Five imported feline cases of Mycobacterium bovis associated with international movement of cats from Turkey

This is the authors' abstract. We don't add key points for this paper.

Mycobacterium bovis (M. bovis) is the most important cause of bovine tuberculosis (bTB), but it can also infect a variety of other domestic and wild animals and has zoonotic potential. Some countries, such as Switzerland and most of the United States of America (USA), are officially free of bTB. However, sporadic cases and wildlife reservoirs persist, and there remains a constant risk of reintroduction. This case series details five cats with M. bovis infection that were relocated from Turkey to Switzerland and the USA. Owing to severe clinical manifestations, three cats were euthanized and subsequently demonstrated gross and histopathological alterations characteristic of tuberculosis. Infection with M. bovis was confirmed by real-time PCR from tissue samples and cultured isolates and genotyping from cultured isolates. Whole genome sequencing revealed that the isolates clustered predominantly with M. bovis strains originating from Turkey, corroborating Turkey as the most likely origin of infection. Two additional cats relocated from Turkey to Switzerland were treated for tuberculosis. One cat, which exhibited typical clinical signs and radiological changes consistent with tuberculosis, was serologically positive, whereas the other cat, with no clinical signs and no radiological changes was seronegative. These findings underscore the potential risk of reintroducing M. bovis through the relocation of animals, in this case domestic cats. Implementation of serological screening, such as ELISA-based assays, prior to animal relocation could represent a practical measure to reduce this risk.