Tuberculosis in domestic cats (Felis catus) in southern Rio Grande do Sul

Clinical pathological aspects of four cases of tuberculosis in domestic cats in southern Rio Grande do Sul is described. A retrospective study was conducted of cats diagnosed with tuberculosis and necropsied at the Regional Diagnostic Laboratory of the Federal University of Pelotas (LRD/UFPel) from January 2000 to December 2014. In two cases, the amplification of genetic sequence IS6110 specific to Mycobacterium tuberculosis demonstrated that the disease was of human origin. The other two were positive for Mycobacterium spp. The clinical signs were characterized by progressive weight loss, anorexia, and dyspnea. The evident macroscopic changes were cachexia, swelling of submandibular lymph nodes with focal areas of caseous aspect on cut surface. The lungs had multifocal caseous areas at the pleural surface. Histologically, the cats had pneumonia and granulomatous lymphadenitis. The Ziehl-Neelsen staining revealed the presence of alcohol-acid resistant bacteria. There was a positive immunostaining for mycobacteria by immunohistochemistry technique. We alert to the importance of feline tuberculosis as a public health problem, because infected cats may serve as source for dissemination of mycobacteria in the environment, and be sentinels for the occurrence of the disease in humans.