Pine Processionary Caterpillars and Dogs

By Josie F. Turner, Journalist specialized in Animal Welfare. July 21, 2022
Pine Processionary Caterpillars and Dogs

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While most caterpillars as harmless creatures which could do no harm to an animal the size of a dog, there are a few important exceptions. The pine processionary caterpillar (Thaumetopoea pityocampa) is one of them. Simple contact with one of these spiny caterpillars can require immediate emergency veterinary treatment. In the most serious cases, ingestion of the caterpillar can be fatal in dogs. Although this is a creature which is usually only found in the Mediterranean, its distribution appears to be growing.

Whether you go to areas where there are pine processionary caterpillars or they come to you, it is important to both know how to prevent contact, as well as what to expect if our dog does come in contact with one. This is why AnimalWised looks at pine processionary caterpillars and dogs.

You may also be interested in: My Dog's Tongue Is Turning Black

Where do pine processionary caterpillars live?

The pine processionary caterpillar is increasingly common in the pine forests of southern Europe, specifically in the Mediterranean area. It can also be found in North Africa, southern regions of South America, Germany, Switzerland, Hungary and Bulgaria, among others. Their name comes from a predilection for pine trees, on which they can feed. They can also inhabit fir and cedar forests.

Registered as a pest in the countries in which it is found, it is common to find forestry agents and others using population control methods for pine processionary caterpillars. This not only helps to protect dogs, but anyone that may come in contact with them. This is especially so during spring and summer.

Pine Processionary Caterpillars and Dogs - Where do pine processionary caterpillars live?

The life cycle of pine processionary caterpillars

To understand when the processionary caterpillar is most dangerous for dogs, we must pay attention to its biological cycle. We explain the life cycle of pine processionary caterpillars here with a helpful infographic below.

During the months of March and April, processionary caterpillars descend from their nests which are located in treetops. When this happens, they form a long row of individuals which move together in a linked chain. It is at this time the caterpillars become most dangerous. This is due to their hairs contain a chemical irritant known as thaumetopoein which they can project into the air if they feel threatened.

Once they reach the ground, the caterpillars bury themselves for protection. They develop into chrysalises which will hatch into moths around the months of May and June. Mating and egg laying then take place in the trees, during the summer.

Barely thirty days later, the eggs will hatch and the larvae will begin to develop. They pass through five different larval stages until they are mature enough to begin to climb the trees. They then form their characteristic nests, ideal for protecting themselves with the onset of winter cold.

Between the months of November and February, the larvae will remain hidden in the nests. They will begin to interact with each other, creating social bonds and going out at night to feed. When spring comes again, the caterpillars prepare to descend from the trees once more, forming as always a procession led by a female.

For a more detailed explanation of their habits, take a look at our article on the life cycle of pine processionary caterpillars.

Pine Processionary Caterpillars and Dogs - The life cycle of pine processionary caterpillars

Pine processionary caterpillars and dogs

As explained above, pine processionary caterpillars have stinging hairs on the upper part of their body. They are capable of projecting them into the air when they feel threatened. These hairs resemble the spikes of some plants, due to their rigidity. Once they penetrate the individual, they release the toxic thaumetopoein.

The pine processionary caterpillar toxin is especially strong, causing severe irritation and inflammation. If it comes into contact with mucus membranes or the tongue, intoxication can cause wounds that are susceptible to necrosis. This means the cells of the tissue die. It can also cause a blockage of the respiratory tract, causing severe breathing difficulties in the dog.

Symptoms of a processionary caterpillar sting in dogs

If we have detected the presence of a pine processionary caterpillar in our garden or our waking route, it will be essential to take certain precautions. We will also need to know the signs that indicate a possible intoxication in our dog.

The symptoms produced by contact with a processionary caterpillar in dogs are:

  • Hypersalivation
  • Skin inflammation
  • Allergic reaction
  • Skin irritation
  • Blisters
  • Ulcers
  • Tongue swelling
  • Red, bruised or black tongue
  • General discomfort
  • Nervousness
  • Excessive scratching
  • Breathing difficulties

These are some of the most frequent symptoms that we can observe after the contact of a pine processionary with our dogs, but there are many more. Part of the issue is that dogs use their nose to both analyze and interact with their environment. If a dog has never come in contact with a pine processionary it is normal they will want to go smell them to find out what they are. Unfortunately, it also means they put their most sensitive areas in danger, i.e. their eyes, mouth, nose, etc.

We will provide you with the best course of action in terms of first aid for dogs when they come into contact with pine processionary caterpillars. However, it is important to note you will need to take them to a veterinarian as they will likely need emergency veterinary attention. Even if they don't, it is best to have them assessed by a professional in case there is anything we miss.

Pine Processionary Caterpillars and Dogs - Symptoms of a processionary caterpillar sting in dogs

What to do if your dog touches or eats a pine processionary caterpillar?

Now that you know the serious effects even brief contact with a pine processionary caterpillar can result in a dog, it is is essential you review the first aid requirements for pine processionaries:

  1. Never use our bare hands. Always use gloves and/or tweezers to carefully remove the pine processionary caterpillar hairs (villi) that may remain in our dog's fur.
  2. Wash the affected area with abundant fresh water and clean.
  3. Avoid rubbing, manipulating or putting pressure on possible wounds. We can cause the stinging hairs to release more toxic substances in the body of our dog.
  4. Go immediately to a veterinary center, going to an emergency clinic if necessary.

Treatment of contact with a processionary caterpillar in dogs

The consequences of contact or ingestion of the processionary caterpillar in the dog are serious. In some cases, they can be fatal if the dog is not treated in time. Aside from skin reactions, a dog that has been poisoned can drown or suffer necrosis in some parts of their body. This can require debriding or even amputation of that specific tissue or body part.

The treatment to be applied will depend on the reaction of the dog's body to the toxic substance. It may include the administration of antibiotics, as well as corticosteroids and antihistamines. When the pine processionary has been ingested, induced vomiting may be required. In the most serious cases, hospitalization and the use of fluid therapy may be necessary to keep the dog properly hydrated, especially if they are in a state of toxic or anaphylactic shock.

Treatment for tongue necrosis in dogs

When eating a pine processionary caterpillar, it is common for the affected dog's tongue to develop necrosis. Although this is the most common reaction, we have already seen that other symptoms may also appear, so it important to pay attention and go to the clinic as soon as possible.

Once there, if cell death (necrosis) of any part of the tongue is observed, the veterinarian will most likely start intravenous treatment for greater efficacy. They will hospitalize the patient to monitor their development. It will also be necessary to remove the necrotic tissue. Only a veterinarian can carry out this type of treatment in case of observing necrosis in the dog's tongue after eating a pine processionary caterpillar.

Pine Processionary Caterpillars and Dogs - Treatment of contact with a processionary caterpillar in dogs

How to prevent pine processionary caterpillar stings in dogs

Climate change directly influences the biological cycle of the processionary caterpillars. An increase in global temperatures causes them be active and out of their nests for longer parts of the year. The increased temperatures are also seeing their populations spread further north. Although they are not yet found in places such as the United States or the United Kingdom, this doesn't mean we won't see them migrate in the future.

If we do live or visit somewhere with pine processionary caterpillars, it is essential we prevent contact or inhalation. To do so, we must regularly monitor the trees in our garden or walking areas for early detection of nests. In the case of locating them in our garden, we will contact a phytosanitary professional directly. If we observe them in a public space we will contact our local animal control services. As guardians, we must remain vigilant during walks, especially in the spring and summer.

To best ensure our dog's health, we also highlight the necessity of deworming your dog regularly and following the vaccination schedule prescribed by the veterinarian. Deworming and vaccinations contribute to the good health of the animal, help prevent the development of certain diseases and avoid a possible infestation of fleas, ticks and worms, with all its consequences.

Pine Processionary Caterpillars and Dogs - How to prevent pine processionary caterpillar stings in dogs

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Pine Processionary Caterpillars and Dogs, we recommend you visit our Other health problems category.

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