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.
After using the toilet or changing diapers
Before handling food
After handling stools from animals
After gardening or other direct contact with soil
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.
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.
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:
Drinking water that is considered safe for persons with healthy immune
systems may contain some Cryptosporidium oocysts;
No one knows whether a few ooeysts could create a risk for someone who
is immunocompromised;
Some researchers think that ooeysts ingested while you are still relatively
healthy may remain in your gallbladder until your immune system is
severely depressed and then cause serious illness.
What are some options for safer beverages?
1. Bring tap water to a full boil for one minute before using.
This will kill all organisms including Cryptosporidium.
To avoid burning yourself, allow water to cool before pouring into clean, dry containers.
Taste can be improved by adding lemon or other flavorings.
Use the boiled water for ice cubes, toothbrushing and mixing with concentrates. You don't need to use boiled water for food that will be cooked before eating.
Dishes, silverware, pots and pans may be washed with tap water as long as they are dry before being used.
2. Use a submicron, personal-use filter (home or office type water filter) that will remove particles as small as one micron in diameter.
Use filters that are certified by the Water Quality Association or National Sanitation Foundation (the certification seal can be found on the filter).
Be sure to follow directions accurately.
3. Use bottled water
Be careful, because bottled water doesn't have to meet the same standards as water coming from a treatment plant.
If you can verify with the manufacturer that the water has been passed through filters capable of removing particles as small as one micron in diameter or has undergone reverse osmosis prior to bottling, then it has been treated for the removal of Cryptosporidium oocysts.
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.