Inaccurate reporting of cat bite dangers

“Why even a tiny cat bite could leave you in hospital: Cats’ teeth ‘inject bacteria deep into the joints and tissue’, doctors warn”. The Daily Mail inaccurately claims that one in three people bitten by cats need to go into hospital, and that two-thirds of those people need surgery.

The paper reports on a US study that reviewed the records of 193 people who presented to their hospital (the Mayo Clinic) with a cat bite to the hand during a three year period. They wanted to look at how well they’d recovered, and what factors were associated with them being admitted to hospital.

Overall the majority were middle-aged women, and they found that 30% needed hospital admission and 20% needed surgical treatment to clean out the wound. The important thing to be aware of is that these figures relate only to this specific group of people who presented to the clinic with a hand bite.

However it is important to point out that this may not be a representative sample of cat bite ‘victims’. It cannot tell us what proportion of people who are bitten by a cat but do not feel the need to seek medical attention.

Neither can it tell us anything about bites elsewhere on the body, as this was not assessed.

If you were hypercritical you could make the case that this is not a particularly useful study in terms of analysing the outcomes of cat bites. Perhaps a better approach would have been a survey of cat owners.

Where did the story come from?

The study was carried out by three researchers from Mayo Medical School and the Department of Plastic Surgery at the Mayo Clinic, Rochester, US. No sources of funding were received.

The study was published in the peer-reviewed, open access American Journal of Hand Surgery.

The Mail has vastly over-interpreted the findings of this research and applied them to all people with cats.

For example, they say that one in three people bitten need to go into hospital. The actual finding is that of the people who presented to this specific hospital with a cat bite to the hand over this three year period, one third of them needed to be admitted to the hospital.

It does not mean that of everyone who gets a cat bite in the outside world, a third would need to be admitted. A US study estimated that only 6% of people bitten by a cat require hospital admission.

The research is also only looking at bites to the hand, not elsewhere. 

What kind of research was this?

The authors of this study reviewed the records for their hospital (the Department of Plastic Surgery at the Mayo Clinic) for the three year period between January 2009 and December 2011 to look at all people treated for cat bites to the hand. They wanted to look at how well they’d recovered, and what factors were associated with them being admitted into hospital.

In the US, animal bites are said to account for approximately 1% to 2% of emergency room visits each year. Most bites (60% to 90%) come from dogs, while a smaller proportion come from cat bites (10% to 15%). As the researchers say, while a dog can be mechanically destructive because of the stronger jaws, the sharp teeth of cats can deeply penetrate the tissues with bacteria. The most common bacteria involved in animal bites is said to be Pasteurella multocida which is part of the normal mouth bacteria of many animals, including dogs and cats.

The important thing to realise with such a study is that it is only the experience of a single US hospital, and the people who were treated there. The many other people who may have received cat bites or nips and not sought medical treatment are not included. Neither can it inform about bites elsewhere on the body apart from the hand; nor tell us how common cat bites are, and the likelihood of needing hospital treatment for them. The results also cannot be assumed to reflect the situation in the thousands of other hospitals across the US or in other countries.

Links To The Headlines

Why even a tiny cat bite could leave you in hospital: Cats’ teeth ‘inject bacteria deep into the joints and tissue’, doctors warn. Daily Mail, February 7 2014

Middle-aged women ‘most at risk of cat attacks’. Metro, February 6 2014

Links To Science

Babovic N, Cayci C, Carlsen BT. Cat Bite Infections of the Hand: Assessment of Morbidity and Predictors of Severe Infection. The Journal of Hand Surgery. Published online February 2014