Reports have emerged from the UK of a mother and daughter with subclinical and clinical TB, respectively, caused by M. bovis, connected with an infected pet cat. Whilst it is unclear as to the exact nature of transmission, it has certainly raised awareness regarding the small but possible risk of catching this infection from companion animals. M. bovis accounts for less than 1% of all cases of human TB in the UK, with the majority of these occurring in older people with suspected reactivation of latent infection, likely acquired before widespread control measures came into place, such as TB testing of cattle and pasteurisation of milk.
Bovine TB remains endemic in dairy herds in parts of the UK due to reservoirs of infection in wildlife such as badgers and rodents. While it is uncertain whether pet or feral cats have any direct interaction with badgers, it is certainly possible that cats are acquiring infection from eating or being bitten by infected rodents. Although the news of these cases should not raise alarm, it is a reminder that there is a small risk to cat owners, and that people should ideally not allow cats to roam and hunt wildlife – especially in areas of TB endemicity. As some of the feline cases recently reported were also possibly acquired after surgery, it is also reminder to veterinarians to remain diligent with regards to minimising the risk of nosocomial transfer of organisms.
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