Occupational allergy and asthma among table grape farm workers in the Hex-river Valley, Western Cape

Thesis (MTech (Environmental Health))--Peninsula Technikon, Cape Town, 2003Recent studies have reported an increased prevalence (19%) of respiratory symptoms among furm workers exposed to pesticides. International studies suggest excessive pesticide use and biological factors such as outdoor mites as important factors responsible for asthma symptoms. Studies in Korea suggest that spider mites may be responsible for allergic asthma symptoms among workers on fruit (citrus, apple, and . pear) furms. The fuming of wine and table grapes in South Africa involves about 3000 farms employing over 50,000 workers. Workers on table grape farms, in contrast to other fruit farms have not been previously investigated for occupational respiratory allergy to spider mites. Objectives • To determine the spectrum and prevalence of work-related allergy and asthma among table grape farm workers • To determine the environmental and host factors associated with work-related symptoms and allergic outcomes. Methods: A cross-sectional study was conducted on 207 workers employed on nine table grape farms in the Hex River valley of South Africa. A modified European Community Respiratory Health Survey questionnaire was used to interview workers. Skin prick tests used 8 commercial extracts of common airborne allergens (ALK) and potential occupational allergens, which included grape mould (Botrytis cinerea) and an in-house extract of spider mite, Tetranychus urticae. Specific IgE to Tetranychus urticae was determined using enzyme-linked immunosorbent assay (ELISA) and to house dust mite (Dermatophagoides Pteronyssinus) and storage mite (Lepidoglyphus Destructor) using Pharrnacia CAPRAST. Results: The mean age of the workers was 36 years with a standard deviation of 11 years