Two-spotted Spider Mite as a Factor for Occupational Asthma in Nonfarmer Apple-packing Workers.

Few cases of asthma caused by the two-spotted spider mite (TSM) have been reported among nonfarmer apple-packing workers. This study investigated whether allergic sensitization due to the TSM occurs in workers at the Agricultural Products Processing Center. The polymerase chain reaction was used to analyze apples and leaves provided to the Agricultural Products Processing Center for the presence of TSM. Skin prick tests using TSM antigen were administered to 10 workers, and serum levels of total immunoglobulin E (IgE) and specific IgE for TSM antigens were quantified. Of the 10 workers, four tested positive for TSM in the skin prick test, three had elevated total IgE levels, and one had also elevated specific IgE levels to TSM. This confirms that apple-packing workers risk allergic sensitization due to TSM exposure. Preventive measures are recommended not only for apple farmers but also for nonfarmer apple-packing workers.