First cases alert: Cats spread TB to four people

Experts stressed that cat-to-human transmission is very rare
  • @kashmiragander

Two people have developed tuberculosis (TB) after coming into contact with a domestic cat, in the first ever recorded cases of cat-to-human transmission, Public Health England (PHE) has said.

The cat was infected with the Mycobacterium bovis (M.bovis)  bacteria, which causes bovine TB in cattle and other animals.

Nine cases of M. bovis infection in domestic cats in Berkshire and Hampshire were investigated by the Animal Health and Veterinary Laboratories Agency (AHVLA) and PHE last year.

PHE said there have been no further cases of TB in cats reported in the two areas since March 2013, and said it believed the risk of transmission from cats to humans was “very low”.

The organisation said it had offered TB screening to 39 people identified as having had contact with the nine infected cats, with 24 people accepting.

Two were found to have active TB in their systems, and are responding to treatment. There were two additional cases of latent TB, meaning the people had been exposed to TB at some point but did not have an active infection.

Analysis of the samples of active TB from the humans and the infected cats by the AHVLA showed the M. bovis was “ indistinguishable”.

This “indicates transmission of the bacterium from an infected cat”, PHE said.

In the cases of latent TB infection, it was not possible to confirm if they were caused by M. bovis.

According to PHE, transmission of the bacteria from infected animals to humans “can occur by inhaling or ingesting bacteria shed by the animal or through contamination of unprotected cuts in the skin while handling infected animals or their carcasses”.

Dr Dilys Morgan, head of gastrointestinal, emerging and zoonotic diseases department at PHE, said: “It's important to remember that this was a very unusual cluster of TB in domestic cats.

M. bovis is still uncommon in cats - it mainly affects livestock animals.

"These are the first documented cases of cat-to-human transmission and so, although PHE has assessed the risk of people catching this infection from infected cats as being very low, we are recommending that household and close contacts of cats with confirmed M. bovis infection should be assessed and receive public health advice."

TB is a serious condition but can be cured with proper treatment, namely antibiotics taken for at least six months. The disease mainly affects the lungs but can affect any part of the body, including the bones and nervous system.

Typical symptoms include having a persistent cough for more than three weeks that brings up phlegm (which may be bloody), weight loss and night sweats.

People can also experience a fever, tiredness and fatigue and a loss of appetite.

Usually, TB only spreads after prolonged exposure to someone with the illness, such as living in the same house.

In 2012, 8,751 cases of TB were reported in the UK.

Mike Mandelbaum, chief executive of the charity TB Alert, said: “ In the UK we are a nation of cat lovers, so this may prove quite shocking for people who may now look at their pets in a different light.

"Although I would stress that the risk of catching TB from a cat is likely to remain very low, this is a stark reminder that TB is still a problem in the UK today, with almost 9,000 people developing it last year.

"As TB is airborne, the best way to control the spread of all forms of this curable illness, including those transmitted by animals, is for it to be diagnosed and treated as early as possible."

Additional reporting by PA