Even today, an outbreak can be costly in both dollars and human suffering. In 1993, during an outbreak in Milwaukee, Wisconsin, 400,000 people became ill.
One problem assessing the impact of this disease in an altered climate regime is the prevalence of very tiny Cryptosporidium oocysts -- the protozoan equivalent of a fertilized chicken egg. Reservoirs for Cryptosporidium exist in livestock, such as cattle and dairy cows and wildlife such as deer. Runoff from agricultural areas can release the Cryptosporidium oocysts into the drinking water supply.
Another problem is that the standard purification approach for drinking water in the United States, chlorination, has little effect on the organism. Filtration can remove the oocysts, but because of their small size, filters must be properly monitored and managed. The U.S. Environmental Protection Agency is currently proposing expanding water treatment requirements to safeguard water supplies from Cryptosporidium.
"We are looking at a situation where there is no known medical cure, where water treatment must be closely monitored because standard purification methods do not work, where testing of water is not routinely carried out and where routine screening for the disease only takes place in previously immunocompromised individuals," says Kocagil. "What happens now if global warming increases the frequency of a 100-year flood to every 50 years?"
The researchers have estimated that doubling of the frequency of 100 year floods could add up to $70 to the per person cost under certain conditions.
"Part of the problem is that we do not know how prevalent this disease is now," says Kocagil. "Many people do not go to the doctor with diarrheal diseases that clear up on their own."
It was only in 1982, when the number of cases among HIV-infected people
began to rise that outbreaks a
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Contact: A'ndrea Elyse Messer
aem1@psu.edu
814-865-9481
Penn State
26-May-1998