Failure to Induce Homologus Immunity to ‘Fasciola Hepatica’ in Sheep Vaccinated With Irradiated Metacercariae

Title
Failure to Induce Homologus Immunity to ‘Fasciola Hepatica’ in Sheep Vaccinated With Irradiated Metacercariae
Publication Date
1978
Author(s)
Campbell, N J
Gregg, Peter
( author )
OrcID: https://orcid.org/0000-0001-7534-3567
Email: pgregg@une.edu.au
UNE Id une-id:pgregg
Kelly, J D
Dineen, J K
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Elsevier BV
Place of publication
Netherlands
DOI
10.1016/0304-4017(78)90005-5
UNE publication id
une:22402
Abstract
Vaccination of sheep with either 100 or 1000 γ-irradiated (2.5 krad) metacercariae of Fasciola hepatica, on two occasions six weeks apart, did not generate significant protection against intraruminal challenge with F. 'hepatica' six weeks after the second vaccinating dose as measured by recovery of flukes from liver and bile ducts, twenty weeks after challenge. There was, however, a significant increase in the proportion of flukes retarded in the parenchyma of both vaccinated groups. The percentage of retarded flukes was positively correlated with the degree of liver damage and increased weight of the hepatic lymph nodes. It was not possible to determine if the retarded flukes were derived from the vaccine or challenge infections or both. Challenge infection of both vaccinated and unvaccinated sheep significantly increased the numbers of eosinophils and globule leucocytes in the parenchymal bile duct and the numbers of mast cells and globule leucocytes in the abdominal bile duct. In addition the numbers of eosinophils and globule leucocytes in the parenchymal bile duct were significantly correlated with the percentage of retarded flukes in both vaccinated groups. In the abdominal bile duct, only the numbers of eosinophils in the low level vaccination group were significantly correlated with fluke retardation. Vaccination did not protect against the pathogenic effects of challenge infection as measured by reduced packed cell volumes and weight gain.
Link
Citation
Veterinary Parasitology, 4(2), p. 143-152
ISSN
1873-2550
0304-4017
Start page
143
End page
152

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