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
Health Hazard Evaluation Program Health Hazard Evaluation Program The Health Hazard Evaluation (HHE) program is a workplace health program administered by the National Institute for Occupational Safety and Health (NIOSH). NIOSH developed the HHE program to comply with a mandate in the Occupational Safety and Health Act of 1970 to investigate workplace health hazards reported by employers and employees. According to Section 20(a)(6) of the Act, the Secretary of Health and Human Services is authorized "following a written request by any employer or authorized representative of employees, to determine whether any substance normally found in the place of employment has potentially toxic effects in