The world is divided into cat people and those who remain immune to their charms. However, Britain’s eight million cat owners have been given a nasty wake-up call.
An alarmingly high number of pet cats harbour a hidden parasite that causes serious illness, birth defects and may even make people more prone to suicide, a report warned this week.
It found a staggering 1,000 people a day are being infected with toxoplasma after contact with cats or infected, uncooked meat.
And according to the paper by the Food Standards Agency, there are 350,000 new infections each year. Out of those, 80 per cent of victims are unaware they have the parasite, and its eggs will simply remain dormant in their bodies for life. But around 20 per cent need hospital treatment for complications that arise from infection, such as brain inflammation or miscarriage.
The scale of toxoplasma infection has stunned microbiologists, who say not enough is being done to warn of the risks. Some argue young families should not have cats, while others insist everyone should avoid eating pink lamb – the meat thought most likely to spread the disease. This is because the parasites are killed if meat is cooked at 70c for two minutes – the point where it turns brown. Traditionally, lamb is served pink.
The parasite in question is Toxoplasma gondii – a single-celled organism that has evolved to breed only in the guts of cats, where it produces millions of tiny egg-like spores called oocysts. For two weeks after infection, a cat sheds several million cysts in its droppings.
Cats are oblivious to the infection and show no signs of disease. But anywhere it uses as a toilet will be contaminated.
If these eggs are consumed by another animal – say a mouse or bird – they can become lodged in their new host’s brains, liver, or muscles, where they can survive for years. When another cat eats the infected mouse or bird, they, too, become infected – it’s a devastatingly effective survival technique for the parasite.
Of course, it’s not just birds and rodents at risk from the eggs lurking in grass, flower beds, or soil. Sheep, cattle and pigs pick up the parasite, contaminating their meat and entering the food chain. People can also be infected if they put their hands in their mouths without washing them, having picked up the parasite from their moggies.
Professor Bill Reilly, past president of the British Veterinary Association, says: ‘Around 20 to 40 per cent of people have been infected at some point in their lives. But infected meat is a much more important source of infection than contact with cats.’
His evidence for that comes from other countries with a similar proportion of cat owners – but a much higher incidence of toxoplasma. In France, for instance, twice as many people are thought to have been infected at some point. The French are much more likely to eat raw or undercooked meat than Brits, Professor Reilly says.
For years, the advice from the Food Standards Agency (FSA) was that the parasites do not pose a risk to healthy people and that they should not be unduly concerned about eating pink meat.
But the FSA and Department of Health have long argued there is a more serious threat to pregnant women. The parasites can damage the developing brains and nervous systems of unborn babies, leading to miscarriage or birth defects such as cerebral palsy. Around three babies in every 100,000 are born with problems because of infection.
Toxoplasma can also be deadly for those with compromised immune systems – such as those with Aids or those on cancer treatments.
This week’s report by a panel of experts for the FSA called for a review into the guidance about pink meat. Professor Reilly says: ‘I wouldn’t want any of my family who might be pregnant to eat any undercooked meat.’
But Dr Barbara Lund, of the Institute of Food Research in Norwich, believes official advice on eating pink meat should be changed. ‘My advice to everyone – not just pregnant women – would be avoid eating undercooked lamb,’ she said.
What’s more, recent studies have linked the parasite to behaviour and personality changes – and even suicides.
In 2003, Dr Fuller Torrey, of the Stanley Medical Research Institute near Washington DC, discovered people with schizophrenia were nearly three times more likely than the general population to have been infected with toxoplasma.
The study didn’t prove cause and effect, but it raised alarmed bells. Since then, more evidence linking the parasite to behavioural changes has emerged.
Research at Charles University in Prague found people involved in road accidents were more likely to have been infected with toxoplasma in the past. They also had shorter attention spans and reduced reaction times.
Earlier this summer, a study of 54 Swedes suggested exposure to the parasite might make people more likely to be suicidal.
The idea that a parasite found in pink meat alters behaviour sounds like something out of science fiction – but there does seem to be a scientific basis for it. British researchers have suggested that the parasite alters a mouse’s brain chemistry, making it
act strangely. In lab tests, infected mice behave in a way that increases their risk of being hunted and eaten by cats.
In evolutionary terms, this makes sense. A parasite will boost its chances of being passed back to cats for breeding if its host becomes easier to catch.
Dr Torrey, who found worryingly high levels of the parasite in playground sandpits, is so concerned he believes families should avoid having pet cats.
‘I would certainly advise families not to get a cat if they have small children,’ he told a newspaper this week. ‘I gave this advice to my own daughter and granddaughter.’
It’s an extreme view – and one challenged by the British Veterinary Association, which says anti-cat scaremongering is pointless and unnecessary – and that simple, common-sense hygiene can prevent the spread.
The cysts only become infectious a couple of days after leaving a cat’s body. Cat owners should regularly empty and disinfect of cat litters, wear gloves when changing litter and wash hands after handling cats with soapy, hot water.
‘There is no reason why someone planning on having children should not have cats,’ a spokesman said.
The irony is study after study has shown that stroking and handling cats helps people relieve stress – and may even protect against heart disease and stroke.
So if the latest warnings make depressing reading, there’s no reason you shouldn’t give your beloved moggie a nice cuddle. Just wash your hands afterwards.