OCCUPATIONAL ALLERGIC DISEASE IN CEREAL WORKERS BY STORED GRAIN PESTS

It is well known that workers occupationally exposed to grain dust hav e a high prevalence of respiratory symptoms, but their pathogenesis re mains obscure when sensitization to cereal flour cannot be demonstrate d. Storage mites, tenebroids, and cockroaches are stored-grain pests f ound in grain and cereal products frequently in our area, where the ce real industry is the most important industry. An epidemiological analy sis of sensitization to these stored-grain pests was performed on 4379 patients residing in an area of cereal industries. Fifty grain worker s were selected for in vivo diagnostic tests with nine genera of mites , Tenebrio molitor and Blatta orientalis. Specific IgE antibodies to t he extracts were demonstrated by prick tests and RAST. Association bet ween respiratory symptoms and occupational exposure was confirmed by c hallenge tests (specific and methacholine). The prevalence of mite sen sitization in the total sample studied (4379) was 18.96% (SEM 0.58, 95 % CI 16.93-19.19). The prevalence of sensitization to storage mites am ong mite-sensitive patients was 11.88% (SEM 1.15, 95% CI 9.63-14.3). A mong the 50 selected patients the most frequent sensitization was that to Dermatophagoides pteronyssinus (58%), followed by Dermatophagoides frinae (48%), Lepidoglyphus destructor and Tyrophagus putrescentiae ( 38%), Blomia kulagini (34%), and Acarus siro and Chortoglyphus arcuatu s (24%), In addition, 22% of the patients presented negative prick tes ts and RAST for Dermatophagoides species with positive test to storage mites. Fifty percent of the 50 patients were sensitizated to Tenebrio molitor (SEM 0.7, CI 95% 36-64), and 36% to Blatta orientalis (SEM 0. 67, CI 95% 23-49). The identification of mites, tenebroids, and cockro aches in dust samples yields useful data for the diagnosis of our pati ents.