PATHOLOGY OF GASTROINTESTINAL LESIONS AND SCREENING FOR ASSOCIATED ENTEROPATHOGENIC VIRAL INFECTIONS IN PIGS
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Date
2022-06-17
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES POOKODE, WAYANAD
Abstract
The present study entitled “Pathological study of gastrointestinal lesions and
screening for associated enteropathogenic viral infections in pigs” focused on
systematic recording of gross and histopathological changes in stomach, intestine
and mesenteric lymph nodes and screening for Group A rotavirus (GARV),
transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhoea virus
(PEDV) and porcine sapovirus (PSaV). A detailed necropsy of 57 pig carcasses
were conducted, gross lesions were recorded and samples of stomach, intestine and
mesenteric lymph nodes were collected for histopathology and molecular
screening. Gross and histopathological changes in either stomach, intestine or
mesenteric lymph nodes were evident in all the carcasses presented. Major gross
lesions in stomach varied from mucosal erosions to ulcerations, hyperkeratinised
pars oesophagea and diphtheritic membrane. Microscopically, the important
lesions observed were mucosal necrosis, erosions and ulcers, cellular infiltration in
lamina propria, hyperkeratinisation and fibrino-necrotic membrane. Salient gross
lesions in intestines were catarrhal to haemorrhagic enteritis, mucosal ulcers in
caecum and colon, fibrino-necrotic membranes in ileum, caecum and colon, flaccid
and thin-walled small intestine and mesocolonic edema. Principal microscopic
changes included Brunner gland hyperplasia, fibrino-necrotic membrane in ileum,
caecum and colon, hyperplastic crypts, villous atrophy and fusion, crypt abscess,
neutrophilic colitis, hyperplasia and necrosis in Peyer’s patches in ileum and
granulomatous infiltration in ileum and colon. Gross lesions in mesenteric lymph
nodes were enlargement, congestion and haemorrhage. Major histological changes
were varying degrees of lymphocytic depletion, histiocytic and granulomatous
infiltration. GARV, TGEV, PEDV and PSaV were not detected in any of the
samples screened. However, 80.70 per cent were infected with either PCV2,
Salmonella or E. coli among which the incidence of Salmonella isolates were the
highest (50.88%). It was observed that weaners were the most commonly affected
age groups. Coinfections with at least two of these pathogens were observed in
49.12 per cent cases and severe lesions were encountered in coinfections.
Description
Submitted in partial fulfillment of the requirement for the degree of
Master of Veterinary Science in Veterinary Pathology