Oak Processionary Moth in Germany: Health Risks and How to Stay Safe

Introduction

If you are spending time in parks, forests, or gardens in Germany this spring and summer, there is a local hazard worth knowing about: the oak processionary moth (Eichenprozessionsspinner). This caterpillar looks unremarkable, but its microscopic stinging hairs can cause significant health problems — skin rashes, eye irritation, and in some cases serious allergic reactions or breathing difficulties. As the species continues to spread across Germany, expats who have not encountered it before should know how to recognize and avoid it.

What Is the Oak Processionary Moth?

The Eichenprozessionsspinner is a moth whose caterpillars live in colonies on oak trees, moving in characteristic procession-like lines — hence the name. The caterpillars develop from April onwards and are most active between May and July. They produce vast quantities of tiny barbed hairs (Brennhaare) that contain a protein called thaumetopoein, which triggers inflammatory reactions on contact.

These hairs are not just a problem when you touch the caterpillar directly. They detach easily and are carried by the wind, meaning you can be affected simply by walking beneath an infested oak tree without ever seeing the caterpillar.

Over the past decade, the Eichenprozessionsspinner has expanded its range significantly northward and westward across Germany, driven by warmer summers and milder winters associated with climate change. Areas including North Rhine-Westphalia, Brandenburg, Berlin, and Saxony-Anhalt have reported increasing infestations.

What Health Risks Do They Pose?

Contact with the hairs — whether through skin, eyes, or inhalation — can cause:

• Skin reactions: Intense itching, redness, and a nettle-rash-like eruption that can last days
• Eye irritation: Conjunctivitis and in severe cases more serious inflammation
• Respiratory symptoms: Coughing, difficulty breathing, and in rare cases asthmatic attacks
• Allergic reactions: People with existing allergies or asthma are at higher risk of severe responses

Pets and other animals are also vulnerable, particularly dogs that sniff around the base of infested trees.

How to Identify Infested Trees and Stay Safe

The caterpillars are grey-brown with red-tipped hairs and typically found on oak trees between April and July. Signs of infestation include:

• White, silky nests on tree trunks or in the forks of branches
• Lines of caterpillars moving head-to-tail along bark
• Warning signs posted by local authorities (many German cities and municipalities mark infested trees)

Practical steps to protect yourself:

1. Do not touch nests, caterpillars, or bark in areas with visible infestation — even with gloves, as hairs can penetrate many fabrics
2. Keep distance from oak trees showing warning signs, especially on windy days
3. Cover up in known infestation areas: long sleeves, closed shoes, and glasses or sunglasses offer some protection
4. Shower and change clothes if you think you may have been exposed
5. Do not attempt to remove nests yourself — this is a job for trained pest control professionals and municipal services

If you live in or near an area with known infestations, check your local municipality's website or app — many German cities (including Berlin and Cologne) publish infestation maps during the season.

What to Do If You Are Exposed

If you or a family member develops symptoms after being near oak trees:

• Rinse the affected skin or eyes with plenty of water
• Remove and wash clothing that may carry hairs (40°C wash minimum)
• Contact your GP (Hausarzt) or an urgent care clinic (Notaufnahme) if symptoms are severe, especially any breathing difficulties
• For mild reactions, antihistamine cream or tablets can help — ask your pharmacist (Apotheke)

Do not attempt to treat severe allergic reactions at home. Call the emergency number 112 if someone is having difficulty breathing.

Frequently Asked Questions

Are there areas in Germany where the risk is higher?

Yes. The Eichenprozessionsspinner is most prevalent in eastern and central Germany, including Berlin, Brandenburg, and Saxony-Anhalt, as well as parts of North Rhine-Westphalia. However, the range is expanding, and infestations are increasingly reported in areas where they were previously rare. Check with your local Ordnungsamt or municipality for current local information.

Can my dog or cat be affected?

Yes. Pets that sniff or roll near infested trees can pick up hairs on their fur or in their mouths and eyes. Symptoms in animals include excessive pawing at the face, drooling, and skin irritation. Contact your vet if you suspect your pet has been exposed.

Conclusion and Next Steps

The oak processionary moth is a genuinely underappreciated health hazard for people new to Germany. The risk peaks between May and July but can persist as long as nests remain on trees. Staying informed about local infestation reports, recognizing warning signs on trees, and knowing the basic response steps are the most practical things you can do to protect yourself and your family this season.

Source: Tagesschau