Pine processionary caterpillars: the veterinary emergency for dogs in Île-de-France, summer 2026

A TF1 news report broadcast at the end of June 2026 shows pharmacists in Rambouillet running out of corticosteroids, antihistamines and soothing creams in a single day: "we were overwhelmed, we've never seen anything like it". At the same time, Prefectoral Order SIDPC no. 2026-045 signed by the prefect of Yvelines extends the partial closure of the Rambouillet forest until 5 June 2026, and new departmental orders are multiplying in Essonne, Val-d'Oise and Seine-et-Marne. Behind these images lies a reality that is still too often underestimated by owners: in France, every year, dogs die or lose part of their tongue after a simple contact with a pine processionary caterpillar. With the July-August 2026 activity peak approaching, here is what you need to know to protect your pet — and what to do in the minute after contact, before reaching the vet.

Key point: the pine processionary caterpillar (Thaumetopoea pityocampa on pines, Thaumetopoea processionea on oaks) releases millions of microscopic urticating hairs containing a heat-stable protein called thaumetopoein. In dogs, intoxication can lead to tongue necrosis in under 2 hours, sometimes fatal without immediate treatment.

Why summer 2026 is especially high-risk

Spring 2026 has stacked up the factors that fuel the demographic explosion of the oak processionary caterpillar — the species most involved in veterinary emergencies in the Paris region this season:

• Mild 2025-2026 winter and wet spring: excellent hatching conditions for eggs laid last summer.
• Early heatwave end of May-early June: acceleration of the larval cycle, caterpillars descend earlier from the tops of the oaks.
• 4th heatwave of 2026 confirmed by Météo-France: favouring the "procession of pupation", the moment when caterpillars leave the tree in a single file to bury themselves in the soil.
• Decree of 25 April 2022 classifying the processionary caterpillar as an animal harmful to human health: this status has not yet curbed the population dynamics.

Result: according to data relayed by TF1 and the ARS Île-de-France, the Rambouillet, Senart, Fontainebleau, Fausses-Reposes forests and the Meudon woods concentrate this summer 2026 exceptional infestation levels. The Rambouillet forest had to be partially closed to the public by prefectoral order, and the Île-de-France region has recorded a record number of veterinary reports in the first six months of the year.

Worth knowing: the oak processionary caterpillar (Thaumetopoea processionea) is now more problematic in the Paris region than the pine one (T. pityocampa), because oaks are everywhere in Île-de-France forests, in suburban areas, and even in the cities themselves.

The specific danger for dogs: why it is an absolute emergency

The dog is the animal most exposed to the serious consequences of the processionary caterpillar, for three reasons:

1. Olfactory and oral curiosity: dogs explore their environment with their muzzle and tongue. They sniff, lick, sometimes bite the caterpillars in procession or the nests that have fallen to the ground. This is precisely the most vascularised area of the body, where the urticating hairs penetrate the deepest.
2. Highly reactive lingual mucosa: the thaumetopoein released by the urticating hairs triggers a fulminant inflammatory reaction (oedema, ischaemic necrosis) on the tongue mucosa. Without treatment, the tongue can turn black and fall off partially within 24 to 72 hours.
3. Rapid systemic absorption: if ingested, the hairs cross the digestive wall, enter the bloodstream and cause generalised allergic reactions (angioedema, anaphylactic shock), potentially fatal.

Key statistic: according to data from the Lyon veterinary poison control centre (CNITV) and the National Observatory of Pine Processionary Caterpillars run by Alice Samama, dogs account for more than 80% of emergency veterinary consultations linked to processionary caterpillars, compared with 15% for cats and 5% for other animals (horses, exotic pets).

Dog on a leash in an oak forest in summer, the main area of exposure to pine processionary caterpillars in Île-de-France

Recognising the symptoms: every minute counts

The signs appear within minutes of contact and worsen very quickly. The prognosis depends directly on how quickly treatment is started.

Early symptoms (0 to 30 minutes)

• Excessive, foamy, sometimes bloody salivation: this is the earliest sign, almost always present.
• Swollen tongue: the dog can no longer pull it back into its mouth.
• Intensive rubbing of the muzzle on the ground, paws, furniture.
• Agitation, whimpering, refusal of food.
• Compulsive licking of the lips.

Intermediate symptoms (30 minutes to 2 hours)

• Vomiting, sometimes with visible urticating hairs (small orange grains).
• Diarrhoea in some cases.
• Rapid, noisy breathing if the oedema reaches the pharynx.
• Fever (rectal temperature > 39.5 °C).
• Purplish, then black, colouring of a portion of the tongue: this is the stage of ischaemic necrosis.

Late symptoms (2 to 24 hours, life-threatening emergency)

• Partial tongue necrosis (black, dry, insensitive tip).
• Major breathing difficulties due to obstruction of the upper airways.
• Anaphylactic shock: drop in blood pressure, collapse, pale mucous membranes, loss of consciousness.
• Convulsive seizures in extreme cases.
• Death without emergency veterinary care.

The trap to avoid: the first signs (salivation, licking) are often mistaken for a simple "foreign body in the mouth" or "indigestion". At the slightest doubt after a walk in a forest or an infested garden, call your vet or the CNITV (0 810 80 80 80) without waiting. A 30-minute wait can be enough to turn a reversible situation into permanent necrosis.

The 4-step emergency protocol (before the clinic)

If you suspect contact, here is the minute-by-minute protocol to apply while waiting for the veterinary consultation. These steps do not replace the consultation, but they significantly improve the prognosis.

1. Rinse the mouth thoroughly with LUKEWARM water (without rubbing)

• Use a garden shower, a fine-spout watering can or a kitchen shower head.
• Lukewarm water (20-25 °C): not cold (risk of thermal shock), not hot (dilates the pores and promotes hair penetration).
• Never rub the tongue or lips: you would break the hairs and multiply the inoculation points.
• Rinse for at least 5 to 10 minutes, letting the water run from the muzzle outwards (avoid letting contaminated water be swallowed).
• Do not give water from a bottle: risk of swallowing urticating hairs.

2. Put on gloves and prevent the dog from licking itself

• Latex or nitrile gloves are essential to protect yourself (the urticating hairs are also dangerous for humans, see below).
• Elizabethan collar or inflatable collar if you have one (otherwise, hold the muzzle closed with an improvised splint made of clean cloth).
• Prevent licking during the entire journey to the clinic.

3. Call the vet or the CNITV immediately

• Treating vet: call before you go, they can prepare the emergency kit (IV corticosteroids, antihistamines, oxygen).
• CNITV (French National Veterinary Toxicological Information Centre): 0 810 80 80 80 (€0.15/min), accessible 24/7.
• Specify: time of contact, location (forest, garden, street), observed symptoms, dog's weight and any ongoing treatments.

4. Take the dog to the clinic within the hour

• Veterinary care generally combines: rinsing under sedation, intravenous corticosteroid therapy (dexamethasone or prednisolone), antihistamines (dexchlorpheniramine), analgesics, coverage antibiotics, cardio-respiratory monitoring and hospitalisation for 24 to 72 hours.
• If necrosis is established, the vet will perform a surgical excision (ablation) of the affected portion of the tongue. This is the operation that saves the dog's life, but often leaves functional after-effects (difficulty drinking, eating, panting to regulate body temperature).

Prevention: the 2026 strategy for dog owners

Before the walk

• Check the map of current prefectoral orders on the website of your departmental prefecture (Yvelines, Essonne, Val-d'Oise, Seine-et-Marne, Hauts-de-Seine).
• Consult the national observatory chenille-risque.info and the ONF maps to identify infested massifs.
• Avoid oak and pine forests between mid-May and end of July in flagged areas.
• Prefer urban routes, open parks without dense undergrowth, the banks of the Seine.

During the walk

• Keep the dog on a short lead (≤ 1.5 m), especially in wooded areas, forest edges, sunken paths.
• Keep the dog in sight: it must not be able to push into the undergrowth.
• Watch for processions: a line of orange caterpillars moving in a "train" on the ground is an absolute warning sign. Change paths immediately, do not try to destroy the procession without protection.
• Do not stop under an oak or pine with white silk nests ("bags") attached to the branches or against the trunk.
• Avoid forest picnic areas and parking areas under oaks (caterpillars come down the trunks and fall to the ground).

When returning from the walk

• Inspect the coat and the interdigital spaces (between the toes), the ear folds, the belly, the inner thighs: these are the areas where urticating hairs cling the most.
• Brush the coat with a hard-bristle brush outdoors, gloves required (the hairs remain urticating for several months, even when dry).
• Wash the dog with mild shampoo in lukewarm water if exposure is suspected (without rubbing the muzzle).
• Machine wash at 60 °C the textiles that have touched the dog (blanket, harness, fabric lead): heat destroys the urticating hairs.
• Monitor for 6 hours: any sign of excessive salivation, licking or swelling should trigger the call to the vet.

Background treatment of the garden and house surroundings

• Mechanical nest removal by a Certibiocide-certified professional: vacuuming of nests in winter, destruction by burning with FFP3 respiratory protection.
• Pheromone traps set up in June to capture male moths and limit reproduction.
• Biological treatment by spraying Bacillus thuringiensis var. kurstaki (Btk) on young colonies in early autumn, authorised in frequented areas.
• Tit nesting boxes (natural predator) installed in the trees of the garden and shared green spaces.
• Fencing around children's play areas and kennels.
• Informing neighbours and reporting to the town hall if a nest is spotted in a public area.

What about humans? A frequently underestimated risk

Urticating hairs are also dangerous for humans, especially children playing on the ground and gardeners trimming hedges or raking leaves:

• Immediate urticaria, sometimes angioedema (swollen face, difficulty breathing).
• Severe conjunctivitis if hairs enter the eye.
• Asthma attack in sensitive people.
• Anaphylactic shock in extreme cases (life-threatening emergency, call 15 or 112).

Same gestures as for dogs: rinse with lukewarm water without rubbing, do not scratch, call 15 or 112 in case of breathing difficulty.

The role of ProDeratisation: protecting sites frequented by animals and families

In Île-de-France (Paris, Seine-et-Marne, Yvelines, Essonne, Val-de-Marne, Hauts-de-Seine, Seine-Saint-Denis, Val-d'Oise), our Certibiocide-certified technicians work with dog owners, breeders, boarding kennels, dog clubs, residences, co-ownerships, campsites, leisure centres and local authorities to set up an integrated processionary caterpillar strategy:

• Territorial diagnosis: mapping of nests and processions on your property or business site.
• Secure nest removal by vacuuming, in winter, with full PPE (overalls, FFP3 mask, goggles).
• Installation of pheromone traps and biological Btk control in areas frequented by animals.
• Advice and training for building caretakers, green space managers and dog trainers.
• Annual contract for sensitive sites: veterinary clinics, breeding facilities, shelters, SPA pounds, schools, nurseries, leisure centres, campsites.
• Rapid intervention within 24-48 hours in the event of a report of an active procession near an area frequented by children or animals.

To go further, see our pages Pest control in Île-de-France and Request your processionary caterpillar diagnosis. In an emergency for your dog, call your vet or CNITV at 0 810 80 80 80 without waiting.

What to remember for summer 2026

• ✅ 2026 activity peak of pine processionary caterpillars: mid-May to end of July, with a second peak at pupation in August-September.
• ✅ Rambouillet forest partially closed, pharmacies in the Paris region under pressure on corticosteroids.
• ✅ Danger no. 1: tongue necrosis in less than 2 hours after contact.
• ✅ 80% of veterinary emergencies concern dogs.
• ✅ Rinse with lukewarm water WITHOUT rubbing + gloves + vet within the hour.
• ✅ CNITV: 0 810 80 80 80 (24/7, €0.15/min).
• ✅ Prevention: short lead, no infested forest, inspection on return.
• ✅ ProDeratisation works on sites welcoming the public and animals in Île-de-France.

Sources and references: ARS Île-de-France — Urticating caterpillars, TF1 Info — Rambouillet forest overrun by processionary caterpillars, June 2026, Le Parisien — Pine processionary caterpillars: alert to dog owners, 23 March 2026, ONF — Be vigilant about the dangers of oak and pine processionary caterpillars, CNITV — Veterinary Poison Control Centre, 0 810 80 80 80, ANSES — Urticating caterpillars, National Observatory of Pine Processionary Caterpillars — Alice Samama, Decree no. 2022-668 of 25 April 2022 classifying the processionary caterpillar as harmful to human health.

Don't let a walk ruin your dog's life: vigilance and calling the vet quickly save lives. Request your processionary caterpillar diagnosis in Île-de-France today or see our pricing.