Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-06T02:23:50.920Z Has data issue: false hasContentIssue false
  • English
  • Français

Observations on the infection of bulinid snails with Schistosoma mattheei

II. The mechanism of resistance to infection

Published online by Cambridge University Press:  06 April 2009

G. K. Kinoti
G. K. Kinoti
Affiliation:
Department of Zoology, University College, Nairobi
Get access Rights & Permissions [Opens in a new window]

Extract

In an attempt to determine the mechanisms of resistance to schistosome infection operative in bulinid snails, an histological study was carried out on batches of a refractory strain of Bulinus truncatus and two highly susceptible strains of B. africanus killed at various intervals of time, ranging from 7 h to over 3 months, after exposure to infection with Schistosoma mattheei miracidia.

It was found that only a small fraction (less than 1%) of the miracidia penetrated B. truncatus, and that they penetrated only a few of the snails exposed. Much larger proportions (up to 26%) of the miracidia penetrated B. africanus and they penetrated nearly all the snails exposed.

In the susceptible B. africanus only miracidia which settled in the loose tissues of the head-foot proceeded to develop: those settling in dense tissue failed to develop and degenerated within about 2 days.

A strong infiltration reaction of amoebocytes rapidly destroyed the few miracidia that successfully penetrated B. truncatus. In contrast, B. africanus did not respond to the presence of miracidia in its tissues, nor to mother or to daughter sporocysts before the onset of cercarial shedding: it reacted only to cercariae.

It is concluded (a) that the combination of an effective surface barrier and an active defence mechanism due to amoebocytes were responsible for complete resistance to S. mattheei infection in B. truncatus (b) that successful establishment of S. mattheei infection in B. africanus depended on the failure of the snail to recognize the schistosome miracidia and sporocysts as foreign material.

I am indebted to Professor George S. Nelson for advice and encouragement in this work which was carried out at the London School of Hygiene and Tropical Medicine. I am most grateful to Dr R. J. Pitchford, Dr C. A. Wright and Dr F. Arfaa for providing material for schistosome and snail cultures and to the East African Community and the British Ministry of Overseas Development for financial support.

Type
Research Article
Information
Parasitology , Volume 62 , Issue 1 , February 1971 , pp. 161 - 170
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

REFERENCES

Barbosa, F. S. & Barreto, A. C. (1960). Differences in susceptibility of Brazilian strains of Australorbis glabratus to Schistosoma mansoni. Experimental Parasitology 9, 137–40.CrossRefGoogle ScholarPubMed
Brooks, C. P. (1953). A comparative study of Schistosoma mansoni in Tropicorbis havanensis and Australorbis glabratus. Journal of Parasitology 39, 159–65.CrossRefGoogle ScholarPubMed
Burnet, M. (1959). The Clonal Selection Theory of Acquired Immunity. London. Cambridge University Press.CrossRefGoogle Scholar
Coelho, M. de V. (1962). Suscetibilidade de Australorbis teganophilus a infeccao por Schistosoma mansoni, Revista do Instituto de Medicina Tropical do São Paulo 4, 289–95.Google Scholar
Fretter, V. & Graham, A. (1962). The British Prosobranch Molluscs. London: Ray Society Publication.Google Scholar
Haughton, I. (1934). Amoebocytes and allied cells in Invertebrata. Journal of the Royal Microscopical Society 54, 246–62.CrossRefGoogle Scholar
Kinoti, G. (1964). A note on the susceptibility of some gastropod molluscs to Schistosoma bovis and S. mattheei. Annals of tropical Medicine and Parasitology 58, 270–5.CrossRefGoogle ScholarPubMed
Kinoti, G. (1967). Studies on some factors affecting the development of schistosomes in their molluscan hosts. Ph.D. thesis, London University.Google Scholar
Kinoti, G. (1968). Observations on the infection of bulinid snails with Schistosoma mattheei. I: The susceptibility of Bulinus africanus and Bulinus truncatus. Annals of tropical Medicine and Parasitology 62, 382–92.CrossRefGoogle ScholarPubMed
Newton, W. L. (1952). The comparative tissue reaction of two strains of Australorbis glabratus to infection with Schistosoma mansoni. Journal of Parasitology 38, 362–6.CrossRefGoogle Scholar
Pan, C. T. (1958). The general and topographic anatomy of Australorbis glabratus. Bulletin of the Museum of Comparative Zoology, Harvard College 119, 237–99.Google Scholar
Pan, C. T. (1965). Studies on the host-parasite relationship between Schistosoma mansoni and the snail Australorbis glabratus. American Journal of tropical Medicine and Hygiene 14, 931–76.CrossRefGoogle ScholarPubMed
Pitchford, R. J. (1959). Cattle schistosomiasis in man in Eastern Transvaal. Transactions of the Royal Society of tropical Medicine and Hygiene 53, 386.CrossRefGoogle ScholarPubMed
Pitchford, R. J. (1965). Differences in egg morphology and certain biological characteristics of some African and Middle Eastern schistosomes, genus Schistosoma, with terminal-spined eggs. Bulletin of the World Health Organisation 32, 83–104.Google ScholarPubMed
Salt, G. (1960). Surface of a parasite and the haemocytic reaction of its host. Nature, London 188, 162–3.CrossRefGoogle ScholarPubMed
Wajdi, N. (1964). Some observations on the relationship of Schistosoma haematobium with its intermediate host. Journal of Helminthology 38, 383–90.CrossRefGoogle ScholarPubMed
Wajdi, N. (1966). Immunity to Schistosoma haematobium in Bulinus truncatus. Transactions of the Royal Society of tropical Medicine and Hygiene 60, 774–6.CrossRefGoogle ScholarPubMed
Wright, C. A. (1962). The significance of infra-specific taxonomy in bilharziasis. In Ciba Foundation Symposium on Bilharziasis, 1962, edited by Wolstenholme, G. E. W. and Maeve, O'Connor. London: J. and A. Churchill.Google Scholar