Toxoplasma not cat-astrophic, says Washington State researcher

There's been plenty of yowling about the link between cats and toxoplasmosis. (Getty Images)Mention Toxoplasma gondii and most people will give you a blank stare. Others will blame a cat. But this cunning parasite that infects one-third of the world's population is more likely to be spread by eating undercooked meat than by stroking a feline.

Toxoplasmosis causes few, if any, symptoms among most people who are healthy. But it can be dangerous to those with weak immune systems or pregnant women who can pass it to their unborn babies. At worst, it leads to blindness, brain damage, dementia and even death.

Although the parasite is found in all kinds of birds and mammals, there's only one place where it can sexually reproduce: inside a cat's gut.

Typically, cats contract toxoplasmosis from infected rodents and birds when they hunt. Once inside the intestines, the parasite produces millions of oocysts, which the cat sheds in its feces, says Heather Fritz, DVM, PhD, a veterinary parasitologist at Washington State University.

When excreted by outdoor cats, the oocysts can survive more than 18 months in soil and water. From there, the parasite is typically picked up by animals such as rodents, sheep and pigs grazing on the ground, she says. As for indoor cats, unless they snag an infected rodent in the house, “it's nearly impossible for them to contract the parasite.” 

So yes, cats do shed the parasites in their stool. But the chances of the pathogens being passed on to humans are slimmer than most people have been led to believe by hyped-up media reports.

“You stand a greater chance of contracting toxoplasmosis by drinking contaminated water or eating contaminated meat that's raw or inadequately cooked than getting it from your cat-especially if it's an indoor cat,” says Fritz.

And if a cat is infected? “The cat will only excrete the oocysts in its feces for three weeks or so-and typically only once during its lifetime,” Fritz explains. 

So don't throw out the cat with the kitty litter. But do practice good hygiene, handling meat properly, cleaning the litter box often and wearing gloves while doing it, Fritz advises.