The pathology of bracken-associated tumours in cattle

McNeil, Pauline E (1984) The pathology of bracken-associated tumours in cattle. PhD thesis, University of Glasgow.

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Abstract

This thesis describes the pathology of UAT carcinoma and urinary bladder neoplasia in cattle in the West of Scotland. The UAT tumours are squamous carcinomas which occur as verrucose protruberances or ulcerative downgrowths. In a survey of 100 cases, predilection sites were the tongue, soft palate and oropharynx, the oesophagus, the reticular groove and the dorsal sac of the rumen; sites where viral papillomas were also commonly found. The microscopical appearance of the tumours is detailed and a grading system is proposed, based on the degrees of cellular atypia and anaplasia, which correlates well with the incidence of secondary tumours. Examination of 60 cases of urinary bladder neoplasia revealed vascular, epithelial or fibrous tumours. A striking feature of most cases was the variety and multiplicity of lesions in each bladder. A spectrum of changes was seen ranging from epithelial hyperplasia and dysplasia, capillary proliferation and ectasia and stromal hyperplasia to frank neoplasms which occasionally infiltrated widely and in a few cases produced secondary deposits. The bladder tumours were indistinguishable from those described by other authors in association with CEH and presumed to be due to long term ingestion of bracken fern. A high incidence of bovine UAT carcinoma has been described by workers in Kenya, but only in Brazil has the co-incidence of UAT and urinary bladder neoplasia in cattle been reported previously. Brazilian authors attributed the occurrence of tumours at both sites to the oncogenic action of bracken fern. Epidemiological studies of cases in the West of Scotland have also implicated bracken fern as a possible aetiological agent. Chapter II of the thesis describes a preliminary experiment in which four cattle received intra-ruminal inoculations of bovine papillomavirus and were fed bracken fern, intermittently, for up to eight years. Only minimal haematological changes were observed and the acute toxic effects of the plant were avoided, yet three animals which survived more than five years developed haematuria and had bladder tumours at necropsy. No UAT carcinoma was found and the results do not clarify the possible role of papillomavirus in the development of bovine cancer. This work does confirm the major aetiological role of bracken fern in bovine bladder neoplasia but evidence for its role in the aetiology of UAT carcinoma remains circumstantial.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: William Jarrett
Keywords: Animal diseases, Pathology
Date of Award: 1984
Depositing User: Enlighten Team
Unique ID: glathesis:1984-71589
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 10 May 2019 14:11
Last Modified: 10 May 2019 14:11
URI: http://theses.gla.ac.uk/id/eprint/71589

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