Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-20T00:45:07.619Z Has data issue: false hasContentIssue false
  • English
  • Français

Temporal patterns in the epidemiology of schistosome infections of snails: a model for field data

Published online by Cambridge University Press:  06 April 2009

M. E. J. Woolhouse  and
S. K. Chandiwana
M. E. J. Woolhouse
Affiliation:
Department of Pure and Applied Biology, Imperial College, Prince Consort Road, London SW7 2BB
S. K. Chandiwana
Affiliation:
Blair Research Laboratory, P.O. Box 8105, Causeway, Harare, Zimbabwe
Get access Rights & Permissions [Opens in a new window]

Summary

The prevalence of patent schistosome infections of intermediate host snails often shows seasonal variations. For schistosome, mainlySchistosoma haematobium, infections of Bulinus globosus field data from Zimbabwe show annual ranges in prevalence from 2% to 30%. In this paper a mathematical model is developed for B. globosus population dynamics and the epidemiology of schistosome infection. The model is a discrete-time analogue of a catalytic model, with an added recruitment term. Snail fecundity and survival are functions of age, infection, and temperature. The pre-patent period of infection is dependent on temperature.Parameter values, and relationships with temperature, are taken from earlier field and laboratory studies. The force-of-infection is estimated from analysis of age-prevalence data. Model predictions, making use of temperature data recorded in the field, are in good agreement with observations over a 2-year period at a study site in Zimbabwe. The key features of interest are a fall in the prevalence of patent infections during the cold season and a rapid rise to a peak early in the hot season. This pattern results from the accumulation of pre-patent infections which fail to develop at low temperatures, but mature en masse, together with new infections, after a few weeks at higher temperatures. Model analysis demonstrates that seasonal patterns in the prevalence of patent infections may be due largely to the influence of temperature on the pre-patent period. Seasonal and year-to-year variations in temperature may therefore have significant epidemiological effects.

Keywords

Bulinus globosusepidemiologymathematical modelSchistosoma haematobiumseasonality
Type
Research Article
Information
Parasitology , Volume 100 , Issue 2 , April 1990 , pp. 247 - 253
Copyright
Copyright © Cambridge University Press 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Anderson, R. M. & Crombie, J. (1984). Experimental studies of age—prevalence curves for Schistosoma mansoni infections in populations of Biomphalaria glabrata. Parasitology 89, 79–104.CrossRefGoogle ScholarPubMed
Anderson, R. M. & May, R. M. (1979). Prevalence of schistosome infections within molluscan populations: observed patterns and theoretical predictions. Parasitology 79, 63–94.CrossRefGoogle ScholarPubMed
Babiker, A., Fenwick, A., Daffalla, A. A. & Amin, M. A. (1985). Focality and seasonality of Schistosoma mansoni transmission in the Gezira Irrigated Area, Sudan. Journal of Tropical Medicine and Hygiene 88, 57–63.Google ScholarPubMed
Chandiwana, S. K. (1987). Community water contact patterns and the transmission of Schistosoma haematobium in the highveld region of Zimbabwe. Social Science and Medicine 25, 495–505.CrossRefGoogle ScholarPubMed
Chandiwana, S. K., Christensen, N. O. & Frandsen, F. (1987). Seasonal patterns in the transmission of Schistosoma haematobium, S. mattheei and S. mansoni in the highveld region of Zimbabwe. Acta Tropica 44, 433–44.Google ScholarPubMed
Minchella, D. J. & Loverde, P. T. (1983). Laboratory comparison of the relative success of Biomphalaria glabrata stocks which are susceptible and insusceptible to infection with Schistosoma mansoni. Parasitology 86, 335–44.CrossRefGoogle ScholarPubMed
Muench, H. (1959). Catalytic Models in Epidemiology. Cambridge, Mass.: Harvard University Press.CrossRefGoogle Scholar
Pesigan, T. P., Hairston, N. G., Jauregui, J. J., Garcia, E. G., Santos, A. T., Santos, B. C. & Besa, A. A. (1958). Studies on Schistosoma japonicum infection in the Philippines. 2. The molluscan host. Bulletin of the World Health Organization 18, 481–578.Google ScholarPubMed
Shiff, C. J. (1964 a). Studies on Bulinus (Physopsis) globosus in Rhodesia. I. The influence of temperature on the intrinsic rate of increase. Annals of Tropical Medicine and Parasitology 58, 94–105.CrossRefGoogle Scholar
Shiff, C. J. (1964 b). Studies on Bulinus (Physopsis) globosus in Rhodesia. III. Bionomics of a natural population in a temporary habitat. Annals of Tropical Medicine and Parasitology 58, 240–55.CrossRefGoogle Scholar
Shiff, C. J., Coutts, W. C. C., Yiannakis, C. & Holmes, R. W. (1979). Seasonal patterns in the transmission of Schistosoma haematobium in Rhodesia, and its control by winter application of molluscicide. Transactions of the Royal Society of Tropical Medicine and Hygiene 73, 375–80.CrossRefGoogle ScholarPubMed
Shiff, C. J., Evans, A., Yiannakis, C. & Eardley, M. (1975). Seasonal influence on the production of Schistosoma haematobium and S. mansoni cercaria in Rhodesia. International Journal for Parasitology 5, 119–23.CrossRefGoogle ScholarPubMed
Sturrock, B. M. (1967). The effects of infection with Schistosoma haematobium on the growth and reproduction rates of Bulinus (Physopsis) nasutus productus. Annals of Tropical Medicine and Parasitology 61, 321–5.CrossRefGoogle ScholarPubMed
Sturrock, B. F. (1973). Field studies on the transmission of Schistosoma mansoni and on the bionomics of its intermediate host, Biomphalaria glabrata, on St Lucia, West Indies. International Journal for Parasitology 3, 175–94.CrossRefGoogle Scholar
Sturrock, B. F. & Webbe, G. (1971). The application of catalytic models to schistosomiasis in snails. Journal of Helminthology 45, 189–200.CrossRefGoogle ScholarPubMed
Woolhouse, M. E. J. (1988). A mark-capture method for ecological studies on schistosome vector snails. Annals of Tropical Medicine and Parasitology 82, 485–97.CrossRefGoogle Scholar
Woolhouse, M. E. J. (1989 a). Estimation of the effects of patent schistosome infections on the mortality rates of Bulinus globosus and Biomphalaria pfeifferi. Annals of Tropical Medicine and Parasitology 83, 137–41.CrossRefGoogle Scholar
Woolhouse, M. E. J. (1989 b). On the interpretation of age—prevalence curves for schistosome infections of host snails. Parasitology 99, 47–56.CrossRefGoogle ScholarPubMed
Woolhouse, M. E. J. & Chandiwana, S. K. (1989 a). Spatial and temporal heterogeneity in the population dynamics of Bulinus globosus and Biomphalaria pfeifferi and the epidemiology of their infection with schistosomes. Parasitology 98, 21–34.CrossRefGoogle ScholarPubMed
Woolhouse, M. E. J. & Chandiwana, S. K. (1989 b). Population biology of the freshwater snail Bulinus globosus in the Zimbabwe highveld. Journal of Applied Biology 26, 000–000.Google Scholar