Death on tap

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

In late May, when Dallas AIDS activist John Thomas learned he was infected with a microbe called cryptosporidium parvum, he finally decided to conclude his private battle with death. Thomas had earned national respect over the last two decades for his leadership in the global battle against death by AIDS. He knew the score. For him, the arrival in his body of this single-celled parasite was the unmistakable knell of his personal endgame.

Since 1976, when cryptosporidium first surfaced as a threat to human life, it has been associated mainly with HIV-infected victims. But that may be changing, and the question is whether John Thomas' fate is a bell that tolls for us all.

Crypto, as it is usually called, is a single-celled protozoan, like an amoeba, carried in the gut of cows and deer, sometimes transported by birds, but most efficiently carried by water. Crypto was long believed not to be harmful in human beings. It was not known to have taken a single human life before 1976.

But crypto has changed. Scientists believe it may have become increasingly resistant to chlorination and other forms of disinfection. It escapes most of the commonly used water filtration systems. And it seems to be broadening the number and types of human beings it can attack.

In 1993, cryptosporidium took root in the public drinking-water system in Milwaukee and caused the largest waterborne human epidemic in America this century, severely sickening 400,000 people and killing more than 100.

Most of the fatalities in Milwaukee were people with AIDS, but not all were. The deaths also included elderly people and very young children, and the very sick included people of all ages and descriptions.

The Milwaukee outbreak was blamed at the time on unusually low water levels, high turbidity or murkiness of the water, and mistakes made in the filtration process. But later studies threw doubt on those explanations, showing that the Milwaukee drinking-water system was meeting all federal standards when the outbreak occurred.

Tests by the U.S. Environmental Protection Agency laboratories eventually showed that the strain of crypto in the Milwaukee outbreak could actually live in pure Clorox bleach.

Since then, the U.S. Centers for Disease Control in Atlanta has logged a succession of smaller outbreaks around the nation, including one in Las Vegas in 1994 that took 39 lives, all associated with HIV infection.

In July 1993, 35,000 residents of New York City had to boil their water because of a crypto invasion of the water system. That same year, residents of Washington, D.C., and suburban Virginia had to boil water for the same reason.

Erik D. Olson of the Natural Resources Defense Council, speaking in Dallas last week, said data from the U.S. Centers for Disease Control indicate that approximately one million Americans a year are falling sick from waterborne diseases, including cryptosporidiosis. The Natural Resources Defense Council estimates that 900 a year are dying.

Some of the outbreaks have been traced to fecal contact in daycare centers and nursing homes or water contamination after water has been out of the tap. Most of the outbreaks documented by the CDC, however, have been traced to public drinking-water supply systems. About half of those systems were found later to have suffered some defect or accident that could be linked to the outbreak. But several outbreaks have been linked to water-treatment systems where everything was running smoothly.

Cryptosporidium has learned to withdraw into a hard-shelled spore that can travel and survive in chlorinated water, sea water, and fairly hot and cold water. Its normal home is in the bowels of ruminants--cud-chewing animals.

In the human gut, the spores break open and flower into a billowing plague of microbes that attach to the lining of the bowel, reproducing so fast that they literally fill a victim's insides.

There are no drug cures. The onset, once it is in full bloom, is violent and overwhelming. The only weapon against it is a healthy immune system.

A new text on crypto says, "In fact, if this parasite were not efficiently eliminated from the body, it would quickly kill an animal through dehydration and electrolyte imbalance and rapidly eliminate host species from the environment."

That means that, if crypto ever developed the ability to outwit healthy immune systems, it would eliminate human life on the planet.

As it is now, in all susceptible species other than humans, only the newborns die because their immune systems have not had time to mature. In humans, where immune failure can occur at any age, crypto attacks and kills all generations.

Terry Stewart, director of the Dallas Water Utilities, denies emphatically that crypto is carried in Dallas drinking water and says his assertion is backed by scientific test data. After a delay of several days, he produced a table of test findings that showed no crypto in "finished" or treated water in Dallas. But Dallas tests for crypto only once a month. The United Kingdom recently went from testing every 24 hours to continual testing, because crypto is so hard to find. Stewart admits there is crypto in the water coming into Dallas' treatment plants, but he did not provide data to show how much. On these findings, he asserts that Dallas is totally crypto-free.

If Stewart's assertion is accurate, it is truly remarkable, since Dallas has exactly the kind of water-treatment system in which scientists say crypto has been found all over the country and world. His claim also flies in the face of a little-known Dallas water department policy:

According to a Dallas Water Utilities pamphlet published in 1995 called "Should I Be Concerned About Cryptosporidium?" and available on request at City Hall, the answer is definitely "yes."

In a very low-key description of a disease that is actually ferocious and horrific in its assault, the pamphlet says, "Symptoms include diarrhea, abdominal cramps, headaches, nausea, vomiting, low-grade fever. These symptoms may lead to weight loss and dehydration.

"For people in good health," the pamphlet warns, "the average recovery period is 10 to 14 days. For people with severely weakened immune systems, however, the disease can last for months and can be fatal.

"People with AIDS, people receiving treatment for certain cancers, organ transplant recipients, people suffering from certain illnesses, and malnourished children should take special precautions, such as boiling their drinking water."

That's Dallas drinking water.
John Thomas, former head of human resources at the Dallas Times Herald, a cofounder of the Dallas Gay and Lesbian Community Center, and a former executive director of the Dallas AIDS Resource Center, knew all of that. He told friends by e-mail in the last week of May that he had decided to refuse continued injections of saline and potassium needed to keep him alive because he had been informed crypto had invaded his body.

At the same time, three other crypto cases became known to the staff of AIDS Services of Dallas. ASD director Don Maison says two of the cases were people with HIV and one was a person who has tested negative for HIV.

"The only common factor in the cases was Dallas drinking water," Maison says.

Dr. Daniel J. Skiest, who treats HIV patients at Parkland's AIDSclinic, said that it is "fairly common" for people with advanced AIDS in Dallas to become infected by crypto and that it is "occasionally" the ultimate cause of death. At least one child has died of crypto at Bryan's House, a hospice for juvenile AIDS victims, according to director Cynthia Nunn.

But Stewart, the Dallas water boss, suggests cryptosporidium is only an issue because it is being stirred up by companies selling the new membrane-filter technology required to get crypto out of the water.

"The people selling these membranes want to sell them," Stewart says. "If they can unnerve the public and scare them into thinking that this is their only protection, then they can sell their product."

The cost of adding the necessary "membrane" filtration equipment to the treatment plants that supply Dallas with drinking water would be substantial. Russell Davis of California-based U.S. Filter, one of several companies that sell the new membrane technology to cities, says the one-time capital cost for installing the filters is about 50 cents per gallon of peak capacity, which would come to about $300 million in Dallas.

After it's built, Davis says, it may cost less to operate his company's system than the kind of system Dallas now uses, because the filters do not produce chemical sludge or the highly contaminated backwash effluent that comes out of the existing system and must be disposed of.

Of course, the prospect of spending $300 million for new treatment facilities and tacking the cost of the bonds onto the water rate is not at all attractive to officials in Dallas, where water-rate money is already spoken for. Most of the very expensive maintenance of the huge new levee system recently approved by voters for the Trinity River project, for example, will have to be borne by future water rates.

Stewart, head of Dallas Water Utilities, is emphatic that it would be a waste of the taxpayers' money to install the new generation of membrane filters here.

"We put out an excellent water," Stewart says. "I just got an award at the American Waterworks Association convention yesterday. Why would I want to put that on the backs of the citizens of Dallas?"

The AWWA Convention where Stewart was given his award was held in Dallas last week. His award, given for having completed a set of federal requirements on water testing, was largely ceremonial and typical of the sort of thing visiting firemen do for their local host.

Away from the hoopla on the main floor of the convention, however, in Spartan meeting rooms in the basement of the Dallas Convention Center, ranks of pocket-protector water-nerds from all over the nation and world sat on folding chairs and listened gravely while a number of experts made technical presentations arguing that crypto is a major issue and an issue everyone should be concerned about--definitely not just people with AIDS.

Jeffrey Griffiths, an assistant professor at Tufts University in Boston, told a roomful of water-types that crypto and other waterborne pathogens pose a serious, even mortal threat to many classes of people who suffer immune problems at various points in their lives.

Showing slide after slide of pregnant women, elderly people, infants, transplant recipients, cancer victims, and others whose immune systems may be permanently or temporarily impaired, Griffiths hammered home his point: Rather than being alone in their susceptibility to crypto, AIDS victims may actually be the coal-mine canaries whose demise is a warning of death for us all.

"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.

"If you don't look for it, you don't find it," Tulu says.
In fact, the tests required to find crypto in a stool sample are extremely specialized. Some experts think definitive testing requires a biopsy. In the absence of a major education program, there is little inclination on the part of doctors to seek such tests every time a patient has a bout of extreme diarrhea.

"We have only had five [non-fatal] cases of cryptosporidiosis reported in the last year," Tulu says. "We don't know if there is a greater magnitude, because our reporting system isn't strong."

Two of the cases known to Don Maison of AIDS Services were fatal. But Tulu says he had no data at all showing cryptosporidiosis associated with deaths in Dallas County. He conceded that there may be many cases not captured by his data-gathering system.

"There may be a lot that people don't tell us about," he says.
Tulu dismisses crypto as "not a very serious problem," but it's an eerily casual analysis, given the response of many other communities and governments around the world.

Last month the British government ordered its water industry to spend between $12 and $16 million a year on new filtering technology and testing to take crypto out of drinking water. The new rules require water companies to test their product for crypto "continuously" rather than every 24 hours.

Stewart says proudly that the Dallas agency tests for crypto once a month.
Daniel Okun, a professor at the University of North Carolina at Chapel Hill who is considered one of the world's top authorities on testing for crypto, says monthly tests would be "not at all adequate or useful" for a system such as Dallas'--a groundwater and reservoir system subject to sudden runoff and muddiness.

Stewart concedes that there is crypto in the "raw" water that comes into the Dallas system, but by the time this story went to press, he still had not shown the Dallas Observer any test data for raw water. Okun said these numbers would be "essential" to knowing whether Dallas' drinking water is at risk.

The membrane filters capable of eradicating crypto from water are based on bundles of tiny straws gathered in long silver tubes. Water is forced into the skin of the straws through holes far too small to allow microbes like crypto or giardia lamblia to pass.

Milwaukee installed the new membrane micron filters after its 1993 outbreak. Since then, some mid-sized cities have followed suit, including Marquette, Michigan; and Kenosha, Wisconsin.

New York City, which has never filtered its drinking water at all, relying instead on "pristine" sources for its water, promised in federal court last May to build a $1 billion filtration plant. Experts and public-health advocates are pushing hard to ensure that the level of filtration at the new plant will go up to and include the membrane technology needed to eradicate crypto from drinking water.

Until the EPA brought suit against it, New York had been among a select sorority of cities--including Seattle, Portland, San Francisco, and Boston--that owned or controlled all of their own reservoirs and the land around them. These cities typically fenced the land around the reservoirs and guaranteed the purity of the run-off. Because their source water was considered pure, they were allowed to use it unfiltered.

But the EPA convinced a federal judge this year that New York's Croton watershed in Westchester and Putnam Counties is no longer pristine, fenced or not, and that the city needs to filter all of its water to protect the public health.

One of the concerns about the Dallas water system is that it draws drinking water from unprotected reservoirs in North and East Texas. In response to a question about source water for the city, Stewart said at first that all of the reservoirs serving the city were protected and included a "buffer zone of like 1,000 feet or 2,000 feet or something where you can't come in and do anything close to the lake."

When I suggested that I had personally fished on several of those lakes and that the lakes seemed to be surrounded by houses and cows, Stewart said, "Well, subdivisions within that buffer are not your problem, even where you have septic tanks, if they are monitored, and cows are only a problem where you have large feedlots."

The bottom line is that Dallas has an unprotected water source--considered by experts to be extremely dangerous, because dirty run-off tends to front-load the water-treatment system with way more crypto, giardia, and other disease than it can possibly filter.

The filtration system used in the three main plants that provide water to Dallas does not include membrane-filter technology--the only method known to remove crypto entirely from the water.

The Elm Fork Plant does include a system that uses ozone, in addition to chlorine, to enhance disinfection. According to the Centers for Disease Control, ozone appears to be effective against crypto and does not produce the same harmful by-products as chlorine.

But on any given day, as little as a third of the city's drinking water may come from the Elm Fork plant. And while scientists have not yet determined how many oocysts it takes to launch an infection of a human being, the number appears to be quite small. Minuscule traces in the water, in other words, may be enough to severely sicken the unlucky people who drink at the wrong moment.

Ironically, people in the organized and informed AIDS community probably are better protected against crypto, generally, than the general population, simply because they know it's out there. A large population of poor and uninformed AIDS victims will continue to drink and shower in tap water, but the people with AIDS who know what they're doing will not.

As soon as Don Maison learned John Thomas had crypto--and then realized he knew of three other recent cases--Maison rushed to install thousands of dollars' worth of membrane filters on the apartment buildings owned and managed by Aids Services of Dallas.

"It doesn't do any good to filter the drinking water," he says, "if you don't also do the ice-makers and the showers, so we had to go ahead and do it all."

But if cryptosporidium is in Dallas drinking water, even in trace amounts, what does that mean for people who do not have AIDS or any other conditions that compromise their immune systems?

Lisa Ragain, the expert who worked on the study that called Dallas an "extreme risk city," says it is possible that many otherwise healthy people may be suffering the rigors of disabling diarrhea, lasting for days and even weeks and resulting in extreme weight loss, without even knowing that the culprit is crypto.

"Crypto tends to be reported only in people with compromised immune systems," she says. "It's generally not diagnosed in the general population. It's too hard to diagnose, too hard to find in the human body."

As Laurie Garrett illustrates in example after example in The Coming Plague, science is discovering that it's not a good idea to subject anybody to repeated doses of a pathogen like crypto, because the germ may be learning: The more it sees of our defenses, the better able it may be to reconfigure itself to kill us.

In the basement of the Convention Center last week, some of the scientists and experts quietly--almost shyly at times--broached another issue with their audiences of water engineers. They talked about the moral question.

What can a society expect for itself and what may it even deserve if its approach to plague is to banish the victims from inside the fortress of community?

Jeffrey Griffiths of Tufts approached it with a complex view of self-interest: "There is some merit in thinking of sensitive populations not just as people with AIDS but also other populations [such as pregnant women and infants]," he said. "It may be unfair to fragment us.

"Perhaps we need to think of everyone in the society as being, at one time or another, immune-compromised."

Erik D. Olson of the Natural Resources Defense Council went at the moral question a little more head-on. "After all," he reminded his stony-faced audience, "the best measure of a society is how we protect our most vulnerable people.

Show Pages
 
My Voice Nation Help
0 comments
 
Loading...