Seafood allergy in South Africa: studies in the domestic and occupational setting

Background: Increased consumption of seafood due to the promotion of a healthy diet and increased processing of seafood to meet these domestic consumption needs, has lead to more frequent reporting of allergic reactions. The spectrum of seafood allergy associated with domestic and occupational exposure in the South African setting was investigated. Methods/data base:In vitro studies were conducted on sera of 80 subjects reporting allergic symptoms associated with ingesting seafood. The distribution of positive immunoglobulin E (IgE) responses was evaluated (by UniCAP-RAST) as well as patterns of concurrent reactivity and cross-reactivity (by Western-blotting) to different seafood groups, commonly encountered in South Africa. The contribution of occupational factors was investigated through a postal survey of 68 seafood-processing workplaces. Results: Patterns of IgE sensitization indicate that the majority of subjects (50%) were positive to crustaceans, 30% to molluscs, and 20% to fish species. More than half of the individuals reacted to one seafood group, 36% to two seafood groups, and 11% to all three seafood groups. The complexity of immune responses to finfish and mollusc species was evident in the different allergen profiles obtained for fresh and cooked seafood. The strongest immune response among the four tested fish species was to hake – the most common seafood processed in workplaces and therefore likely to pose an allergenic hazard to workers in the seafood processing industry. Among seafood processing factories the prevalence of work-related skin symptoms per workplace was substantially higher (0%–100%) than that for asthmatic (0%–5%) and other allergic symptoms (0%–37%). Conclusions: Our preliminary investigations into the spectrum of seafood allergy in South Africa indicate that the potential of local seafood species in causing sensitization, either through ingestion, skin contact or inhalation are important considerations when investigating seafood allergy in the domestic or occupational setting