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Update: Pulmonary Hemorrhage/Hemosiderosis Among Infants --- Cleveland, Ohio, 1993-1996
Please note: An erratum has been published for this article. To view the erratum, please click here.
A review within CDC and by outside experts of an investigation of acute pulmonary hemorrhage/hemosiderosis in infants has identified shortcomings in the implementation and reporting of the investigation described in MMWR (1,2) and detailed in other scientific publications authored, in part, by CDC personnel (3-5). The reviews led CDC to conclude that a possible association between acute pulmonary hemorrhage/hemosiderosis in infants and exposure to molds, specifically Stachybotrys chartarum, commonly referred to by its synonym Stachybotrys atra, was not proven. This report describes the specific findings of these internal and external reviews.
In December 1994 and January 1997, articles in MMWR described a cluster of 10* infants from Cleveland, Ohio, with acute idiopathic pulmonary hemorrhage, also referred to as pulmonary hemosiderosis (1,2). The children resided in seven contiguous postal tracts and had had one or more hemorrhagic episodes, resulting in one death, during January 1993-December 1994. Preliminary results of a CDC case-control study (2) indicated that hemorrhage was associated with 1) major household water damage during the 6 months before illness and 2) increased levels of measurable household fungi, including the toxin-producing mold S. chartarum (syn. S. atra).
These findings and the observation that tricothecene mycotoxins were produced in the laboratory by some S. chartarum isolates recovered from the homes of study subjects have been published and referenced in peer-reviewed scientific literature (3-9). The hypothesis from the findings of the investigation was that infant pulmonary hemorrhage may be caused by exposure to potent mycotoxins produced by S. chartarum or other fungi growing in moist household environments (4,5). The findings also were cited in environmental health guidelines (10,11), congressional testimony (12), and the popular media (13-16), and have been debated among industrial hygienists and other occupational and environmental health scientists (17-21). Despite caution that "further research is needed to determine...causal[ity] (4)," the findings have influenced closure of public buildings, cleanup and remediation, and litigation (16,22-28).
In June 1997, a CDC scientific task force, in a review of the agency's response to the problem, advised the CDC director that concerns about the role of S. chartarum in pulmonary hemorrhage needed to be addressed. In response, CDC convened a multidisciplinary internal group of senior scientists (working group) and sought the individual opinions of outside experts. The working group and the outside experts conducted separate reviews of the Cleveland investigation. The working group reviewed background literature, internal CDC documents, and published CDC reports; examined the data set; and interviewed the principal investigators. The external experts reviewed relevant literature, including internal CDC documents and the working group report, and invited additional consultants to address specific topics. The working group and the external consultants each concluded that further work is needed to better describe the clinical problem, its public health impact, and the factors that put infants at risk (29,30).
The reviewers had concerns about the characterization of the clinical problem as "hemosiderosis." The acute presentation in all 10 cases, the narrow age distribution (6 weeks to 6 months), and the absence of iron deficiency suggest that the illness described in the cluster of cases in Cleveland (1,3) is clinically distinct from idiopathic pulmonary hemosiderosis (IPH), the condition to which this cluster was linked (31). Hemosiderosis (i.e., hemosiderin-laden macrophages in the interstitium and alveolar spaces of the lung) is a pathologic finding indicative of pulmonary bleeding of any type, not a unique characteristic of a specific disease, etiology, or pathophysiologic process (32,33). Therefore, in referring to the cluster of cases in Cleveland, the working group defined that cluster as AIPH in infants. From the limited clinical and historic information available to the reviewers on cases added to the Cleveland series since the original cluster (D. Dearborn, Case Western Reserve Department of Pediatrics, personal communication, September 1999), the external consultants concluded that some of these additional cases (6), including several identified in a retrospective review of sudden infant death syndrome cases (2), do not conform to the clinical patterns of cases in the original cluster. Both groups of reviewers recognized limitations that precluded drawing conclusions about clinical or etiologic ties to IPH.
Association of Household AIPH with Water Damage and Fungi
Both groups of reviewers concluded that the available evidence does not substantiate the reported epidemiologic associations---between household water damage and AIPH (3) or between household fungi and AIPH (4)---or any inferences regarding causality. The interpretation of water damage and its association with AIPH was considered to have been hampered by the limited descriptive information, by the lack of standard criteria for water damage, and by the absence of a standard protocol for inspecting and recording information from home to home. Similarly, assessment of exposure to fungi or mycotoxin also was difficult to interpret because the methods did not distinguish between contamination and clinically meaningful exposure. No isolates or serologic evidence of exposure to fungi or mycotoxin were obtained in individual case-infants.
Evaluation of Analysis Methods
Three factors, considered together, contributed to the groups' conclusions that S. chartarum was not clearly associated with AIPH:
Overall, the reviewers concluded that on the basis of these limitations the evidence from these studies was not of sufficient quality to support an association between S. chartarum and AIPH. In addition, the reviewers noted that evidence from other sources supporting a causal role of S. chartarum in AIPH is limited. First, AIPH is not consistent with historic accounts of animal and human illness caused by S. chartarum or related toxigenic fungi. Second, clusters of AIPH have not been reported in other flood-prone areas where growth of S. chartarum or other toxigenic fungi might be favored. Third, the mold-disease association observed in the Cleveland investigation was not observed in the investigation of a similar cluster in Chicago (34; CDC, unpublished data, May 1997).
Reported by: Office of the Director, CDC.
On the basis of the findings and conclusions in the reports of the CDC internal working group and the individual opinions of the external consultants, CDC advises that conclusions regarding the possible association between cases of § The working group's reported reanalysis used the value originally coded in the laboratory record (0 CFU/m3). The result was identical to that obtained by excluding the household from the analysis. pulmonary hemorrhage/hemosiderosis in infants in Cleveland and household water damage or exposure to S. chartarum are not substantiated adequately by the scientific evidence produced in the CDC investigation (2-4). Serious shortcomings in the collection, analysis, and reporting of data resulted in inflated measures of association and restricted interpretation of the reports. The associations should be considered not proven; the etiology of AIPH is unresolved.
As a result of the reviews, CDC will implement the following:
Copies of the report of the working group and a synthesis prepared by CDC of the reports individually submitted by the external experts can be accessed at http://www.cdc.gov/od/ads , then click on "Pulmonary Hemorrhage/Hemosiderosis Among Infants."
* The first report (1) described eight infants identified through November 1994. Two additional infants, identified in December 1994, were added to the original study.
An imputed value, 4 CFU/m3 (half the limit of detection divided by the number of plates), was used because colonies were detected on one or more of the plates, but were too few to count on the final platings and, therefore, recorded in the laboratory record as 0 CFU/m3.
§ The working group's reported reanalysis used the value originally coded in the laboratory record (0 CFU/m3). The result was identical to that obtained by excluding the household from the analysis.
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