TY - JOUR
T1 - Fine-scale variation in malaria prevalence across ecological regions in Madagascar
T2 - a cross-sectional study
AU - Rice, Benjamin L.
AU - Golden, Christopher D.
AU - Randriamady, Hervet J.
AU - Rakotomalala, Anjaharinony Andry Ny Aina
AU - Vonona, Miadana Arisoa
AU - Anjaranirina, Evelin Jean Gasta
AU - Hazen, James
AU - Castro, Marcia C.
AU - Metcalf, C. Jessica E.
AU - Hartl, Daniel L.
N1 - Funding Information:
First, we would like to thank members of the local communities and local community leaders for their participation. The MAHERY field teams provided invaluable assistance in completing the field sampling: Jean Frederick Randrianasolo, Ambinintsoa Nirina Tafangy, Mamy Yves Andrianantenaina, Robuste Fenoarison Faraniaina Mahonjolaza, Hermann Paratoaly Raelson, Vololoniaina Ravo Rakotoarilalao, Alex Dominique Rasamison, Rebaliha Mahery, Jean Adolphe Manambina, Pascal Andriamahazorivosoa, Gerandine Zafindalana, and Laurent Ravaoliny. We thank Bapu Vaitla for assistance with data from Maroantsetra and for discussions of the analysis. Amy Wesolowski, Amy Winter, Aimee Taylor, and Nicholas Arisco provided fruitful discussions while in the field and while analyzing data. BLR is currently a postdoctoral fellow in the Department of Ecology and Evolutionary Biology at Princeton University after completing a PhD in the Department of Organismic and Evolutionary Biology at Harvard University. CDG is an assistant professor of Nutrition and Planetary Health at the Harvard TH Chan School of Public Health. HJR is an agricultural economist and the national director of Madagascar Health and Environmental Research (MAHERY), a research consortium focused on examining the linkages between environmental change and human health in Madagascar. AANAR is currently a PhD student in the Department of Entomology at the University of Antananarivo. AANAR, MAV, and EJGA are researchers working for MAHERY. JH is the Chief of Party of the SPICES and FARARANO programs at Catholic Relief Services Madagascar. MCC is a professor in the Department of Global Health and Population at the Harvard TH Chan School of Public Health. CJEM is an assistant professor in the Department of Ecology and Evolutionary Biology at Princeton University. DLH is a professor in the Department of Organismic and Evolutionary Biology at Harvard University.
Funding Information:
We are grateful for the support from the United States Agency for International Development (grant AID-FFP-A-00008) implemented by Catholic Relief Services (CRS) in consortium with four local implementing partners in Madagascar. The views and opinions expressed in this paper are those of the authors and not necessarily the views and opinions of the United States Agency for International Development. We also thank the Wellcome Trust Our Planet, Our Health program (grant 106866/Z/15/Z) for providing funding to CJEM for this research. − 14
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - Background: Large-scale variation in ecological parameters across Madagascar is hypothesized to drive varying spatial patterns of malaria infection. However, to date, few studies of parasite prevalence with resolution at finer, sub-regional spatial scales are available. As a result, there is a poor understanding of how Madagascar’s diverse local ecologies link with variation in the distribution of infections at the community and household level. Efforts to preserve Madagascar’s ecological diversity often focus on improving livelihoods in rural communities near remaining forested areas but are limited by a lack of data on their infectious disease burden. Methods: To investigate spatial variation in malaria prevalence at the sub-regional scale in Madagascar, we sampled 1476 households (7117 total individuals, all ages) from 31 rural communities divided among five ecologically distinct regions. The sampled regions range from tropical rainforest to semi-arid, spiny forest and include communities near protected areas including the Masoala, Makira, and Mikea forests. Malaria prevalence was estimated by rapid diagnostic test (RDT) cross-sectional surveys performed during malaria transmission seasons over 2013–2017. Results: Indicative of localized hotspots, malaria prevalence varied more than 10-fold between nearby (< 50 km) communities in some cases. Prevalence was highest on average in the west coast region (Morombe district, average community prevalence 29.4%), situated near protected dry deciduous forest habitat. At the household level, communities in southeast Madagascar (Mananjary district) were observed with over 50% of households containing multiple infected individuals at the time of sampling. From simulations accounting for variation in household size and prevalence at the community level, we observed a significant excess of households with multiple infections in rural communities in southwest and southeast Madagascar, suggesting variation in risk within communities. Conclusions: Our data suggest that the malaria infection burden experienced by rural communities in Madagascar varies greatly at smaller spatial scales (i.e., at the community and household level) and that the southeast and west coast ecological regions warrant further attention from disease control efforts. Conservation and development efforts in these regions may benefit from consideration of the high, and variable, malaria prevalences among communities in these areas.
AB - Background: Large-scale variation in ecological parameters across Madagascar is hypothesized to drive varying spatial patterns of malaria infection. However, to date, few studies of parasite prevalence with resolution at finer, sub-regional spatial scales are available. As a result, there is a poor understanding of how Madagascar’s diverse local ecologies link with variation in the distribution of infections at the community and household level. Efforts to preserve Madagascar’s ecological diversity often focus on improving livelihoods in rural communities near remaining forested areas but are limited by a lack of data on their infectious disease burden. Methods: To investigate spatial variation in malaria prevalence at the sub-regional scale in Madagascar, we sampled 1476 households (7117 total individuals, all ages) from 31 rural communities divided among five ecologically distinct regions. The sampled regions range from tropical rainforest to semi-arid, spiny forest and include communities near protected areas including the Masoala, Makira, and Mikea forests. Malaria prevalence was estimated by rapid diagnostic test (RDT) cross-sectional surveys performed during malaria transmission seasons over 2013–2017. Results: Indicative of localized hotspots, malaria prevalence varied more than 10-fold between nearby (< 50 km) communities in some cases. Prevalence was highest on average in the west coast region (Morombe district, average community prevalence 29.4%), situated near protected dry deciduous forest habitat. At the household level, communities in southeast Madagascar (Mananjary district) were observed with over 50% of households containing multiple infected individuals at the time of sampling. From simulations accounting for variation in household size and prevalence at the community level, we observed a significant excess of households with multiple infections in rural communities in southwest and southeast Madagascar, suggesting variation in risk within communities. Conclusions: Our data suggest that the malaria infection burden experienced by rural communities in Madagascar varies greatly at smaller spatial scales (i.e., at the community and household level) and that the southeast and west coast ecological regions warrant further attention from disease control efforts. Conservation and development efforts in these regions may benefit from consideration of the high, and variable, malaria prevalences among communities in these areas.
KW - Community health
KW - Ecology
KW - Madagascar
KW - Malaria
KW - Spatial variation
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U2 - 10.1186/s12889-021-11090-3
DO - 10.1186/s12889-021-11090-3
M3 - Article
C2 - 34051786
AN - SCOPUS:85107251915
SN - 1471-2458
VL - 21
JO - BMC Public Health
JF - BMC Public Health
IS - 1
M1 - 1018
ER -