High Prevalence of Sensitization to Mites and Insects in Greenhouses Using Biologic Pest Control

Background Mites and insects are widely used as biologic pest control in greenhouses. A few studies have reported sensitization to mites among greenhouse workers, but the prevalence of sensitization to pest control insects is not known. Objective We aimed to determine the prevalence of IgE-mediated sensitization to pests and their control organisms in the population of exposed greenhouse workers and the relationship between sensitization and allergic symptoms. Methods In a cross-sectional study, we interviewed 117 tomato and cucumber greenhouse workers from eight companies that use biologic pest control. Sensitization to nine organisms was assessed by serum-specific IgE measurement. We also measured fractional exhaled nitric oxide. Results The prevalence of specific sensitization to pests and pest control organisms was 50%; to mites, 29%; and to insects, 46%. Of the individual species, Macrolophus pygmaeus insect sensitization had the highest prevalence (46%). Asthma symptoms were significantly associated with sensitization to pest and pest control organisms (odds ratio [OR] = 3.9; 95% confidence interval [CI], 1.2-12.5) and with a fractional exhaled nitric oxide level of 25 ppb or greater (OR = 4.8; 95% CI, 1.7-13.8), indicating eosinophilic airway inflammation. Southeast Asian origin was significantly associated with sensitization (OR = 5.1; 95% CI, 2.1-12.1) and rhinitis (OR = 2.8; 95% CI, 1.2-6.3). Conclusions Tomato and cucumber greenhouse workers were commonly sensitized to predatory insect M pygmaeus and pest control mites. Our findings stress the importance of surveilling and preventing work-related allergic diseases among greenhouse workers.