| Two Outbreaks of Occupationally Acquired Histoplasmosis: More Than Workers at Risk Gregory D. Huhn,1,2 Connie Austin,3 Mark Carr,4 Diana Heyer,5 Pam Boudreau,6 Glynnis Gilbert,7 Terry Eimen,7 Mark D. Lindsley,8 Salvatore Cali,9 Craig S. Conover,2 and Mark S. Dworkin2 1Centers for Disease Control and Prevention, Atlanta, Georgia, USA; 2Division of Infectious Diseases, Illinois Department of Public Health, Chicago, Illinois, USA; 3Division of Infectious Diseases, and 4Division of Environmental Health, Illinois Department of Public Health, Springfield, Illinois, USA; 5Macon County Health Department, Decatur, Illinois, USA; 6Kankakee County Health Department, Division of Chronic and Communicable Disease, Kankakee, Illinois, USA; 7Ford-Iroquois Public Health Department, Watseka, Illinois, USA; 8Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA; 9University of Illinois Chicago, School of Public Health, Chicago, Illinois, USA Abstract
Objective: The objective of this study was to determine the etiology and risk factors for acute histoplasmosis in two outbreaks in Illinois among laborers at a landfill in 2001 and at a bridge reconstruction site in 2003.
Design: We performed environmental investigations during both outbreaks and also performed an analytic cohort study among bridge workers.
Participants: Workers at the landfill during May 2001 and those at the bridge site during August 2003 participated in the study. At the landfill, workers moved topsoil from an area that previously housed a barn ; at the bridge, workers observed bat guano on bridge beams.
Evaluations/Measurements: We defined a case by positive immunodiffusion serology, a ≥ 4-fold titer rise in complement fixation between acute and convalescent sera, or positive urinary Histoplasma capsulatum (HC) antigen. Relative risks (RR) for disease among bridge workers were calculated using bivariate analysis.
Results: Eight of 11 landfill workers (73%) and 6 of 12 bridge workers (50%) were laboratory-confirmed histoplasmosis cases. Three bridge workers had positive urinary HC antigen. At the bridge, seeing or having contact with bats [RR = 7.0 ; 95% confidence interval (CI) , 1.1-43.0], jack-hammering (RR = 4.0 ; 95% CI, 1.2-13.3) , and waste disposal (RR = 4.0 ; 95% CI, 1.2-13.3) were the most significant job-related risk factors for acquiring histoplasmosis.
Conclusions: Workers performing activities that aerosolized topsoil and dust were at increased risk for acquiring histoplasmosis.
Relevance to professional and clinical practice: Employees should wear personal protective equipment and use dust-suppression techniques when working in areas potentially contaminated with bird or bat droppings. Urinary HC antigen testing was important in rapidly identifying disease in the 2003 outbreak.
Key words: antigen, bat guano, bridge, dust, histoplasmosis, landfill, occupationally acquired, spores, workers. Environ Health Perspect 113: 585-589 (2005) . doi:10.1289/ehp.7484 available via http://dx.doi.org/ [Online 4 February 2005]
Address correspondence to G. Huhn, Rush University Medical Center, 600 S. Paulina St., Suite 140-143 AC.FAC, Chicago, IL 60612 USA. Telephone: (312) 942-3263 ext. 3410. Fax: (312) 942-5865. E-mail: Gregory_Huhn@rush.edu We thank L.J. Wheat, A. Winquist, and J. Morgan for their thoughtful comments during preparation of this manuscript. The authors declare they have no competing financial interests. Received 11 August 2004 ; accepted 27 January 2005.
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