[FOUNTAIN]Efforts to make a society too ‘clean’ can failCryptosporidium parvum is a microscopic single-cell pathogen. It is highly resistant to chlorine, so regular water treatment cannot kill this waterborne parasite. It can enter the human body through drinking water, causing stomach- ache and diarrhea. In tropical regions, up to 23 percent of children are infected.
In 1989, over 8,000 people were infected with Cryptosporidium parvum in England. In Milwaukee, Wisconsin, in the United States, over 400,000 were infected in 1993. Of that total, 4,400 were hospitalized and 69 died of cryptosporidiosis, the disease caused by the pathogen.
What makes Cryptosporidium parvum more unusual is that mass outbreaks of the disease are more common in developed countries, where the infection rate is relatively low. Maybe people residing in a clean environment are not immune to unsanitary influences and are more susceptible to infection.
A similar phenomenon was found in a study conducted by a research team at the University of Hamburg in 1995. The researchers studied the allergy symptoms of 8,000 children aged 9 to 12. They found that children in the former West Germany, who grew up in a relatively cleaner environment, had two to three times more atopy and pollen allergy than the children of the former East Germany. In a study of adults over age 45 conducted in 1996, those from West Germany were more likely to have an allergic reaction than those from East Germany.
The research team found that East Germans had higher reaginic antibody Immunoglobulin E, or IgE, which protects the host against invading parasites. They concluded that the eradication of parasites and the number of allergic patients is inversely proportional.
According to Dr. Koichiro Fujita, a parasitologist at the Tokyo Medical and Dental University, Japanese tourists who travel to developing countries are vulnerable to endemic diseases because they are used to a germ-free environment.
The more you pursue cleanliness, the more your immune system can drop. Just like in the human body, too much effort to keep a society clean can backfire. Coexistence can make a society healthier than some extreme measures such as eradication and cleaning. Cleanliness is a virtue, but extreme sanitation is a sickness.
by Nahm Yoon-ho
The writer is a deputy city news editor of the JoongAng Ilbo.