Cases of tuberculosis in indoor cats may have been linked to a particular type of raw pet food, research has suggested.
Some 13 cats from across the UK are thought to have been affected so far and experts have stressed that the risk to people is very low.
The issue came to light when six cats were taken to separate vet practices across England with clinical signs of TB. Tests confirmed the animals were infected with bacteria that usually cause TB in cattle, called Mycobacterium bovis. This bacteria can also infect other animals including rodents and deer.
An additional seven cats living in the same households were also found to be infected but did not have symptoms of disease.
All of the affected animals were exclusively indoor pets and had no contact with any wildlife that could have passed on the disease.
Vets at the University of Edinburgh’s Royal (Dick) School of Veterinary Studies carried out an investigation to identify the source of infection.
They found the only common factor was that they had all eaten the Wild Venison variety of a commercial brand of pet food, called Natural Instinct. However, the team did not test food samples so they cannot confirm that it was the source of the infections.
The company voluntarily recalled the product in December 2018 and has advised people who may still have stocks to return unused items for a full refund. At the time, the company released a statement which said some of the ingredients were not inspected in line with EU requirements which meant the safety of the product could not be confirmed.
Symptoms of TB in cats include swollen belly, persistent cough and enlarged lymph nodes.
A report on the first six cases is published in the Journal of Feline Medicine and Surgery. The study was funded by the Biotechnology and Biological Sciences Research Council.
Professor Danièlle Gunn-Moore, of the University of Edinburgh’s Royal (Dick) School of Veterinary Studies, said: “We found circumstantial evidence that these cases of TB in cats were linked to a particular brand of raw food diet. Not all animals that are infected with the bacteria will develop disease but we would encourage owners with concerns about their pets to get them checked by their local vet.”
A spokesperson from Natural Instinct added: “Everything we do at Natural Instinct is done so with the best interests of our customers and their pets in mind. We can assure our customers that Natural Instinct followed, and continues to follow, every food standard, hygiene regulation and best practice required to produce raw pet food in the commercial marketplace.
“As a responsible manufacturer, we are regularly inspected by the Animal and Plant Health Authority (APHA). We have complied with all of the necessary requirements, and consequently APHA have confirmed they are satisfied all standards have been met by us.
“Even though we no longer manufacture and sell the venison cat product, we are continuing to work with Food Standards Agency as part of the investigation into the venison cat food product.”
