Authors

Discussion

Schistosomiasis is a neglected tropical disease (NTD) that affects over 240 million people worldwide. Repeated mass drug administration (MDA) is currently the World Health Organization’s recommended strategy to control morbidity and transmission of the disease. However, the effect of the drug on the genetic diversity of the parasite has rarely been investigated. In this study, we looked at the effect of multiple MDAs on the genetics of Schistosoma mansoni over a period of three years. Three primary schools in separate villages in a high endemicity region of Uganda were sampled at 11 time points over the study period. This represents one of the most complete longitudinal datasets to date in terms of data coverage. A total of 4743 parasites were collected from 207 children and genotyped at seven microsatellite loci. Overall, genetic diversity decreased after drug administration. Analysis of Molecular variance showed a very low, but sometimes significant structure between villages, with most of the genetic structure being within hosts and parasites. This and other analyses will be discussed in terms of the long-term effects of MDA and potential implications for the success of control programmes.