A new review, published Tuesday in the journal Trends in Parasitology, determined that parasites found in cat feces are a "vast and underappreciated" public health hazard.
Scientists have long understood that cats carry the Toxoplasma gondii parasite -- and depositing the parasites' embryonic oocysts in their poop -- which is why pregnant women, newborns and people with poor immune systems are warned to stay away from kitty litter. Studies have also linked the parasite to mental illnesses like schizophrenia.
But researchers at Johns Hopkins University Medical Center say that oocysts are actually more common than we think.
Cats could be releasing as many as 55 million oocysts per day.
Though you shouldn't be afraid of your own cats. Cat owners actually experience lower rates of infection because they frequently wash their hands and clean out the litter box. Gardeners and outdoorsy children are at greater risk from feral cats.
Drs. E. Fuller Torrey and Robert H. Yolken, the two researchers responsible for the article, told CNN that most indoor cats won't become infected with the harmful parasites.
Almost all cats that become infected, and thus deposit infective oocysts, are outdoor cats. Keep in mind cats are no respecters of property lines so a neighbor's cat could deposit Toxoplasma gondii oocysts in your garden or children's play areas.
Torrey and Yolken said that there are steps that humans can take to protect themselves and their families.
Cat litter, for example, should be thrown out with the garbage and not flushed down the toilet. Cats relieve themselves in gardens and sand boxes, so people should take car to wear gloves when handling soil or garden vegetables.