Hostname: page-component-7479d7b7d-c9gpj Total loading time: 0 Render date: 2024-07-11T12:27:15.391Z Has data issue: false hasContentIssue false
  • English
  • Français

The Application of Catalytic Models to Schistosomiasis in Snails

Published online by Cambridge University Press:  05 June 2009

R. F. Sturrock  and
G. Webbe
R. F. Sturrock
Affiliation:
Research and Control Department, St. Lucia, West Indies
G. Webbe
Affiliation:
London School of Hygiene and Tropical Medicine, London, England
Get access Rights & Permissions [Opens in a new window]

Extract

1. With the aid of field growth curves, age-prevalence curves can be derived from field collections of snails, using cercarial shedding as proof of infection by schistosomes.

2. Such curves were obtained from eight collections of field snails: one sample each of Bulinus (Physopsis) nasutus productus and Biomphalaria pfeifferi, intermediate hosts respectively of Schistosoma haematobium and S. mansoni in Tanzania, and six samples of Biomphalaria glabrata, intermediate host of S. mansoni on St. Lucia, West Indies.

3. Catalytic curves were fitted to the data and in each case the two-stage curve gave the most satisfactory fit.

4. This curve is the resultant of two opposing forces: one force being the rate of infection and the other the rate of loss of infection in a snail population.

5. The rate of infection may be defined as the number of successful snail-miracidium contacts per 1,000 snails per week, while the rate of loss of infection is taken to represent the number of deaths per 1,000 infected snails per week.

6. The underlying assumptions of this form of analysis are discussed and, in view of the independent verification of some of the calculated rates, the values are considered realistic.

7. Besides providing quantitative data for inclusion in mathematical models of schistosome transmission, the technique offers an additional means of assessing the efficacy of certain methods of controlling transmission.

Type
Research Article
Information
Journal of Helminthology , Volume 45 , Issue 2-3 , June 1971 , pp. 189 - 200
Copyright
Copyright © Cambridge University Press 1971

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

Barbosa, F. S. and Barreto, A. L., 1960.—“Differences in susceptibility of Brazilian strains of Australorbis glabratus to Schistosoma mansoni.” Expl Parasit., 19, 137–.CrossRefGoogle Scholar
Barbosa, F. S. and Barreto, A. L., and Coelho, M. V., 1953.—“Effects of desiccation on the intra-snail larval stages of Schistosoma mansoni in Australorbis glabratus.” Publ. avuls. inst. Aggeu Magalhaes, 2, 159–.Google Scholar
Barbosa, F. S. and Barreto, A. L., and Coelho, M. V., and Olivier, L., 1958.—“Studies on the snail vectors of Bilharziasis mansoni in North-eastern Brazil.” Bull. Wld Hlth Org., 18, 895–.Google ScholarPubMed
Cridland, C. C., 1957.—“Ecological factors affecting the numbers of snails in temporary bodies of water.” J. trop. Med. Hyg., 60, 287–.Google ScholarPubMed
Foster, R., 1964.—“The effect of temperature on the development of Schistosoma mansoni Sambon, 1907 in the intermediate host.” J. trop. Med. Hyg., 67, 289–.Google ScholarPubMed
Goffman, G. and Warren, K. S., 1970.—“An application of the Kermack-McKendrick theory to the epidemiology of schistosomes.” Am. J. trop. Med. Hyg., 19, 278–.CrossRefGoogle Scholar
Hairston, N., 1965a.—“On the mathematical analysis of schistosome populations.” Bull. Wld Hlth Org., 33, 45–.Google ScholarPubMed
Hairston, N., 1965b.—“An analysis of age-prevalence data by catalytic models. A contribution to the study of bilharziasis.” Bull. Wld Hlth Org., 33, 163–.Google Scholar
Macdonald, G., 1965.—“The dynamics of helminth infections with special reference to schistosomes.” Trans. R. Soc. trop. Med. Hyg., 59, 489–.CrossRefGoogle ScholarPubMed
Muench, H., 1959.—Catalytic models in epidemiology. Harvard University Press, Cambridge, U.S.A.CrossRefGoogle Scholar
Najarian, H. H., 1961.—“Egg-laying capacity of the snail Bulinus truncatus in relation to infection with Schistosoma haematobium.” Tex. Rep. Biol. Med., 19, 327–.Google ScholarPubMed
Olivier, L., Barbosa, F. S. and Coelho, M. V., 1958.—“The influence of infection with schistosomiasis on the longevity of Australorbis glabratus.” Bol. Ofic. Sanat. Panamer., 40, 416–.Google Scholar
Pan, C., 1963.—“Some biochemical and immunological aspects of host-parasite relationships: generalised and local tissue responses in the snail Australorbis glabratus infected with Schistosoma mansoni.” Ann. N.Y. Acad. Sci., 113, 475–.CrossRefGoogle Scholar
Richards, C. S., 1967.—“Aestivation of Biomphalaria glabrata (Basommatophora: Planorbidae). Associated characteristics and relation to infection with Schistosoma mansoni.” Am. J. trop. Med. Hyg., 16, 797–.CrossRefGoogle ScholarPubMed
Stirewalt, M. A., 1954.—“Effect of snail maintenance temperature on development of Schistosoma mansoni.” Expl Parasit., 3, 504–.CrossRefGoogle ScholarPubMed
Sturrock, B. M., 1966.—“The influence of infection with Schistosoma mansoni on the growth and reproduction of Biomphalaria pfeifferi.” Ann. trop. Med. Parasit., 60, 187–.CrossRefGoogle ScholarPubMed
Sturrock, B. M., 1967.—“The effect of infection with Schistosoma haematobium on the growth and reproduction of Bulinus (Physopsis) nasutus productus.” Ann. trop. Med. Parasit., 61, 321–.CrossRefGoogle ScholarPubMed
Sturrock, B. M., 1968.—“Resistance of Bulinus (Physopsis) nasutus productus to infection by Schistosoma haematobium.” Ann. trop. Med. Parasit., 62, 393–.CrossRefGoogle Scholar
Sturrock, B. M., and Sturrock, R. F., 1970.—“Laboratory studies of the host-parasite relationship of Schistosoma mansoni and Biomphalaria glabrata from St. Lucia, West Indies.” Ann. trop. Med. Parasit., 64, (at press).CrossRefGoogle ScholarPubMed
Teesdale, C., 1962.—“Ecological observations on the molluscs of significance in the transmission of Bilharziasis in Kenya.” Bull. Wld Hlth Org., 27, 579–.Google ScholarPubMed
Upatham, E., 1970.—“Bionomics of miracidia of Schistosoma mansoni.” Ph.D. Thesis, University of Michigan, U.S.A.Google Scholar
Webbe, G., 1962a.—“The transmission of Schistosoma haematobium in an area of Lake Province, Tanganyika.” Bull. Wld Hlth Org., 27, 59–.Google Scholar
Webbe, G., 1962b.—“Population studies of intermediate hosts in relation to transmission of Bilharziasis in East Africa.” In Ciba Foundation Symposium on Bilharziasis, p. 7. Edd, G. E., Wolstenholme, W and O'Connor, M.London: Churchill.CrossRefGoogle Scholar