Cryptosporidiosis

Disease Fact Sheet

What is cryptosporidiosis?

Cryptosporidiosis is an intestinal infection caused by the parasite Cryptosporidium which can cause a diarrheal illness in humans and animals (especially very young animals). It is a very small organism, about 4- 6 microns, and 1-16 cysts of the parasite may be capable of causing illness.

What are the symptoms?

Most persons experience watery diarrhea, stomach cramping and weight loss. About half of the cases will have low-grade fever and vomiting. Symptoms may be intermittent and some people can be infected but have no symptoms. The illness is mild to moderate in severity and self-limited, usually lasting about 2 weeks (range 1-30 days). However in persons with severely weakened immune systems the illness can be severe and long-lasting.

How soon do symptoms appear?

The incubation period probably ranges from 1 to 30 days with an average of 7 to 14 days.

How do you get it?

Cryptosporidium is transmitted by fecal/oral spread. The parasite is shed in the feces (stools) of infected people and animals. You get Cryptosporidium by eating food, drinking water or placing objects in your mouth that have been contaminated with feces from an infected person or animal. Cryptosporidium may spread among family members, intimate sexual contacts, playmates, young children in child care settings, pets and pet owners. Infections may also occur in persons who drink or swallow unfiltered lake, stream, or river water, or contaminated drinking water. Outbreaks of cryptosporidiosis have been related to drinking water from contaminated municipal water systems that obtained their source water from rivers, lakes or streams.

How do you find out if you have it?

Many laboratories are not yet routinely testing for this parasite. A physician usually must ask a lab to specifically look for this organism when doing a stool test for parasites. Unfortunately, the laboratory tests currently available to diagnose cryptosporidiosis are not very accurate.

How is it treated?

No standard treatment of infected persons is recognized at this time.

How can you keep from getting it?

Taking precautions to reduce the risk of infection is ESPECIALLY IMPORTANT for persons with weakened immune systems. Some things you can do are:

• Avoid drinking or unintentionally swallowing water from lakes, streams, or rivers. If you can't avoid drinking such water, use a water filter capable of removing particles less than 1 micron in diameter. These may include "Absolute" 1 micron filters, and those labeled as meeting National Sanitation Foundation (NSF) standard #53 for cyst removal, and devices using reverse osmosis. Drinking water which comes from streams, rivers, and lakes must be filtered properly or boiled in order to remove this parasite. Disinfectants such as chlorine bleach or iodine tablets are NOT effective in killing Cryptosporidium.
• Make sure that you and persons preparing food for you wash hands carefully and thoroughly before preparing food, or assisting others with feeding. This is especially important after using the toilet, caring for small children or persons with diarrhea, or cleaning up after pets.
• Avoid intimate/sexual practices which increase the risk of fecal/oral exposure.
• In the unlikely event that your public water system issues a "boil-water" advisory because Cryptosporidium has been identified, and water quality is considered to be unsafe, you can do one of the following:
  • boil water for 1 minute
  • use an "Absolute" 1 micron filter or reverse osmosis method
  • use bottled water. Research the source of the water to determine if it is derived from springs or wells (versus lakes or rivers) and if the source has been shown to be free of coliform bacteria. Municipal tap water that is bottled after treatment with charcoal, or after exposure to UV light offers no additional protection against Cryptosporidium. If the bottled water meets the standards outlined in the first precaution, it will be safe.
• Since the risk of waterborne transmission is not zero, immunocompromised persons may independently wish to take the above precautions that are recommended during outbreaks.

How can you keep from spreading it if you have it?

WASH YOU HANDS--after going to the bathroom, before fixing food, before wiping children's faces.

Produced by: Communicable Disease Epidemiology Program (303) 692-2700 Colorado Department of Public Health and Environment June, 2001