Researchers at Purdue University have...
In 1988, I traveled to South Korea with the American/Canadian Tae Kwon Do karate team. I spent two weeks there, the first week competing, the second week staying with our interpreter’s family in a village north of Pusan. I had a great time, but on the 26–hour flight back, I had problems. Watery diarrhea and stomach cramps forced me into the little cubicle of the airplane bathroom and there I stayed most of the trip. I had a fear of flying but half way over the Pacific, I just wanted the plane ride to be over.
Later on, through an ova and parasites test, I found I was hosting a nasty little single-cell protozoa called Cryptosporidium. Since that time I have discovered that what once was a common affliction to travelers of underdeveloped countries is now a common outbreak in communities and daycare centers in the U.S.
Some Cryptosporidium outbreaks have been major in magnitude. In 1987 the university town of rural Carrollton, Ga. had a Cryptosporidium outbreak that inflicted 13,000 people out of a total population of 65,000. All had the same symptoms, vomiting, stomach cramps and diarrhea. In 1993, the city of Milwaukee, Wis. had an outbreak that effected 400,000 residences. Four thousand of these people were hospitalized and 104 died. Estimated cost for the medical care was in the range of $54 million.
The word “cryptosporidium” is Greek for “hidden spore.” The name is derived from the difficulty in detecting the animal in water samples.
It is a protozoan parasite that
ranges from 2–6 microns in size.
This animal was first discovered in 1907 but was not recognized as a cause to human illness until 1976.
It is nature’s weapon of mass destruction. The Cryptosporidium Parvum is able to live for weeks in dark, cold pipes and reservoirs. The dormant or inactive form of this protozoa is called oocyst. The oocyst’s tough wall protects the animal from outside disinfectants such as chlorine. Some researchers theorize that the organism has a built in pump mechanism that expels the toxins before they can harm it. A study by the U.S. Environmental Protection Agency (EPA) suggested that Cryptosporidium could even
live on chlorine products.
Cryptosporidium can be found
in humans, cattle, sheep, dogs, cats, beavers, squirrels and other animals. Drinking is not the only form of introducing this contamination to the body. Eating contaminated foods, handling contaminated material (baby diapers, working around contaminated cattle or sheep, etc.) anywhere the hand comes into contact with this organism and then is placed near the mouth could serve as an entrance point for infecting the body.
When ingested, the oocyst pass through the stomach into the small intestines. The oocysts then release sporozites, which invade the cells lining the intestinal tract. The cells lining the intestinal tract lose their ability to absorb nutrients and water. The nutrients and water just pass through the intestinal tract as a watery diarrhea. To further complicate the situation, the oocysts formed in the intestinal tract will release additional sporozites which will end up in the fecal matter that is excreted from the body. Coming into contact with this excretion could lead to infecting another person and so on.
The Cryptosporidium illness is called Cryptosporidiosis. The average incubation period is about seven days with symptoms of watery diarrhea, nausea, abdominal cramps (sometimes severe), vomiting and sometimes a low-grade fever.
Cryptosporiodisis can last one to
two weeks but may last as long as a month. There is no known cure at this point in time. You usually have to let the illness run its course. To a majority of the population the only problems from this illness will be abdominal discomfort and loss of work time. Other groups, such as young children, the elderly and the immuno-depressed (people with HIV, cancer, etc.), could find this illness
life threatening if not fatal.
The Carrollton, Ga. incident, mentioned earlier, had contaminated water in every household on the municipal water system, yet the town’s filtration system complied with national filtration standards. The municipality used two effective methods for cleaning their water: chlorination and filtration; however, the organisms were able to slip through. A need for a better understanding of this organism and for improved sampling and the testing methodologies were most evident.
In 1996, the Safe Drinking Water Act Amendments required the EPA to evaluate the risk to public health posed by waterborne parasites such as Cryptosporidium. The EPA was charged with investigating new methods of protozoan sampling and analysis. They collaborated with commercial laboratories, universities, and other experts in the field to develop EPA Method 1622 (for Cryptosporidium) and 1623 (for Giardia and Cryptosporidium). The final revisions of these test methods were completed in April 2001.
These methods are now used for the sampling and analysis of the organism. More information on these test methods can be found on EPA Microbiology website (www.epa.gov/nerlcwww/index.html).
Cryptosporidium was added to the EPA’s list of Priority Substances which may require regulation under the Safe Drinking Water Act (Federal Register, Vol. 56, No.9, January 14, 1991). According to Jennifer Hitchcock, surface water treatment coordinator for the state of Maine, Cryptosporidium will be included in the Long Term 2 Enhanced Water Surface Treatment Rule (LT2EWSTR) when it is finalized in 2005. This rule will require that surface water systems test for Crypto-sporidium for a period of 12 months. The results of theses tests will dictate the courses of action that the systems will have to follow—improved filtration and/or better disinfection. The smaller systems (under 10,000 population) will be required to perform E.coli tests as an indicator of possible Cryptosporidium problems.
There are very few laboratories
qualified to test for Cryptosporidium. The first commercial laboratory in the nation to receive approval pending from the EPA under LT2EWSTR was BioVir Laboratories, Benicia, Calif. Craig Johnson, president of BioVir, recommends that to locate a qualified laboratory one should visit www.epa.gov/ogwdw/LT2/aprvlabs.html.
The keyword is qualified. The last thing anyone needs is a misdiagnosis or a false positive when it comes to interpreting cryptosporidium in their water system.
There are a number of ways to lessen the possibility of a Cryptosporidium outbreak. In residential homes, putting an in-line filter rated for cyst removal. The filter size must be small enough to keep out cysts, which would mean a filter size of less than 2 microns.
For community water systems it will mean improved filtration and disinfection methods. Estimates of the cost for community water systems to comply with LT2EWSTR are between $8,000–10,000 per year for just Cryp-tosporidium sampling and analysis.
Carlton Gardner, senior training specialist for the Maine Rural Water Association says the cryptosporidium issue must be taken into perspective. You could encounter Cryptosporidium by simply letting your dog lick your face. There have been incidences of someone picking a fresh vegetable out of the garden, wiping it on the moist grass to remove dirt and picking up the protozoa from the lawn.
When dealing with this protozoa remember that “the best defense is a good offense.” The more we know about its habits and life-cycle the more we can prepare against its contamination. In day-care centers or hospitals Cryptosporidium is highly infectious and can be easily transmitted from person to person. If an individual’s water well system becomes contaminated, test for E.coli and install cyst removal filters.
Improved sampling and analytical techniques combined with better filtration and disinfection procedures will ensure a safer, cleaner water and a wiser, healthier consumer.