Hymenoptera stings and serum venom-specific IgE in Japanese Pest-control operators

Pest-control operators represent a high occupational risk for Hymenoptera sting and a possibility of Hymenoptera allergic reactions, but the information is not well documented. A history of Hymenoptera stings was found in 118 (59.0%) of 200 Japanese pest-control operators. To evaluate the details of Hymenoptera stings and the factors associated with venom-specific IgE level which indicates Hymenoptera allergy, a questionnaire was administered and serum venom-specific IgE levels were measured in 105 subjects selected from 118 operators. The number of past stings was a mean of 3, and in most cases, they had been stung at only one site on the hand or the head and neck. Systemic reactions to Hymenoptera stings were also less frequent among them (5/105). Venom-specific IgE (to a yellow jacket, a wasp, and a honeybee) was measured by the CAP system, and it was found to be positive in 31.4% of the 105 subjects. The frequency of positive CAP was significantly associated with the following factors: the total serum IgE level (P<0.001), the time interval from the last sting-incident (P<0.001), the number of past stings (P<0.05), the most recent clinical symptoms (P<0.05), and an individual atopic history (P<0.05). Among these 5 factors, the former 4 factors were shown to influence the venom-specific IgE titer in the multiple-regression analysis using a forward-stepwise technique (multiple R=0.708, adjust R(2)=0.482, P<0.001). In particular, the influences of the total serum IgE level and the time interval were strong. These findings indicate that the frequency of Hymenoptera stings in pest-control operators is not as high as in beekeepers or forestry workers, and that venom-specific IgE is affected mainly by the total serum IgE level and the time interval from the last sting-incident.