Schistosomiasis in rice fields and implications for biocontrol: Case studies from Senegal and Madagascar show sharp contrasts in detection of intermediate snail hosts
Abstract
Approximately 230 million people worldwide are infected with schistosomes, and more than 90% of those requiring treatment live in sub-Saharan Africa. Senegal and Madagascar both have high prevalences of schistosomiasis, which has a significant impact on human health and on each country's economy. In Africa, schistosomiasis is caused by Schistosoma trematodes with a life cycle that depends on a definitive human host and intermediate Bulinus or Biomphalaria snail hosts. Drug treatment kills adult stages of the parasite but does not prevent reinfection, and elimination strategies therefore require prevention or targeted control of the intermediate host snail. In Senegal, irrigation canals and rice fields often harbour schistosome host snails and are well-described potential sites of infection. In Madagascar, it remains unknown whether similar habitats harbour host snails despite schistosomiasis and rice cultivation being highly prevalent. This study presents results of a snail survey in Senegal in 2024 and repeated surveys in 2022 and 2023 in Madagascar as case studies to compare schistosomiasis as an aspect of human health in the context of rice farming in the 2 countries. To account for differences in sampling effort, total snail counts per site were normalized by the number of sweeps deployed. Detection of intermediate host snails for the parasite was significantly associated with country. While snails were found in fields and canals in Senegal, competent hosts were not detected in Madagascar, indicating possible differences in habitat and population dynamics and that geographic differences may require different research and intervention approaches.
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BibTeX
@article{senff2026schistosomiasis,
title = {{Schistosomiasis in rice fields and implications for biocontrol: Case studies from Senegal and Madagascar show sharp contrasts in detection of intermediate snail hosts}},
author = {Paula Senff and Nantenaina Andriantsoa and Alexandra Sack and Daniela Fusco and Emily Selland and Nicolas Jouanard and Ndeye Mbaye and Jean-Michel Mortillaro and Jason R. Rohr},
journal = {Parasitology},
year = {2026},
month = sep,
doi = {10.1017/s0031182026102777},
url = {https://hal.science/hal-05828506v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Schistosomiasis in rice fields and implications for biocontrol: Case studies from Senegal and Madagascar show sharp contrasts in detection of intermediate snail hosts
AU - Paula Senff
AU - Nantenaina Andriantsoa
AU - Alexandra Sack
AU - Daniela Fusco
AU - Emily Selland
AU - Nicolas Jouanard
AU - Ndeye Mbaye
AU - Jean-Michel Mortillaro
AU - Jason R. Rohr
PY - 2026
DA - 2026/09/21
JO - Parasitology
DO - 10.1017/s0031182026102777
UR - https://hal.science/hal-05828506v1
AB - Approximately 230 million people worldwide are infected with schistosomes, and more than 90% of those requiring treatment live in sub-Saharan Africa. Senegal and Madagascar both have high prevalences of schistosomiasis, which has a significant impact on human health and on each country's economy. In Africa, schistosomiasis is caused by Schistosoma trematodes with a life cycle that depends on a definitive human host and intermediate Bulinus or Biomphalaria snail hosts. Drug treatment kills adult stages of the parasite but does not prevent reinfection, and elimination strategies therefore require prevention or targeted control of the intermediate host snail. In Senegal, irrigation canals and rice fields often harbour schistosome host snails and are well-described potential sites of infection. In Madagascar, it remains unknown whether similar habitats harbour host snails despite schistosomiasis and rice cultivation being highly prevalent. This study presents results of a snail survey in Senegal in 2024 and repeated surveys in 2022 and 2023 in Madagascar as case studies to compare schistosomiasis as an aspect of human health in the context of rice farming in the 2 countries. To account for differences in sampling effort, total snail counts per site were normalized by the number of sweeps deployed. Detection of intermediate host snails for the parasite was significantly associated with country. While snails were found in fields and canals in Senegal, competent hosts were not detected in Madagascar, indicating possible differences in habitat and population dynamics and that geographic differences may require different research and intervention approaches.
SN - 0031-1820
SN - 1469-8161
ER -