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Pinworms, Roundworms, Tapeworms: The Microscopic Invaders That Could Infect Your Kids

kids and worms, worm infections in humans
There are many different kinds of worm infections here in the States, some of which can be transmitted by your pets.

For most parents, runny noses, potty training mishaps and projectile vomiting lose their “ick factor” over time. But worms living inside your little one — that is a little harder to take in stride. Fortunately, if you live in the U.S., chances are you won’t ever have a run-in with these microscopic invaders. But in other parts of the world, worms are a significant health burden, especially for kids.

“In general, worms are one of the most common pediatric infections globally,” says Debbie-Ann Shirley, MD, who specializes in pediatric infectious diseases. “Infection with worms can lead to issues with weight loss, growth and developmental delays, so we’re fortunate that it isn’t as common here in the U.S. thanks to access to good hygiene and sanitation.”

The bad news: we aren’t completely immune to worm infections, adds Shirley. And there are many different kinds. Below is a breakdown of some of the most common worm infections doctors see here in the States, including tips for treatment and prevention:


The most common worm infection in kids, pinworms are tiny white roundworms (less than ½-inch long) that live in the intestines. Pinworms are also known as threadworms.

How Do You Get Pinworms?

Pinworms are easily spread from person to person via fecal-oral transmission. Typically, their tiny eggs hitch a ride on hands, then get ingested and take up residence in the intestines. Once the eggs mature, the female worm travels at night to the anus and lays more eggs on the skin in the surrounding perianal area. You may actually see the worms upon close inspection.

Pinworm Symptoms

The eggs on the skin around the anus cause extreme itching, especially at night when the female worms are most active. If your child is scratching or complaining about pain or discomfort in that area, it’s a good idea to take a closer look.

Pinworm Treatment and Risks

Fortunately, pinworms are easily treated with anti-parasitic medication, which is available by prescription or over the counter. If left untreated, a pinworm infection typically won’t cause any serious problems, according to Shirley. In rare cases, the worms may enter the vagina and cause a discharge in girls. Or the excess scratching can cause a bacterial infection.

Pinworm Prevention

While the risks are minor with a pinworm infection, the sooner your child is treated, the less likely he is to pass on pinworms to others. Good hand hygiene is the most effective way to prevent pinworms, so encourage children to wash hands regularly, especially prior to eating.

Dog and Cat Roundworms

Animals can transmit roundworm infections as well, and the dog and cat roundworms are among the most common of these.

How Do You Get Dog and Cat Roundworms?

Because the worm’s eggs are excreted into the stool of cats and dogs, they can be transmitted to humans as well. “If a child is playing outside in contaminated dirt or soil and puts his hand in his mouth, then he can ingest the eggs,” says Shirley. “We often see roundworm infections in lower socioeconomic areas where there is less access to healthcare and more exposure to pet feces.” Unlike pinworms, roundworms are not transmitted from person to person.

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Roundworm Symptoms and Risks

Roundworm infection causes a disease called Toxocariasis. Symptoms may include abdominal pain, fever, cough, wheezing or even seizures. “The worm matures in the gut and then likes to travel to the lung,” says Shirley. “From the lung, the worm can occasionally travel to the eyes, leading to vision loss. Or it may go to the brain where it can cause encephalitis, which leads to seizures and brain damage.”

Roundworm Treatment

Once diagnosed, Toxocariasis can be treated with medication. The key is getting the right diagnosis. “Doctors may try to treat a child’s asthma symptoms with asthma medications,” says Shirley. “Not only do they not work, they may actually cause the condition to worsen because steroids compromise the immune system.”

If your child is exhibiting symptoms and you believe your child may have been exposed to dog or cat feces, be sure to mention this to your doctor.

Roundworm Prevention

Pet owners, be sure to dispose of feces appropriately. Make sure your children wash hands regularly if playing outdoors in an area where pets frequently defecate. Note that raccoons also carry a deadly roundworm that goes straight to the brain, so avoid locations raccoons may use as a latrine such as an uncovered sandbox.


Tapeworms are long, flat worms with segmented bodies that can grow to more than 20 feet long and reside in the human intestines for decades, according to the Centers for Disease Control and Prevention (CDC). There are several types of tapeworms.

How Do You Get a Tapeworm?

Ingesting food or water contaminated with tapeworm eggs or larvae is the cause of tapeworm infection in humans. Most often, people are infected after eating raw or undercooked meat or fish. “When you ingest one of these worms, it goes into the intestines where it matures and lays eggs, which then pass on through the stool to continue the life cycle,” says Shirley.

Tapeworm Symptoms and Risks

Taeniasis is the infection of a human with an adult pork or beef tapeworm. Typically, symptoms are mild to nonexistent, but you may experience some stomach upset, loss of appetite, abdominal pain and weight loss. In rare cases, pork tapeworms travel to the brain and cause seizures, a condition known as neurocysticercosis.

Tapeworm Treatment

Most tapeworm infections can be treated effectively with medication. Tapeworms in the brain are an exception. “Once the worm reaches the brain, as it dies it can cause inflammation, so doctors may need to prescribe steroids to reduce the inflammation, along with anti-parasitic medication,” says Shirley.

Tapeworm Prevention

Your best bet at preventing a tapeworm infection is to mind your diet. Cook all meats to the recommended temperatures prior to eating. And those less-than-stellar hand washing habits? This is just one more reason to get on the scrub bus.

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