Cluster of presumed organic dust toxic syndrome cases among urban landscape workers-Colorado, 2007.

Background: Organic dust toxic syndrome (ODTS) is an influenza-like illness typically affecting agricultural workers exposed to organic dusts. In July 2007, Tri-County Health Department investigated a cluster of acute respiratory illnesses among urban landscape workers with known mulch exposure.

Methods: An epidemiologic study of landscape workers was conducted. Employees were interviewed regarding illness and occupational exposures. Medical records were reviewed. Mulch samples were tested for fungi and endotoxins.

Results: Five (12%) of 43 employees experienced respiratory illness compatible with ODTS. Illness was associated with prolonged mulch exposure (>or=6 vs. <6 hr/day; relative risk = 24.7; 95% confidence interval = 3.3-184.9). Mulch samples contained high levels of Aspergillus spores and endotoxin.

Conclusions: Contaminated mulch was implicated as the source of presumed ODTS among landscape workers, highlighting that ODTS is not limited to rural agricultural settings. Education of employers, safety officers, and clinicians is necessary to improve recognition and prevention of ODTS within urban occupational groups.