Drugged Marshmallows Can Keep Urban Raccoons From Spreading Disease

By Alison Bruzek

Published November 25, 2014 at 1:50 PM CST

Does this little guy look familiar? Clean up his feces in your yard to avoid infection from his parasites.

The masked garbage crusaders of the night can be more than just a nuisance. Raccoons also can be bad news for human health, carrying diseases such as rabies and roundworms.

And because raccoons have happily colonized cities and suburbs, a particular roundworm called Baylisascaris procyonisthat the critters often carry can make its way into humans. The parasite's eggs are carried in raccoon poop.

When ingested, the eggs release the worm, which can burrow into the eyes and brain causing blindness or even death, in rare cases.

Don't freak out. There have only been 30 reported cases of severe or fatal human infection in the U.S. over the past 30 years. And while researchers believe that many of the infections aren't reported, they say most infections are likely subtle and go unnoticed.

Small children face a higher risk, because they're more likely to stick a fistful of dirt into their mouth from the backyard or playground. Raccoons often use the areas around decks, patios and playhouses as bathrooms.

But if you can't beat 'em, it turns out you can bait 'em. Putting baits containing worm medicine in the raccoon poop zones can keep the animals from spreading the parasite, according to a study published in the December issue of Emerging Infectious Diseases.

The researchers, led by Kristen Page, an ecologist at Wheaton College in Illinois, got down and dirty, studying raccoon hangouts at about 60 sites around Chicago. They wanted to know if there were practical solutions for keeping city folks safe from the critter's parasite.

They tested raccoon poop from each site and found about 13 percent of the droppings contained roundworm eggs. However, after baiting monthly for a year with a delicious mix of marshmallow creme laced with pyrantel pamoate (a drug used to deworm dogs and cats), only 3 percent of the feces from the baited sites contained worm eggs.

"If you deworm the raccoons once a month, then the worms never mature enough to produce eggs," Page tells Shots.

The baiting is a more environmentally friendly way to get rid of the parasites. Current methods use a blowtorch to burn the land. "The eggs are really resistant to temperature change," says Page. "[A] Midwestern summer won't kill them and certainly our winters won't kill them." We don't know how long the eggs last in the wild, she says, but it's upwards of 10 years.

As Shots has reported before, you can keep yourself and your kids safe by checking the yard once a month for raccoon feces. You should wear gloves to pick up any feces and put it in the garbage. If you're worried there may be roundworms still lurking, pour boiling water over the spot to ensure the eggs are dead.

Otherwise, use common sense: "Keep raccoons away from your home, monitor your children ... wash your hands, wear gloves when you work outside," says Sarah Sapp, a Ph.D. student at the University of Georgia who is studying the raccoon parasite.

And if you're thinking about an exotic pet raccoon, you might think again. The same worms are found in cute pet kinkajous, or, if you happen to be in China, the variety found in the local zoological garden.