A Mold's Toxic Legacy Revisited

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http://www.sciencemag.org/content/vol288/issue5464/

PUBLIC HEALTH:

> A Mold's Toxic Legacy Revisited

>

> Hagmann

>

> In 1995, the Centers for Disease Control and Prevention (CDC) in Atlanta

> set off

> a cascade of alarms when an agency task force linked certain

> toxin-producing

> molds to a cluster of cases of sometimes fatal lung bleeding, or pulmonary

> hemorrhage, in infants. But last month, the CDC published the findings of

> two

> expert panels that identified what they called " serious shortcomings " in

> the

> initial investigation and concluded that " a possible

> association between acute pulmonary hemorrhage ... and [mold] exposure ...

> was

> not proven. "

>

> The reexamination is already stirring debate. Investigators involved in

> the

> original study are preparing a rebuttal of the CDC

> report to be posted on the Internet (gcrc.meds.cwru.edu/stachy). And

> resolving

> the issue is important, because sick infants may

> be just the tip of the iceberg of much broader public health problems.

> Toxic

> molds, which cause allergies and asthma attacks in

> sensitive individuals, have also been linked to the elusive sick building

> syndrome, which, in turn, has led to lawsuits and efforts to

> clean up mold-contaminated buildings--both costing millions of dollars.

>

> Dorr Dearborn, a pediatric pulmonologist at the Rainbow Babies' and

> Children's

> Hospital in Cleveland, triggered the original

> investigation in November 1994 when he alerted the CDC to a cluster of

> eight

> babies the hospital had treated for a normally

> rare bleeding of the lungs. The CDC immediately sent in a task force to

> look for

> possible causes. The team focused on the

> infants' homes. " We realized that it must have to do with a home

> environment

> problem, " Dearborn recalls, " because if we sent

> the infants home again, they restarted bleeding. "

>

> It turned out that all the houses with sick babies had recent water

> damage.

> After sampling these homes and several control

> houses in the same area, the investigators concluded that the likely

> culprit was

> Stachybotrys chartarum and other toxic molds

> that thrive in damp buildings and can under certain conditions produce

> spores

> containing a nasty cocktail of toxic chemicals.

> Although the investigators cautioned that more research was needed to

> prove the

> case, their findings precipitated a frenzy of

> activity. Public health guidelines were issued, contaminated buildings

> were

> evacuated and closed, multimillion-dollar lawsuits

> ensued--and the media jumped on the bandwagon.

>

> But many in the scientific community felt that some questions remained

> unresolved. So in November 1997, then-CDC director

> Satcher asked an internal working group and a panel of outside

> experts to

> review the Cleveland investigation. The groups

> delivered their reports last June and December, respectively, and the CDC

> published a synopsis in the 10 March issue of the

> Morbidity and Mortality Weekly Report (MMWR)

> (www.cdc.gov/epo/mmwr/preview/mmwrhtml/mm4909a3.htm).

>

> Both panels spotted several flaws in the Cleveland study. For example,

> investigators collected twice as many samples in sick

> infants' homes as in control homes, and did so much more rigorously, the

> report

> states. " It's no surprise if you find more fungi in

> case homes this way, " says Shelton, a microbiologist at Pathcon, a

> private

> laboratory that specializes in building and

> environmental health assessments.

>

> There was also no clear-cut clinical definition of the so-called

> idiopathic

> pulmonary hemorrhage. " The mere presence of blood,

> it seems, was enough to include infants as cases, " says expert panel

> member Alan

> Cohen of Georgia Pediatric Pulmonology

> Associates, an Atlanta-based private association of pulmonologists. " But

> how can

> you define a common cause if you don't even

> have a defined disease? " And a statistical reanalysis of the original data

> indicated that the results might have been skewed by the

> finding of " extremely high, outlying values " for S. chartarum

> contamination of

> one home. This " magnified the risk about fivefold, "

> says Sudakin, a medical toxicologist at the Veterans Administration

> Medical Center in Portland, Oregon.

>

> These and additional minor problems, taken together with other evidence

> from the

> literature, led the panels to conclude that S.

> chartarum's role in pulmonary hemorrhage was not proven. " That doesn't

> mean that

> S. chartarum is dismissed as a possible

> cause, but right now we just don't know what killed the Cleveland babies, "

> says

> Cohen.

>

> Dearborn acknowledges that because their study was designed rapidly, " it

> can't

> be perfect. " But, he says, the " minor

> deficiencies are not enough to invalidate our conclusions. " As support,

> Dearborn

> cites the fact that the number of infants with

> pulmonary hemorrhage has gone down recently in Cleveland--a change he

> attributes

> to public health officials inspecting homes

> for water damage and mold, and then having any contamination cleaned up.

>

> Both sides do agree on one thing: Further studies are needed. " We could be

> missing something that is right in front of us because

> we think we already have the answer, " Cohen says. And despite his

> disagreement

> with the MMWR report, Dearborn is happy

> the CDC is again studying the topic. " While we have continued our research

> efforts, the CDC stopped surveying and looking at

> pulmonary hemorrhage a few years ago. Now they're willing to do follow-up

> studies--that's great, " he says.

>