Many parents are surprised to learn that children are at risk of infection from a parasitic disease. However, these parasites are not just found in developing countries, but are present right in your child’s playground, daycare or preschool, or even your own home. Here are the five most common parasitic infections that cause disease in children:

  • GiardiasisGiardia is an intestinal parasite that can cause watery diarrhea, abdominal pain, and gas. In severe cases, the diarrhea can become chronic, leading to weight loss and failure to thrive.
  • Cryptosporidiosis—Cryptosporidium is a parasite that is often spread by contaminated water. When children drink the water from a contaminated lake, pond or other water source, the cyst of the parasite then invades the intestines, causing prolonged bouts of diarrhea.
  • PinwormPinworm infection is caused by the parasite Enterobius vermicularis. A child becomes infected by ingesting the eggs of the pinworm. The worm lives in the colon and rectum of the infected individual, then leaves the rectum to deposit eggs on the skin around the anus, causing itching.
  • Toxoplasmosis—Toxoplasmosis can be contracted by eating undercooked meat or by ingesting the parasite after coming into contact with the feces of an infected cat. Many people in the United States carry this parasite in their intestines, but most people do not show any symptoms if they have a healthy immune system.
  • Toxocariasis—Infection from the contaminated feces of a dog or cat can cause toxocariasis. Young children have a particularly high chance of becoming infected if they accidentally swallow dirt contaminated by animal feces that contains parasite eggs. Most people with a strong immune system show no signs of disease, but some people can develop infection in the eyes, liver, or nervous system.

If you are concerned that your child has a parasite infection, be sure to visit the pediatrician. Most parasitic infections are diagnosed by a simple stool test, but sometimes repeat tests are necessary to capture the parasite.

Teaching your child the importance of hand washing is a key step in preventing parasite infections. Also, be sure that adults who care for your child also practice good hand hygiene. Keep your child away from potentially contaminated bodies of water, and make sure all food is properly cooked before they eat it. Finally, be sure that all pets are seen regularly by a veterinarian to prevent the spread of infection from your pet to your child.

Reviewed by Dr. Sara Connolly, February 2019


  • Parasitic infections are common throughout the developed world.
  • Common parasites include giardia, cryptosporidium, pinworms, and toxoplasmosis.
  • Parasites are diagnosed by a pediatrician.
  • Good hygiene can help prevent parasitic infections.


  1. Pediatrics in Review. Giardiasis and Cryptosporidiosis.
  2. Centers for Disease Control and Prevention. Cryptosporidiosis.
  3. Centers for Disease Control and Prevention. Pinworms.
  4. Centers for Disease Control and Prevention. Parasites in Children.


  1. Interesting article- what about ringworms? How can a child get this? I feel like it is something very common, but I’m not exactly sure what causes it.

    1. Ringworm is actually caused by a fungus, not a worm as the name implies. But it is certainly contagious if your child is around someone else who has the skin fungus. Check out our Bundoo A to Z article on ringworm for all the details!

      1. Thank you so much for your reply! Going to check out the article now. 🙂


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