Outbreak of feline tuberculosis caused by <i>Mycobacterium bovis</i> in a German household, a possible domestic zoonosis

Infections with Mycobacterium bovis can lead to clinical tuberculosis in many mammals. Here, we describe M. bovis infections in 4 of 7 cats from 1 household in Germany. These cats had respiratory disorders at intervals of several months. Two of 4 euthanized animals (cats 3 and 4) were submitted for postmortem examination; lungs failed to collapse and were firm in both cats. In cat 4, a severely enlarged pulmonary lymph node was found, as well as small white granulomas in the spleen, liver, and kidney. Bacterial cultivation identified M. bovis spoligotype SB0120 as the causative pathogen in cats 3 and 4. Molecular genetic fine typing revealed that this genotype had not been reported previously in animals or humans in Germany. Serum from cat 4 shortly before euthanasia, and from cats 5-7, were tested for TB-specific antibodies by ELISA. Cat 4 was strongly positive. In contrast, cats 5-7 were negative and remained negative 4 mo later. Based on our case series, tuberculosis should be considered as a differential diagnosis in pet animals, even in countries that are officially free of the disease. A lack of awareness about tuberculosis could increase the risk of zoonotic infections with M. bovis -for both owners and other animals living in affected households.