Clinical and histopathological diagnosis of bovine paratuberculosis in a dairy herd in Colombia

Objective. To analyze retrospectively and systematicaly the histological and clinical findings of bovine paratuberculosis Mycobacterium avium subsp. Paratuberculosis (MAP). The data were obtained at different times over a period of 8 years (2000-2008) in a dairy herd in Colombia. Materials and methods. Historical data of clinical and histopathological findings, in five cases compatible with bovine paratuberculosis, were studied. Additional information was also analysed from other studies related to the disease in the herd in the same period of time. Results. The infected animals showed intermittent chronic diarrhea, decreased production of milk, progressive weight loss, normal appetite, increased water consumption and normal physiological constants. The necropsy revealed variable thickening of the intestinal mucous membrane in the ileum and proximal portion of the large intestine with multiple uprisings and depressions, which did not disappear in the stretched tissue. Mesenteric vessels were dilated and congestive. Mesenteric lymph nodes were found increased up to three times, without clear delineation of bark and cord. Histological alterations were enteritis and lymphomatoid granulomatosis. Three animals showed abundant acid alcohol resistant Bacilli (AARB) in macrophages, giant cells and in the interstitial tissue by using the Ziehl-Neelsen staining. However, it was not found the granulomatous inflammation in other tissues evaluated. Conclusion. Diagnostic based on clinical, histopathological and necropsy findings as well as on analysis of diagnostic information from other studies, allow us to confirm the presence, circulation and permanence of MAP in the herd with an apparent high number of infected animals.