Picture by John H. Ghent, USDA Forest Service, Bugwood.org, under CC BY 3.0 license
The pine processionary (Thaumetopoea pityocampa) is a type of caterpillar. It is considered one of the most important plagues on Mediterranean pines, although it can affect other trees as well. The name is due to their characteristic way of moving from the trees to the ground during their migratory phase.
Besides damaging trees, the pine processionary can cause health issues to humans and animals — cats, dogs, ferrets. They have urticating hairs which cause allergic reactions (see Pest profile – Pine processionary moth). The most frequent result in animals are swellings in the area of the mouth. In the most serious cases, they might lose part of the tongue and lips, or even suffer asphyxia.
Life Cycle of the Pine Processionary
We should know a little about the life cycle of this insect to avoid risking contact with the caterpillar.
At the end of summer, adult moths mate, and the females lay eggs on the leaves of trees. The caterpillars hatch out of the eggs 4 weeks later. The most characteristic stages they go through are: the building of nests — to spend the winter —, and the migration from the tree tops in the spring to form the chrysalis underground. In the summer, moths hatch out of the chrysalis, and the biological cycle starts again when they reach adulthood.
Contact with the pine processionary is most dangerousduring the migration periods:
- at the end of autumn (when they build the nests)
- at the beginning of spring (when the rise of the temperatures stimulates the caterpillars to move from the tree to the ground)
Also risk is also high whenever the nests are manipulated to be removed, mainly in the winter.
Symptoms
If your pet has been in contact with processionary caterpillars, you will see that:
- the animal appears nervous
- their lips, mouth, and tongue itch, or are even swollen
- when there has been contact with the inside of the mouth, they salivate more than usual, and swallow too quickly
These symptoms might be due to other reasons, such as poisonings from some plants. Therefore, it is better to visit a veterinarian. They will determine the exact cause, and prescribe the right treatment.
The most usual effects of the pine processionary on animals are:
- Inflammation of the mouth, tongue, and lips. Such reactions happen when the animal licks, or manipulates the caterpillar with the mouth. These are the most frequent afflictions, and the ones causing the most trouble.
Besides the swelling, there could be death of tissue in the affected areas. The animal might lose part of the tongue or lips.
If your pet swallows a pine processionary, the consequences can be even worse: in some cases it might cause inflammation of the larynx. That would compromise breathing, and lead possibly to the death of the animal.
- Inflammation of the eyelids and ulcers in the cornea, when the caterpillar’s urticanting hairs are carried from the nests by the wind.
- Inflammation of the nasal cavity, when the animal sniffs the caterpillar — or spots where there are nests —, and the bug’s hairs get inside the nose.
Prognosis
The prognosis varies depending on the affected area, the extension of the damage, and the timeliness of treatment. Therefore, if you suspect that your pet has been in contact with pine processionary caterpillars, our advice is to take them immediately to a veterinary center. They will evaluate the seriousness of the injuries, and prescribe the most suitable treatment.
Prevention
It is essential to keep in check the areas where our dogs or cats spend time during the autumn and spring. Prevent by any means their contact with pine processionary caterpillars — either by eliminating them, or avoiding the areas where they live.
