SYDNEY • Each year, hundreds of people die in Australia after being infected by cat-dependent diseases, and the impact on the Australian economy has been finally quantified by Australian researchers and released on Friday.
The study, led by Professor Sarah Legge from the Australian National University and the University of Queensland, found that such diseases caused more than 500 deaths and 11,000 hospitalisations in Australia each year, costing the Australian economy A$6 billion (S$5.8 billion) a year.
Prof Legge said the cost they studied included medical treatment, lost income and other reasonable relevant expenses related to the cat-dependent diseases, which were not presented in Australia until cats arrived.
"Toxoplasmosis, cat roundworm and cat-scratch disease arrived in Australia with cats in 1788. The pathogens that cause these diseases depend on cats for part of their life cycle, so without cats, these diseases wouldn't be here," she said.
Among those three diseases, toxoplasmosis, which is caused by a single-cell parasite called Toxoplasma gondii, causes the greatest damage to human health in Australia and can be lethal to immunocompromised people and unborn babies, according to Prof Legge.
"Some of the most insidious effects of the Toxoplasma gondii parasite come from the possible long-term effects on behaviour and mental health," she said.
"Toxoplasma gondii infections may increase risk-taking behaviour and reduce reaction times, and this may explain why people involved in car accidents are more likely to have Toxoplasma gondii infections," she said.
She added that without this parasite, about 200 deaths and 6,500 hospitalisations due to car accidents could be avoided in Australia each year.
Toxoplasma gondii infections are also associated with a higher risk of many mental health disorders, she added. "One in five cases of schizophrenia and one in 10 suicides and suicide attempts could be avoided if we eliminated Toxoplasma gondii infections."
To reduce the human infection rate of cat-dependent diseases, researchers suggest cat owners keep their pet cats indoors at all times and wash their hands thoroughly after handling cat litter or gardening.
It is also important to reduce the feral cat population around residential areas, according to the study's co-author, Dr John Read from the University of Adelaide in Australia.
"Feral cats around towns are a disease reservoir. People can keep the feral cat population down by not feeding strays or letting them access bins, desexing pet cats by five months and supporting local government initiatives to manage cats," he said.