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Cryptosporidiosis is an intestinal parasitic infection caused by ingestion of Cryptosporidium parvum. The parasite produces cysts (hardy, resistant eggs) which are passed from the body in the stool. The infection is spread through ingestion of cysts in untreated surface water and contaminated swimming pools or other recreational water; contact with infected livestock, wild animals, and pets; and through person-to-person transmission via the fecal-oral route. The cysts are resistant to chlorine, and most swimming pool filters do not remove Cryptosporidia.

Resources for the general public

Resources for health care professionals

Purpose of surveillance:

  • To identify outbreaks and potential sources of ongoing transmission
  • To eliminate sources of transmission including contaminated food and water
  • To educate people about how to reduce their risk of transmission

Cryptosporidiosis case data

Local epidemiology:

In 2015, 26 confirmed and probable cases of cryptosporidiosis were reported, compared to a five-year average of 18 cases per year. One case was reported to be hospitalized. Of those interviewed, four cases traveled internationally to Europe, Mexico, or Central America during their exposure period.

Cryptosporidiosis has been reportable in Washington state since December 2000. Since that time, no large common-source outbreaks have been identified. Each year in Washington state between 60 and 140 cases are reported.