**5. Conclusion**

Given the widespread distribution of *Biomphalaria pfeifferi* in the Senegal River, understanding the seasonal variation and the principal drivers of snail abundance is important for local snails control to prevent upcoming human risk of *Schistosoma mansoni* infection. Our findings support that the rainy season is significantly associated (*p-value* = 0.003) with the abundance of intermediate hosts because of highly favorable environmental conditions for periphyton (snail food) and dissolved oxygen levels required by *B. pfiefferi*. Conditions were less ideal in the Dry2 season than the rainy season, and, thus, more environmental parameters were significant for this period than in the rainy season. In contrast, environmental conditions were so poor in the Dry1 season that few snails occurred and significant trends were absent. Our findings on the seasonal fluctuations of snail hosts are useful for targeting a snail control program during a time of year when it may be most effective to eliminate or reduce the vectors of schistosomiasis.

*Update on Malacology*
