Many people don't know much about cryptosporidium, also known more simply as crypto, yet.
Although outbreaks of crypto, a parasite that is often active in the summer, seem to be occurring more often, they are still rather local. Therefore, crypto outbreaks don't get as much national attention as outbreaks of the flu, RSV, or salmonella.
As crypto becomes more common, it is likely something you want to learn more about though, both so you can avoid it and so that you can recognize the symptoms if your kids catch it.
There have been several crypto outbreaks and an overall increase in reported cases:
- Dallas, Texas (2008 - about 3,000 cases in Texas, with about half in North Texas)
- Phoenix, Arizona (2008)
- Utah (July to September 2007 - 1949 cases)
- Douglas County, Colorado (August to October 2006 - 11 cases)
- East Baton Rouge parish, Louisiana (July to October 2006 - 35 cases)
- South Carolina (2006 - 123 cases)
- Wyoming (2006 - 34 cases)
- Seneca Lake State Park, New York (2005 - over 4,000 cases)
Overall, crypto cases nationwide have increased from 3,016 in 2002 to 8,269 in 2005. Overall case counts dropped back down in 2006 to just 6,071, but that likely reflects that lack of a single large outbreak that year. Nationwide levels will likely increase again for 2007 because of the large Utah outbreak.
Controlling Crypto Outbreaks
Is it possible to control a crypto outbreak before it spreads through an entire community?
For example, during the 2008 crypto outbreak in Dallas/Ft. Worth, would it have been possible to contain the outbreak when the first cases were linked to Burger's Lake, a popular community lake in Ft. Worth where the first cases were found? Or was it inevitable that it would spread throughout the community pools and water parks in the Dallas and Ft. Worth area?
During the 2007 outbreak in Utah, in addition to weekly hyperchlorination of pools, health officials took steps that some people considered extreme, including banning children under age five from public pools. They later eased the ban to just include toddlers in diapers. The idea behind the bans was likely that those younger children are the ones most likely to get and spread crypto.
Did the swimming pool bans work? It is possible, but considering the the Utah crypto outbreak continued until the end of September, when children are back in school and less likely to visit pools and water parks, it is hard to say if it was just a coincidence.
Things that might help in areas where there is a crypto outbreak include:
- a close review of the Recreational Water Illness Outbreak Response Toolkit from the CDC and call health department officials in areas that have recently had to deal with crypto outbreaks
- regular, even weekly, hyperchlorination of pools, in which the chlorine level is raised to a high enough level to kill the crypto parasite in the pool water
- educating the public that people should not get in the water when they have diarrhea and until they have been well for at least two weeks
- encouraging people to shower before getting in the pool
- encouraging parents to wash their child's rear end with soap and water after they have a bowel movement and before they get back into the pool
- temporarily closing and hyperchlorinating a pool if anyone reports a child has diarrhea or a stooling accident in the pool, including stooling into a swim diaper
- educating everyone in the community about crypto, including how it is passed from one person to another and how it can be prevented
- alerting area laboratories to the fact that there is a concern for crypto, so that they either start doing routine crypto antigen testing on submitted stool samples or at least alert doctors that certain tests, including routine stool cultures for bacteria and the classic O&P (ova and parasite) test for parasites, do not actually test for crypto
- have the media alert people to which pools and water parks have had confirmed cases of crypto, not to scare people, but so that anyone who was in those pools and has symptoms will avoid swimming in other pools until they are well for at least two weeks
- making sure doctors report all cases of crypto to their local health department so that they can work to figure out which pools are contaminated and if the person with crypto contaminated any other pools
- suspending certain activities, such as visits from toddlers and preschoolers in daycare, swim classes, and other group events, might be helpful
- suggesting that people who swam in a contaminated pool that closes to not swim in other pools for a few weeks, since it can take 2 to 10 days for them to develop symptoms of crypto, and they may just contaminate these other pools if they get sick
And to identify outbreaks early, doctors should consider testing for crypto when kids have watery diarrhea or other symptoms of crypto during the summer, instead of simply blaming the symptoms on food poisoning or a virus.
Sources:
Cryptosporidiosis Surveillance -- United States, 2003-2005. MMWR Surveill Summ. September 7, 2007 / 56(SS-7);1-10.
Cryptosporidiosis Surveillance --- United States 1999--2002. MMWR Surveill Summ. January 28, 2005 / 54(SS-1);1-8.
Summary of Notifiable Diseases --- United States, 2006. MMWR March 21, 2008 / 55(53), 1-94.
CDC. Recreational Water Illness Outbreak Response Toolkit.
Cryptosporidiosis outbreaks associated with recreational water use; five states, 2006
MMWR (July 27, 2007 / 56(29), 729-732).
Cryptosporidiosis in children. Huang DB - Semin Pediatr Infect Dis - 01-OCT-2004; 15(4): 253-9.
