Pathological Studies on Johnes Disease induced Enteritis in Egyptian Cattle

We described the gross and histopathological lesions of naturally occurring Johne's disease- induced enteritis in Egyptian cattle. A total of 100 cattle with history of enteritis, slaughtered at the regional slaughter-houses or recently died at dairy farms of Dakahlia province, Egypt were examined. The results showed that 7 animals were infected with mycobacterium paratuberculosis subsp. Avium. The acid-fast bacilli were detected in fecal smears and tissue sections stained by Ziehl-Neelsen's (ZN) technique and serum samples had positive antibody levels detectable by enzyme-linked immunosorbent assay (ELISA). Grossly, the intestinal mucosa of lower ileum and upper large intestine were thickened and folded into transverse rugae. The subserosal lymphatics were prominent and dilated and the mesenteric lymph nodes were congested, and edematous. Microscopically, granulomatous enteritis was the main consistent lesion. In less sever affected cases; the lamina propria and submucosa was multifocally infiltrated with mixed inflammatory cells composed mainly of lymphocytes, plasma cells, few macrophages and a large number of eosinophils. Occasionally, granulomatous lymphangitis occluded the lumen of submucosal lymphatics. In severe cases; the intestinal villi were fused, markedly atrophic and diffusely infiltrated with epithelioid macrophages with fewer lymphocytes and plasma cells. Multinucleated giant cells were occasionally seen. Acid-fast rods were seen within the cytoplasm of macrophages. It was concluded that the lesions of Johne's disease in cattle were characteristic; these findings emphasize the importance of a careful histopathological examination of the intestines and mesenteric lymph nodes for the diagnosis of the disease. Moreover, control and prevention programs should be initiated in Egypt.