Cat poop is, as poop goes, pretty gross. Pregnant women have been warned for years now not to get near it because of the bacteria it holds, which can cause dangerous infections and pose serious threats to a fetus. But now scientists are saying that an infectious parasite called Toxoplasma gondii is much, much more common than they thought, and feral cats are depositing it in all our backyards.

Well, maybe not all our backyards. But with felines laying down 1.2 million metric tons of waste a year, there’s a good chance you’ve been around some even if you don’t own a cat. It takes just one parasite egg to cause an infection, and scientists say there could be up to 434 eggs per square foot of soil depending on where you live. Samples were taken in a study in various countries, and they all show similar results. The issue arises when cats get hold of infected birds or other small animals and ingest the parasite, which passes right through their system. And with feral and outdoor cats being the crafty little buggers they are, they’ll find a nice little sandbox or an area with loose soil to poop in.

“It should give you pause before you put your child in a public sandbox,” Dr. E Fuller Torrey of the Stanley Medical Research Institute said.

One of the scariest things about the parasite is that studies are linking it to mental issues–like schizophrenia–and, because it’s hard to kill, is a serious problem for people with weak immune systems.

“This is a public health problem that bears more scrutiny,” Torrey says. “We’re walking a tight line between alarming people and failing to point out obvious health problems that need to be paid attention to.”

Though some of the studies haven’t been proven yet, Torrey–and the researchers who are looking into the effects of the bug and its eggs–say it’s still obviously wise to always wear gloves when gardening, cover children’s outdoor play areas, and thoroughly wash your cat’s litter box once a week. Unless you’re pregnant, of course.