RESPIRATORY HEALTH AND IMMUNOLOGICAL PROFILE OF POULTRY WORKERS

Objectives. To examine work-related respiratory symptoms in poultry wo rkers, and to test for immunologically mediated responses to poultry-r elated agents. Design. A cross-sectional survey of differentially expo sed poultry workers and unexposed blue-collar workers. Setting. Three poultry farms and a poultry plant in Gauteng (exposed workers) and a m unicipal workers' clinic In Johannesburg (controls). Participants. 134 poultry workers (85.4% of all eligible workers) and 122 controls (> 9 5% response rate). Outcome measures. Respiratory symptoms plus allergy and hypersensitivity to poultry agents identified by skin-prick tests , and by the presence of specific IgE and IgG enzyme-linked immunoflow assay and nonspecific (radial immunodiffusion) antibodies. Results. S moking habits and atopic status were similar in the poultry workers an d the controls. Symptoms were very common in poultry workers, for exam ple work-related in 32% and work-related wheeze in 23% of highly expos ed workers. Significantly more poultry workers than controls complaine d of chest symptoms (increasing with increasing exposure), and of eye, skin and nose irritation at work. More poultry workers than controls had symptoms consistent with asthma (e.g. 3%, 4%, 13% and 11% in contr ols and subjects with low, medium and high exposure, respectively), an d symptom complexes associated with organic dust exposure. Five poultr y workers had positive skin-prick test reactions to poultry-specific a ntigens, but none of the unexposed controls reacted. More poultry work ers than controls had positive immunodiffusion test reactions to chick en feed, feathers and serum, and IgE to chicken faeces. There was no a ssociation between immunological status and respiratory symptoms. Conc lusions. We found a very high prevalence of exposure-related symptoms in poultry workers; improved hazard control is strongly indicated. Tes ts of allergy and hypersensitivity were associated with exposure, but not with disease. The possibility of useful tests of sensitisation has not been excluded; a prospective study design is likely to be more re warding than cross-sectional approaches such as in this study.