Return to search

Plagiorchis elegans in the molluscan intermediate host : infection, susceptibility, growth, reproduction, mortality and cercarial production

The host/parasite association between the pulmonate snail Stagnicola elodes and the digenean Plagiorchis elegans was examined with a view to identifying some of the biotic and abiotic factors that govern parasite egg development, infectivity and survival, the dynamics of cercarial production, as well as host susceptibility to infection, growth, reproduction and mortality. Plagiorchis elegans eggs passed with the feces of the hamster (Mesocricetus auratus) experimental definitive host were unembryonated. Between 0 and 30 C, the rate of embryonation continued to increase with temperature, whereas infectivity and survival were optimal between 10 to 20 C. Light adversely affected embryonation. Parasite acquisition increased with the intensity of exposure and sexual maturity. Infection invariably enhanced pre-patent host growth in a dose-dependent manner. Cercarial production increased with time and reached a plateau. Snails infected prior to sexual maturity released more cercariae than mature individuals. Heavily infected snails tended to die prematurely regardless of age at infection and parasite dose, thereby reducing their total production of cercariae to levels below those of more lightly infected individuals. Even light infections castrated the snail host. Snails infected when immature never reproduced, whereas reproductive snails ceased egg production within days of infection. Similar effects were observed in the incompatible snail host Biomphalaria glabrata, although no cercariae were ever produced. Both enhanced growth and parasitic castration are attributable to the mother sporocyst.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.35657
Date January 1998
CreatorsZakikhani, Mahvash.
ContributorsRau, M. E. (advisor)
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageDoctor of Philosophy (Department of Natural Resource Sciences.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 001641625, proquestno: NQ44641, Theses scanned by UMI/ProQuest.

Page generated in 0.0024 seconds