By Mark Moran, MPH
WebMD Medical News

July 26, 2000 (Cleveland) --
In 1994, a dark fungus gained notoriety as an apparent cause of a frightening condition striking a number of Cleveland infants, some of whom died.

Six years later, opinions remain divided about stachybotrys chartarum. Some see it as simply the most publicized of a host of indoor molds affecting human health. Others view it primarily as an insurance liability disaster in the making for countless homes and office buildings with water damage.

But to others, it is a potent symbol of the difficulty of linking environmental exposure and human disease -- and of formulating public policy in the face of scientific uncertainty.

Local and national public health leaders agree the controversy has obscured the overwhelming consensus among scientists that mold and water-damaged housing are threats to human health. But they are almost as unanimous that the connection between stachybotrys and the malady that struck the infants, called pulmonary hemosiderosis, is far less conclusive.

"No one has ever claimed causation," says Dorr Dearborn, MD, PhD, associate chief of the pediatric pulmonary division at Rainbow Babies and Children's Hospital of the University Hospitals of Cleveland.

It was Dearborn who originally alerted the CDC about a rash of infants with what appeared to be pulmonary hemosiderosis, a condition in which victims cough up blood from their lungs.

In response to his call, the CDC sent a team of researchers to the city to assess the situation. The result was a "case-control" study in which measures of stachybotrys in homes of infants with the disease were compared to those without it. The study suggested a link between the mold and the disease, reporting 10 cases of what appeared to be pulmonary hemosiderosis associated with stachybotrys chartarum in the home.

But last year, the CDC released a new report that suggested shortcomings in the original study. The report called into question the small size of the study, the way mold calculations were done, and the diagnosis of pulmonary hemosiderosis, which the CDC says is not a disease but a condition that accompanies a host of ailments.

The agency's conclusion: Scientific evidence is insufficient to link stachybotrys chartarum to pulmonary hemosiderosis.

Dearborn, who was one of the investigators in the case-control study, defends the study and says more cases of pulmonary hemosiderosis locally and nationwide have been reported in conjunction with stachybotrys. Over the past seven years, there have been 45 cases of pulmonary hemorrhage in young infants and 16 deaths, he says.

Dearborn acknowledges that the study was too small, but says it was the CDC that stopped the trial before it could gather enough data to make a more convincing case.

Tom Sinks, PhD, a CDC epidemiologist, says that when the agency responds to an urgent request for an investigation, its mission is to rapidly assess a situation, not to do long-term research. "We do not have the luxury in these situations to do the most exquisite type of research," he tells WebMD. "Our purpose is not to start something we can't finish."

Sinks says the CDC recognizes the link between mold and human health, and urges people to take preventive action when there is water damage in the home. But regarding a connection between stachybotrys and hemosiderosis, the evidence is too weak to justify policymaking, he says.

That conclusion generated controversy about the way the CDC handled the case. Ruth Etzel, MD, an epidemiologist formerly with the CDC who headed the original study, says the agency's review of the work is "dead wrong" and that the CDC has sought to bury the connection between mold and disease.

"Normally, when a new idea is presented, you do more work and test it further in other places," says Etzel, who says she left the CDC as a result of the controversy and is now director of the division of epidemiology and risk assessment at the food safety and inspection service of the USDA. "What happened here was that instead of moving forward, a decision was made to put a stop to our work."

She says the current scientific consensus on the dangerous health effects of mold stems largely from the Cleveland study. "Previously, most physicians thought of mold as quite innocuous," she tells WebMD. "We were able to focus on mold in a way that the medical world had never done before."

Both Dearborn and Etzel acknowledge that showing an association is not the same as saying the mold caused the deaths. "You can't prove causation from epidemiologic studies," Dearborn says. "All you can do is show that there is a correlation."

Dearborn says stachybotrys may have played a role in the deaths of the Cleveland infants along with other factors, such as second-hand smoke or underlying genetic problems. The exact relationship between the mold and those other factors is unknown, he says.

"This is a difficult game at any time in history," says David Miller, PhD, a biochemist at Carlton University in Ottawa, Canada, and an expert on fungal toxins. "You can't have a cut-and-dried scientific discussion without having all the facts. With regard to stachybotrys, we don't have all the facts."

Miller illustrates the problem by recalling alflatoxin, a mold that grows on crops, now known to be a potent carcinogen. "In the early 1970s when the FDA made a decision to regulate the substance, the epidemiologic studies showing it was a human carcinogen were very weak," Miller says. "Everyone agreed it was weak, but it was the best anyone could do."

It wasn't until the early 1990s that the FDA decision was proven well-founded, when the ability to measure alflatoxin in the blood was refined and the substance was shown to be one of the most potent carcinogens known, Miller says.

Stu Greenberg, executive director of Environmental Health Watch, a local environmental advocacy group, says that in the Cleveland case, the scientific complexities of risk assessment were obscured by the drama of dying babies. "It raises the question for public health leaders, 'how do you take action in the absence of solid data?'" Greenberg says.

He cites the "precautionary principle" to suggest that heightened concern was probably warranted. "When there is a potential risk to human life, you can't wait for the body count," Greenberg says. "You have to take prudent action, even though you may not be certain."

In wake of the original report, the Cuyahoga County Board of Health and the Cleveland Department of Public Health initiated an expensive program designed to find and remove stachybotrys from the homes of newborns in east Cleveland.

Terry Allan, MPH, the Cuyahoga County board's director of community health services, tells WebMD the program has had only limited success. The difficulty of reaching inner-city populations and entering homes to fix water damage is similar, he says, to that confronting public health leaders trying to improve vaccination rates in medically underserved areas.

He defends the effort despite the fact that no one has proved the mold made babies sick. "How long does it take to discover causality?" Allan asks. "Do you ever get that definitive study? Not very often. At some point, public health leaders have to make a decision based on what they know today."

Allan says the stachybotrys prevention effort is continuing, but will be folded into a larger project looking at all kinds of mold and moisture in low-income housing. This year the Cuyahoga County Board of Health received $3.1 million from the U.S. Department of Housing and Urban Development to track mold and moisture in low-income homes, to determine their relationship to disease, and to make repairs.

Meanwhile, the link between stachybotrys chartarum and pulmonary hemosiderosis awaits further research. Dearborn says he is conducting studies on the effects of airborne stachybotrys spores on animals.

He believes the Cleveland babies may have served as "canaries in the coal mine" -- that is, indicators of something foul in Cleveland's inner-city environment.

"They are telling us that our inner city is not a healthy environment," he says, "and that indoor pollution problems may be a very significant player in the increase in inner-city childhood asthma."

© 2000 Healtheon/WebMD. All rights reserved.

University Hospitals, Cleveland -- Pulmonary Hemosiderosis and Stachybotrys Mold
<http://gcrc.meds.cwru.edu/stachy/default.htm>

EHW Mold Links