International Journal of Agriculture Extension and Social Development

author(s)
Subhash, Deepika Lather, Renu Gupta, Vikas Nehra, Shoorvir Singh, RP Gupta, Paras Saini and Gulshan Narang

abstract
The present study was carried out to investigate the pathobiology of paratuberculosis in ruminants having history of gastrointestinal tract disorders brought to the Department of Veterinary Pathology, LUVAS, Hisar, Haryana. Out of 65 ruminant (38 buffalo, 10 cattle, 5 goat and 12 sheep) carcasses examined, 15 cases were confirmed for Mycobacterium avium subsp. paratuberculosis including 12 bovine (8 adult and 4 calves), two cases of caprine and one case of ovine species. Confirmation of paratuberculosis was done by conventional PCR method using IS900 primers on intestinal and mesenteric lymph nodes samples. Gross pathological studies revealed transverse folds/corrugations (60% cases), necrotic mucosa with thickening (26.7% cases) and vascular changes (13.3% cases) in intestine. Mesenteric lymph nodes showed enlargement, necrosis and induration with caseation in 80%, 13.3% and 6.7% cases respectively. Histopathology investigations in intestine revealed necro-hemorrhagic enteritis (53.3%) and granulomatous enteritis (46.7%). Mesenteric lymph nodes showed most prominent histopathological changes as granulomatous lymphadenitis (53.3%) followed by chronic lymphadenitis and hemorrhagic lymphadenitis (6.7%). Histopathological classification of paratuberculosis lesions on the basis of inflammatory cells and microgranuloma in intestinal tissue sections revealed focal (7), multifocal(1), diffuse multibacillary (1), diffuse paucibacillary (5) and diffuse intermediate (1) type lesions, while mesenteric lymph nodes showed focal (8), diffuse multibacillary (1), diffuse paucibacillary (5) and diffuse intermediate (1) type lesions. Evaluation of acid fast bacilli in MAP positive cases in intestinal and mesenteric lymph nodes sections showed positive reaction in 26.7% and 33.3% cases respectively. Immunohistochemical detection of MAP in formalin fixed intestine and mesenteric lymph nodes tissue sections using anti-MAP polyclonal antibody showed positive results in the cytoplasm of the macrophages, giant cells and epithelioid cells. Results of present study confirm the prevalence of paratuberculosis disease in Haryana and describe the pathobiology of this disease and corroborate that immunohistochemistry complements the histopathology for the accurate confirmatory diagnosis of paratuberculosis.