Published July 27, 2011
"An infectious parasite spread by cats may be a cause of brain cancer in humans, research suggests. The single-celled organism Toxoplasma gondii infects about a third of the world's population. Often it causes no symptoms, but the parasite can be fatal to unborn babies and damage the nerve systems of people with weak immune systems.
The new study shows a positive correlation between rates of infection by T. gondii and brain cancer incidence around the world. Scientists collected global data on brain cancers in men and women and compared them with figures on T. gondii prevalence. Adjusting for a range of factors that can influence brain cancer statistics, the researchers found that cancer rates went up with greater exposure to the parasite.
Across the range of infection prevalence, from 4 of the population, T. gondii was associated with a 1.8-fold increase in the risk of brain cancer. The scientists, led by Frederic Thomas, from the CNRS research institute in Montpellier, France, wrote in the Royal Society journal Biology Letters: "We feel our results are sufficiently strong to propose that T. gondii potentially increases the risk of brain cancer in humans." Previous research had already linked the parasite to brain tumours in animals. There is also other evidence that T. gondii has effects on the brain leading to changes in behaviour."
According to a comment following this article a reader commented that there is very little risk of contracting this from healthy indoor cats and he goes on to advise that the most common method of infection in humans is actually via the consumption of undercooked or raw meat.