A recent article from the Veterinary Information Network (VIN) News Service describes a strange cluster of feline tuberculosis (TB) cases in the UK, with a possible link to food. In cats, TB is rare and usually caused by Mycobacterium bovis, a bacterium most often associated with cattle and bovine TB. M. bovis is present in the UK and circulates in some wildlife species. TB can be a nasty disease, and without treatment, it’s fatal (in humans and animals). While potentially treatable, the prognosis is still guarded and months of antibiotics are required. There is also some (but poorly understood) risk to owners of infected animals, since M. bovis can infect people too. Cat-human infections are rare (or rarely identified) but it’s still a concern.

The cluster of cases in the UK is unusual for a few reasons:

  • One is that it occurred at all, since TB is cats is rare.
  • Another is that it affected young cats with no history of outdoor access. Typically, cats get infected outside from bites and scratches that occur when hunting.
  • All cats were fed the same brand of a commercial frozen raw diet.
  • Some of the cases were in cats living in low risk areas of the UK.

In cats, M. bovis usually causes skin and soft tissue infections, a testament to the typical route of exposure in this species (i.e. bites). However, the cases in this report had intestinal disease, characterized by signs such as weight loss, abdominal masses and diarrhea, consistent with exposure through ingestion of contaminated food.

Dr. Danielle Gunn-Moore of the University of Edinburgh is leading the investigation and emphasizes a few points:

  • Veterinarians in the UK should be aware of TB in cats, as infected animals may show non-specific signs of infection.
  • If TB is a possible reason for a cat’s illness, diagnostic testing should be performed ASAP.
  • Food history should be questioned in potential cases, with particular attention to raw diets.
  • Veterinarians in the UK that suspect they have a case of feline TB should contact Dr. Gunn-Moore.