a1 Department of Infectious Disease Epidemiology, Imperial College Faculty of Medicine (St Mary's Campus), Norfolk Place, London W2 1PG, UK
a2 Institut National de Recherche en Santé Publique, Ministère de la Santé, Bamako, Mali; Service de Radiologie, Hôpital National du Point G, Bamako, Mali
a3 Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK
The recent implementation of mass drug administration (MDA) for control of uro-genital schistosomiasis has identified an urgent need for molecular markers to both directly monitor the impact of MDA, for example to distinguish re-infections from uncleared infections, as well as understand aspects of parasite reproduction and gene flow which might predict evolutionary change, such as the development and spread of drug resistance. We report the development of a novel microsatellite tool-kit allowing, for the first time, robust genetic analysis of individual S. haematobium larvae collected directly from infected human hosts. We genotyped the parasite populations of 47 children from 2 schools in the Ségou region of Mali, the first microsatellite study of this highly neglected parasite. There was only limited evidence of population subdivision between individual children or between the two schools, suggesting that few barriers to gene flow exist in this population. Complex relationships between parasite reproductive success, infection intensity and host age and gender were identified. Older children and boys harboured more diverse infections, as measured by the number of unique adult genotypes present. Individual parasite genotypes had variable reproductive success both across hosts, a pre-requisite for evolutionary selection, and, phenotypically, in hosts of different ages and genders. These data serve as a baseline against which to measure the effect of treatment on parasite population genetics in this region of Mali, and the tools developed are suitable to further investigate this important pathogen, and its close relatives, throughout their range.
(Received January 10 2011)
(Revised April 11 2011)
(Accepted April 13 2011)
(Online publication June 17 2011)
p1 Current address: Prevention Chemotherapy and Transmission Control, Department of Control of Neglected Tropical Diseases, World Health Organisation, 20, Avenue Appia, CH-1211 Geneva 27 Switzerland.