Schistosome population genetics

The major impetus behind schistosome population genetics studies in SCORE is to provide insights into potential changes in schistosome population structures due to varying levels of MDA pressure, in hope that this will provide an early warning system for the possible development of drug resistance. Given that praziquantel is the only drug used for MDA for schistosomiasis, development of resistance would be devastating. Studies of schistosome population genetics are being included in selected villages involved in the efforts related to gaining control of schistosomiasis and in the project on elimination of schistosomiasis.

Because the genome of S. mansoni is published, adequate information about microsatellites is available to characterize S. mansoni. However, there was much less experience with S. haematobium microsatellites, and genome-wide sequencing had not been done. With SCORE support, a consortium involving the University of Georgia (Athens, Georgia, USA), the Natural History Museum (London, UK), and Centro de Pesquisas “Rene Rachou”/FIOCRUZ (Belo Horizonte, Brazil) conducted low coverage genomic sequencing to identify thousands of microsatellite loci from field isolates of S. haematobium from Zanzibar. The data generated from these studies are now available.

As part of SCORE’s efforts related to gaining control and elimination of schistosomiasis, most of the well-characterized cercarial and miracidial specimens generated are being banked, with the anticipation that costs of assessing population genetic changes is expected to decrease over time, allowing cost-effective analysis of schistosome population genetics changes under MDA pressure. Specimens are being shared with SCAN, a global repository of schistosomiasis collections at the Natural History Museum.