SREL Reprint #2164
Neotropical schistosomiasis: African affinities of the host
snail Biomphalaria glabrata (Gastropoda: Planorbidae)
DAVID S. WOODRUFF
Department of Biology and Center for Molecular Genetics, University of California, San
Diego, La Jolla, CA, 92093-0116, U.S.A
MARGARET 'MULVEY
Savannah River Ecology Laboratory, University of Georgia, Drawer E,, Aiken, SC
29802, U. S.A.
Schistosoma mansoni, the blood fluke responsible for human intestinal
schistosomiasis in the Neotropics, was imported repeatedly with African slaves
during the period 1500-1800. This trematode, and its intermediate host snails of
the genus Biomphalaria, are widely distributed across Africa and the disease is
thought to have quickly become established in South America and the West
Indies because of' the presence of an endemic susceptible congener, B.
glabrata. We compared B. glabrata with four other Neotropical and three
African species of' Biomphalaria using 20 allozyme loci and found that it is
phonetically and phylogenetically more like the African species; both parasite
and American host snail are apparently of' historically or geologically recent
African origin. Furthermore, genetic distances, cladistic analyses and fossil data
suggest the African Biomphalaria species may themselves have evolved from
Neotropical founders following an initial trans-Atlantic dispersal in the reverse
direction 2.3-4.5 Mya. Interpretation of existing patterns remains problematic as
few African snails have been characterized genetically and both B. pfeifferi
appear to comprise several cryptic species.
SREL Reprint #2164
Woodruff, D.S. and M. Mulvey. 1997. Neotropical schistomiasis: African
affinities of the host snail Biomphalaria glabrata (Gastropoda: Planorbidae).
Biological Journal of the Linnean Society 60:505-516.
