'˜Link' between road rage and parasite spread by cats

Infection by the organism Toxoplasma gondii doubles the chances of suffering a mental condition that triggers bouts of uncontrollable anger, a study found.

The parasite is thought to alter brain chemistry, resulting in “intermittent explosive disorder” (IED).

People with IED are liable to display outbursts of violent rage which are disproportionate to the provocation received - for instance, when annoyed by another driver on the road.

Scientists who assessed a group of 358 US adults found that more than a fifth (22 per cent) of those diagnosed with IED tested positive for T. gondii. In comparison, nine per cent of non-infected individuals had the condition.

Lead researcher Professor Emil Coccaro, from the University of Chicago, said: “Our work suggests that latent infection with the Toxoplasma gondii parasite may change brain chemistry in a fashion that increases the risk of aggressive behaviour.

“However, we do not know if this relationship is causal, and not everyone that tests positive for toxoplasmosis will have aggression issues.”

Many people are believed to carry the parasite, found in cat faeces and contaminated food, without realising it.

Each year around 350 cases of toxoplasmosis are reported in England and Wales, but experts believe the actual number of infections could be a thousand times greater.