Schistosomiasis in the Mekong region: epidemiology and phylogeography.

An account is given of progress made over the last 20 years in the study of Mekong schistosomiasis, causative agent Schistosoma mekongi (Trematoda: Digenea). Emphasis is given to the discussion of work concerning the origin and subsequent dispersal of S. mekongi and related taxa, including relevant snails. The role of such phylogeographical data in schistosomiasis control and the prediction of areas at risk is examined. New palaeogeographical models are reviewed in relation to traditional explanations for the biogeographic deployment of Southeast Asian Schistosoma and their intermediate hosts. The demographics and molecular ecology of Neotricula aperta (Gastropoda: Pomatiopsidae), the snail host of S. mekongi, are reviewed with particular reference to new models for the life cycle of this species and their importance in snail control. The use of population genetic data in the limitation of N. aperta populations is evaluated and strategies suggested for schistosomiasis control efforts directed against the intermediate host. Developments in the taxonomy of N. aperta, and related taxa, and changes in nomenclature are covered. The direction of future investigations into the problem of Mekong schistosomiasis is also discussed.