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A model of schistosomiasis incorporating the searching capacity of the miracidium

Published online by Cambridge University Press:  06 April 2009

F. A. B. Coutinho
Affiliation:
School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG
M. Griffin
Affiliation:
School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG
J. D. Thomas
Affiliation:
School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG

Summary

This paper describes a modification of the model for the transmission of schistosomiasis proposed by Macdonald (1965), which allows the snail host-locating efficiency of the miracidium to be taken into account. The modified model allows for a choice of miracidia efficiency. If it is assumed that the miracidia are inefficient hunters then the resulting model is very sensitive to perturbations; relatively small changes in snail numbers not only cause appreciable changes in the percentage of snails infected but result in attainment of the threshold (the point at which schistosomiasis ceases to be endemic). If, however, the miracidia are efficient snail hunters then the model is much less sensitive to perturbations; here the percentage of snails infected is much less affected by changing snail numbers, and the threshold is much more difficult to reach by reducing snail numbers. It is argued that, on the whole, the empirical data give more support to the latter model, although there are some circumstances under which the former model might apply. However, even with these modifications it is considered that the Macdonald model does not provide a satisfactory explanation of field observations.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1981

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References

REFERENCES

Anderson, R. M. (1978). Population dynamics of snail infection by miracidia. Parasitology 77, 201–24.CrossRefGoogle ScholarPubMed
Berrie, A. D. (1970). Snail problems in African schistosomiasis. In Advances in Parasitology, 8. (ed. Dawes, Ben), pp. 4396. London and New York: Academic Press.Google Scholar
Bradley, D. J. & May, R. M. (1978). Consequences of helminth aggregation for the dynamics of schistosomiasis. Transactions of the Royal Society of Tropical Medicine and Hygiene 72, 262–73.Google Scholar
Cheever, A. W. (1968). A quantitative post-mortem study of Schistosoma mansoni in man. American Journal of Tropical Medicine and Hygiene 17, 3864.CrossRefGoogle ScholarPubMed
Chernin, E. (1974). Some host-finding attributes of Schistosoma mansoni miracidia. American Journal of Tropical Medicine and Hygiene 23, 320–7.CrossRefGoogle ScholarPubMed
Chernin, E. & Dunavan, C. A. (1962). The influence of host-parasite dispersion upon the capacity of Schistosoma mansoni miracidia to infect Australorbis glabratus. American Journal of Tropical Medicine and Hygiene 11, 455–71.Google Scholar
Hairston, N. G. (1973). The dynamics of transmission. In Epidemiology and Control of Schistosomiasis (Bilharziasis), (ed. Ansari, N.) Basel: S. Karger AG.Google Scholar
Jordan, P. (1977). Schistosomiasis – Research to control. American Journal of Tropical Medicine and Hygiene 26, 877–86.CrossRefGoogle ScholarPubMed
Jordan, P. & Webbe, G. (1969). Human Schistosomiasis. London: Heinemann Medical Books.Google Scholar
Macdonald, G. (1965). The dynamics of helminth infection with special reference to schistosomes. Transactions of the Royal Society of Tropical Medicine and Hygiene 59, 489506.CrossRefGoogle ScholarPubMed
Mason, P. R. (1977). Stimulation of the activity of Schistosoma mansoni miracidia by snail conditioned water. Parasitology 75, 325–38.Google Scholar
May, R. M. (1977). Togetherness among Schistosomes. Its effects on the dynamics of the infection. Mathematical Biosciences 35, 301–43.Google Scholar
Na˙ssel, I. & Hirsch, W. M. (1973). The transmission dynamics of schistosomiasis. Communications in Pure and Applied Mathematics 26, 395453.CrossRefGoogle Scholar
Na˙ssel, I. (1976 a). A hybrid model of Schistosomiasis. Theoretical Population Biology 10, 4769.CrossRefGoogle Scholar
Na˙ssel, I. (1976 b). On eradication of schistosomiasis. Theoretical Population Biology 10, 133–44.Google Scholar
Na˙ssel, I. (1977). On transmission and control of schistosomiasis with comments on Macdonald's model. Theoretical Population Biology 13, 335–65.CrossRefGoogle Scholar
Polderman, A. M. (1974). Schistosomiasis in Begemder Province, Ethiopia. Final report Laboratory of Parasitology, Rapenberg 33, Leiden, Netherlands.Google Scholar
Shiff, C. J. (1969). Influence of light and depth on location of Bulinus (Physopsis) globosus by miracidia of Schistosoma haematobium. Journal of Parasitology 55, 108–10.CrossRefGoogle ScholarPubMed
Sturrock, R. F. (1973 a). Field studies on the population dynamics of Biomphalaria glabrata, intermediate host of Schistosoma mansoni on the West Indian island of St. Lucia. International Journal for Parasitology 3, 165–74.CrossRefGoogle ScholarPubMed
Sturrock, R. F. (1973 b). Field studies on the transmission of Schistosoma mansoni and on the bionomics of its intermediate host Biomphalaria glabrata on St. Lucia. International Journal for Parasitology 3, 175–94.Google Scholar
Sturrock, R. F. & Upatham, E. S. (1973). An investigation of the interactions of some factors influencing the infectivity of Schistosoma mansoni miracidia to Biomphalaria glabrata. International Journal for Parasitology 3, 3541.Google Scholar
Takahashi, T., Moris, K. & Shigeta, Y. (1961). Phototactic, thermotactic and geotactic responses of miracidia of Schistosoma japonicum. Japanese Journal of Parasitology 10, 686–91.Google Scholar
World Health Organization (1973). Expert Committee on Schistosomiasis control, Geneva, 3–7 July 1972. WHO Technical Report Series No. 515.Google Scholar
Wright, C. A. (1968). Some views on biological control of trematode diseases. Transactions of the Royal Society of Tropical Medicine and Hygiene 62, 320–4.Google Scholar