Colorado health officials are reporting a large outbreak of cryptosporidiosis, an intestinal disease caused by a microscopic parasite.
The Colorado Department of Public Health and Environment said about 50 cases were reported in August, more than four times the usual number.
The disease is caused by the cryptosporidium parasite. It is spread through human and animal feces, often in swimming pools, water parks, lakes and streams, and less frequently in drinking water.
Symptoms of the illness, commonly known as crypto, include watery diarrhea, stomach cramps and nausea.
Investigators from the health department haven’t identified the sources of the outbreak and don’t know why more cases are being reported.
Alicia Cronquist, an epidemiologist with the department, said Monday that the reported cases are spread along the Front Range and Western Slope.
“At this point, there does not appear to be a common source for these infections among ill individuals,” she said. “The state health department is working with local health departments to investigate possible sources.”
Cronquist said it is likely that many more cases haven’t been reported. The illness can be confirmed only by laboratory testing of stool samples.
Infectious-disease specialists typically estimate that there are 40 times as many diarrhea- related illnesses as are officially diagnosed and reported.
In addition to its spread in pools and other water bodies, crypto can be carried from person to person, especially in homes and day-care centers where diapers are changed regularly.
The parasite is resistant to chlorine and can survive in chlorinated swimming pools and even in municipal water systems.
Symptoms generally appear five to 15 days after exposure and usually pass in a few days. For people with weakened immune systems, however, diarrhea can persist for months.
The single-cell parasite in August 2006 sickened at least 12 people who attended a birthday party at the Lone Tree Recreation Center swimming pool.
The Atlanta-based Centers for Disease Control and Prevention reported 18 crypto outbreaks nationally last year.
Cryptosporidiosis killed 110 people and sickened 400,000 in 1993 when it contaminated the Milwaukee municipal water supply.
City water systems in Philadelphia, New York City and Washington, D.C., among other locations, also have been hit with crypto.
In a report this year, the CDC said “the resistance to cryptosporidium to chlorination suggests that treatment strategies for recreational water facilities need to be improved.”
Staff writer Steve Raabe can be reached at 303-954-1948 or sraabe@denverpost.com.
Avoiding crypto
Colorado health officials say the spread of the intestinal disease cryptosporidiosis can be limited with these steps:
