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Feline TB
Key Facts:

TB in cats is rare and only VERY rarely spreads from cats to people
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TB is caused by a bacteria called Mycobacterium
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There are several different types of Mycobacterium, some affecting just humans,
some affecting lots of different types of animals including cats
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TB in cats normally causes skin lesions, sometimes diarrhoea, vomiting, coughing
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Diagnosis and treatment is possible, but can be difficult

There is no vaccine
The Full Story:
There have been several stories recently in the news regarding TB in cats, following a cluster of
cases in the Berkshire (although this actually happened over a year ago now). TB is not a
common disease in cats, obviously is a lot more common in cattle and humans. It seems that
TB may be becoming more prevalent in the feline population, so it’s worth being aware of it.
Human TB is caused by the infection Mycobacterium tuberculi, it rarely affects other animals
and cats are actually naturally resistant to it (it can however affect dogs). TB in cattle is caused
by a slightly different type of mycobacterium - Mycobacterium bovis. Mycobacterium bovis
affects lots of different species including humans, mice/rats and other rodents, badgers, deer,
cats, dogs and ferrets. There is a third strain of mycobacterium - Mycobacterium microti - that
affects voles and mice, and cats.
It’s thought that cats most often become infected from a bite from a mouse (or other rodent)
they have caught whilst hunting, but the exact way the disease is spread is still not 100% clear.
Cats may catch it from close contact with infected badgers or other infected cats. Most
importantly the infection can spread from cats to humans, but this is incredibly rare.
Unlike in humans, TB in cats normally causes skin lesions on areas likely to be bitten by a
rodent whilst hunting eg paws, legs, face. The lesions can look like infected wounds or
sometimes look more like a fleshy growth. Cats are sometimes affected with a cough like TB in
humans, but it can cause a wide range of symptoms, such as diarrhoea, vomiting, weight loss,
lethargy. Not all cats will show symptoms of the disease despite being carriers. Obviously there
are lots of more common reasons why your cat may have a wound on its paw or may have a
cough, probably the commonest reasons owners bring cats in to the vets are for cat fight
injuries or for cat flu.
Diagnosing TB in cats is not always straightforward and can be time consuming. There isn't a
simple blood test for diagnosis, we normally need to take a biopsy sample of tissue from a skin
lesion and send this to the lab for analysis. If we do diagnose TB, we then have to inform the
Animal Health and Veterinary Laboratories Agency (AHVLA) because of the risk to public health.
Treating cats with TB is a contentious issue. The advice from AHVLA and public health
authorities is that infected cats should not be treated and should be put to sleep. Cats carrying
TB pose a serious risk to public health. Treating the disease involves the use of antibiotics that
are not liceinced for use in cats. Cats often need long courses of multiple drugs to try to fight
the condition and even then are not fully cured. There is a very real risk that treatment of such
cats with antibiotics (that really are reserved for human use) may promote antibiotic resistance.
The vaccine humans receive for TB, the BCG vaccine, protects against Mycobacterium tuberculi.
There isn't an equivalent vaccine for Mycobacterium bovis or microti for cats. If you have any
concerns about your cat's health please just get them checked by a vet, or if you have any
concerns about your own health with regards to feline TB, please speak to your doctor.