Health hazards to timber and forestry workers from the Douglas fir tussock moth

A heavy infestation of the tussock moth caterpillar (Orgyia pseudotsugata McDonnough) in forested areas of Oregon was associated with itching of the skin and eyes, nasal discharge, cough, and, at times, respiratory difficulty, Personal interviews and inspection of forty-one occupationally exposed persons were supplemented by a questionnaire administered to 428 individuals, composing three groups at various degrees of risk and a control group. There was a cause and effect relationship between the adverse symptoms and the exposure to tussock moth larvae. The specific etiologic agent was not identified, but it was felt that the secretion, hairs, or other substances in the larvae or cocoons of the moth acted as a potent allergenic substance and, for some persons, was also a primary skin irritant.