Death on tap

Cryptosporidium kills AIDS victims in Dallas. Who will the pathogen claim next?

"I think there is a disadvantage in thinking of this as an issue only for people with AIDS," Griffiths said. "We also have to think that everybody in the society at one time or another may have a susceptibility."

Looming in the background of the discussions at the Dallas Convention Center--treated very gingerly in front of this audience of water-purveyors--is the very frightening scientific work being done now dealing with the ability of germs to continually and rapidly change their own structure and mechanisms of attack in order to defeat drugs and even immune systems.

In her 1995 book The Coming Plague, Pulitzer Prize-winning health reporter Laurie Garrett describes how the AIDS virus itself may have developed its own impregnable powers in response to bombardments of drugs prescribed in the 1970s to combat other sexually transmitted diseases. Garrett paints in disturbing detail the way micro-organisms scoop up fragments of each other's DNA and even read the DNA and chemical structure of substances attacking them, including human antibodies, in order to re-arm themselves against their foes.

For that reason, man may be creating new and more virulent microbes by throwing more and more drugs and chemical disinfectants at them. In effect, our man-made compounds only teach the microbes how better to kill us. Garrett quotes Dr. Harold Neu at Columbia University as saying, "Bacteria are cleverer than men."

Crypto is one of a variety of bugs that is of special concern because of its ability to change its physical form in a process called sporulation. Under attack by drugs, chlorine, heat, acid, organic compounds, whatever, the microbe more or less rolls itself up into a hard-shelled ball or spore and simply waits for the coast to clear.

Researchers in recent years have found that crypto either has always been or has recently become very good at sporulation. In the spore or oocyst form, crypto can tough out attacks by almost all of the conventional water-treatment techniques including chlorination.

Very high levels of chlorine will finally burn it up, but a clear trade-off sets in when the use of chemical disinfectants reaches a certain intensity. Chlorine itself at high levels is associated with serious risks, including cancer.

A California study last year showed a correlation between high levels of chlorine by-products in tap water and increased rates of spontaneous abortion among pregnant women who drink the water.

A New Jersey study found a correlation between chlorine by-products and neural tube birth defects. In Iowa and in Italy, low-birth-weight rates have been linked to chlorine and other disinfection chemicals.

Dallas is not among the places where chlorine levels have been tied to serious health risks. The problem in Dallas, say some experts who've looked at the local water system, is perhaps less in the system itself than in the arrogance of the people running it and their unwillingness to admit the possibility of problems.

Water director Stewart, for example, flatly denied at first that his agency had ever told people to boil their drinking water.

"We do not tell people to boil their water," he said. "We provide an excellent product that does not need that."

Questioned about his own agency's 1995 pamphlet warning a wide variety of people to boil their water, he first denied that the pamphlet even existed. "I've never heard of that," he said. "We have never distributed anything like that."

When a reporter read the pamphlet to him over the phone, Stewart seemed to recognize some of the language, but quickly offered a number of qualifications: "What we have said is that, if your health-care professional advises you to boil your water, then you should. We were saying it in that context."

But that is not at all what Dallas Water Utilities' pamphlet says. It says clearly that Stewart's agency warns susceptible populations, which go far beyond the AIDS community, that they should "take special precautions, such as boiling their drinking water."

If Stewart is unfamiliar with his own department's pamphlet, it may be because the pamphlet, by his own admission, has never actually been distributed. It seems instead to have been a sort of "pamphlet for the file" created while the National Association of People With AIDS (NAPWA) was studying water systems and health departments around the country to see how they dealt with crypto.

Not long after Dallas Water Utilities created its obscure pamphlet, NAPWA published its own report listing Dallas as one of the nation's "extreme risk cities" for cryptosporidium outbreaks. Lisa Ragain, one of the scientists who worked on the NAPWA report, says Dallas was considered an extreme risk not only because its system lacked the ability to eradicate crypto from drinking water but because there was so little willingness by local water and health officials to look for and report the presence of crypto.

"The big problem in Dallas was the county health department," Ragain said. "Without an early-warning system in place and good relations with the AIDS organizations, there is a much higher level of risk for everyone."

Before the NAPWA report, crypto was not even a "reportable" disease in Dallas County: No numbers were gathered, no records kept. Since then it has become reportable, but Dallas County epidemiologist Assefa Tulu admits that reporting levels are very low and informal. Few physicians outside the AIDS community, even when confronted with cases of violent diarrhea, test their patients for crypto.

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