Diagnosis of paratuberculosis in sheep

Paratuberculosis in sheep usually is manifested as emaciation and decreased wool production. Diarrhea occurred in only 18% of affected animals. Significant hematologic changes included decreased RBC count, hemoglobin level and hematocrit. Necropsy revealed pallor, cachexia and serous fluid in body cavities. Staining of intestinal mucosal scrapings and mesenteric lymph node impression smears for acid-fast organisms revealed bright-red clumps of Mycobacterium paratuberculosis bacilli. Fecal examination identified 70% of affected animals, intradermal injection of johnin 60%, and avian tuberculin 39%.