Respiratory allergy to laboratory fruit flies (Drosophila melanogaster).

Workers in a scientific laboratory, complaining of respiratory symptoms related to their contact with fruit flies, were tested to detect allergy to these insects. Seven of 22 of these individuals had respiratory symptoms, and six of these seven demonstrated both immediate-type skin reactions and positive RAST results. Nasobronchial challenge tests elicited responses also in six of the seven exposed workers with symptoms. Neither the majority of the exposed group without symptoms nor the nonexposed control group reacted to the skin test, RAST, or nasobronchial challenge. Specificity of the fruit-fly allergen and its presence in the dust of the laboratory cultivation room were confirmed by RAST-inhibition experiments. The present results reflect the high prevalence of occupational respiratory disease caused by an IgE-mediated allergy induced by the contact with laboratory fruit flies and fruit-fly cultures.