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.

Characterization of endotoxin and mouse allergen exposures in mouse facilities and research laboratories.

OBJECTIVES: Researchers and technicians who use mice in research are exposed to complex mixtures containing mouse allergen, endotoxin and particulates from animals, bedding and feed. The particle characteristics of these different exposures, and whether they are encountered together or separately, are important to better understand their adjuvant and allergic effects. Endotoxin and mouse allergen are derived from the same animal source, but have different physicochemical attributes. It is not known if airborne exposures to these agents are correlated in the laboratory animal workplace. METHODS: Side-by-side personal and area samples for airborne endotoxin (52), mouse allergen (46) and total particulates (43) were obtained in the animal facility and laboratories of a medical research institution. Animal handlers and researchers reported time spent on work tasks with mice, symptoms upon exposure to mice and mouse sensitization was determined by skin test or RAST. RESULTS: Mean airborne endotoxin exposure was highest during mouse experiments in the animal facility at 960 pg m(-3), peaked at 3125 pg m(-3), and ranged from 46 to 678 pg m(-3) with work in mouse rooms and research labs. Mouse allergen concentrations were highest during direct mouse work and background in research labs (mean 63-68 ng m(-3), range 41-271 ng m(-3)), but were undetectable during mouse research performed under a hood. Endotoxin and mouse allergen concentrations were correlated during direct research with mice and mouse care activities. Particle counts were low, typically < 1 cm(-3), varied widely, and exhibited peaks and valleys during different work tasks. From 80-90% of particles were < 1 microm in aerodynamic diameter during background measurements. The contribution of respirable particles 1-5 microm in size increased to 25-30% during mouse care and mouse research activities, but we found no association between any particle size and endotoxin or mouse allergen concentrations. Animal handlers and researchers in the mouse facility were exposed to the highest daily endotoxin concentrations, whereas researchers working with mice in the mouse facility and in laboratories were exposed to the highest daily mouse allergen concentrations. CONCLUSIONS: These findings suggest that endotoxin and mouse allergen are co-exposures during mouse handling and research, and that control of exposure peaks may be necessary to limit allergic disease in the laboratory animal workplace.

Airborne endotoxin predicts symptoms in non-mouse-sensitized technicians and research scientists exposed to laboratory mice.

Research scientists, laboratory technicians, and animal handlers who work with animals frequently report respiratory and skin symptoms from exposure to laboratory animals (LA). However, on the basis of prick skin tests or RASTs, only half are sensitized to LA. We hypothesized that aerosolized endotoxin from mouse work is responsible for symptoms in nonsensitized workers. We performed a cross-sectional study of 269/310 (87%) workers at a research institution. Subjects completed a questionnaire and underwent prick skin tests (n = 254) or RASTs (n = 16) for environmental and LA allergens. We measured airborne mouse allergen and endotoxin in the animal facility and in research laboratories. Of 212 workers not sensitized to mice, 34 (16%) reported symptoms compared with 26 (46%) of mouse-sensitized workers (p < 0.001). Symptomatic workers were more likely to be atopic, regardless of mouse sensitization status. Symptomatic non-mouse-sensitized workers spent more time performing animal experiments in the animal facility (p = 0.0001) and in their own laboratories (p < 0.0001) and had higher daily endotoxin exposure (p = 0.008) compared with asymptomatic coworkers. In a multivariate model, daily endotoxin exposure most strongly predicted symptoms to mice in non-mouse-sensitized workers (odds ratio = 30.8, p = 0.003). We conclude that airborne endotoxin is associated with respiratory symptoms to mice in non-mouse-sensitized scientists and technicians.

Evaluation of concurrent personal measurements of acrylonitrile using different sampling techniques.

In a retrospective assessment of employee exposure to acrylonitrile (AN) for an epidemiological study, investigators from the National Cancer Institute (NCI) and the National Institute for Occupational Safety and Health (NIOSH) evaluated the feasibility of using historic acrylonitrile air samples without modification. The evaluation discussed here was to determine whether the air sampling results across plants were comparable. During site visits to each plant conducted between 1984 and 1986, study investigators collected personal air samples for four days on approximately ten jobs per day. During these visits, IHs at seven of the eight plants also collected personal samples to compare their sample values to the study-collected sample values. Each plant's IH collected these concurrent measurements for their own use and independent of the IHs at the other plants. The plant IHs had no common sampling protocol but, rather, used professional judgment in deciding sampling logistics for their concurrent measurement. In addition, each plant IH used a different laboratory to analyze samples (the study industrial hygienists used one laboratory). Three sampling methods were used by plant industrial hygienists to collect concurrent measurements: charcoal tubes, passive monitors, and porous polymer tubes. The study investigators only used charcoal tubes. Two hundred and sixty four (264) pairs of concurrent measurements were collected. To assess the +/- comparability of the data sets, paired-observation tests were used. The two sets of charcoal tubes were found to compare favorably with each other. The study's charcoal tubes were 1.2 times higher than results from plant passive monitors. No correlation was found between the study's charcoal tube results and plant porous polymer tube results, although the means for 34 pairs of samples were equivalent. As a result of this evaluation, the investigators decided that no adjustments would be made to the plant measurements. This type of evaluation should be considered when using measurement data in multisite epidemiological studies.