Occupational exposure to pigs greatly increases workers' risk of swine influenza virus infection. Swine workers should be included in pandemic surveillance and in antiviral and immunization strategies.

Numerous articles have been published regarding the adverse respiratory health consequences of working in intensive livestock and poultry housing. Threshold limit exposure guidelines are not currently applied to this environment, but they are essential to implement and monitor effective environmental controls. Previous dose-response research work with swine workers has resulted in exposure limit recommendations of 2.5 mg/m3 total dust, 0.23 mg/m3 respirable dust, 100 EU/m3 endotoxin, and 7 ppm ammonia. No similar recommendations have been reported previously for poultry workers. Therefore, an industry-wide study was conducted to examine dose-response relationships of bioaerosol exposures and worker respiratory health. A total of 257 poultry workers were studied for respiratory symptoms, pulmonary function, and exposure to dust (total and respirable), endotoxin (respirable and total), and ammonia. Details of the sampling plan and environmental assessment are described elsewhere. Relationships between exposures and response were studied by correlation and multiple regressions. Significant dose-response relationships were observed between exposures and pulmonary function decrements over a work shift. Exposure concentrations associated with significant pulmonary function decrements were as follows: 2.4 mg/m3 total dust, 0.16 mg/m3 respirable dust, 614 EU/m3 endotoxin, and 12 ppm ammonia.

Farmers are known to be at high risk for the development of occupational airway disease. The aim of this European study was to determine which airway symptoms predominate in different types of animal farmers (cattle, pigs, poultry, sheep) and to compare the prevalence of symptoms to the general population.A total of 6,156 randomly selected animal farmers in Denmark, Germany (SchleswigHolstein, Niedersachsen), Switzerland, and Spain completed a questionnaire on respiratory symptoms and farming characteristics in 1995±1997. The prevalence of general respiratory symptoms was compared to the results of the European Community Respiratory Health Survey (ECRHS) obtained in the same regions.Pig farmers were at highest risk for the development of work-related symptoms. A signi®cant dose-response relationship between daily hours worked inside animal houses and symptoms was established for pig and poultry farmers. Additionally, self-reported nasal allergies (odds ratio (95% con®dence interval): 3.92 (3.26±4.71)) and nasal irritation during work (3.98 (3.35±4.73)) were shown to be associated with the development of chronic phlegm. The prevalence of wheezing, shortness of breath, asthma and nasal allergies was sign®cantly lower among all farmers in the age group 20±44 yrs than among the general population. However, the prevalence of usually bringing up phlegm in winter among farmers was signi®cantly higher than in the general population (9.4 (8.3±10.5%) versus 7.5 (6.5±8.5%)).Individual factors have been shown to be related to the prevalence of chronic phlegm among farmers. Additionally, this study could support the hypothesis that farming could be negatively related to allergic diseases. Eur Respir J 2001; 17: 747±754.