What Cancer Patients Need to Know About Drinking Water

Why is drinking water safety important?
Water is essential to support human life, and as such, the safety of drinking water is of significant importance to all people. After all, people cannot survive without adequate clean water. The Centers for Disease Control and Prevention estimates that each year a million Americans will become infected with water-borne pathogens and a thousand will die. Most cases are isolated, but outbreaks do occur. An outbreak of cryptosporidium in Milwaukee occurred in 1993, killing over 100 people and infecting 400,000 others. This outbreak was caused by contamination of the public water supply. The issue of drinking water safety becomes even more important in people who have weakened immune (disease-fighting) systems. The United States has come a long way toward making its drinking water supply clean and safe, but the current mechanisms for disinfection and filtration cannot remove every substance that might do the body harm, especially if the body’s immune system is weakened.

Are there groups of people at higher risk for water-borne diseases?
The immune system serves to protect people from disease. Consequently, people who have problems with their immune systems are more susceptible to disease. These people include cancer and transplant patients undergoing immunosuppressive therapy, people with HIV/AIDS, and people born with immune system deficiencies. The elderly, children, and pregnant women may also be at increased risk of water-borne infections.

What is cryptosporidiosis?
Cryptosporidium enteritis, also known as cryptosporidiosis, is an infection of the small intestine with a parasite, cryptosporidium, found in water contaminated with human or animal feces. Symptoms of cryptosporidiosis include diarrhea, abdominal cramping, nausea, and fever. While infection with cryptosporidium in most people is not severe, infection in immunocompromised individuals can be quite dramatic with resulting malnutrition, dehydration, wasting, and even death. Outbreaks of cryptosporidiosis occur from time to time and may be associated with contaminated public water supplies.

If I am worried about cryptosporidium, what can I do?
Cryptosporidium is a hardy species and can survive the typical methods of disinfection employed by public water suppliers. Boiling water is the most effective way to kill cryptosporidium. Bringing water to a full boil for one minute is sufficient. Alternatively, a point-of-use water filter may be used. The filter must remove particles measuring 1 micrometer or less in diameter to be effective against cryptosporidium. Bottled water may be a reasonable alternative, but the quality of bottled water varies. Where the water originated, microorganisms in that water, and water treatment methods used prior to bottling vary from brand to brand. In the case of a local or regional outbreak, the health department or other health or government agency typically issues a boil water advisory.

Where can I get more information?
For further information on alternate sources of water for immunocompromised individuals, refer to the Environmental Protection Agency guidance document entitled “Safe Drinking Water - Guidance for People with Severely Weakened Immune Systems” (http://www.epa.gov/safewater/crypto.html).

For further information on drinking water safety, please refer to the following sources:

Environmental Protection Agency: http://www.epa.gov/safewater

Safe Drinking Water - Guidance for people with severely weakened immune systems: http://www.epa.gov/safewater/crypto.html

Drinking Water and Health: What You Need to Know: http://www.epa.gov/safewater/dwinfo/index.html

All public water suppliers must publish an annual drinking water quality report. The report should be mailed to you annually but may also be accessed via the following Web resources:

• EPA Local Drinking Water Information: http://www.epa.gov/safewater/dwinfo/index.html
• Allegheny County Health Department: http://www.achd.net/pdw/