Cryptosporidium in Drinking Water

Cryptosporidium is the parasite that shattered our confidence in chlorine as a way of disinfecting our drinking water of all microorganisms. In 1993, an outbreak of diarrhea and intestinal disorders in Milwaukee, was discovered to be due to this parasite which had gotten into the water system. The Milwaukee water treatment system was functioning well and there was no reason to suspect infection coming through the water; but after weeks of searching, it became clear that cryptosporidium had just cause the largest waterborne outbreak of illness in the history of the United States. It is estimated that 400,000 people were infected.

Question #1: What is Cryptosporidium?

It is a microscopic parasite, similar to giardia, which is bred and multiplied in humans as well as animals and discharged in their waste or sewage. Cow dung are one of the chief sources of cryptosporidium parvum. It causes an intestinal illness called cryptosporidiosis. It can be spread not only by water but by any contact with infected human or animal waste. Hence, failure to wash one's hands after a bowel movement can become a means of infecting food and others.

Question #2: How does Cryptosporidium get into our water?

Imagine a herd of cattle that is infected with this parasite. Their dung, filled with the cysts of this parasite, is then used as fertilizer and spread on the fields. Rain and snow come and wash the cysts into streams and rivers and lakes. Other cysts seep into the ground and become a part of ground water, eventually appearing in wells. These cysts are so durable that they can survive in or out of bodies and they can resist disinfectants, such as chlorine.

It's not just through water that one can become victim of cryptosporidiosis, but there are various ways of being contaminated. Anything that comes in contact with infected human or animal waste can be infected. It enters the body through the mouth. Food that is touched by unwashed hands can infect the eater. Water taken in by accident in a pool or lake can give you cryptosporidiosis.

Question #3: How can Cryptosporidium affect my health?

It only takes a relatively few cysts to infect a person. The incubation period of the illness, cryptosporidiosis, is about one week but can be anywhere from 2 to 25 days. The cyst germinates and reproduces causing symptoms such as severe diarrhea, gas, stomach cramps, nausea, headaches and even slight fever. The degree of intensity varies with the person. Some people in fact have no symptoms. On the other hand, for those with low resistance (HIV/Aids patients, transplant patients, cancer patients) or those vulnerable to dehydration (as small children and pregnant women), the attack of this parasite can be life threatening.

The symptoms last normally a week or two but can last up to a month or longer. There are really no good drugs to cure cryptosporidiosis. Some drugs help with the symptoms. What is important is to replenish your body fluids through drinking or receiving intravenous fluids if necessary.

Question #4: How big a problem is Cryptosporidium in my drinking water?

It's hard to say for sure how many Americans are infected per year since many are infected without consulting a doctor and because the cysts are so hard to detect in the laboratory. A small quantity of cysts in water can be hard to find in a laboratory yet can infect the person who drinks them. The fact that it resists disinfection and that it can even get through well-operated water treatment systems, means that it is a very big problem facing the clean water industry.

Discussing this and similar hard to detect waterborne diseases, Doctor Robert Morris in his recent book, The Blue Death, says,

So how much waterborne disease is there in the United States? The truth is that we don't know, but several lines of evidence suggest that millions of cases of waterborne disease, perhaps more than ten million, may be occurring every year in the United States. How is this possible? How could water treatment plants that rely on methods refined over the past century allow pathogens to reach our taps?

He goes on to discuss the complications facing the water treatment industry in providing clean water today. This is a book I recommend if you really want to understand the history and challenges facing us in the West today when it comes to pure drinking water.

Question #5: How can I know if Cryptosporidium is in my drinking water?

The cysts are so small that they are difficult to find even under a microscope. They are particularly hard to find in water where it takes only a relatively few cysts to infect a person. The Environmental Protection Agency set new standard for this parasite to be met by 2001, for water systems serving the majority of U.S. populations (those serving surface water to 10,000 or more). The new standard says that the parasite should be totally disinfected (killed) or removed (by filer) from the water. Water treatment systems are required to report the presence of these cysts in your tap water.

If you get your tap water from a public water system, they are required by law to send you annually a Consumer Confidence Report (CCR). If you don't have a copy you can get one from your city hall. Look to see if there is cryptosporidium in your water. They cite the "Level Found" and the "MCL" (Maximum Contaminant Level). For this parasite, the standard set by the EPA is "zero". Any water which has cysts in it is not safe. The water company is required to state in the CCR that cryptosporidium is present. They are also required to inform the public through newspapers and television of the presence of this parasite in the water. Usually, they will tell you to boil your water for drinking or food preparation.

Question #6: How would I go about removing Cryptosporidium from my drinking water?

When there is an outbreak of cryptosporidiosis in an area due to drinking water, the public is usually advised to boil their drinking water until told otherwise. One should boil the water for a full minute to kill the parasite. This, however, is a short-term solution.

The best long-term solution for protecting you against this and other parasites is that of filtration. There are two kinds of filters that can remove this parasite from your tap water: Filtration (carbon/charcoal) with a pore size of 1 micron or smaller and Ultraviolet water treatment systems that meet Standard 55A of the NSF. Which ever one you choose should not only claim to destroy or remove cysts but also have third party certification of that claim. For example, the NSF International is the organization best suited for certifying water filters.

For further information on the best filters in the categories of Filtration and Ultraviolet go to "Best Water Filters". Or for a broader discussion of the multiple considerations you need to keep in mind in selecting a filter go to "How to Choose a Water Filter".

For more information about this and other toxic contaminants, go to "Cryptosporidium in Drinking Water".

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