AN OVERVIEW OF THE INDIGENOUS AND ALIEN ALLERGENS OF SOUTHERN AFRICA

Since the allergens causing clinical disease in Southern Africa were first identified in 1956 there has been a steady rise in the prevalence of allergic diseases in all populations. Although initial allergens were found to represent alien or introduced species, e.g. Bermuda grass, maize, lucerne, it later became apparent that indigenous allergens were also allergenic. Other major alien allergens which were imported into our region include oak, plane, pine and eucalyptus trees, the American, German and Oriental cockroaches, and fruits, e.g. kiwi and olive. The first truly African indigenous pollen allergen to be characterised was kikuyu grass (Pennisetum clandestinum) followed by buffalo grass (Stenotaphrum secundatum). Subsequently indigenous food allergens identified and characterised include abalone (Haliotis midae), cobra venom (Hemachatus hemachatus), mopane worms (Imbrasia belina), Rhodesian flame lily, Locusta migratoria and the African penguin (Spheniscus demersus). Several indigenous food sources are suspected to be causing food allergies in Botswana and are currently being investigated for allergenicity. In addition to the indigenous allergens described in this overview, South African researchers have also contributed to investigating and understanding the immunogenicity of other 'global allergens' such as Imbuia wood, verbena hybrida and Anisakis. The database of the aerobiology of the region shows a wide diversity of pollen and mould allergens.