Oak processionary the same manner. Oak is its preferred food source, but the moth also eats the leaves of hazel, hornbeam, sweet chestnut, birch and beech. The moths pose an increasing threat to humans as their range is extended. The backs of older caterpillars (3rd to 6th instars) are covered with up to 63,000 pointed defensive bristles, which contain an urticating toxin (e.g., the protein thaumetopoein). The setae break off readily, become airborne and can cause epidemic caterpillar dermatitis (lepidopterism), manifested as a papular rash, pruritus, conjunctivitis and, if inhaled, pharyngitis and respiratory distress, including asthma or even anaphylaxis; however, as of
California Office of Environmental Health Hazard Assessment against expansion of OEHHA: OEHHA's vision is to be California's leading scientific organization for evaluating risks to human and ecological health. OEHHA's goals as a governmental agency include: OEHHA assesses the risk of environmental chemicals based on health considerations alone. In contrast, risk managers consider economic and technical feasibility as factors in their decisions. This separation is essential to prevent undue political influence on the evaluation of health risks. These factors are and should remain explicitly excluded from the assessment of risk. OEHHA plays a critical and unique role that allows for the separation of risk assessment and hazard evaluation