Oak processionary moth: Protecting cats from spring and summer risks
Oak processionary moth caterpillars, or OPM, are an invasive species primarily found on oak trees, especially in South East England. Active from May through July, these caterpillars pose a notable health hazard for cats due to their thousands of tiny, toxin-laden hairs.
These hairs contain a substance called thaumetopoein, which can cause severe irritation and allergic reactions not only in humans but also in pets such as cats. Even indirect exposure—through airborne hairs shed by the caterpillars—can be dangerous.
It is vital for cat owners across the UK to understand OPM, how it affects cats, and what steps can be taken to protect beloved feline companions.
What Are Oak Processionary Moth Caterpillars?
OPM caterpillars get their name from their unique behaviour of moving nose-to-tail in lengthy processions. They build distinctive white silken nests on oak trees and are mainly prevalent in Southeastern England but are increasingly spreading to other regions.
The caterpillars are covered in long white irritating hairs interspersed with shorter ones. These microscopic hairs can detach easily and become airborne, presenting a risk to cats even without physical contact.
Why Are Oak Processionary Moth Caterpillars Dangerous to Cats?
The hairs of these caterpillars contain the toxin thaumetopoein, which causes itchiness, inflammation, and allergic reactions. Exposure can lead to symptoms such as skin rashes, swelling of the tongue or nasal passages, eye irritation like conjunctivitis, drooling, and respiratory distress from swelling of airways.
Most severe symptoms arise from direct contact, such as when a cat climbs infested oak trees or sniffs caterpillars on the ground. However, airborne hairs can also provoke milder irritation.
How Might Cats Be Exposed?
Cats that roam outdoors, especially in areas with many oak trees, are at risk. Curious cats often investigate nests or processions on trees and on the ground. The hairs easily disperse by wind and can settle on a cat’s fur or face, which can be ingested during grooming.
Areas in Southeastern England are typically higher risk, though potential spread means all cat owners should be aware during spring and summer months.
Recognising Symptoms of OPM Exposure in Cats
- Excessive drooling or pawing at the mouth
- Swollen tongue, lips or nasal tissues
- Eye redness, irritation, or conjunctivitis
- Itchy skin rashes or dermatitis
- Breathing difficulties or coughing
- Vomiting or gagging
If you notice these signs, seek veterinary advice promptly as respiratory distress or swelling may require emergency treatment.
What To Do If Your Cat Is Exposed
- Remove your cat from the area to prevent further contact.
- Gently wipe or bathe your cat to remove any hairs, using lukewarm water—avoid harsh rubbing which can spread irritants.
- Monitor your cat closely for any signs of distress or worsening symptoms.
- Contact your vet immediately if symptoms such as difficulty breathing, swelling, or excessive drooling appear.
- Do not attempt to remove caterpillar nests yourself to avoid spreading hairs and risking your own safety.
How to Protect Your Cat from OPM
- Keep cats indoors or supervise their outdoor time during May to August.
- Avoid known OPM-infested oak trees or areas displaying white silken nests.
- Stay updated on local OPM reports and warnings from authorities such as The Forestry Commission.
- Report sightings of OPM nests or caterpillar processions to official channels to aid management efforts.
- Clean your hands and clothes after outdoor activities in oak-rich environments to reduce risk of hair transfer.
Why Is This Becoming More of a Concern?
First recorded in the UK in 2005 as an invasive species, OPM caterpillars have since established breeding populations and are spreading beyond their initial Southern strongholds. Climate changes and human activity have facilitated this expansion, increasing the likelihood of encounters with pets.
As public awareness grows, vet clinics report occasional cases of OPM exposure in cats, underscoring the importance of vigilance and education.
Summary Table: Protecting Cats from Oak Processionary Moth
| Situation | Recommended Action |
|---|---|
| Known OPM presence in area | Limit outdoor access or supervise cats; avoid oak trees |
| Suspected cat exposure | Wash cat gently and contact vet promptly |
| Spotting nests or caterpillars | Report to Forestry Commission via official site |
| Symptoms of irritation or respiratory distress | Seek emergency veterinary care immediately |
Conclusion
Oak processionary moth caterpillars pose an emerging risk to outdoor cats during the UK spring and summer months due to their toxic hairs containing thaumetopoein. Understanding the threat, recognising symptoms early, and practising preventative measures are vital steps to safeguarding your cat’s health. Always seek veterinary care promptly if exposure is suspected, and help local authorities by reporting any sightings of this invasive species.
