Information about cat TB
We are currently investigating a cluster of tuberculosis (TB) infections in cats that may be linked to a certain type of raw pet food.
The description of the first six cases has been published in the Journal of Feline Medicine & Surgery.
Further information is available in the Q&A below. We will update this website as new information becomes available.
What is TB and how is it passed on?
Tuberculosis is an infectious disease caused by bacteria and is spread between people and animals primarily through coughs and sneezes or through open skin wounds. There are several species of bacteria that can cause TB. Most cases that affect animals are caused by Mycobacterium bovis, which is commonly found in cattle, badger and deer. Cats can catch the disease too and this is usually caused by hunting wildlife, including rodents. They can also be infected by drinking contaminated raw milk or eating infected meat.
What does TB look like in cats?
Most cases of TB in cats are caused by infected bites, so skin wounds and swollen lymph nodes are usually the first signs. When TB is passed on by eating contaminated food products, it typically affects the intestines and/or lungs. It can cause swollen abdomen, enlarged lymph nodes, and persistent cough. It can also spread to joints and eyes. Cats may also be more tired than usual and may have signs of weight loss.
Infected cats usually develop symptoms within six months. The infection can lie dormant, however, and some of the cats who appear healthy may go on to develop symptoms later in their life.
How common is TB in cats?
More than a hundred cases of TB in cats are reported in the UK each year. The majority are caused by infected bites from wild animals.
In autumn 2018, we were notified of six cases involving indoor cats that could not have been infected in this way. They were from five different households from different parts of England. Four of these are areas where M. bovis is not usually found in cattle, badger or rodents. The only common factor was that they had all been fed a commercial brand of raw food – a Wild Venison product from Natural Instinct. A further seven cats living in the same households were found to have evidence of infection but did not have symptoms of disease, taking the number of cases to 13.
Were these infections definitely caused by food?
We did not test the food itself so we cannot say with certainty that the food was the source of the infection. We were not able to identify any other source of infection.
I have bought this food, can I still feed it to my cat?
Natural Instinct voluntarily recalled their Wild Venison product from the market on 11 December 2018. The company has advised owners not to feed Wild Venison products sold before this date to their cats. Anyone with unused product can return it to the store they purchased it from for a full refund. No other products from this company are affected. For further information, please visit the Natural Instinct website - https://www.naturalinstinct.com/product-recall.
I have fed this food to my cat – what should I do?
The link between the recalled food and the disease has not been proven. Even if the link is confirmed, not all cats fed this food will be infected and not all cats that are infected will develop disease. If your cat shows signs of ill health, you should take it to your local vet immediately. TB infections can lie dormant for many years so if you have fed this recalled product to your cat you should remain vigilant throughout its life. If your cat becomes ill at any stage, you should mention to your vet that they have eaten this food so that appropriate tests can be arranged.
How did you test for TB in cats?
We use a test that detects the presence of bacterial DNA in a tissue sample from the cat, called a PCR. We also use a blood test that detects if the cat’s immune system has been exposed to the bacteria, called an Interferon Gamma Release Assay or IGRA. Another test involves incubating tissue samples from the cat in the lab to see if the bacteria grows, which is the most conclusive test for the infection.
The IGRA was initially developed to detect bacteria in ill cats with clinical symptoms of TB. We have also used it to check if healthy cats have been exposed to the bacteria, but interpreting the results is challenging.
Can I catch TB from my cat?
The risk of people catching TB from their cats is extremely low. There have been only six confirmed cases of owners catching the M. bovis bacteria from their cats in the past 150 years.
I feed my cats a different type of raw pet food could they be affected?
There is no evidence of any other raw pet foods being affected.
What can be done if a cat is found to have TB?
Treatment for TB in cats is challenging and depends on the severity of the infection and how early the disease is diagnosed. Your local vet can advise on the most appropriate options if your cat is confirmed to be infected.
I am an owner and I would like to speak to somebody at the Royal (Dick) School of Veterinary Studies about my cat, who should I contact?
In line with the Royal College of Veterinary Surgeons’ Code of Professional Conduct, we are unable to speak to owners unless their pet has been referred to us. We recommend owners speak to their local vet in the first instance. Their vet can then speak to us.
I am a vet and I have identified a case of feline TB that I think may be linked to this cluster, what should I do?
The Companion Animal TB Team at the Royal (Dick) School of Veterinary Studies are happy to discuss all cases of potential TB with veterinary surgeons. The clinical signs associated with this cluster of infections vary from the usual symptoms of TB. We can provide tailored advice and are keen to gather information on all cases, including details of outcomes. Please contact Companion.AnimalTB@ed.ac.uk.
In addition, the Animal and Plant Health Agency should be notified of all suspected cases of M. bovis infection in cats. Public Health England, Public Health Wales and Health Protection Scotland can help assess the risk of potential exposure to the owner and veterinary staff.