Treating Cryptosporidiosis in Children

Cryptosporidium, or crypto for short, is a parasite that frustrates many parents each summer as it causes small outbreaks of diarrhea in places like community pools, water parks, and water spray parks that recycle the water.​

Cryptosporidiosis, an infection with the crypto parasite, can follow drinking contaminated water and often leads to a few weeks of diarrhea, stomach cramps, and nausea.

Boy in inner tube floating in pool
Imgorthand / Getty Images

A sick child is upsetting enough, but that they got sick in a chlorinated pool, which most parents assume kills most germs, is what usually gets them the most frustrated.

Unfortunately, crypto is a chlorine-resistant germ and can live in a properly chlorinated pool for up to 10 days. Crypto can be killed in a pool, but only by hyperchlorination, during which time the pool will have to be closed until the chlorine levels return to a safe level.


Symptoms of cryptosporidiosis usually develop about seven days (can range from two to 10 days though) after being exposed to the crypto parasite (incubation period), including:

Other symptoms, especially if a child is not able to drink enough fluids, can include dehydration and weight loss. Symptoms can be more severe in children with immune system problems.

Unlike many other germs that cause diarrhea in children, the symptoms of crypto can come and go for up to 30 days. Fortunately, they usually only last a week or two.


Although you may suspect that your child has crypto if he has diarrhea and has recently been in at a water park or pool that has been involved in a known crypto outbreak, it is best to actually have your child tested.

This usually involves specific stool tests for the Cryptosporidium parasite, such as the Cryptosporidium antigen test, which your pediatrician can order. Crypto can be hard to detect and a single test may miss a diagnosis of crypto. That is why your pediatrician may order several stool samples over a few days to get accurate testing.


Cryptosporidiosis, in otherwise healthy children without immune system problems, can go away by itself. There is a treatment for crypto, though. Alinia (nitazoxanide) is a prescription medication that is approved to treat diarrhea caused by the parasites Cryptosporidium parvum and Giardia lambia, another parasite, in children who are at least 12 months old.

Alinia is not thought to be very effective in children with crypto and immune system problems, such as AIDS, though.

As with other causes of diarrhea, other treatments for crypto can include fluids to prevent dehydration and perhaps probiotics. Things to usually avoid in kids include anti-diarrheal medicines and a BRAT diet.


Unfortunately, outbreaks of crypto continue to happen each year. From 2011 to 2012, for example, they accounted for just over half of the recreational water-associated outbreaks in the United States.

Since you can't simply rely on the chlorine in a pool to protect your kids from crypto, one of the most important things you can do is to encourage them to not swallow water when they are in a swimming pool, water park, or lake.

You can also protect everyone else from crypto by practicing basic healthy swimming techniques, such as:

  • keeping your kids out of the water when they have diarrhea (and for up to two weeks after the diarrhea goes away), pink eye, hepatitis A, or other contagious diseases.
  • encouraging your kids to take a shower or bath before swimming.
  • encouraging your kids to wash their hands after using the bathroom, especially if they are going to get back in the water.
  • taking younger children to the bathroom frequently so that they are less likely to have accidents in the water.
  • check and change swim diapers frequently for your infants and toddlers who aren't yet potty trained. This is especially important because swim diapers and swim pants are not leakproof and may seep germs into the water.
  • not changing diapers by the pool. Instead, take your child to the bathroom when he needs a new diaper and then wash your child's bottom well and wash your hands too.

In addition to hyperchlorination, ozone and ultraviolet light treatment of pool water are alternatives that may keep swimming pool water clear of cryptosporidium.

What to Know About Cryptosporidiosis

There are thousands of Crypto infections in the US each year. Take precautions so that your kids don't get this parasite when they swim and they don't end up with weeks of diarrhea and stomach cramps.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Pumipuntu N, Piratae S. Cryptosporidiosis: A zoonotic disease concern. Vet World. 2018;11(5):681-686. doi:10.14202/vetworld.2018.681-686

  2. Sparks H, Nair G, Castellanos-gonzalez A, White AC. Treatment of Cryptosporidium: What We Know, Gaps, and the Way Forward. Curr Trop Med Rep. 2015;2(3):181-187. doi:10.1007/s40475-015-0056-9

  3. Hlavsa MC, Cikesh BL, Roberts VA, et al. Outbreaks Associated with Treated Recreational Water - United States, 2000-2014. MMWR Morb Mortal Wkly Rep. 2018;67(19):547-551. doi:10.15585/mmwr.mm6719a3

Additional Reading
  • Gharpure R, Perez A, Miller AD, Wikswo ME, Silver R, Hlavsa MC. Cryptosporidiosis Outbreaks - United States, 2009-2017. MMWR Morb Mortal Wkly Rep. 2019;68(25):568-572. doi:10.15585/mmwr.mm6825a3

  • Huang DB. An updated review on Cryptosporidium and Giardia. Gastroenterol Clin North Am - 01-JUN-2006; 35(2): 291-314

  • CDC. Healthy Swimming Frequently Asked Questions. Chlorine Disinfection Time Table.
  • Cryptosporidiosis Outbreaks Associated with Recreational Water Use - Five States, 2006. MMWR Weekly. 56(29), 729-732.

By Vincent Iannelli, MD
 Vincent Iannelli, MD, is a board-certified pediatrician and fellow of the American Academy of Pediatrics. Dr. Iannelli has cared for children for more than 20 years.