Acute exposure to swine dust causes bronchial hyperresponsiveness in healthy subjects.
Six urban subjects, with little or no previous experience of farm-work, were exposed to dust while weighing swine for 2-5 h. Three subjects experienced toxic symptoms 4-5 h after the beginning of exposure. Bronchial responsiveness increased in all subjects within 6 h (more than three doubling steps difference in a methacholine test). One week later, airway responsiveness had partly normalized. The mean (interquartile range) cumulative dose of methacholine causing a 20% decrease in forced expiratory volume in one second (FEV1) was 3.1 (1.0-6.6) mg, before exposure, fell to 0.13 (0.01-0.76) mg 6 h after exposure (p < 0.02), and was 0.99 (0.42-1.5) mg one week later (n = 5, p < 0.05), Mean (SD) FEV1 decreased 5 (2)%. The concentration of total dust varied between 9 and 14 mg.m-3 and of endotoxin between 0.1 and 0.5 mu g.m-3. Thus inhalation of swine farm dust, caused a marked increase in bronchial responsiveness in non-sensitized subjects.
Malmberg
P
P
National Institute of Occupational Health, Solna, Sweden.
Larsson
K
K
D000328:Adult; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000209:etiology*; D001985:Bronchial Provocation Tests; D004391:Dust / Q000009:adverse effects*; D004731:Endotoxins / Q000009:adverse effects*; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D012129:Respiratory Function Tests; D013552:Swine; D013997:Time Factors
D004391:Dust; D004731:Endotoxins; D016210:Methacholine Chloride