Population biology of the freshwater snail Biomphalaria pfeifferi in the Zimbabwe highveld.
Abstract
The population dynamics of Biomphalaria pfeifferi were studied at 4 river sites in the Zimbabwe highveld for periods of 4 to 28 months during 1986 to 1988. Adult snail abundances were monitored at weekly intervals using a fractional sampling method. At 2 sites a mark-recapture method was used to estimate absolute abundances and recruitment and loss rates. Seasonal variations in abundance were related to temperature and water flow. Mortality rate was not significantly influenced by temperature but recruitment rate increased over the range 13 to 24°C. It is concluded that the geographic distribution of intestinal schistosomiasis in Zimbabwe may at least partly reflect the range of conditions suitable for B. pfeifferi (warm temperature and permanent water bodies).
Key words
- aquatic animals
- aquatic invertebrates
- aquatic organisms
- climate
- epidemiology
- freshwater invertebrates
- freshwater molluscs
- helminthoses
- helminths
- hosts
- human diseases
- infections
- intermediate hosts
- parasites
- parasitoses
- population dynamics
- schistosomiasis
- seasonal variation
- snail-borne diseases
- temperature
- trematode infections