The oak processionary caterpillar can cause a lot of nuisance. The culprits in this pest are not the caterpillars themselves, but their so-called nettle or stinging hairs.
Each caterpillar has about 700,000 hairs that break off easily and can be spread with the slightest breath of wind. Especially from mid-May to June when the insects get hair, a lot of hairs come into the air. In July to September, hair can blow out of the empty nests. These are virtually invisible to the naked eye.
So you do not have to have been in direct contact with the caterpillars to get complaints. The stinging hairs blow through the air and penetrate the skin, eyes and respiratory tract with their barbs. Not everyone suffers from this equally. But especially people who come into frequent contact with the stinging hairs or who are allergic can suffer from irritation.
Complaints
Most people experience itching and/or rash. Sometimes this occurs quickly, often it takes a few hours before the first symptoms appear. Annoying, but not really dangerous. Most complaints disappear after a few days. When you have inhaled the stinging hairs, you may experience an irritated nose or throat. Your eyes may also become irritated.
Some people are allergic and react much faster and more fiercely to the stinging hairs. Then it is wise to consult your doctor. He or she may prescribe an antihistamine to combat the allergy.
Appearance
It is best not to cycle or walk under trees with caterpillars and avoid nature areas where the caterpillars are. Old nests with stinging hairs can still be found in the trees that were infected last year. If you can’t get around it, cover your arms, legs and neck as much as possible. Do not sit on the floor.
Leave the caterpillars and nests alone and do not touch them, including dead caterpillars on the ground. If you come into contact with the hair, do not rub or scratch, but wash or rinse your skin and eyes with water. Some people also recommend stripping your skin with masking tape first to remove the hairs. It is best to wash your clothes properly, for example in the washing machine at 60 degrees.
Sources:
• Report ‘Health consequences of exposure to stinging hairs of the oak processionary caterpillar’
• RIVM brochure
