Prepared by Division of Environment - Water Section. VDH

What is cryptosporidiosis?
Cryptosporidiosis is a disease caused by a parasite called Cryptosporidium parvum. Cryptosporidiosis was responsible for a large drinking water outbreak of diarrheal disease in Milwaukee, Wisconsin in 1993.
Who can get cryptosporidiosis:
Anyone, but it may be more common in persons with impaired immune systems and in children in daycare centers.
Where is this parasite found:
Cryptosporidium is found in the digestive systems of infected animals and humans. Any pet, farm animal or wild animal, including birds, fish, and reptiles, can become infected. Calves are the most likely animals to be infected. When infected animals or humans go to the bathroom, they pass Cryptosporidium oocysts (egg-like forms of the organism) in their stools.
How is cryptosporidiosis spread:
People or animals become infected by swallowing the oocysts. This can occur after touching stools from infected humans or animals or after handling objects contaminated with infected stool material. Unwashed hands can then transfer the oocysts to the mouth. Persons and animals can also become infected by drinking water or eating raw or undercooked food contaminated with stool material from infected animals or humans. Some people have become sick after swimming in public pools contaminated with stools from infected persons.
What are the symptoms of cryptosporidiosis:
The major symptoms are watery diarrhea and abdominal cramping. Vomiting and low-grade fever may occur. Symptoms may come and go and generally last for two weeks, but may continue for a month. Many people do not have any symptoms.
Can cryptosporidiosis cause severe problems:
In persons who lack normal immune function, cryptosporidiosis can cause severe, life-threatening diarrhea and has been associated with liver and gall bladder disease. Persons at greatest risk for severe problems include those having HIV infection, receiving cancer chemotherapy or taking drugs that suppress the immune system.
How soon after exposure do symptoms occur:
After swallowing the oocysts, illness may occur in about two to ten days.
What should I do if I think I have cryptosporidiosis:
See your physician as soon as possible, especially if your immune system is suppressed. If your doctor suspects cryptosporidiosis, you will be asked to submit a stool sample. Diagnosis is made by using special stains on the sample and then examining it under a microscope. Not all laboratories have the capability or experience to do the test and it must be specifically requested by the doctor.
Should infected people be excluded from school or work.
Since Cryptosporidium is passed in the stool, children and staff in daycare centers, health care workers, or people who handle food should not go to school or work while they have diarrhea. After diarrhea ends, persons may return to work or school but they should carefully wash their hands after using the toilet.
What is the treatment for cryptosporidiosis?
People with healthy immune systems usually get well on their own. People with diarrhea should drink plenty of fluids. Currently, there are no antibiotics proven to be effective, although one is being studied.
Can people who get cryptosporidiosis get it again?
It is unknown whether past infection means people are protected from getting it again.
How can cryptosporidiosis be prevented?
1. Avoid water or food that may be contaminated, including unpasteurized milk. Do not
drink water directly from streams, lakes, springs or any0 unknown source. If you suspect
your drinking water is unsafe, bring it to a rolling boil for one minute prior to using.

2. Always wash hands with soap and water.

3. If you work in a child-care center where you change children's diapers, wash hands properly between each child. If you use gloves, change gloves between each child.

4. If you take care of cryptosporidiosis patients, wash hands after bathing patients, emptying bedpans, changing soiled linen, or otherwise coming in contact with the patients' stools.

5 If you have cryptosporidiosis, wash your hands often to prevent spreading the disease to other members of your household.

6. Persons with diarrhea should not use public swimming facilities.


Cryptosporidiosis and Drinking Water

In the past ten years, at least five outbreaks of cryptosporidiosis have been associated with contaminated drinking water, including the well-publicized one in Milwaukee, Wisconsin in 1993. This information sheet answers the most common questions that we receive about drinking water and cryptosporidiosis.

How do Cryptosporidium oocysts get into drinking water?
Cryptosporidium gets into surface water sources such as rivers and lakes from the stools of infected animals. Many municipal water treatment plants get their water from these surface water sources that can contain Cryptosporidium oocysts.

Does the treatment process remove the oocysts?
Filtration treatment will usually remove Cryptosporidium oocysts. Chlorination by itself is not effective. All Virginia localities that use surface water sources provide filtration treatment. The better the equipment and the more experienced the operators the less likely it is for oocysts to get through, but it is possible to have oocysts show up in drinking water that has been adequately treated.

What does it mean if Cryptosporidium oocysts are found in drinking water?
Authorities believe that the detection of a few oocysts in drinking water does not pose a threat to people with healthy immune systems. It takes an unusual combination oŁ events to lead to a situation where drinking water causes disease. An increased number of organisms in the source water and a breakdown in the water treatment system would have to occur at the same time. This is the combination that occurred in Milwaukee.

How will officials decide that water is not safe to drink?
They will look at all indicators of water quality including such things aa changes in the source water, number of Cryptosporidium oocysts, turbidity (cloudiness of the water), particle counts, presence of other organisms, water plant performance and maintenance records. The presence of oocysts alone does not necessarily indicate an increased risk for disease.

What will they recommend if water isn't safe?
Bringing water to a rolling boil for one minute will kill all organisms including Cryptosporidium.

What laws regulate Cryptosporidium in drinking water?
There are no federal or state regulatory standards for Cryptosporidium in drinking water because there is not enough information on which to base standards. In an effort to learn more, the Environmental Protection Agency will soon be requiring large and medium sized water systems that obtain their water from surface water sources to test for Cryptosporidium oocysts.

Are there any problems with the laboratory tests?
There are several things to be aware of regarding Cryptosporidium test results:

1. The laboratory test used to detect Cryptosporidium in water cannot tell the
difference between viable (able to cause illness) and nonviable oocysts.

2. In most cases, the results of the tests on drinking water will not be available until several weeks after the sample was taken and so will not be an accurate measure of present conditions.

3. The number or concentration of oocysts is not necessarily a predictor of when illness will occur. Other factors, such as clumping of oocysts and water temperature may play a role.

Has any water been tested in Virginia?

Yes. To date, in Virginia, levels of Cryptosporidium have been low in water before it enters the treatment plant and have not been found in filtered water.

Additional Information on Preventing Cryptosporidiosis for Persons who are Immunocompromised

Do the precautions listed for persons with healthy immune systems apply to me?

If you are HIV positive or otherwise immunocompromised, you should adhere strictly to the preventive measures suggested for persons with healthy immune systems. Be extra careful about what you eat and drink. Be careful not to let raw foods contaminate other foods. Be a fanatic about hand washing, including after touching animals. Avoid accidentally swallowing water from lakes, rivers or swimming pools.

What about my drinking water?

Current data are inadequate to recommend that all immunocompromised persons boil or avoid drinking tap water in non-outbreak settings. However, you may want to discuss the need for taking further protective measures with your medical provider because:

What are some options for safer beverages?

1. Bring tap water to a full boil for one minute before using.

2. Use a submicron, personal-use filter (home or office type water filter) that will remove particles as small as one micron in diameter.

3. Use bottled water

4. Use distilled water, commercially bottled soft drinks and seltzers. Bottled juices are safe if they have been pasteurized and do not require refrigeration before opening.