Oak processionary moth: The poisonous hairs of this caterpillar irritate the skin and respiratory tract!

In many parts of Germany and Austria there are currently warnings about the oak processionary moth - how dangerous is it really?

The insect has possible health effects from the 3rd larval stage. From here on, the stinging hairs on the back of the oak processionary moth contain the allergy-causing poison ( thaumetopoein ). Contact with leaves or wind movements can cause the hair to break off and fall to the ground. The wind can then cover short or long distances (several 100 m) before the hair hits the ground or can be picked up in some other way. From here it CAN potentially become “dangerous”. For both humans and dogs.

When and where can the oak processionary moth be found?

Depending on the weather (it should have been dry and warm for a long time), the time for the critical 3rd larval stage must be dated differently each year and differentiated specifically according to the regions in Germany and Austria. The beginning of summer (beginning of May) is usually an approximate value, but this is increasingly shifting as a result of climate change. Pupation finally takes place in June in nests on the tree.

The caterpillar is a so-called health or hygiene pest and can be found on all types of oak It is more common in the south and center of Germany than in the north. However, as a result of global warming, monitoring also shows a significant increase in northern Germany.

• Forest edges
• sports ground
• Swimming pool
• Children's playground
• Camping facilities
• Parking spaces
• Green strips/parks
• etc.

In urban areas as well as in the countryside or in the forest. The nests in which the caterpillars retreat to pupate are located on the trunk and at the upper branch forks. These nests remain after the butterflies have “moved out” and can still contain active stinging hairs years after colonization, so the problem actually exists all year round if the nests are close to the ground.

So is the oak processionary moth dangerous for humans and dogs?

The allergic reaction of the immune system can vary greatly from person to person . The oak processionary moth can have a minor impact on the health of dogs or humans or can also pose a (massive) threat. The spectrum of danger depending on the individual way it works in the body .

Symptoms include :

• Local skin rashes (caterpillar dermatitis), which manifest themselves as local skin redness, slight swelling, severe itching and burning. Blisters often form in the affected areas.
• Irritation of the mouth and nasal mucosa due to inhalation of hair, which can lead to coughing and asthma.
• Other symptoms such as dizziness, fever, fatigue and conjunctivitis due to irritation of the eyes can also occur.
• In rare cases, allergic shocks also occur.

The caterpillars' stinging hairs contain the protein thaumetopoein. The hairs penetrate the skin mechanically (similar to stinging nettle) and thus spread the substance biochemically throughout the body.

Areas of skin on the snout or in the mouth are particularly affected. The eyes or paws and hands (especially in children) also represent a potential contact point.

If the hair enters the body with food, irritation/swelling of the tongue and esophagus is possible.

What should you do if you come into contact with the caterpillars or a nest?

Of course, you should consult a doctor or veterinarian immediately to describe the possible suspicion or incident. Everything else can only be determined by the individual reaction of the person, the dog, the cat or even the horse.

The severe cases in humans represent a major challenge for doctors, as the individual reaction required an equally individual approach to treatment and the lack of experience with the pest made targeted therapy difficult. Cortisone is often the drug of choice.

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