Cryptosporidium: What you need to know - Wyoming Medical Center

Cryptosporidium: What you need to know

By Kristy Bleizeffer Sep 5, 2013


Cryptosporidium life cycle

Wyoming health officials reported this week that 54 people so far this year have been infected with Cryptosporidium – a hard-shelled microscopic parasite. It is one of the most frequent causes of waterborne disease in the U.S., according to the Centers for Disease Control and Prevention.

More than half of this year’s cases have come from Campbell County and linked more specifically to Keyhole Reservoir about 60 miles away, according to the Wyoming Department of Health.

But there’s no reason to panic, says Dr. Mark Dowell, an infectious disease doctor at Wyoming Medical Center and the Natrona County health officer.

“This is not new, this is stuff we’ve seen before,” he said. “I think it’s a fluke. I think some years there are just more parasites in a particular body of water. It’s no different than our West Nile cases. Some years there are more than others.”

Cryptosporidium is associated with animal feces. It may wash from the soil to ponds and streams. It is resistant to chlorine so it is sometimes found in municipal swimming pools and may also be found in daycares.

Cryptosporidiosis, or commonly called Crypto, can affect anyone, from the very young to very old. But people with a normal immune system will get over it in a week or two, Dowell said.

Here’s what you need to know:


Symptoms can mimic the flu or other gastrointestinal illnesses. They include:

  • diarrhea
  • nausea
  • vomiting
  • loss of appetite


Antibiotics do not work against Cryptosporidium infections. Instead, they are treated symptomatically, Dowell said. That typically means fluids, over-the-counter medicines such as Immodium and Pepto-Bismol, and time. Most cases will pass from the system within a week or two.

If you experience the above symptoms and you are particularly uncomfortable, call your doctor. You might also be suffering from something more serious such as a salmonella infection or an unrelated gastrointestinal issue.

“Don’t panic because you have had two days of diarrhea just because of this outbreak,” Dowell said.


Cryptosporidium is found in the environment – and probably in whatever reservoir you like to frequent. Some years, there just happens to be a higher concentration of it, for whatever reason, Dowell said.

You may be able to avoid an infection if you:

  • Wash your hands frequently: Because it is transmitted fecal-orally – from feces to mouth – it is important to wash your hands with soap and water before touching your mouth. So don’t climb out of your favorite pond and then grab your picnic sandwich. Wash your hands before eating. “It’s common sense, but people don’t always think about that,” Dowell said.
  • Close your mouth: When swimming, try to limit the amount of water you swallow. “People tend, whether they admit it or not, to let water go into their mouths. That’s all it takes, and that’s often how you get it,” Dowell said.
  • Take a shower: Rinse the pool, pond or reservoir water off your skin as soon as you are able.
  • Relax: The best advice Dowell can give is to just go ahead and go swimming. Cryptosporidium was there before this outbreak and will be there when it passes. “You don’t close a reservoir for this,” Dowell said. “Just follow the typical, common sense things such as hand washing and keeping your mouth shut and I think it’s perfectly OK to swim there. I would.”
Professional headshot of

Mark Dowell M.D.

Dr. Dowell is board certified in infectious disease and is the medical director of Infectious Disease at Wyoming Medical Center. He practices at Rocky Mountain Infectious Diseases.