Cryptosporidiosis Outbreaks on the Rise, CDC Warns

Educate Patients on How to Best Avoid Pool-related Illnesses

July 01, 2015 01:38 pm Chris Crawford

One of the best summer outings is loading up the car for a trip to the pool with the kids. But in addition to lathering up the brood with plenty of sunscreen, keeping them hydrated and teaching them about the dangers that lurk poolside, your patients need to know how to best avoid illnesses associated with recreational water use.

[Mom and three kids wearing sunglasses at the pool]

A CDC Morbidity and Mortality Weekly Report (MMWR)(www.cdc.gov) from June 26 explained that for 2011-2012 (the most recent years for which finalized data are available), public health officials from 32 states and Puerto Rico reported 90 recreational water-associated illness outbreaks, which resulted in at least 1,788 cases, 95 hospitalizations and one death.

Seventy-seven percent of the 90 outbreaks occurred in treated recreational water, and of these, 52 percent were caused by Cryptosporidium. According to the MMWR article, Cryptosporidium is an extremely chlorine-tolerant parasite that can survive in properly chlorinated water for more than 10 days.

Lead author Michele Hlavsa, R.N., M.P.H., who is an epidemiologist and chief of Healthy Swimming in the CDC's Waterborne Disease Prevention Branch, told AAFP News that because only 32 states and Puerto Rico voluntarily reported their data, this is probably just a small sample of the number of actual recreational water-associated illness outbreaks. And there are other reasons to suspect there might be more outbreaks out there that haven't been reported, she added.

Story highlights
  • As summer heats up and people head to the swimming pool, a CDC Morbidity and Mortality Weekly Report from June 26 highlights a rise in outbreaks of waterborne illnesses.
  • Seventy-seven percent of 90 outbreaks in 2011-2012 occurred in treated recreational water, and of these, 52 percent were caused by Cryptosporidium.
  • Because routine examination of stool for ova and parasites is unlikely to include testing for Cryptosporidium, health care professionals need to specifically request Cryptosporidium testing when exposure is suspected.

For example, because cryptosporidiosis has an incubation period of roughly a week or so, it can be easy to miss an outbreak at a given location, Hlavsa said.

"It's not like with the norovirus, where I  go swimming and a few hours later I become sick," she said.

Educating Patients on Healthy Swimming

According to Hlavsa, the biggest message to convey to patients about how to prevent recreational water illnesses is, "If you have diarrhea, stay out of the water."

It's also important to shower for at least one minute before entering a pool to remove dirt and any other bodily substance that chlorine will seek to break down instead of doing its job to kill germs.

In addition, the CDC recommends that people not swallow pool or similar aquatic facilities' water. "Chlorine kills germs, but doesn't do so instantly," she said. "So germs like E(scherichia) coli and Shigella can also cause outbreaks."

And finally, make sure to relay the simple message to parents and their children that it's important to not urinate or defecate in the pool.

The CDC offers additional tips(www.cdc.gov) on protecting against recreational water illnesses, along with a free downloadable brochure(www.cdc.gov) that can be printed and handed out to patients.

Diagnosing, Treating Cryptosporidiosis

A May 1 MMWR Surveillance Summary(www.cdc.gov) on cryptosporidiosis and giardiasis recommended that health care professionals consider cryptosporidiosis in the differential diagnosis when a patient experiences diarrhea that lasts for more than three days.

And Hlavsa emphasized that because routine laboratory examination of stool for ova and parasites is unlikely to include testing for Cryptosporidium, health care professionals need to specifically request Cryptosporidium testing when exposure is suspected.

Furthermore, said the surveillance summary, because oocyst excretion can be intermittent, the parasite might not be detected in a given stool specimen. Therefore, three stool specimens should be collected on separate days for examination before considering test results to be negative.

Hlavsa said if a patient is diagnosed with cryptosporidiosis, he or she should be told to not only stay out of the pool when they have diarrhea, but also to stay out of the water for the following two weeks to avoid spreading the Cryptosporidium oocysts.

Nitazoxanide (Alinia) is FDA-approved for treatment of cryptosporidiosis(www.cdc.gov) in immunocompetent patients ages 1 and older.

Related AAFP News Coverage
Help Your Patients Prepare for a Safe Summer
AAFP Resource Offers Tips for Hydration, Sun Protection and Pool Safety

(5/21/2015)

More From AAFP
Summer Safety

Additional Resource
CDC Healthy Swimming/Recreational Water Information for Medical Professionals(www.cdc.gov)


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