Parasitology

SECTION 4 MONITORING AND EVALUATION OF INTERVENTIONS

Genetic diversity of schistosomes and snails: implications for control

DAVID ROLLINSONa1 c1, JOANNE P. WEBSTERa2, BONNIE WEBSTERa1, SILVESTER NYAKAANAa3, ASLAK JØRGENSENa4 and J. RUSSELL STOTHARDa1

a1 Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK

a2 Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College (St Mary's Campus), Norfolk Place, London, W2 1PG

a3 Makerere University, P.O. Box 7062, Kampala, Uganda

a4 DBL Parasitology, Health and Development, University of Copenhagen, Thorvaldsensvej 57, 1871 Frederiksburg C, Denmark

SUMMARY

Molecular approaches are providing new insights into the genetic diversity of schistosomes and their intermediate snail hosts. For instance, molecular tools based on the polymerase chain reaction are being developed for the diagnosis of schistosomiasis and the detection of prepatent schistosome infections in snails at transmission sites. Robust phylogenies of the different species of Schistosoma, Bulinus and Biomphalaria have been determined and novel methods are available to identify the different and cryptic taxa involved. Microsatellite analyses and mitochondrial DNA sequencing methods have been developed and are contributing to a better understanding of the genetic structure of both schistosome and snail populations. New sampling procedures to capture DNA of eggs and larval stages of schistosomes in field situations are facilitating more detailed and ethically advantageous studies on parasite heterogeneity. Knowledge of the genetic diversity of schistosome and snail populations adds a further dimension to the monitoring and surveillance of disease, and the implementation of new molecular-based approaches will be of increasing importance in helping to assess the impact of schistosomiasis control strategies.

(Received March 30 2009)

(Revised May 29 2009)

(Accepted May 30 2009)

(Online publication July 27 2009)

Correspondence:

c1 Corresponding author: David Rollinson, Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK. Tel: +44 20 7942 518. Fax: +44 20 7942 5518. E-mail: d.rollinson@nhm.ac.uk

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