Roundworm, tapeworm, hookworm: You know your dogs and cats can get these nasty parasites, but did you know you and your children could catch them from your pets?

You’re unlikely to get hookworms or tapeworms, which are rare in the United States, but roundworms are a different story. Roundworms are the most likely worm your pet could pass on — with children the most likely victims.

Tens of millions of Americans have likely been exposed to roundworms, which causes an infection called toxocariasis, according to the Centers for Disease Control and Prevention (CDC).

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Often the infection causes no symptoms, so you may not even know you have it and the parasites may die on their own within a few months. Or you may have mild symptoms, including a cough, fever, rash, headache or stomach pain.

But if the parasite travels to organs like the liver or eyes, it can be devastating. Toxocariasis can lead to seizures, an enlarged liver, breathing difficulties or pneumonia if it invades the liver, lungs or central nervous system. If it infects the eye, it can cause inflammation, scarring and even blindness.

In fact, roundworms infect 10,000 children in the United States every year, according to the ASPCA, and eye infections involving roundworm blind about 70 children here annually, according to the CDC. Toxocariasis usually affects only one eye and is most common among 5 to 10-year-olds, the agency notes.

Small wonder that the CDC calls toxocariasis “a neglected parasitic infection” and has targeted it for public health action.

Beware the uncovered sandbox

The parasite is spread from animals to people when soil, sand (think: sandboxes) or something else contaminated with animal feces ends up in the mouth. That’s why young children — especially those who have pets — are most at risk. Here’s how to protect them.

Deworm puppies and kittens. Have all puppies tested and treated if necessary. Kids love to snuggle with puppies, and who can blame them? But get your pets tested and treated before you bring them home as puppies or adult dogs.

“We test all puppies for roundworms,” says Garrett Wood, DVM, a veterinarian in Charlottesville, VA. “It used to be that almost all puppies had it, but nowadays, we are seeing fewer cases because there is better treatment of the mother. If the mother was on a regular [worm] medication, her puppies are usually born without it.”

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Don’t forget to get your kittens dewormed, too. “Today we probably see more roundworms in kittens than in puppies,” says Wood. “Cats tend to be treated less and seen by vets less often than dogs are.

Put your pet on a monthly heartworm medication and see your vet regularly. “Heartworm can kill adult dogs, so it’s important to treat them,” says Wood. “And as a free benefit, these medications also kill roundworms.”

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Pick up dog and cat waste right away and wash your hands with soap and water afterward. The roundworm larvae (toxocara) in dog and cat feces take 10 to 21 days to be able to infect anyone, so fresh poop is not infectious. That’s why it’s important to scoop up your animal’s waste right away.

Always cover the sandbox when not in use, and keep pets away from it. “In terms of transmission to humans, cats are better at hiding their poop, and they dig holes. But of course, they do like the sandbox, so it is important to keep it covered.” Keep an eye out even when your kids are there, especially if you see your cat jump in and start scratching around. Roundworm eggs can survive in sand or soil for many months.

Don’t allow children to play in areas where dogs and cats poop. If your kids like to play in the yard, make sure you don’t get lazy and send Fido out to poop there.

Have your kids wash their hands often, especially after playing with animals, before meals and coming in from outside. Try to keep your toddlers from putting dirty hands or toys in their mouths, especially while playing outside or in the sandbox.

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Cook meat thoroughly Although uncommon, people can also become infected from eating undercooked meat containing roundworm larvae, according to the CDC.

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See a doctor right away if you have a pet and your child has a skin infection, stomach cramps or symptoms of toxocariasis, especially if one or both eyes look inflamed.

If you take these precautions, your child shouldn’t have to miss out on snuggle time with his favorite pet.  

Mary Purcell is a freelance writer and health researcher in Piedmont, Calif., with expertise in policy analysis. She has a master's degree in Latin American studies from Georgetown University.