of schistosomiasis. An effective anti schistosome vaccine would greatly contribute to decreasing schistosomiasis-associated morbidity via protective immune responses leading to reduced worm burdens and decreased egg production. Vaccine development is a long process that can take decades. There have been three candidate vaccines that have been produced by Good Manufacturing Procedure and entered human clinical trials for S. mansoni are Sm14, SmTSP-2, and Sm-p80. Other candidates that are in pre-clinical trials at various stages include paramyosin, Sm29, SmKI-1, and Sm23. Since the growth of several new technologies, including genomics, transcriptomics, microarrays, immunomic profiling, and proteomics, have helped in the identification of promising new target schistosome antigens. Therefore, this review considers the present status of protein vaccine candidates against Schistosoma mansoni and provides some insight on prospects vaccine design and discovery.
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Key Words
- AE, Asparaginyl Endopeptidase
- Ab, Antibody
- Ag, Antigen
- CB, Cathepsin B
- CD, Cathepsin D
- CL3, Cathepsin L3
- DNA, Deoxyribonucleic Acid
- FA, Fatty Acid
- FABP, Fatty Acid Binding Protein
- GLA-Alum, Glucopyranosyl Lipid A Formulated in Aluminum
- GLA-SE, Glucopyranosyl Lipid Adjuvant Stable Emulsion
- IFN-γ, Interferon Gamma
- IL, Interleukin
- Ig, Immunoglobulin
- KI, Kunitz Type Protease Inhibitor
- LcP, Lipid Core Peptide
- Pmy, Paramyosin
- Protein vaccine
- Schistosoma mansoni
- Schistosomiasis
- Sm, Schistosoma mansoni
- TSP, Tetraspanins
- Th, T-helper Cells
- Vaccine candidates
- WHO, World Health Organization
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Dhewantara PW, Zhang W, Al Mamun A, Yin WW, Ding F, Guo D, Hu W, Soares Magalhães RJ. Spatial distribution of leptospirosis incidence in the Upper Yangtze and Pearl River Basin, China: Tools to support intervention and elimination. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 725:138251. [PMID: 32298905 DOI: 10.1016/j.scitotenv.2020.138251] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/14/2020] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Since 2011 human leptospirosis incidence in China has remained steadily low with persistent pockets of notifications reported in communities within the Upper Yangtze River Basin (UYRB) and Pearl River Basin (PRB). To help guide health authorities within these residual areas to identify communities where interventions should be targeted, this study quantified the local effect of socioeconomic and environmental factors on the spatial distribution of leptospirosis incidence and developed predictive maps of leptospirosis incidence for UYRB and PRB. METHODS Data on all human leptospirosis cases reported during 2005-2016 across the UYRB and PRB regions were geolocated at the county-level and included in the analysis. Bayesian conditional autoregressive (CAR) models with zero-inflated Poisson link for leptospirosis incidence were developed after adjustment of environmental and socioeconomic factors such as precipitation, normalized difference vegetation index (NDVI), modified normalized difference water index (MNDWI), land surface temperature (LST), elevation, slope, land cover, crop production, livestock density, gross domestic product and population density. RESULTS The relationship of environmental and socioeconomic variables with human leptospirosis incidence varied between both regions. While across UYRB incidence of human leptospirosis was associated with MNDWI and elevation, in PRB human leptospirosis incidence was significantly associated with NDVI, livestock density and land cover. Precipitation was significantly and positively associated with the spatial variation of incidence of leptospirosis in both regions. After accounting for the effect of environmental and socioeconomic factors, the predicted distribution of residual high-incidence county is potentially more widespread both in the UYRB and PRB compared to the observed distribution. In the UYRB, the highest predicted incidence was found along the border of Chongqing and Guizhou towards Sichuan basin and northwest Yunnan. The highest predicted incidence was also identified in counties in the central and lower reaches of the PRB. CONCLUSIONS This study demonstrated significant geographical heterogeneity in leptospirosis incidence within UYRB and PRB, providing an evidence base for prioritising targeted interventions in counties identified with the highest predicted incidence. Furthermore, environmental drivers of leptospirosis incidence were highly specific to each of the regions, emphasizing the importance of localized control measures. The findings also suggested the need to expand interventional coverage and to support surveillance and diagnostic capacity on the predicted high-risk areas.
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Affiliation(s)
- Pandji Wibawa Dhewantara
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia; Pangandaran Unit of Health Research and Development, National Institute of Health Research and Development (NIHRD), Ministry of Health of Indonesia, West Java 46396, Indonesia.
| | - Wenyi Zhang
- Center for Disease Control and Prevention of PLA, Beijing 100071, People's Republic of China.
| | - Abdullah Al Mamun
- Institute for Social Science Research, The University of Queensland, Indooroopilly, QLD 4068, Australia.
| | - Wen-Wu Yin
- Chinese Center for Disease Control and Prevention, Beijing 102206, People's Republic of China.
| | - Fan Ding
- Chinese Center for Disease Control and Prevention, Beijing 102206, People's Republic of China.
| | - Danhuai Guo
- Scientific Data Center, Computer Network Information Center, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
| | - Wenbiao Hu
- School of Public Health and Social Work, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia.
| | - Ricardo J Soares Magalhães
- School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia; Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD 4101, Australia.
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Abstract
INTRODUCTION Tuberculosis (TB), a major public health concern in Ethiopia, is distributed heterogeneously across the country. Mapping TB prevalence at national and subnational levels can provide information for designing and implementing control strategies. Data for spatial analysis can be obtained through systematic review of the literature, and spatial prediction can be done by meta-analysis of published data (geospatial meta-analysis). Geospatial meta-analysis can increase the power of spatial analytic models by making use of all available data. It can also provide a means for spatial prediction where new survey data in a given area are sparse or not available. In this report, we present a protocol for a geospatial meta-analysis to investigate the spatial patterns of TB prevalence in Ethiopia. METHODS AND ANALYSIS To conduct this study, a national TB prevalence survey, supplemented with data from a systematic review of published reports, will be used as the source of TB prevalence data. Systematic searching will be conducted in PubMed, Scopus and Web of Science for studies published up to 15 April 2020 to identify all potential publications reporting TB prevalence in Ethiopia. Data for covariates for multivariable analysis will be obtained from different, readily available sources. Extracted TB survey and covariate data will be georeferenced to specific locations or the centroids of small administrative areas. A binomial logistic regression model will be fitted to TB prevalence data using both fixed covariate effects and random geostatistical effects based on the approach of model-based geostatistics. Markov Chain Monte Carlo simulation will be conducted to obtained posterior parameter estimations, including spatially predicted prevalence. ETHICS AND DISSEMINATION Ethical approval will not be required for this study as it will be based on deidentified, aggregate published data. The final report of this review will be disseminated through publication in a peer-reviewed scientific journal and will also be presented at relevant conferences.
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Affiliation(s)
- Kefyalew Addis Alene
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Nedlands, Western Australia, Australia
- Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Zeleke Alebachew Wagaw
- National Tuberculosis Control Programme, Ghana Health Service, Accra, Greater Accra, Ghana
| | - Archie C A Clements
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Nedlands, Western Australia, Australia
- Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
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Clark NJ, Owada K, Ruberanziza E, Ortu G, Umulisa I, Bayisenge U, Mbonigaba JB, Mucaca JB, Lancaster W, Fenwick A, Soares Magalhães RJ, Mbituyumuremyi A. Parasite associations predict infection risk: incorporating co-infections in predictive models for neglected tropical diseases. Parasit Vectors 2020; 13:138. [PMID: 32178706 PMCID: PMC7077138 DOI: 10.1186/s13071-020-04016-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 03/10/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Schistosomiasis and infection by soil-transmitted helminths are some of the world's most prevalent neglected tropical diseases. Infection by more than one parasite (co-infection) is common and can contribute to clinical morbidity in children. Geostatistical analyses of parasite infection data are key for developing mass drug administration strategies, yet most methods ignore co-infections when estimating risk. Infection status for multiple parasites can act as a useful proxy for data-poor individual-level or environmental risk factors while avoiding regression dilution bias. Conditional random fields (CRF) is a multivariate graphical network method that opens new doors in parasite risk mapping by (i) predicting co-infections with high accuracy; (ii) isolating associations among parasites; and (iii) quantifying how these associations change across landscapes. METHODS We built a spatial CRF to estimate infection risks for Ascaris lumbricoides, Trichuris trichiura, hookworms (Ancylostoma duodenale and Necator americanus) and Schistosoma mansoni using data from a national survey of Rwandan schoolchildren. We used an ensemble learning approach to generate spatial predictions by simulating from the CRF's posterior distribution with a multivariate boosted regression tree that captured non-linear relationships between predictors and covariance in infection risks. This CRF ensemble was compared against single parasite gradient boosted machines to assess each model's performance and prediction uncertainty. RESULTS Parasite co-infections were common, with 19.57% of children infected with at least two parasites. The CRF ensemble achieved higher predictive power than single-parasite models by improving estimates of co-infection prevalence at the individual level and classifying schools into World Health Organization treatment categories with greater accuracy. The CRF uncovered important environmental and demographic predictors of parasite infection probabilities. Yet even after capturing demographic and environmental risk factors, the presences or absences of other parasites were strong predictors of individual-level infection risk. Spatial predictions delineated high-risk regions in need of anthelminthic treatment interventions, including areas with higher than expected co-infection prevalence. CONCLUSIONS Monitoring studies routinely screen for multiple parasites, yet statistical models generally ignore this multivariate data when assessing risk factors and designing treatment guidelines. Multivariate approaches can be instrumental in the global effort to reduce and eventually eliminate neglected helminth infections in developing countries.
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Affiliation(s)
- Nicholas J. Clark
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD 4343 Australia
| | - Kei Owada
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD 4343 Australia
- Children Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD 4101 Australia
| | - Eugene Ruberanziza
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Giuseppina Ortu
- Schistosomiasis Control Initiative (SCI), Department of Infectious Diseases Epidemiology, Imperial College, London, UK
| | - Irenee Umulisa
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Ursin Bayisenge
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Jean Bosco Mbonigaba
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Jean Bosco Mucaca
- Microbiology Unit, National Reference Laboratory (NRL) Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda
| | | | - Alan Fenwick
- Schistosomiasis Control Initiative (SCI), Department of Infectious Diseases Epidemiology, Imperial College, London, UK
| | - Ricardo J. Soares Magalhães
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD 4343 Australia
- Children Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD 4101 Australia
| | - Aimable Mbituyumuremyi
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda
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Kulinkina AV, Sarkar R, Mohan VR, Walz Y, Kaliappan SP, Ajjampur SSR, Ward H, Naumova EN, Kang G. Prediction of hookworm prevalence in southern India using environmental parameters derived from Landsat 8 remotely sensed data. Int J Parasitol 2019; 50:47-54. [PMID: 31756313 DOI: 10.1016/j.ijpara.2019.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 09/30/2019] [Accepted: 10/03/2019] [Indexed: 11/20/2022]
Abstract
Soil-transmitted helminth infections propagate poverty and slow economic growth in low-income countries. As with many other neglected tropical diseases, environmental conditions are important determinants of soil-transmitted helminth transmission. Hence, remotely sensed data are commonly utilised in spatial risk models intended to inform control strategies. In the present study, we build upon the existing modelling approaches by utilising fine spatial resolution Landsat 8 remotely sensed data in combination with topographic variables to predict hookworm prevalence in a hilly tribal area in southern India. Hookworm prevalence data collected from two field surveys were used in a random forest model to investigate the predictive capacity of 15 environmental variables derived from two remotely sensed images acquired during dry and rainy seasons. A variable buffer radius (100-1000 m) was applied to the point-prevalence locations in order to integrate environmental conditions around the village centroids into the modelling approach and understand where transmission is more likely. Elevation and slope were the most important variables in the models, with lower elevation and higher slope correlating with higher transmission risk. A modified normalised difference water index was among other recurring important variables, likely responsible for some seasonal differences in model performance. The 300 m buffer distance produced the best model performance in this setting, with another spike at 700 m, and a marked drop-off in R2 values at 1000 m. In addition to assessing a large number of environmental correlates with hookworm transmission, the study contributes to the development of standardised methods of spatial linkage of continuous environmental data with point-based disease prevalence measures for the purpose of spatially explicit risk profiling.
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Affiliation(s)
- Alexandra V Kulinkina
- Department of Public Health and Community Medicine, Tufts University School of Medicine, Boston, MA, USA; Partners In Health, Neno, Malawi.
| | - Rajiv Sarkar
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India
| | - Venkata R Mohan
- Department of Community Health, Christian Medical College, Vellore, Tamil Nadu, India
| | - Yvonne Walz
- Institute for Environment and Human Security, United Nations University, Bonn, Germany
| | | | - Sitara S R Ajjampur
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India
| | - Honorine Ward
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India; Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA, USA
| | - Elena N Naumova
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India; Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA, USA
| | - Gagandeep Kang
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India
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Mupfasoni D, Bangert M, Mikhailov A, Marocco C, Montresor A. Sustained preventive chemotherapy for soil-transmitted helminthiases leads to reduction in prevalence and anthelminthic tablets required. Infect Dis Poverty 2019; 8:82. [PMID: 31575378 PMCID: PMC6774215 DOI: 10.1186/s40249-019-0589-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/14/2019] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND The goal of soil-transmitted helminthiases (STH) control programmes is to eliminate STH-associated morbidity in the target population by reducing the prevalence of moderate- and heavy-intensity infections and the overall STH infection prevalence mainly through preventive chemotherapy (PC) with either albendazole or mebendazole. Endemic countries should measure the success of their control programmes through regular epidemiological assessments. We evaluated changes in STH prevalence in countries that conducted effective PC coverage for STH to guide changes in the frequency of PC rounds and the number of tablets needed. METHODS We selected countries from World Health Organization (WHO)'s Preventive Chemotherapy and Transmission control (PCT) databank that conducted ≥5 years of PC with effective coverage for school-age children (SAC) and extracted STH baseline and impact assessment data using the WHO Epidemiological Data Reporting Form, Ministry of Health reports and/or peer-reviewed publications. We used pooled and weighted means to plot the prevalence of infection with any STH and with each STH species at baseline and after ≥5 years of PC with effective coverage. Finally, using the WHO STH decision tree, we estimated the reduction in the number of tablets needed. RESULTS Fifteen countries in four WHO regions conducted annual or semi-annual rounds of PC for STH for 5 years or more and collected data before and after interventions. At baseline, the pooled prevalence was 48.9% (33.1-64.7%) for any STH, 23.2% (13.7-32.7%) for Ascaris lumbricoides, 21.01% (9.7-32.3%) for Trichuris trichiura and 18.2% (10.9-25.5%) for hookworm infections, while after ≥5 years of PC for STH, the prevalence was 14.3% (7.3-21.3%) for any STH, 6.9% (1.3-12.5%) for A. lumbricoides, 5.3% (1.06-9.6%) for T. trichiura and 8.1% (4.0-12.2%) for hookworm infections. CONCLUSIONS Countries endemic for STH have made tremendous progress in reducing STH-associated morbidity, but very few countries have data to demonstrate that progress. In this study, the data show that nine countries should adapt their PC strategies and the frequency of PC rounds to yield a 36% reduction in drug needs. The study also highlights the importance of impact assessment surveys to adapt control strategies according to STH prevalence.
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Affiliation(s)
- Denise Mupfasoni
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Mathieu Bangert
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Alexei Mikhailov
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Chiara Marocco
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Antonio Montresor
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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21
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Mapping Schistosoma mansoni endemicity in Rwanda: a critical assessment of geographical disparities arising from circulating cathodic antigen versus Kato-Katz diagnostics. PLoS Negl Trop Dis 2019; 13:e0007723. [PMID: 31568504 PMCID: PMC6786642 DOI: 10.1371/journal.pntd.0007723] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 10/10/2019] [Accepted: 08/20/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Schistosomiasis is a neglected tropical disease caused by Schistosoma parasites. Intervention relies on identifying high-risk regions, yet rapid Schistosoma diagnostics (Kato-Katz stool assays (KK) and circulating cathodic antigen urine assays (CCA)) yield different prevalence estimates. We mapped S. mansoni prevalence and delineated at-risk regions using a survey of schoolchildren in Rwanda, where S. mansoni is an endemic parasite. We asked if different diagnostics resulted in disparities in projected infection risk. METHODS Infection data was obtained from a 2014 Rwandan school-based survey that used KK and CCA diagnostics. Across 386 schools screened by CCA (N = 19,217). To allow for uncertainty when interpreting ambiguous CCA trace readings, which accounted for 28.8% of total test results, we generated two presence-absence datasets: CCA trace as positive and CCA trace as negative. Samples (N = 9,175) from 185 schools were also screened by KK. We included land surface temperature (LST) and the Normalized Difference Vegetation and Normalized Difference Water Indices (NDVI, NDWI) as predictors in geostatistical regressions. FINDINGS Across 8,647 children tested by both methods, prevalence was 35.93% for CCA trace as positive, 7.21% for CCA trace as negative and 1.95% for KK. LST was identified as a risk factor using KK, whereas NDVI was a risk factor for CCA models. Models predicted high endemicity in Northern and Western regions of Rwanda, though the CCA trace as positive model identified additional high-risk areas that were overlooked by the other methods. Estimates of current burden for children at highest risk (boys aged 5-9 years) varied by an order of magnitude, with 671,856 boys projected to be infected by CCA trace as positive and only 60,453 projected by CCA trace as negative results. CONCLUSIONS Our findings show that people in Rwanda's Northern, Western and capital regions are at high risk of S. mansoni infection. However, variation in identification of environmental risk factors and delineation of at-risk regions using different diagnostics likely provides confusing messages to disease intervention managers. Further research and statistical analyses, such as latent class analysis, can be used to improve CCA result classification and assess its use in guiding treatment regimes.
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22
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Wrable M, Kulinkina AV, Liss A, Koch M, Cruz MS, Biritwum NK, Ofosu A, Gute DM, Kosinski KC, Naumova EN. The use of remotely sensed environmental parameters for spatial and temporal schistosomiasis prediction across climate zones in Ghana. ENVIRONMENTAL MONITORING AND ASSESSMENT 2019; 191:301. [PMID: 31254149 DOI: 10.1007/s10661-019-7411-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 03/20/2019] [Indexed: 06/09/2023]
Abstract
Schistosomiasis control in sub-Saharan Africa is enacted primarily through preventive chemotherapy. Predictive models can play an important role in filling knowledge gaps in the distribution of the disease and help guide the allocation of limited resources. Previous modeling approaches have used localized cross-sectional survey data and environmental data typically collected at a discrete point in time. In this analysis, 8 years (2008-2015) of monthly schistosomiasis cases reported into Ghana's national surveillance system were used to assess temporal and spatial relationships between disease rates and three remotely sensed environmental variables: land surface temperature (LST), normalized difference vegetation index (NDVI), and accumulated precipitation (AP). Furthermore, the analysis was stratified by three major and nine minor climate zones, defined using a new climate classification method. Results showed a downward trend in reported disease rates (~ 1% per month) for all climate zones. Seasonality was present in the north with two peaks (March and September), and in the middle of the country with a single peak (July). Lowest disease rates were observed in December/January across climate zones. Seasonal patterns in the environmental variables and their associations with reported schistosomiasis infection rates varied across climate zones. Precipitation consistently demonstrated a positive association with disease outcome, with a 1-cm increase in rainfall contributing a 0.3-1.6% increase in monthly reported schistosomiasis infection rates. Generally, surveillance of neglected tropical diseases (NTDs) in low-income countries continues to suffer from data quality issues. However, with systematic improvements, our approach demonstrates a way for health departments to use routine surveillance data in combination with publicly available remote sensing data to analyze disease patterns with wide geographic coverage and varying levels of spatial and temporal aggregation.
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Affiliation(s)
| | | | - Alexander Liss
- School of Engineering, Tufts University, Medford, MA, USA
| | - Magaly Koch
- Center for Remote Sensing, Boston University, Boston, MA, USA
| | - Melissa S Cruz
- Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, 02111, USA
| | | | - Anthony Ofosu
- Ghana Health Service, Policy, Planning, Monitoring, and Evaluation Division, Accra, Ghana
| | - David M Gute
- School of Engineering, Tufts University, Medford, MA, USA
| | | | - Elena N Naumova
- School of Engineering, Tufts University, Medford, MA, USA.
- Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, MA, 02111, USA.
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23
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Ruberanziza E, Owada K, Clark NJ, Umulisa I, Ortu G, Lancaster W, Munyaneza T, Mbituyumuremyi A, Bayisenge U, Fenwick A, Soares Magalhães RJ. Mapping Soil-Transmitted Helminth Parasite Infection in Rwanda: Estimating Endemicity and Identifying At-Risk Populations. Trop Med Infect Dis 2019; 4:tropicalmed4020093. [PMID: 31207897 PMCID: PMC6630518 DOI: 10.3390/tropicalmed4020093] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 01/17/2023] Open
Abstract
Soil-transmitted helminth (STH) infections are globally distributed intestinal parasite infections caused by Ascaris lumbricoides, Trichuris trichiura, and hookworms (Ancylostoma duodenale and Necator americanus). STH infection constitutes a major public health threat, with heavy burdens observed in many of the world’s tropical and subtropical regions. Mass drug administration and sanitation improvements can drastically reduce STH prevalence and associated morbidity. However, identifying targeted areas in need of treatment is hampered by a lack of knowledge on geographical and population-level risk factors. In this study, we applied Bayesian geostatistical modelling to data from a national school-based STH infection survey in Rwanda to (1) identify ecological and population-level risk factors and (2) provide comprehensive precision maps of infection burdens. Our results indicated that STH infections were heterogeneously distributed across the country and showed signatures of spatial clustering, though the magnitude of clustering varied among parasites. The highest rates of endemic clustering were attributed to A. lumbricoides infection. Concordant infection patterns among the three parasite groups highlighted populations currently most at-risk of morbidity. Population-dense areas in the Western and North-Western regions of Rwanda represent areas that have continued to exhibit high STH burden across two surveys and are likely in need of targeted interventions. Our maps support the need for an updated evaluation of STH endemicity in western Rwanda to evaluate progress in MDA efforts and identify communities that need further local interventions to further reduce morbidity caused by STH infections.
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Affiliation(s)
- Eugene Ruberanziza
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Kei Owada
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, the University of Queensland, Gatton 4343, Queensland, Australia.
- Children Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane 4101, Queensland, Australia.
| | - Nicholas J Clark
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, the University of Queensland, Gatton 4343, Queensland, Australia.
- Children Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane 4101, Queensland, Australia.
| | - Irenee Umulisa
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Giuseppina Ortu
- Schistosomiasis Control Initiative (SCI), Department of Infectious Diseases Epidemiology, Imperial College, London SW7 2AZ, UK.
| | | | - Tharcisse Munyaneza
- Microbiology Unit, National Reference Laboratory (NRL) Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Aimable Mbituyumuremyi
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Ursin Bayisenge
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Alan Fenwick
- Schistosomiasis Control Initiative (SCI), Department of Infectious Diseases Epidemiology, Imperial College, London SW7 2AZ, UK.
| | - Ricardo J Soares Magalhães
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, the University of Queensland, Gatton 4343, Queensland, Australia.
- Children Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane 4101, Queensland, Australia.
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24
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Abou El Dahab MM, Shahat SM, Mahmoud SSM, Mahana NA. In vitro effect of curcumin on Schistosoma species viability, tegument ultrastructure and egg hatchability. Exp Parasitol 2019; 199:1-8. [PMID: 30790572 DOI: 10.1016/j.exppara.2019.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 01/01/2019] [Accepted: 02/16/2019] [Indexed: 12/12/2022]
Abstract
Schistosomiasis remains a severe problem of public health in developing countries. The development of resistance to praziquantel (PZQ) has justified the search for new alternative chemotherapies with new formulations, more effective, and without adverse effects. Curcumin (CUR), the major phenolic compound present in rhizome of turmeric (Curcuma longa L.), has been traditionally used against various diseases including parasitic infections. Here, the antischistosomal activity of CUR (50-500 μM), evaluated in parallel against S. mansoni and S. haematobium adult worms, appeared significant (P < 0.05 to < 0.0001) in a time- and dose-dependent manner. Two h incubation with CUR (500 μM) caused 100% irreversible killing of both schistosomal species. CUR (250 μM) caused the death of S. haematobium and S. mansoni worms after 2 h and 4 h, respectively. As CUR concentration decreases (50 μM), all coupled adult worms were separated into individual male and female but the worms remained viable up to 4 h. Scanning and transmission electron microscopy revealed that S. haematobium are more sensitive than S. mansoni to CUR schistosomicidal effects. In support, CUR was found to affect the antigenicity of surface membrane molecules of S. haematobium, but not S. mansoni. Of importance, CUR significantly (P < 0.05 to < 0.0001) affected S. mansoni eggs hatchability and viability, a ground for its use in chemotherapy of schistosomiasis mansoni and japonicum because of its increased bioavailability in the gastrointestinal tract. The data together emphasize that CUR is a promising potential schistosomicidal drug.
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MESH Headings
- Animals
- Antigens, Helminth/immunology
- Antigens, Helminth/isolation & purification
- Antigens, Surface/immunology
- Antigens, Surface/isolation & purification
- Cricetinae
- Curcumin/pharmacology
- Dose-Response Relationship, Drug
- Enzyme-Linked Immunosorbent Assay
- Female
- Intestine, Small/parasitology
- Liver/parasitology
- Male
- Mesocricetus
- Mice
- Mice, Inbred BALB C
- Microscopy, Electron, Scanning
- Microscopy, Electron, Transmission
- Ovum/drug effects
- Ovum/physiology
- Schistosoma haematobium/drug effects
- Schistosoma haematobium/immunology
- Schistosoma haematobium/physiology
- Schistosoma haematobium/ultrastructure
- Schistosoma mansoni/drug effects
- Schistosoma mansoni/immunology
- Schistosoma mansoni/physiology
- Schistosoma mansoni/ultrastructure
- Schistosomicides/pharmacology
- Time Factors
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Affiliation(s)
- Marwa M Abou El Dahab
- Zoology Department, Faculty of Science, Cairo University, Giza, 12613, Egypt; Zoology Department, Faculty of Science, Ain Shams University, Cairo, 11566, Egypt
| | - Sondos M Shahat
- Zoology Department, Faculty of Science, Cairo University, Giza, 12613, Egypt
| | | | - Noha A Mahana
- Zoology Department, Faculty of Science, Cairo University, Giza, 12613, Egypt.
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Osei FB, Stein A, Ofosu A. Poisson-Gamma Mixture Spatially Varying Coefficient Modeling of Small-Area Intestinal Parasites Infection. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16030339. [PMID: 30691092 PMCID: PMC6388120 DOI: 10.3390/ijerph16030339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/15/2019] [Accepted: 01/18/2019] [Indexed: 06/09/2023]
Abstract
Understanding the spatially varying effects of demographic factors on the spatio-temporal variation of intestinal parasites infections is important for public health intervention and monitoring. This paper presents a hierarchical Bayesian spatially varying coefficient model to evaluate the effects demographic factors on intestinal parasites morbidities in Ghana. The modeling relied on morbidity data collected by the District Health Information Management Systems. We developed Poisson and Poisson-gamma spatially varying coefficient models. We used the demographic factors, unsafe drinking water, unsafe toilet, and unsafe liquid waste disposal as model covariates. The models were fitted using the integrated nested Laplace approximations (INLA). The overall risk of intestinal parasites infection was estimated to be 10.9 per 100 people with a wide spatial variation in the district-specific posterior risk estimates. Substantial spatial variation of increasing multiplicative effects of unsafe drinking water, unsafe toilet, and unsafe liquid waste disposal occurs on the variation of intestinal parasites risk. The structured residual spatial variation widely dominates the unstructured component, suggesting that the unaccounted-for risk factors are spatially continuous in nature. The study concludes that both the spatial distribution of the posterior risk and the associated exceedance probability maps are essential for monitoring and control of intestinal parasites.
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Affiliation(s)
- Frank Badu Osei
- Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, 7522 NB Enschede, The Netherlands.
| | - Alfred Stein
- Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, 7522 NB Enschede, The Netherlands.
| | - Anthony Ofosu
- Policy, Planning, Monitoring and Evaluation (PPME)⁻Ghana Health Service; Accra, Ghana.
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Owada K, Lau CL, Leonardo L, Clements ACA, Yakob L, Nielsen M, Carabin H, Soares Magalhães RJ. Spatial distribution and populations at risk of A. lumbricoides and T. trichiura co-infections and infection intensity classes: an ecological study. Parasit Vectors 2018; 11:535. [PMID: 30285906 PMCID: PMC6171148 DOI: 10.1186/s13071-018-3107-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/11/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Soil-transmitted helminth (STH) infections are highly prevalent in the Philippines. Mapping the prevalence and high-intensity of STH co-infections can help guide targeted intervention programmes to reduce morbidity, especially among vulnerable school-aged children. In this study, we aimed to predict the spatial distribution of the prevalence of Ascaris lumbricoides and Trichuris trichiura co-infection and infection intensity classes in the Philippines to identify populations most in need of interventions. METHODS Data on STH infections from 29,919 individuals during the nationwide parasitological survey in 2005 to 2007 were included in the analysis. To geographically predict the prevalence of A. lumbricoides and T. trichiura co-infections and infection intensity classes, Bayesian multinomial geostatistical models were built including age, sex, environmental variables and a geostatistical random effect. The number of individuals co-infected and belonging to each of the infection intensity classes in 2017 was forecast by combining our predictive prevalence maps with population density maps. RESULTS Our models showed that school-aged children (5-19 years) are most at risk of A. lumbricoides and T. trichiura co-infections and of moderate/high infection intensity compared to other age groups. We identified target provinces where the likelihood of STH-associated morbidity was highest: Luzon (Bulacan, Benguet, Cavite, Sorsogon, Metropolitan Manila, Pampanga and Rizal), the Visayas (Cebu, Iloilo, Leyte and Negros Occidental), and in Mindanao (Agusan Del Norte, Davao Del Sur, Davao Oriental, Lanao Del Sur, Maguindanao, Misamis Oriental, Sulu and Zamboanga Del Sur). Luzon had the highest estimated number of school-aged children with A. lumbricoides and T. trichiura co-infections (estimated total 89,400), followed by the Visayas (38,300) and Mindanao (20,200). CONCLUSIONS Our study provided epidemiological evidence to highlight national priority areas for controlling co-infections and high intensity infections in the Philippines. Our maps could assist more geographically targeted interventions to reduce the risk of STH-associated morbidity in the Philippines.
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Affiliation(s)
- Kei Owada
- School of Medicine, The University of Queensland, QLD, South Brisbane, Australia. .,Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, QLD, South Brisbane, Australia.
| | - Colleen L Lau
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, QLD, South Brisbane, Australia.,Research School of Population Health, Australian National University, ACT, Canberra, Australia
| | - Lydia Leonardo
- Department of Parasitology, College of Public Health, University of the Philippines Manila, Manila, Philippines
| | - Archie C A Clements
- Research School of Population Health, Australian National University, ACT, Canberra, Australia
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Mark Nielsen
- School of Psychology, The University of Queensland, QLD, St Lucia, Australia.,Faculty of Humanities, University of Johannesburg, Auckland Park, South Africa
| | - Hélène Carabin
- Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma, USA
| | - Ricardo J Soares Magalhães
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, QLD, South Brisbane, Australia.,Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, QLD, Gatton, Australia
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27
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Adu-Gyasi D, Asante KP, Frempong MT, Gyasi DK, Iddrisu LF, Ankrah L, Dosoo D, Adeniji E, Agyei O, Gyaase S, Amenga-Etego S, Gyan B, Owusu-Agyei S. Epidemiology of soil transmitted Helminth infections in the middle-belt of Ghana, Africa. Parasite Epidemiol Control 2018; 3:e00071. [PMID: 29988303 PMCID: PMC6020085 DOI: 10.1016/j.parepi.2018.e00071] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 02/19/2018] [Accepted: 04/22/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Helminths are among the most widespread infectious agents prevalent in tropical and sub-tropical regions of the developing world defined by inadequate sanitation, poverty and unsafe water sources. This study was carried out to describe the distribution of helminth and malaria parasite infections in the middle-belt of Ghana in sub-Saharan Africa where disease burden, including anaemia is rife and helminths are perceived to be significant contributors of the burden. METHODS A cross-sectional survey involving 1826 residents located in the middle belt of Ghana where no or very little previous community-based helminth work had been carried out. The participants randomly recruited at household level provided biological samples collected over a 12-month period following a rigorous consenting process and these were analysed to describe the different types and seasonal distribution of helminths. FINDINGS Overall, 19.3% intestinal helminth infection prevalence was documented. Also based on parasites targeted for elimination, 12.1% Hookworm, 4.0% Hymenolepis nana/Hymenolepis dimunita, 1.5% Ascaris lumbricoides, 1.5% Taenia species, 0.9% Strongyloides stercoralis and 0.8% Trichuris trichiura, with about 1.0% polyphelminthiasis were recorded in the survey. About 55.4% and 44.4% of the participants had heavy hookworm and Trichuris infections respectively. Most of the Ascariasis (83.3%) infections were light in intensity. Hookworm infection was identified with significant odds considering decreasing age (OR = 2.09, p = 0.03), inappropriate footwear use (OR = 1.88, p = 0.021), malaria parasite co-infection (OR = 1.62, p = 0.018), not scrubbing nails during hand washing (OR = 0.68, p = 0.048), source of drinking water (OR = 2.51, p = 0.027) and religion (OR = 4.36, p = 0.002). CONCLUSIONS Hookworm infection was significantly higher in younger age groups and among those who did not have safe drinking water. Proper sanitation, protective footwear, religion and good personal hygiene practices were found to influence helminth and hookworm prevalence in the area. Malaria parasite coinfection with helminths, especially hookworm infections increased 2-fold.
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Affiliation(s)
- Dennis Adu-Gyasi
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
| | - Kwaku Poku Asante
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
| | - Margaret T. Frempong
- Kwame Nkrumah University of Science and Technology (KNUST), Department of Molecular Medicine, PMB, Kumasi, Ghana
| | | | | | - Love Ankrah
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
| | - David Dosoo
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
| | - Elisha Adeniji
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
| | - Oscar Agyei
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
| | - Stephaney Gyaase
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
| | - Seeba Amenga-Etego
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
| | - Ben Gyan
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Seth Owusu-Agyei
- Kintampo Health Research Centre, P O Box 200, Kintampo, Brong Ahafo, Ghana
- Institute of Health Research, University of Health & Allied Sciences, Ho. Ghana
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Kulinkina AV, Walz Y, Koch M, Biritwum NK, Utzinger J, Naumova EN. Improving spatial prediction of Schistosoma haematobium prevalence in southern Ghana through new remote sensors and local water access profiles. PLoS Negl Trop Dis 2018; 12:e0006517. [PMID: 29864165 PMCID: PMC6014678 DOI: 10.1371/journal.pntd.0006517] [Citation(s) in RCA: 10] [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: 09/16/2017] [Revised: 06/22/2018] [Accepted: 05/10/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Schistosomiasis is a water-related neglected tropical disease. In many endemic low- and middle-income countries, insufficient surveillance and reporting lead to poor characterization of the demographic and geographic distribution of schistosomiasis cases. Hence, modeling is relied upon to predict areas of high transmission and to inform control strategies. We hypothesized that utilizing remotely sensed (RS) environmental data in combination with water, sanitation, and hygiene (WASH) variables could improve on the current predictive modeling approaches. METHODOLOGY Schistosoma haematobium prevalence data, collected from 73 rural Ghanaian schools, were used in a random forest model to investigate the predictive capacity of 15 environmental variables derived from RS data (Landsat 8, Sentinel-2, and Global Digital Elevation Model) with fine spatial resolution (10-30 m). Five methods of variable extraction were tested to determine the spatial linkage between school-based prevalence and the environmental conditions of potential transmission sites, including applying the models to known human water contact locations. Lastly, measures of local water access and groundwater quality were incorporated into RS-based models to assess the relative importance of environmental and WASH variables. PRINCIPAL FINDINGS Predictive models based on environmental characterization of specific locations where people contact surface water bodies offered some improvement as compared to the traditional approach based on environmental characterization of locations where prevalence is measured. A water index (MNDWI) and topographic variables (elevation and slope) were important environmental risk factors, while overall, groundwater iron concentration predominated in the combined model that included WASH variables. CONCLUSIONS/SIGNIFICANCE The study helps to understand localized drivers of schistosomiasis transmission. Specifically, unsatisfactory water quality in boreholes perpetuates reliance on surface water bodies, indirectly increasing schistosomiasis risk and resulting in rapid reinfection (up to 40% prevalence six months following preventive chemotherapy). Considering WASH-related risk factors in schistosomiasis prediction can help shift the focus of control strategies from treating symptoms to reducing exposure.
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Affiliation(s)
- Alexandra V Kulinkina
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts, United States of America
| | - Yvonne Walz
- Institute for Environment and Human Security, United Nations University, Bonn, Germany
| | - Magaly Koch
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts, United States of America
- Center for Remote Sensing, Boston University, Boston, Massachusetts, United States of America
| | | | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Elena N Naumova
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
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Renal health after long-term exposure to tenofovir disoproxil fumarate (TDF) in HIV/HBV positive adults in Ghana. J Infect 2018; 76:515-521. [PMID: 29702139 DOI: 10.1016/j.jinf.2018.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/11/2018] [Accepted: 03/14/2018] [Indexed: 12/29/2022]
Abstract
OBJECTIVES The study assessed markers of renal health in HIV/HBV co-infected patients receiving TDF-containing antiretroviral therapy in Ghana. METHODS Urinary protein-to-creatinine ratio (uPCR) and albumin-to-protein ratio (uAPR) were measured cross-sectionally after a median of four years of TDF. At this time, alongside extensive laboratory testing, patients underwent evaluation of liver stiffness and blood pressure. The estimated glomerular filtration rate (eGFR) was measured longitudinally before and during TDF therapy. RESULTS Among 101 participants (66% women, median age 44 years, median CD4 count 572 cells/mm3) 21% and 17% had detectable HIV-1 RNA and HBV DNA, respectively. Overall 35% showed hypertension, 6% diabetes, 7% liver stiffness indicative of cirrhosis, and 18% urinary excretion of Schistosoma antigen. Tubular proteinuria occurred in 16% of patients and was independently predicted by female gender and hypertension. The eGFR declined by median 1.8 ml/min/year during TDF exposure (IQR -4.4, -0.0); more pronounced declines (≥ 5 ml/min/year) occurred in 22% of patients and were associated with receiving ritonavir-boosted lopinavir rather than efavirenz. HBV DNA, HBeAg, transaminases, and liver stiffness were not predictive of renal function abnormalities. CONCLUSIONS The findings mandate improved diagnosis and management of hypertension and suggest targeted laboratory monitoring of patients receiving TDF alongside a booster in sub-Saharan Africa.
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Nyarko R, Torpey K, Ankomah A. Schistosoma haematobium, Plasmodium falciparum infection and anaemia in children in Accra, Ghana. TROPICAL DISEASES TRAVEL MEDICINE AND VACCINES 2018; 4:3. [PMID: 29721329 PMCID: PMC5907294 DOI: 10.1186/s40794-018-0063-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 04/11/2018] [Indexed: 11/10/2022]
Abstract
Background Urinary Schistosomiasis and malaria are endemic in Sub-Saharan Africa. There are public health concerns and implications of these parasites. This study sought to assess the prevalence of malaria, urinary schistosomiasis, and anaemia in children of school going age in two municipalities in Ghana. Methods A cross-sectional study design was used to investigate the prevalence of S. haematobium, P. falciparum infection and the haemoglobin concentration of respondents. A total of 404 (231 males and 173 females) school children between ages 9 - 14 years (mean age 11.8 ± 1.4 years) were recruited for the survey. Urine and blood samples were collected using standard operating procedures for urinary schistosomiasis and malaria diagnosis. Haemoglobin concentration was measured using a Hemocue® Hb 201 m. Results The prevalence of mono-infection was 4.7 and 12.9% for S. haematobium and P. falciparum respectively with a small proportion (0.9%) of the respondents infected with both parasites. The prevalence of anaemia in the study population was 59.9%. The risk of developing anaemia was not associated with being infected with any of the parasites. All co-infected children had anaemia. Conclusion High prevalence of anaemia was observed within the study population. Prevalence of malaria was higher compared to schistosomiasis. Interventions to address the high levels of anaemia is required within the community. Electronic supplementary material The online version of this article (10.1186/s40794-018-0063-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ruth Nyarko
- School of Public Health, University of Ghana, P. O Box LG 13, Legon, Accra Ghana
| | - Kwasi Torpey
- School of Public Health, University of Ghana, P. O Box LG 13, Legon, Accra Ghana
| | - Augustine Ankomah
- School of Public Health, University of Ghana, P. O Box LG 13, Legon, Accra Ghana
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Forrer A, Khieu V, Schär F, Vounatsou P, Chammartin F, Marti H, Muth S, Odermatt P. Strongyloides stercoralis and hookworm co-infection: spatial distribution and determinants in Preah Vihear Province, Cambodia. Parasit Vectors 2018; 11:33. [PMID: 29329561 PMCID: PMC5767026 DOI: 10.1186/s13071-017-2604-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 12/25/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Strongyloides stercoralis and hookworm are two soil-transmitted helminths (STH) that are highly prevalent in Cambodia. Strongyloides stercoralis causes long-lasting infections and significant morbidity but is largely neglected, while hookworm causes the highest public health burden among STH. The two parasites have the same infection route, i.e. skin penetration. The extent of co-distribution, which could result in potential high co-morbidities, is unknown in highly endemic settings like Cambodia. The aim of this study was to predict the spatial distribution of S. stercoralis-hookworm co-infection risk and to investigate determinants of co-infection in Preah Vihear Province, North Cambodia. METHODS A cross-sectional survey was conducted in 2010 in 60 villages of Preah Vihear Province. Diagnosis was performed on two stool samples, using combined Baermann technique and Koga agar culture plate for S. stercoralis and Kato-Katz technique for hookworm. Bayesian multinomial geostatistical models were used to assess demographic, socioeconomic, and behavioural determinants of S. stercoralis-hookworm co-infection and to predict co-infection risk at non-surveyed locations. RESULTS Of the 2576 participants included in the study, 48.6% and 49.0% were infected with S. stercoralis and hookworm, respectively; 43.8% of the cases were co-infections. Females, preschool aged children, adults aged 19-49 years, and participants who reported regularly defecating in toilets, systematically boiling drinking water and having been treated with anthelmintic drugs had lower odds of co-infection. While S. stercoralis infection risk did not appear to be spatially structured, hookworm mono-infection and co-infection exhibited spatial correlation at about 20 km. Co-infection risk was positively associated with longer walking distances to a health centre and exhibited a small clustering tendency. The association was only partly explained by climatic variables, suggesting a role for underlying factors, such as living conditions and remoteness. CONCLUSIONS Both parasites were ubiquitous in the province, with co-infections accounting for almost half of all cases. The high prevalence of S. stercoralis calls for control measures. Despite several years of school-based de-worming programmes, hookworm infection levels remain high. Mebendazole efficacy, as well as coverage of and compliance to STH control programmes should be investigated.
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Affiliation(s)
- Armelle Forrer
- 0000 0004 0587 0574grid.416786.aSwiss Tropical and Public Health Institute, Basel, Switzerland
- 0000 0004 1937 0642grid.6612.3University of Basel, Basel, Switzerland
| | - Virak Khieu
- grid.415732.6National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | - Fabian Schär
- 0000 0004 0587 0574grid.416786.aSwiss Tropical and Public Health Institute, Basel, Switzerland
- 0000 0004 1937 0642grid.6612.3University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- 0000 0004 0587 0574grid.416786.aSwiss Tropical and Public Health Institute, Basel, Switzerland
- 0000 0004 1937 0642grid.6612.3University of Basel, Basel, Switzerland
| | - Frédérique Chammartin
- 0000 0004 0587 0574grid.416786.aSwiss Tropical and Public Health Institute, Basel, Switzerland
- 0000 0004 1937 0642grid.6612.3University of Basel, Basel, Switzerland
| | - Hanspeter Marti
- 0000 0004 0587 0574grid.416786.aSwiss Tropical and Public Health Institute, Basel, Switzerland
- 0000 0004 1937 0642grid.6612.3University of Basel, Basel, Switzerland
| | - Sinuon Muth
- grid.415732.6National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | - Peter Odermatt
- 0000 0004 0587 0574grid.416786.aSwiss Tropical and Public Health Institute, Basel, Switzerland
- 0000 0004 1937 0642grid.6612.3University of Basel, Basel, Switzerland
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Assoum M, Ortu G, Basáñez MG, Lau C, Clements ACA, Halton K, Fenwick A, Soares Magalhães RJ. Spatiotemporal distribution and population at risk of soil-transmitted helminth infections following an eight-year school-based deworming programme in Burundi, 2007-2014. Parasit Vectors 2017; 10:583. [PMID: 29169386 PMCID: PMC5701347 DOI: 10.1186/s13071-017-2505-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 10/29/2017] [Indexed: 11/19/2022] Open
Abstract
Background Investigating the effect of successive annual deworming rounds on the spatiotemporal distribution of infection prevalence and numbers at risk for soil-transmitted helminths (STHs) can help identify communities nearing elimination and those needing further interventions. In this study, we aim to quantify the impact of an 8-year mass drug administration (MDA) programme (from 2007 to 2014) on the spatiotemporal distribution of prevalence of STH infections and to estimate the number of school-aged children infected with STHs in Burundi. Methods During annual longitudinal school-based surveys in Burundi between 2007 and 2011, STH infection and anthropometric data for a total of 40,656 children were collected; these data were supplemented with data from a national survey conducted in 2014. Bayesian model based geostatistics (MBG) were used to generate predictive prevalence maps for each STH species and year. The numbers of children at-risk of infection per district between 2008 and 2014 were estimated as the product of the predictive prevalence maps and population density maps. Results Overall, the degree of spatial clustering of STH infections decreased between 2008 and 2011; in 2014 the geographical clusters of all STH infections reappeared. The reduction in prevalence was small for Ascaris lumbricoides and Trichuris trichiura in the centre and central north of the country. Our predictive prevalence maps for hookworm indicate a reduction in prevalence along the periphery of the country. The predicted number of children infected with any STH species decreased substantially between 2007 and 2011, but in 2014 there was an increase in the predicted number of children infected with A. lumbricoides and T. trichiura. In 2014, the districts with the highest predicted number of children infected with A. lumbricoides, T. trichiura and hookworms were Kibuye district (n = 128,903), Mabayi district (n = 35,302) and Kiremba (n = 87,511), respectively. Conclusions While the MDA programme in Burundi resulted in a reduction in STH prevalence, this reduction was spatiotemporally heterogeneous, with some pockets of high prevalence remaining, suggesting that treatment coverage and complementary interventions should be evaluated to improve impact. Electronic supplementary material The online version of this article (10.1186/s13071-017-2505-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mohamad Assoum
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia. .,UQ Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland (Gatton Campus), Via Warrego Highway QLD, Gatton, 4343, Australia. .,School of Medicine, The University of Queensland, Brisbane, Australia.
| | - Giuseppina Ortu
- Present address: Malaria Consortium Headquarters. Development House, 56-64 Leonard Street EC2A 4LT, London, UK
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine (St. Mary's Campus), Imperial College London, School of Public Health, Norfolk Place W2 1PG, London, UK
| | - Colleen Lau
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia.,Research School of Population Health, Australian National University, Canberra, Australia
| | - Archie C A Clements
- Research School of Population Health, Australian National University, Canberra, Australia
| | - Kate Halton
- Queensland University of Technology, Brisbane, Australia
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, W2 1PG, London, UK
| | - Ricardo J Soares Magalhães
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia.,UQ Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland (Gatton Campus), Via Warrego Highway QLD, Gatton, 4343, Australia
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Rivero MR, De Angelo C, Nuñez P, Salas M, Motta CE, Chiaretta A, Salomón OD, Liang S. Environmental and socio-demographic individual, family and neighborhood factors associated with children intestinal parasitoses at Iguazú, in the subtropical northern border of Argentina. PLoS Negl Trop Dis 2017; 11:e0006098. [PMID: 29155829 PMCID: PMC5714390 DOI: 10.1371/journal.pntd.0006098] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 12/04/2017] [Accepted: 11/05/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Intestinal parasitoses are a major concern for public health, especially in children from middle and low-income populations of tropical and subtropical areas. We examined the presence and co-infection of parasites in humans as well as parasitic environmental contamination in Puerto Iguazú, Argentina. We explored the environmental and socio-demographic characteristics of the persistence of parasites in children and their environment. METHODOLOGY/PRINCIPAL FINDINGS This cross-section survey was conducted among children population comprised into the area of the public health care centers of Iguazú during June 2013 to May 2016. Copro-parasitological status of 483 asymptomatic children was assessed. Simultaneously, a design-based sampling of 744 soil samples and 530 dog feces was used for characterize the environmental contamination. The 71.5% of these sites were contaminated. Sixteen genera were detected in the environment being hookworms (62.0%) the main pathogens group detected followed by Toxocara spp (16.3%), Trichuris spp (15.2%) and Giardia (6.5%). Total children prevalence raised 58.8%, detecting twelve genera of parasite with Giardia intestinalis as the most prevalent pathogen (29.0%) followed by Enterobius vermicularis (23.0%), Hymenolepis nana (12.4%) and hookworms (4.4%). Through questionnaires and census data, we characterized the socio-demographics conditions at an individual, family and neighborhood levels. A multi-level analysis including environmental contamination data showed that the ´presence of parasites´ was mostly determined by individual (e.g. age, playing habits, previous treatment) and household level (e.g. UBN, WASH, mother's literacy) determinants. Remarkably, to define the level of 'parasite co-infection', besides individual and household characteristics, environmental factors at a neighborhood level were important. CONCLUSION/SIGNIFICANCE Our work represents the major survey of intestinal parasites in human and environmental samples developed in the region. High prevalence was detected in the children population as well as in their environment. This work shows the importance of considering and promoting multi-level actions over the identified determinants to face this public health problem from integrative approaches.
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Affiliation(s)
- Maria Romina Rivero
- Instituto Nacional de Medicina Tropical, INMeT. Ministerio de Salud de la Nación. Puerto Iguazú, Misiones. Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET. Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Carlos De Angelo
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET. Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
- Instituto de Biología Subtropical (IBS, UNaM-CONICET). Puerto Iguazú, Misiones. Argentina
- Assoc. Civil Centro de Investigaciones del Bosque Atlántico (CeIBA). Puerto Iguazú, Misiones. Argentina
| | - Pablo Nuñez
- Instituto Nacional de Medicina Tropical, INMeT. Ministerio de Salud de la Nación. Puerto Iguazú, Misiones. Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET. Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Martín Salas
- Instituto Nacional de Medicina Tropical, INMeT. Ministerio de Salud de la Nación. Puerto Iguazú, Misiones. Argentina
| | - Carlos E. Motta
- Departamento de Patología Animal, Facultad de Agronomía y Veterinaria, Universidad Nacional de Rio Cuarto. Rio Cuarto, Córdoba. Argentina
| | - Alicia Chiaretta
- Departamento de Patología Animal, Facultad de Agronomía y Veterinaria, Universidad Nacional de Rio Cuarto. Rio Cuarto, Córdoba. Argentina
| | - Oscar D. Salomón
- Instituto Nacional de Medicina Tropical, INMeT. Ministerio de Salud de la Nación. Puerto Iguazú, Misiones. Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET. Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Song Liang
- Department of Environmental and Global Health, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
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Osei FB, Stein A. Spatio-temporal analysis of small-area intestinal parasites infections in Ghana. Sci Rep 2017; 7:12217. [PMID: 28939818 PMCID: PMC5610349 DOI: 10.1038/s41598-017-12397-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/30/2017] [Indexed: 12/23/2022] Open
Abstract
Intestinal parasites infection is a major public health burden in low and middle-income countries. In Ghana, it is amongst the top five morbidities. In order to optimize scarce resources, reliable information on its geographical distribution is needed to guide periodic mass drug administration to populations of high risk. We analyzed district level morbidities of intestinal parasites between 2010 and 2014 using exploratory spatial analysis and geostatistics. We found a significantly positive Moran’s Index of spatial autocorrelation for each year, suggesting that adjoining districts have similar risk levels. Using local Moran’s Index, we found high-high clusters extending towards the Guinea and Sudan Savannah ecological zones, whereas low-low clusters extended within the semi-deciduous forest and transitional ecological zones. Variograms indicated that local and regional scale risk factors modulate the variation of intestinal parasites. Poisson kriging maps showed smoothed spatially varied distribution of intestinal parasites risk. These emphasize the need for a follow-up investigation into the exact determining factors modulating the observed patterns. The findings also underscored the potential of exploratory spatial analysis and geostatistics as tools for visualizing the spatial distribution of small area intestinal worms infections.
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Affiliation(s)
- F B Osei
- Department of Mathematics and Statistics, University of Energy and Natural Resources, Sunyani, Ghana. .,Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, Enschede, Netherlands.
| | - A Stein
- Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, Enschede, Netherlands
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Madinga J, Polman K, Kanobana K, van Lieshout L, Brienen E, Praet N, Kabwe C, Gabriël S, Dorny P, Lutumba P, Speybroeck N. Epidemiology of polyparasitism with Taenia solium, schistosomes and soil-transmitted helminths in the co-endemic village of Malanga, Democratic Republic of Congo. Acta Trop 2017; 171:186-193. [PMID: 28336269 DOI: 10.1016/j.actatropica.2017.03.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 03/10/2017] [Accepted: 03/18/2017] [Indexed: 11/27/2022]
Abstract
Helminth co-infections are common in sub-Saharan Africa. However, little is known about the distribution and determinants of co-infections with Taenia solium taeniasis/cysticercosis. Building on a previous community-based study on human cysticercosis in Malanga village, we investigated co-infections with Taenia solium, soil-transmitted helminths (STHs) and Schistosoma spp and associated risk factors in a random subsample of 330 participants. Real time PCR assays were used to detect DNA of soil-transmitted helminths (STHs), T. solium and Schistosoma in stool samples and Schistosoma DNA in urine samples. Serum samples were tested for T. solium cysticercosis using the B158/B60 monoclonal antibody-based antigen ELISA. Bivariate analysis and logistic regression were applied to assess associations of single and co-infections with common risk factors (age, sex, area, hygiene) as well as pair wise associations between helminth species. Overall, 240 (72.7%) participants were infected with at least one helminth species; 128 (38.8%) harbored at least two helminth species (16.1% with STHs-Schistosoma, 14.5% with STHs-T. solium taeniasis/cysticercosis and 8.2% with Schistosoma-T. solium taeniasis/cysticercosis co-infections). No significant associations were found between Schistosoma-T. solium taeniasis/cysticercosis co-infection and any of the risk factors studied. Males (OR=2 (95%CI=1.1-5), p=0.03) and open defecation behavior (OR=3.8 (95%CI=1.1-6.5), p=0.04) were associated with higher odds of STHs-T. solium taeniasis/cysticercosis co-infection. Village districts that were found at high risk of T. solium taeniasis/cysticercosis were also at high risk of co-infection with STHs and T. solium taeniasis/cysticercosis (OR=3.2 (95%CI=1.1-7.8), p=0.03). Significant pair-wise associations were found between T. solium cysticerci and Necator americanus (OR=2.2 (95%CI=1.2-3.8), p<0.01) as well as Strongyloides stercoralis (OR=2.7 (95%CI=1.1-6.5), p=0.02). These findings show that co-infections with T. solium are common in this polyparasitic community in DRC. Our results on risk factors of helminth co-infections and specific associations between helminths may contribute to a better integration of control within programmes that target more than one NTD.
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Owada K, Nielsen M, Lau CL, Clements ACA, Yakob L, Soares Magalhães RJ. Measuring the Effect of Soil-Transmitted Helminth Infections on Cognitive Function in Children: Systematic Review and Critical Appraisal of Evidence. ADVANCES IN PARASITOLOGY 2017; 98:1-37. [PMID: 28942767 DOI: 10.1016/bs.apar.2017.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recently the role of soil-transmitted helminth (STH) infections in children's cognitive developmental impairment has been under scrutiny. We conducted a systematic review of the evidence for associations between STH infections and cognitive function of children using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. We aimed to identify the domains of cognitive function in three age strata (<24months, 24-59months and ≥60months) and critically appraise the general design protocol of the studies, with a focus on the cognitive function measurement tools used. A total of 42 papers fulfilled the inclusion criteria, including 10 studies from a recent Cochrane review. Our findings demonstrate variation in tested domains, lack of consistency in the use of measurement tools and analysis of results. Cognitive function measures in children aged under 59months have been mainly limited to domains of gross motor, fine motor and language skills, whereas in children aged 60months and above most studies tested domains such as memory and processing speed. Even within the same age group the results on the association between STH infections and measures of cognitive development were often conflicting. The current study highlights the need for methodological consensus in the use of measurement tools and data analysis protocols if the effect of STH infections on cognitive function domains in children is to be correctly established. This will be an imperative next step to generate conclusive evidence of the role of STH infections in cognitive development in children.
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Affiliation(s)
- Kei Owada
- School of Medicine, The University of Queensland, South Brisbane, QLD, Australia; Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD, Australia
| | - Mark Nielsen
- School of Psychology, The University of Queensland, St Lucia, QLD, Australia; Faculty of Humanities, University of Johannesburg, Auckland Park, South Africa
| | - Colleen L Lau
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia; Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD, Australia
| | - Archie C A Clements
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ricardo J Soares Magalhães
- Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia; Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD, Australia
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Knowles SCL, Sturrock HJW, Turner H, Whitton JM, Gower CM, Jemu S, Phillips AE, Meite A, Thomas B, Kollie K, Thomas C, Rebollo MP, Styles B, Clements M, Fenwick A, Harrison WE, Fleming FM. Optimising cluster survey design for planning schistosomiasis preventive chemotherapy. PLoS Negl Trop Dis 2017; 11:e0005599. [PMID: 28552961 PMCID: PMC5464666 DOI: 10.1371/journal.pntd.0005599] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 06/08/2017] [Accepted: 04/26/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The cornerstone of current schistosomiasis control programmes is delivery of praziquantel to at-risk populations. Such preventive chemotherapy requires accurate information on the geographic distribution of infection, yet the performance of alternative survey designs for estimating prevalence and converting this into treatment decisions has not been thoroughly evaluated. METHODOLOGY/PRINCIPAL FINDINGS We used baseline schistosomiasis mapping surveys from three countries (Malawi, Côte d'Ivoire and Liberia) to generate spatially realistic gold standard datasets, against which we tested alternative two-stage cluster survey designs. We assessed how sampling different numbers of schools per district (2-20) and children per school (10-50) influences the accuracy of prevalence estimates and treatment class assignment, and we compared survey cost-efficiency using data from Malawi. Due to the focal nature of schistosomiasis, up to 53% simulated surveys involving 2-5 schools per district failed to detect schistosomiasis in low endemicity areas (1-10% prevalence). Increasing the number of schools surveyed per district improved treatment class assignment far more than increasing the number of children sampled per school. For Malawi, surveys of 15 schools per district and 20-30 children per school reliably detected endemic schistosomiasis and maximised cost-efficiency. In sensitivity analyses where treatment costs and the country considered were varied, optimal survey size was remarkably consistent, with cost-efficiency maximised at 15-20 schools per district. CONCLUSIONS/SIGNIFICANCE Among two-stage cluster surveys for schistosomiasis, our simulations indicated that surveying 15-20 schools per district and 20-30 children per school optimised cost-efficiency and minimised the risk of under-treatment, with surveys involving more schools of greater cost-efficiency as treatment costs rose.
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Affiliation(s)
- Sarah C. L. Knowles
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- * E-mail:
| | - Hugh J. W. Sturrock
- Global Health Group, University of California San Francisco, San Francisco, California, United States of America
| | - Hugo Turner
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
| | - Jane M. Whitton
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Charlotte M. Gower
- The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
| | - Samuel Jemu
- Ministry of Health, Capital City, Lilongwe 3, Malawi
| | - Anna E. Phillips
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Aboulaye Meite
- Ministry of Health and Social Welfare of Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Brent Thomas
- Fliarial Programme Support Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Karsor Kollie
- Neglected Tropical and Non Communicable Diseases Program, Ministry of Health and Social Welfare, Monrovia 10, Liberia
| | - Catherine Thomas
- Neglected Tropical and Non Communicable Diseases Program, Ministry of Health and Social Welfare, Monrovia 10, Liberia
| | - Maria P. Rebollo
- Fliarial Programme Support Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Ben Styles
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- National Foundation for Educational Research, Upton Park, Slough, United Kingdom
| | - Michelle Clements
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Wendy E. Harrison
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Fiona M. Fleming
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
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Wang C, Torgerson PR, Höglund J, Furrer R. Zero-inflated hierarchical models for faecal egg counts to assess anthelmintic efficacy. Vet Parasitol 2017; 235:20-28. [DOI: 10.1016/j.vetpar.2016.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 12/09/2016] [Accepted: 12/11/2016] [Indexed: 10/20/2022]
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Mapping Soil Transmitted Helminths and Schistosomiasis under Uncertainty: A Systematic Review and Critical Appraisal of Evidence. PLoS Negl Trop Dis 2016; 10:e0005208. [PMID: 28005901 PMCID: PMC5179027 DOI: 10.1371/journal.pntd.0005208] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/23/2016] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Spatial modelling of STH and schistosomiasis epidemiology is now commonplace. Spatial epidemiological studies help inform decisions regarding the number of people at risk as well as the geographic areas that need to be targeted with mass drug administration; however, limited attention has been given to propagated uncertainties, their interpretation, and consequences for the mapped values. Using currently published literature on the spatial epidemiology of helminth infections we identified: (1) the main uncertainty sources, their definition and quantification and (2) how uncertainty is informative for STH programme managers and scientists working in this domain. METHODOLOGY/PRINCIPAL FINDINGS We performed a systematic literature search using the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) protocol. We searched Web of Knowledge and PubMed using a combination of uncertainty, geographic and disease terms. A total of 73 papers fulfilled the inclusion criteria for the systematic review. Only 9% of the studies did not address any element of uncertainty, while 91% of studies quantified uncertainty in the predicted morbidity indicators and 23% of studies mapped it. In addition, 57% of the studies quantified uncertainty in the regression coefficients but only 7% incorporated it in the regression response variable (morbidity indicator). Fifty percent of the studies discussed uncertainty in the covariates but did not quantify it. Uncertainty was mostly defined as precision, and quantified using credible intervals by means of Bayesian approaches. CONCLUSION/SIGNIFICANCE None of the studies considered adequately all sources of uncertainties. We highlighted the need for uncertainty in the morbidity indicator and predictor variable to be incorporated into the modelling framework. Study design and spatial support require further attention and uncertainty associated with Earth observation data should be quantified. Finally, more attention should be given to mapping and interpreting uncertainty, since they are relevant to inform decisions regarding the number of people at risk as well as the geographic areas that need to be targeted with mass drug administration.
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Ortu G, Assoum M, Wittmann U, Knowles S, Clements M, Ndayishimiye O, Basáñez MG, Lau C, Clements A, Fenwick A, Magalhaes RJS. The impact of an 8-year mass drug administration programme on prevalence, intensity and co-infections of soil-transmitted helminthiases in Burundi. Parasit Vectors 2016; 9:513. [PMID: 27660114 PMCID: PMC5034474 DOI: 10.1186/s13071-016-1794-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 09/07/2016] [Indexed: 11/18/2022] Open
Abstract
Background Soil-transmitted helminth (STH) infections are amongst the most prevalent infections in the world. Mass drug administration (MDA) programmes have become the most commonly used national interventions for endemic countries to achieve elimination. This paper aims to describe the effect of an 8-year MDA programme on the prevalence, intensity of infection and co-infection of STH in Burundi from 2007 to 2014 and critically appraise the trajectory towards STH elimination in the country. Results Annual STH parasitological surveys (specifically, a “pilot study” from 2007 to 2011, an “extension study” from 2008 to 2011, and a “national reassessment” in 2014; n = 27,658 children), showed a significant drop in prevalence of infection with any STH (“pooled STH”) between baseline and 2011 in both studies, falling from 32 to 16 % in the pilot study, and from 35 to 16 % in the extension study. Most STH infections were of low intensity according to WHO classification. The national reassessment in 2014 showed that prevalence of pooled STH remained significantly below the prevalence in 2007 in both studies but there was no further decrease in STH prevalence from 2011 levels during this time. Spatial dependence analysis showed that prevalence of Trichuris trichiura and Ascaris lumbricoides had a tendency to cluster over the years, whilst only trends in spatial dependence were evident for hookworm infections. Spatial dependence fluctuated over the course of the programme for Ascaris lumbricoides and Trichuris trichiura. However, spatial trends in spatial dependence were evident in 2010 for Ascaris lumbricoides. Analysis of spatial clustering of intensity of infection and heavy infections revealed that the intensity changed over time for all parasites. Heavy intensity was only evident in Ascaris lumbricoides for 2008 and did not appear in proceeding years and other parasites. Conclusions These results demonstrate that sustained annual MDA significantly reduced the prevalence of STH infection in school-age children but was unable to achieve elimination. Additionally, significant decline in prevalence was accompanied by a drop in spatial clustering of infection indicators across all sites from 2008. The lack of consistency in the results of the spatial dependence analysis highlights that MDA programmes can interrupt the normal transmission dynamics of STH parasites. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1794-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Giuseppina Ortu
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK.
| | - Mohamad Assoum
- School of Medicine, The University of Queensland, Brisbane, Australia.,Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia
| | - Udo Wittmann
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Sarah Knowles
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Michelle Clements
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Onésime Ndayishimiye
- Programme National Intégré de lutte contre les Maladies Tropicales Négligées et la Cécité (PNIMTNC) - Ministère de la Santé Publique et de la lutte contre le SIDA, Bujumbura, Burundi
| | - Maria-Gloria Basáñez
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK.,London Centre for Neglected Tropical Disease Research, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Colleen Lau
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia.,Research School of Population Health, Australian National University, Canberra, Australia
| | - Archie Clements
- Research School of Population Health, Australian National University, Canberra, Australia
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Ricardo J Soares Magalhaes
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia.,School of Veterinary Science, The University of Queensland (Gatton Campus), Via Warrego Highway, Gatton, QLD, 4343, Australia
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Phiri BB, Ngwira B, Kazembe LN. Analysing risk factors of co-occurrence of schistosomiasis haematobium and hookworm using bivariate regression models: Case study of Chikwawa, Malawi. Parasite Epidemiol Control 2016; 1:149-158. [PMID: 29988186 PMCID: PMC5991826 DOI: 10.1016/j.parepi.2016.02.001] [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: 11/29/2015] [Revised: 02/20/2016] [Accepted: 02/20/2016] [Indexed: 11/23/2022] Open
Abstract
Schistosomiasis and soil-transmitted helminth (STH) infections constitute a major public health problem in many parts of sub-Saharan Africa. In areas where prevalence of geo-helminths and schistosomes is high, co-infection with multiple parasite species is common, resulting in disproportionately elevated burden compared with single infections. Determining risk factors of co-infection intensity is important for better design of targeted interventions. In this paper, we examined risk factors of hookworm and S. haematobium co-infection intensity, in Chikwawa district, southern Malawi in 2005, using bivariate count models. Results show that hookworm and S. haematobium infections were much localised with small proportion of individuals harbouring more parasites especially among school-aged children. The risk of co-intensity with both hookworm and S. haematobium was high for all ages, although this diminished with increasing age, increased with fishing (hookworm: coefficient. = 12.29; 95% CI = 11.50-13.09; S. haematobium: 0.040; 95% CI = 0.0037, 3.832). Both infections were abundant in those with primary education (hookworm: coef. = 0.072; 95% CI = 0.056, 0.401 and S. haematobium: coef. = 0.286; 95% CI = 0.034, 0.538). However, much lower risk was observed for those who were farmers (hookworm: coef. = - 0.349, 95% CI = - 0.547,-0.150; S. haematobium: coef. - 0.239, 95% CI = - 0.406, - 0.072). In conclusion, our findings suggest that efforts to control helminths infection should be co-integrated and health promotion campaigns should be aimed at school-going children and adults who are in constant contact with water.
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Affiliation(s)
- Bruce B.W. Phiri
- Mathematical Sciences Department, Chancellor College, University of Malawi, PO Box 280, Zomba, Malawi
| | - Bagrey Ngwira
- Department of Environmental Health, The Polytechnic, University of Malawi, P/Bag 333 Chichiri Blantyre 3, Malawi
| | - Lawrence N. Kazembe
- Department of Statistics and Population Studies, University of Namibia, P/Bag 13301, Pionerspark, Windhoek, Namibia
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Li XX, Ren ZP, Wang LX, Zhang H, Jiang SW, Chen JX, Wang JF, Zhou XN. Co-endemicity of Pulmonary Tuberculosis and Intestinal Helminth Infection in the People's Republic of China. PLoS Negl Trop Dis 2016; 10:e0004580. [PMID: 27088504 PMCID: PMC4835095 DOI: 10.1371/journal.pntd.0004580] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 03/05/2016] [Indexed: 11/19/2022] Open
Abstract
Both pulmonary tuberculosis (PTB) and intestinal helminth infection (IHI) affect millions of individuals every year in China. However, the national-scale estimation of prevalence predictors and prevalence maps for these diseases, as well as co-endemic relative risk (RR) maps of both diseases' prevalence are not well developed. There are co-endemic, high prevalence areas of both diseases, whose delimitation is essential for devising effective control strategies. Bayesian geostatistical logistic regression models including socio-economic, climatic, geographical and environmental predictors were fitted separately for active PTB and IHI based on data from the national surveys for PTB and major human parasitic diseases that were completed in 2010 and 2004, respectively. Prevalence maps and co-endemic RR maps were constructed for both diseases by means of Bayesian Kriging model and Bayesian shared component model capable of appraising the fraction of variance of spatial RRs shared by both diseases, and those specific for each one, under an assumption that there are unobserved covariates common to both diseases. Our results indicate that gross domestic product (GDP) per capita had a negative association, while rural regions, the arid and polar zones and elevation had positive association with active PTB prevalence; for the IHI prevalence, GDP per capita and distance to water bodies had a negative association, the equatorial and warm zones and the normalized difference vegetation index had a positive association. Moderate to high prevalence of active PTB and low prevalence of IHI were predicted in western regions, low to moderate prevalence of active PTB and low prevalence of IHI were predicted in north-central regions and the southeast coastal regions, and moderate to high prevalence of active PTB and high prevalence of IHI were predicted in the south-western regions. Thus, co-endemic areas of active PTB and IHI were located in the south-western regions of China, which might be determined by socio-economic factors, such as GDP per capita.
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Affiliation(s)
- Xin-Xu Li
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People’s Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, WHO Collaborating Centre for Tropical Diseases, Shanghai, People’s Republic of China
- National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Zhou-Peng Ren
- State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Li-Xia Wang
- National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Hui Zhang
- National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Shi-Wen Jiang
- National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Jia-Xu Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People’s Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, WHO Collaborating Centre for Tropical Diseases, Shanghai, People’s Republic of China
| | - Jin-Feng Wang
- State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People’s Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, WHO Collaborating Centre for Tropical Diseases, Shanghai, People’s Republic of China
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Hamm NAS, Soares Magalhães RJ, Clements ACA. Earth Observation, Spatial Data Quality, and Neglected Tropical Diseases. PLoS Negl Trop Dis 2015; 9:e0004164. [PMID: 26678393 PMCID: PMC4683053 DOI: 10.1371/journal.pntd.0004164] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Earth observation (EO) is the use of remote sensing and in situ observations to gather data on the environment. It finds increasing application in the study of environmentally modulated neglected tropical diseases (NTDs). Obtaining and assuring the quality of the relevant spatially and temporally indexed EO data remain challenges. Our objective was to review the Earth observation products currently used in studies of NTD epidemiology and to discuss fundamental issues relating to spatial data quality (SDQ), which limit the utilization of EO and pose challenges for its more effective use. We searched Web of Science and PubMed for studies related to EO and echinococossis, leptospirosis, schistosomiasis, and soil-transmitted helminth infections. Relevant literature was also identified from the bibliographies of those papers. We found that extensive use is made of EO products in the study of NTD epidemiology; however, the quality of these products is usually given little explicit attention. We review key issues in SDQ concerning spatial and temporal scale, uncertainty, and the documentation and use of quality information. We give examples of how these issues may interact with uncertainty in NTD data to affect the output of an epidemiological analysis. We conclude that researchers should give careful attention to SDQ when designing NTD spatial-epidemiological studies. This should be used to inform uncertainty analysis in the epidemiological study. SDQ should be documented and made available to other researchers.
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Affiliation(s)
- Nicholas A. S. Hamm
- Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, Enschede, The Netherlands
- * E-mail:
| | - Ricardo J. Soares Magalhães
- School of Veterinary Science, University of Queensland, Brisbane, Australia
- Child Health Research Centre, University of Queensland, Brisbane, Australia
| | - Archie C. A. Clements
- Research School of Population Health, The Australian National University, Canberra, Australia
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Soares Magalhães RJ, Salamat MS, Leonardo L, Gray DJ, Carabin H, Halton K, McManus DP, Williams GM, Rivera P, Saniel O, Hernandez L, Yakob L, McGarvey ST, Clements ACA. Mapping the Risk of Soil-Transmitted Helminthic Infections in the Philippines. PLoS Negl Trop Dis 2015; 9:e0003915. [PMID: 26368819 PMCID: PMC4569387 DOI: 10.1371/journal.pntd.0003915] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/16/2015] [Indexed: 11/19/2022] Open
Abstract
Background In order to increase the efficient allocation of soil-transmitted helminth (STH) disease control resources in the Philippines, we aimed to describe for the first time the spatial variation in the prevalence of A. lumbricoides, T. trichiura and hookworm across the country, quantify the association between the physical environment and spatial variation of STH infection and develop predictive risk maps for each infection. Methodology/Principal Findings Data on STH infection from 35,573 individuals across the country were geolocated at the barangay level and included in the analysis. The analysis was stratified geographically in two major regions: 1) Luzon and the Visayas and 2) Mindanao. Bayesian geostatistical models of STH prevalence were developed, including age and sex of individuals and environmental variables (rainfall, land surface temperature and distance to inland water bodies) as predictors, and diagnostic uncertainty was incorporated. The role of environmental variables was different between regions of the Philippines. This analysis revealed that while A. lumbricoides and T. trichiura infections were widespread and highly endemic, hookworm infections were more circumscribed to smaller foci in the Visayas and Mindanao. Conclusions/Significance This analysis revealed significant spatial variation in STH infection prevalence within provinces of the Philippines. This suggests that a spatially targeted approach to STH interventions, including mass drug administration, is warranted. When financially possible, additional STH surveys should be prioritized to high-risk areas identified by our study in Luzon. Soil-transmitted helminth (STH) infections with A. lumbricoides, T. trichiura and hookworms are endemic in all 80 provinces of the Philippines, but the spatial variation in the prevalence of these infections has not been previously described. This analysis revealed that while A. lumbricoides and T. trichiura infections were widespread and highly endemic, hookworm infections were more circumscribed to smaller foci in the Visayas and Mindanao. The results also suggest that it may be necessary to place greater emphasis on improving the provision of water, sanitation and the promotion of behavioral change for improved hygiene for the control and prevention of STH infections, particularly for hookworm.
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Affiliation(s)
- Ricardo J. Soares Magalhães
- School of Veterinary Science, The University of Queensland, Gatton Campus, Gatton, Australia
- Children’s Health and Environment Program, Queensland Children’s Medical Research Institute, The University of Queensland, Herston Campus, Herston, Australia
- University of Queensland, Infectious Disease Epidemiology Unit, School of Population Health, Herston, Queensland, Australia
- * E-mail:
| | - Maria S. Salamat
- University of the Philippines Manila, College of Public Health, Department of Parasitology, Manila, Philippines
| | - Lydia Leonardo
- University of the Philippines Manila, College of Public Health, Department of Parasitology, Manila, Philippines
| | - Darren J. Gray
- University of Queensland, Infectious Disease Epidemiology Unit, School of Population Health, Herston, Queensland, Australia
- Research School of Population Health, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Hélène Carabin
- Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Kate Halton
- Institute for Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Donald P. McManus
- Infectious Disease Division, QIMR-Berghoffer Medical Research Institute, Herston, Queensland, Australia
| | - Gail M. Williams
- University of Queensland, Infectious Disease Epidemiology Unit, School of Population Health, Herston, Queensland, Australia
| | - Pilarita Rivera
- University of the Philippines Manila, College of Public Health, Department of Parasitology, Manila, Philippines
| | - Ofelia Saniel
- University of the Philippines Manila, College of Public Health, Department of Epidemiology and Biostatistics, Manila, Philippines
| | - Leda Hernandez
- Philippine Department of Health, National Center for Disease Prevention and Control, Manila, Philippines
| | - Laith Yakob
- London School of Hygiene & Tropical Medicine, Department of Disease Control, London, United Kingdom
| | - Stephen T. McGarvey
- International Health Institute, Brown University, Providence, Rhode Island, United States of America
| | - Archie C. A. Clements
- University of Queensland, Infectious Disease Epidemiology Unit, School of Population Health, Herston, Queensland, Australia
- Research School of Population Health, The Australian National University, Canberra, Australian Capital Territory, Australia
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Lai YS, Biedermann P, Ekpo UF, Garba A, Mathieu E, Midzi N, Mwinzi P, N'Goran EK, Raso G, Assaré RK, Sacko M, Schur N, Talla I, Tchuenté LAT, Touré S, Winkler MS, Utzinger J, Vounatsou P. Spatial distribution of schistosomiasis and treatment needs in sub-Saharan Africa: a systematic review and geostatistical analysis. THE LANCET. INFECTIOUS DISEASES 2015; 15:927-40. [PMID: 26004859 DOI: 10.1016/s1473-3099(15)00066-3] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 01/26/2015] [Accepted: 02/24/2015] [Indexed: 01/13/2023]
Abstract
BACKGROUND Schistosomiasis affects more than 200 million individuals, mostly in sub-Saharan Africa, but empirical estimates of the disease burden in this region are unavailable. We used geostatistical modelling to produce high-resolution risk estimates of infection with Schistosoma spp and of the number of doses of praziquantel treatment needed to prevent morbidity at different administrative levels in 44 countries. METHODS We did a systematic review to identify surveys including schistosomiasis prevalence data in sub-Saharan Africa via PubMed, ISI Web of Science, and African Journals Online, from inception to May 2, 2014, with no restriction of language, survey date, or study design. We used Bayesian geostatistical meta-analysis and rigorous variable selection to predict infection risk over a grid of 1 155 818 pixels at 5 × 5 km, on the basis of environmental and socioeconomic predictors and to calculate the number of doses of praziquantel needed for prevention of morbidity. FINDINGS The literature search identified Schistosoma haematobium and Schistosoma mansoni surveys done in, respectively, 9318 and 9140 unique locations. Infection risk decreased from 2000 onwards, yet estimates suggest that 163 million (95% Bayesian credible interval [CrI] 155 million to 172 million; 18·5%, 17·6-19·5) of the sub-Saharan African population was infected in 2012. Mozambique had the highest prevalence of schistosomiasis in school-aged children (52·8%, 95% CrI 48·7-57·8). Low-risk countries (prevalence among school-aged children lower than 10%) included Burundi, Equatorial Guinea, Eritrea, and Rwanda. The numbers of doses of praziquantel needed per year were estimated to be 123 million (95% CrI 121 million to 125 million) for school-aged children and 247 million (239 million to 256 million) for the entire population. INTERPRETATION Our results will inform policy makers about the number of treatments needed at different levels and will guide the spatial targeting of schistosomiasis control interventions. FUNDING European Research Council, China Scholarship Council, UBS Optimus Foundation, and Swiss National Science Foundation.
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Affiliation(s)
- Ying-Si Lai
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland
| | - Patricia Biedermann
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland
| | - Uwem F Ekpo
- Department of Biological Sciences, Federal University of Agriculture, Abeokuta, Nigeria
| | - Amadou Garba
- Réseau International Schistosomose, Environnement, Amenagement et Lutte, Niamey, Niger
| | - Els Mathieu
- National Center of Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Pauline Mwinzi
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Eliézer K N'Goran
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Giovanna Raso
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland
| | - Rufin K Assaré
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Moussa Sacko
- Institut National de Recherche en Santé Publique, Bamako, Mali
| | - Nadine Schur
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland
| | - Idrissa Talla
- Direction de la Lutte Contre la Maladie, Ministère de la Santé, Dakar, Senegal
| | - Louis-Albert Tchuem Tchuenté
- Laboratory of Parasitology and Ecology, University of Yaoundé, and Center for Schistosomiasis and Parasitology, Yaoundé, Cameroon
| | - Seydou Touré
- Programme National de Lutte Contre la Schistosomiase, Ministère de la Santé, Ouagadougou, Burkina Faso
| | - Mirko S Winkler
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
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Forrer A, Vounatsou P, Sayasone S, Vonghachack Y, Bouakhasith D, Utzinger J, Akkhavong K, Odermatt P. Risk profiling of hookworm infection and intensity in southern Lao People's Democratic Republic using Bayesian models. PLoS Negl Trop Dis 2015; 9:e0003486. [PMID: 25822794 PMCID: PMC4378892 DOI: 10.1371/journal.pntd.0003486] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 12/17/2014] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Among the common soil-transmitted helminth infections, hookworm causes the highest burden. Previous research in the southern part of Lao People's Democratic Republic (Lao PDR) revealed high prevalence rates of hookworm infection. The purpose of this study was to predict the spatial distribution of hookworm infection and intensity, and to investigate risk factors in the Champasack province, southern Lao PDR. METHODOLOGY A cross-sectional parasitological and questionnaire survey was conducted in 51 villages. Data on demography, socioeconomic status, water, sanitation, and behavior were combined with remotely sensed environmental data. Bayesian mixed effects logistic and negative binomial models were utilized to investigate risk factors and spatial distribution of hookworm infection and intensity, and to make predictions for non-surveyed locations. PRINCIPAL FINDINGS A total of 3,371 individuals were examined with duplicate Kato-Katz thick smears and revealed a hookworm prevalence of 48.8%. Most infections (91.7%) were of light intensity (1-1,999 eggs/g of stool). Lower hookworm infection levels were associated with higher socioeconomic status. The lowest infection levels were found in preschool-aged children. Overall, females were at lower risk of infection, but women aged 50 years and above harbored the heaviest hookworm infection intensities. Hookworm was widespread in Champasack province with little evidence for spatial clustering. Infection risk was somewhat lower in the lowlands, mostly along the western bank of the Mekong River, while infection intensity was homogeneous across the Champasack province. CONCLUSIONS/SIGNIFICANCE Hookworm transmission seems to occur within, rather than between villages in Champasack province. We present spatial risk maps of hookworm infection and intensity, which suggest that control efforts should be intensified in the Champasack province, particularly in mountainous areas.
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Affiliation(s)
- Armelle Forrer
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Somphou Sayasone
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- National Institute of Public Health, Ministry of Health, Vientiane, Lao People’s Democratic Republic
| | - Youthanavanh Vonghachack
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Faculty of Basic Sciences, University of Health Sciences, Vientiane, Lao People’s Democratic Republic
| | - Dalouny Bouakhasith
- Faculty of Basic Sciences, University of Health Sciences, Vientiane, Lao People’s Democratic Republic
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Kongsap Akkhavong
- National Institute of Public Health, Ministry of Health, Vientiane, Lao People’s Democratic Republic
| | - Peter Odermatt
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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Walz Y, Wegmann M, Dech S, Raso G, Utzinger J. Risk profiling of schistosomiasis using remote sensing: approaches, challenges and outlook. Parasit Vectors 2015; 8:163. [PMID: 25890278 PMCID: PMC4406176 DOI: 10.1186/s13071-015-0732-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/12/2015] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Schistosomiasis is a water-based disease that affects an estimated 250 million people, mainly in sub-Saharan Africa. The transmission of schistosomiasis is spatially and temporally restricted to freshwater bodies that contain schistosome cercariae released from specific snails that act as intermediate hosts. Our objective was to assess the contribution of remote sensing applications and to identify remaining challenges in its optimal application for schistosomiasis risk profiling in order to support public health authorities to better target control interventions. METHODS We reviewed the literature (i) to deepen our understanding of the ecology and the epidemiology of schistosomiasis, placing particular emphasis on remote sensing; and (ii) to fill an identified gap, namely interdisciplinary research that bridges different strands of scientific inquiry to enhance spatially explicit risk profiling. As a first step, we reviewed key factors that govern schistosomiasis risk. Secondly, we examined remote sensing data and variables that have been used for risk profiling of schistosomiasis. Thirdly, the linkage between the ecological consequence of environmental conditions and the respective measure of remote sensing data were synthesised. RESULTS We found that the potential of remote sensing data for spatial risk profiling of schistosomiasis is - in principle - far greater than explored thus far. Importantly though, the application of remote sensing data requires a tailored approach that must be optimised by selecting specific remote sensing variables, considering the appropriate scale of observation and modelling within ecozones. Interestingly, prior studies that linked prevalence of Schistosoma infection to remotely sensed data did not reflect that there is a spatial gap between the parasite and intermediate host snail habitats where disease transmission occurs, and the location (community or school) where prevalence measures are usually derived from. CONCLUSIONS Our findings imply that the potential of remote sensing data for risk profiling of schistosomiasis and other neglected tropical diseases has yet to be fully exploited.
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Affiliation(s)
- Yvonne Walz
- Department of Remote Sensing, Institute for Geography and Geology, University of Würzburg, Würzburg, Germany. .,United Nations University - Institute for Environment and Human Security, Bonn, Germany.
| | - Martin Wegmann
- Department of Remote Sensing, Institute for Geography and Geology, University of Würzburg, Würzburg, Germany.
| | - Stefan Dech
- Department of Remote Sensing, Institute for Geography and Geology, University of Würzburg, Würzburg, Germany. .,German Remote Sensing Data Centre, German Aerospace Centre, Oberpfaffenhofen, Germany.
| | - Giovanna Raso
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
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Anderson SJ, Cherutich P, Kilonzo N, Cremin I, Fecht D, Kimanga D, Harper M, Masha RL, Ngongo PB, Maina W, Dybul M, Hallett TB. Maximising the effect of combination HIV prevention through prioritisation of the people and places in greatest need: a modelling study. Lancet 2014; 384:249-56. [PMID: 25042235 DOI: 10.1016/s0140-6736(14)61053-9] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Epidemiological data show substantial variation in the risk of HIV infection between communities within African countries. We hypothesised that focusing appropriate interventions on geographies and key populations at high risk of HIV infection could improve the effect of investments in the HIV response. METHODS With use of Kenya as a case study, we developed a mathematical model that described the spatiotemporal evolution of the HIV epidemic and that incorporated the demographic, behavioural, and programmatic differences across subnational units. Modelled interventions (male circumcision, behaviour change communication, early antiretoviral therapy, and pre-exposure prophylaxis) could be provided to different population groups according to their risk behaviours or their location. For a given national budget, we compared the effect of a uniform intervention strategy, in which the same complement of interventions is provided across the country, with a focused strategy that tailors the set of interventions and amount of resources allocated to the local epidemiological conditions. FINDINGS A uniformly distributed combination of HIV prevention interventions could reduce the total number of new HIV infections by 40% during a 15-year period. With no additional spending, this effect could be increased by 14% during the 15 years-almost 100,000 extra infections, and result in 33% fewer new HIV infections occurring every year by the end of the period if the focused approach is used to tailor resource allocation to reflect patterns in local epidemiology. The cumulative difference in new infections during the 15-year projection period depends on total budget and costs of interventions, and could be as great as 150,000 (a cumulative difference as great as 22%) under different assumptions about the unit costs of intervention. INTERPRETATION The focused approach achieves greater effect than the uniform approach despite exactly the same investment. Through prioritisation of the people and locations at greatest risk of infection, and adaption of the interventions to reflect the local epidemiological context, the focused approach could substantially increase the efficiency and effectiveness of investments in HIV prevention. FUNDING The Bill & Melinda Gates Foundation and UNAIDS.
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Affiliation(s)
- Sarah-Jane Anderson
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
| | - Peter Cherutich
- National AIDS & STI Control Programme (NASCOP), Nairobi, Kenya
| | | | - Ide Cremin
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Daniela Fecht
- Small Area Health Statistics Unit (SAHSU), MRC-PHE Centre for Environment and Health, Imperial College London, London, UK
| | - Davies Kimanga
- National AIDS & STI Control Programme (NASCOP), Nairobi, Kenya
| | | | | | | | - William Maina
- National AIDS & STI Control Programme (NASCOP), Nairobi, Kenya
| | - Mark Dybul
- The Global Fund to Fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland
| | - Timothy B Hallett
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
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Khieu V, Schär F, Forrer A, Hattendorf J, Marti H, Duong S, Vounatsou P, Muth S, Odermatt P. High prevalence and spatial distribution of Strongyloides stercoralis in rural Cambodia. PLoS Negl Trop Dis 2014; 8:e2854. [PMID: 24921627 PMCID: PMC4055527 DOI: 10.1371/journal.pntd.0002854] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 03/29/2014] [Indexed: 11/21/2022] Open
Abstract
Background The threadworm, Strongyloides stercoralis, endemic in tropical and temperate climates, is a neglected tropical disease. Its diagnosis requires specific methods, and accurate information on its geographic distribution and global burden are lacking. We predicted prevalence, using Bayesian geostatistical modeling, and determined risk factors in northern Cambodia. Methods From February to June 2010, we performed a cross-sectional study among 2,396 participants from 60 villages in Preah Vihear Province, northern Cambodia. Two stool specimens per participant were examined using Koga agar plate culture and the Baermann method for detecting S. stercoralis infection. Environmental data was linked to parasitological and questionnaire data by location. Bayesian mixed logistic models were used to explore the spatial correlation of S. stercoralis infection risk. Bayesian Kriging was employed to predict risk at non-surveyed locations. Principal Findings Of the 2,396 participants, 44.7% were infected with S. stercoralis. Of 1,071 strongyloidiasis cases, 339 (31.6%) were among schoolchildren and 425 (39.7%) were found in individuals under 16 years. The incidence of S. stercoralis infection statistically increased with age. Infection among male participants was significantly higher than among females (OR: 1.7; 95% CI: 1.4–2.0; P<0.001). Participants who defecated in latrines were infected significantly less than those who did not (OR: 0.6; 95% CI: 0.4–0.8; P = 0.001). Strongyloidiasis cases would be reduced by 39% if all participants defecated in latrines. Incidence of S. stercoralis infections did not show a strong tendency toward spatial clustering in this province. The risk of infection significantly decreased with increasing rainfall and soil organic carbon content, and increased in areas with rice fields. Conclusions/Significance Prevalence of S. stercoralis in rural Cambodia is very high and school-aged children and adults over 45 years were the most at risk for infection. Lack of access to adequate treatment for chronic uncomplicated strongyloidiasis is an urgent issue in Cambodia. We would expect to see similar prevalence rates elsewhere in Southeast Asia and other tropical resource poor countries. Data on the prevalence and distribution of Strongyloides stercoralis (threadworm) is scarce in many resource-poor countries. We carried out a cross-sectional study during the dry season among 2,396 rural Cambodians of all ages. We used a rigorous diagnostic approach, involving two stool samples per person and two examination techniques, namely, Koga agar plate culture and the Baermann method. We predicted the spatial distribution of S. stercoralis using Bayesian Kriging analysis. Almost half of the participants (44.7%) were infected with S. stercoralis. Of the S. stercoralis cases, 39.7% involved participants under 16 years old. S. stercoralis infection prevalence was significantly higher in males than in females. Participants younger than 10 years old had a lower risk of infection than did older participants. Furthermore, our study showed that toilet use could prevent threadworm infections by 39%. Infection prevalence in the province was negatively associated with rainfall and soil organic content and positively associated with land covered by rice fields. We conclude that access to adequate treatment for S. stercoralis must be addressed in Cambodia. Infection prevalence is likely to be similar in other countries of the region and the developing world.
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Affiliation(s)
- Virak Khieu
- National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia; Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Fabian Schär
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Armelle Forrer
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Jan Hattendorf
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Hanspeter Marti
- University of Basel, Basel, Switzerland; Medical Department and Diagnostics, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Socheat Duong
- National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | - Penelope Vounatsou
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Sinuon Muth
- National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | - Peter Odermatt
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
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Sang HC, Muchiri G, Ombok M, Odiere MR, Mwinzi PNM. Schistosoma haematobium hotspots in south Nyanza, western Kenya: prevalence, distribution and co-endemicity with Schistosoma mansoni and soil-transmitted helminths. Parasit Vectors 2014; 7:125. [PMID: 24667030 PMCID: PMC3994281 DOI: 10.1186/1756-3305-7-125] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 03/09/2014] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Schistosomiasis studies in western Kenya have mainly focused on the intestinal form, with evidence of urinary schistosomiasis remaining anecdotal. Detailed disease mapping has been carried out predominantly along the shores of Lake Victoria, but there is a paucity of information on intestinal and urinary schistosomiasis in inland sites. METHODS This cross-sectional survey of 3,487 children aged 7-18 years from 95 schools in south Nyanza, western Kenya determined the prevalence, infection intensity, and geographical distribution of Schistosoma haematobium, evaluating its co-endemicity with Schistosoma mansoni and soil-transmitted helminths (STHs). Helminth eggs were analyzed from single urine (for S. haematobium) and stool (for S. mansoni and STHs) samples by centrifugation and Kato-Katz, respectively. Hematuria was used as a proxy indicator for S. haematobium. Schools and water bodies (ponds, water-points, streams, dams and rivers) were mapped using Geographical Information System and prevalence maps obtained using ArcView GIS Software. RESULTS S. haematobium infections with an overall prevalence of 9.3% (95% CI = 8.4-10.2%) were mostly prevalent in Rachuonyo, 22.4% (95% CI = 19.2-25.9% and 19.7 eggs/10 ml) and Migori, 10.7% (95% CI = 9.2-12.3% and 29.5 eggs/10 ml) districts, particularly around Kayuka pond and Ongoche river respectively. Overall infections correlated with hematuria (r = 0.9, P < 0.0001) and were more likely in boys (P < 0.0001, OR = 0.624). S. mansoni infections with an overall prevalence of 13% (95% CI =11.9-14.1%) were majorly confined along the shores of Lake Victoria. STH infections were homogenously distributed with A. lumbricoides occurring in 5.4% (95% CI = 4.7-6.3%) and T. trichiura in 2.8% (95% CI = 2.3-3.4%) of the children. Although S. mansoni infections were more co-endemic with S. haematobium, only A. lumbricoides infections were positively associated with S. haematobium (P = 0.0295, OR = 0.4585). Overall prevalence of S. haematobium monoinfection was 7.2% (95% CI = 6.4-8%), S. mansoni monoinfection was 12.3% (95% CI = 10.4-12.5%), and S. haematobium-S. mansoni coinfection was 1.2% (95% CI = 0.9-1.6%). There was no significant difference in infection intensity between mono and coinfections. CONCLUSION Prevalence distribution maps obtained are important for planning and implementing disease control programs in these areas.
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Affiliation(s)
- Huldah C Sang
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Geoffrey Muchiri
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Maurice Ombok
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Maurice R Odiere
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Pauline NM Mwinzi
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
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