Aspectos clínico-patológicos da paratuberculose em rebanho bovino leiteiro no município de Rio Claro, RJ

Abstract

The epidemic and clinic-pathological aspects of paratuberculois in a dairy cattle herd in the Rio Claro county, southern Rio de Janeiro region, are described. In the years 2006-2009, eight adult cows presented chronic-intermittent diarrhea, chronic weight loss and normal appetite. At necropsy, the subserosal lymphatics were proeminent and dilated, mesenteric nodes were enlarged, and intestinal mucosa was corrugated, thickened and of microgranular aspect. Especially, in duodenum, was observed polipoids lesions in mucosa surface. Histopathology revealed, from the duodenum to the rectum, severe and diffuse granulomatous inflammation of the lamina propria and submucosa, broadened and distorced villi, marked dilatation of the lymphatic vessels in their apex, lymphangioectasia and granulomatous lymphangitis in the submucosa. Ziehl-Neelsen stain revealed variable amounts of acid-fast bacilli in macrophages, Langhan s giant cells and freely in the musosa and submucosa of the small intestine and colon, and in lymphnodes. Lesions in the lamina propria, particularly in the jejun and ileum, in some animals, were severe hypertrophy; polipoids lesions observed in duodenum mucosa was markedly muscularis mucosa hipertrophy , intestinals and duodenal glands hiperplasia. Mycobacterium avium subsp. paratuberulosis was isolated by bacterial cultivation of samples from feces, intestinal mucosa and milk, and identified through IS900 PCR. From 298 cows, older than three years, the percentage of reactive animals was 40%, in indirect ELISA test. The diagnosis of paratuberculosis was based on clinic-epidemiological data, sorology, bacterial isolation and IS900 PCR. After the adoption of control measures, as slaughter of sick cows and selective slaughter of soropositive animals, was observed reduction of clinical cases in the herd, from six cases to one case per year, in three years of study.