Occupational allergies in the seafood industry--a comparative study of Australian and South African workplaces

Although seafood allergy due to ingestion is commonly observed in clinical practice, the incidence of seafood allergies in general and more specifically in the occupational setting in Australia is largely unknown. The work practices, occupational health services and allergic health problems in 140 seafood processing workplaces in Australia were examined and compared to previous studies in South Africa. A cross-sectional employer-based survey design was used to conduct the study in both countries. In the South African study a response rate of 60% (n = 41) was obtained, compared to a response rate of 18% (n = 140) in Australia. The most common seafood processed by workplaces in South Africa was finfish (76%) and rock lobster (34%). Similarly in Australia, finfish (34%) was the most frequently handled seafood. However, processing of prawns (24%) and oysters (21%) was more common in Australia. Common work processes in South Africa involved freezing (71%), cutting/filleting (63%) and degutting (58%) procedures. Similar processes were followed in Australian industries with the exception of shucking of oysters, particularly common in the aquaculture industries. About half of the workplaces in both countries provided an occupational health service and medical surveillance of workers. However, none of the workplaces in South Africa and only 9% of the workplaces in Australia had industrial hygiene programs for seafood aerosols in place. In both countries positive trends were observed between the size of the workforce and the provision of occupational health services (p<0.005). Similarly, skin rash accounted for highest of all reported health problems (78-81%) followed by asthmatic symptoms (7-10%) and other non-specific allergic symptoms (9-15%) in both countries. Most workplaces reported the annual prevalence of work-related symptoms to be less than 5%. In Australia 7% of respondents in workplaces reported workers having left their workplace due to work-related allergic problems. Despite a low response rate of contacted companies in Australia, there were great similarities between the two countries suggesting that there is a significantly elevated prevalence of work related allergic symptoms in both countries. Unexpectedly, mollusc processing was more common in Australia although the occupational health related effects among exposed workers has previously not been investigated in detail and merits further study. It is recommended that further epidemiological studies focus on seafood exposure in Australia and identify specific risk factors for sensitisation.