Paratuberculosis in a Goat: A Rare Type III C (Paucibacillary) Granulomatous Ileitis with Disseminated Secondary Lesions

Abstract

A five years old full-term cross bred female goat was presented for necropsy with the history of chronic weakness for six months. On external examination, carcass was emaciated and showed pale mucous membranes and soiling of perineum with pasty faeces. On detailed examination, distal small intestine (part of distal jejunum and ileum) revealed irregular, rough, multifocal areas of mucosal thickening. Scattered areas showed mucosal wrinkles. Ileocecal valve was congested and thickened. Mesenteric lymph nodes (MLNs) were enlarged and oedematous. Microscopically, ileum revealed villi distortion, atrophy and fusion. Tips of the villi were blunt and fused. Lamina propria was widened with aggregates of lymphocytes and macrophages.  Epithelioid cells were clustered at the centre of the lymphoid aggregation forming a granuloma. Multinucleated giant cells were found within the granuloma. Submucosa revealed lympho-plasmacytic infiltration, oedema and fibrinous exudation. Lymphatic vasculitis with thrombus was seen at the submucosa. Disseminated granulomatous lesions were noticed in liver, lungs and kidney. Lung revealed oedema, focal granuloma and perivascular lymphocytic infiltrations. Liver showed paracentral necrosis. Acute splenitis was also noticed. Kidney revealed congestion and focal granuloma. The MLNs revealed intrafollicular granuloma with typical Langhans-type giant cells at the paracortical zone. Ziehl-Neelsen staining of intestinal scrapings and lymph node impression smear along with tissues sections from ileum revealed scattered acid-fast bacilli within and outside the macrophages. The PCR amplification of MAP IS900 gene was carried out using IS900 primers in tissues of jejunum, ileum and MLNs showed positive amplicon of 572 bp. Based on the histopathomorphological features, this case was diagnosed as multifocal paucibacillary type III subtype c paratuberculosis in a goat.