Hostname: page-component-848d4c4894-ttngx Total loading time: 0 Render date: 2024-05-07T08:15:01.514Z Has data issue: false hasContentIssue false
  • English
  • Français

Studies on the excystment of trematode metacercariae in vivo

Published online by Cambridge University Press:  05 June 2009

M. F. A. Asanji  and
M. O. Williams
M. O. Williams
Affiliation:
Department of Zoology, Fourah Bay College, Freetown, Sierra Leone
Get access Rights & Permissions [Opens in a new window]

Abstract

Metacercariae of two species of trematode (Clinostomum tilapiae, Postodiplostomum nanum) excysted in the stomach of birds, while those of three species (Parorchis acanthus, Posthodiplostomum sp., Postliodiplostomoides leonensis) excysted in the duodenum. Differences were related to the structure of the cyst wall. All could excyst in birds which were not the definitive host and the speed of excystment depended on the speed of movement of food in the gut. All, except P. acanthus, also excysted in the body cavity of the mouse.

There have been few previous reports on the site of excystment of metacercarial cysts in vivo and most indicate that the duodenum is the site for most species studied, e.g. Clonorchis sinensis (Faust and Khaw, 1927), Parorchis avitus (Stunkard and Cable, 1932), Cryptocotyle lingua (Smyth, 1962) and Fasciola hepatica (Smyth, 1966). In their study of the migratory route of Paragonimus westermani in rats, cats and guinea-pigs Yokogawa et al. (1962) found that excystment occurred in the small intestine where the pH range was 5.0–6.0. Also, although the site of excystment has been established for some species, very little quantitative work has been reported about the percentage excystment in vivo and results of work on these lines is reported in this paper.

Type
Research Article
Information
Journal of Helminthology , Volume 48 , Issue 1 , March 1974 , pp. 85 - 91
Copyright
Copyright © Cambridge University Press 1974

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

Asanji, M. F. and WILLIAMS, M. O. (1973). The structure and histochemistry of some trematode metacercarial cysts. Journal of Helminthology, 47, 353–368.Google Scholar
Dawes, B. and Hughes, D. L. (1964). Fasciolasis: the invasive stage of Fasciola hepatica in mammalian hosts. In Advances in Parasitology, Vol. 2: (Ed. Dawes, Ben) pp. 97–168, London: Academic Press.Google Scholar
Dixon, K. E. (1966). The physiology of excystment of metacercaria of Fasciola hepatica. Parasitology, 56, 431–56.Google Scholar
Faust, E. C. and Khaw, O. K. (1927). Excystment phenomenon in Clonorchls sinensis (Cobbold). Am. J. Hyg. Mongr. Ser., 8, 284.Google Scholar
Krull, W. H. and Price, N. F. (1932). Studies on the life history of Diplodicus temperatus (Stafford) from the frog. Oct. Pep. Mus. Zool. Univ. Mich., 237, 1–39.Google Scholar
Smyth, J. D. (1962). Introduction to animal Parasitology. London: English University Press.Google Scholar
Smyth, J. D. (1966). The physiology ofTrematodes. San Francisco: W. H. Freeman.Google Scholar
Stunkard, H. W. and Cable, R. N. (1932). The life history of Parorchis avitus, a trematode from the cloaca of gull. Biological Bulletin, 62, 328–338.Google Scholar
Yokogawa, M., Yoshimura, H., Sano, M., Okura, T. and Tsuji, M. (1962). The route of migration of the larva of Paragonimus westermani in the final host. Journal of Parasitology, 48, 525–531.Google Scholar
Williams, M. O. (1969). Posthodiplostomoides leonensis gen nov. (Strigeida: Trematoda). Rev. Zool. Bot. Afr., 79, 142–144.Google Scholar