Even if you are not a dog owner, but live in or like to travel around Europe I think it could be useful to know something about the Pine Processionary Caterpillars and what can happen if you get the hairs on your hands, face or body.
In certain countries, however, it pays to exercise extreme caution if you come across certain types of the caterpillar, especially Pine Processionary Caterpillars (Thaumetopoea pityocampa). These creatures turn into a month and are to be found in pine woods in central and southern Europe, the Near East, and North Africa. These moths lay their eggs as a single egg mass which is fastened to a needle of a suitable host pine tree. Even though tiny, the newly hatched pine processionary caterpillars have very strong mandibles which are used to pierce the tough needles of its host.
At around March time, the caterpillars leave their nest, and they follow one another forming a trailhead to toe, sometimes numbering several hundred in one long procession. Once they find soft soil they bury themselves in it, change into pupae, then later in the year in the warmer months they evolve into moths.
As moths, they pose no danger, but as caterpillars, they can cause a number of health problems, for both humans and animals. There have been cases in Spain, (where they are known as the "processionary del pino"), where they have caused problems for man and beast. The hairs can cause a human to suffer a bad allergic reaction. Reports have even been made of people suffering some temporary blindness from rubbing their eyes after getting some of the pine processionary caterpillar`s hairs on their hands, then rubbing their eyes. For animals, the effects can be catastrophic.
Dogs, in particular, are inquisitive by nature, and if a dog sniffs the hairs the effect could be a severe allergic reaction, or anaphylactic shock, which could prove fatal. Excessive drooling, difficulty in breathing, or having white spots on the mouth or tongue are some of the signs the dog has been affected. It is imperative to get emergency veterinary treatment for your pet if that happens. I have heard of some cases where part of a dog`s tongue has had to be amputated so bad was its condition.
So, if you do happen to come across some pine processionary caterpillars as they look for a new pine host, or to burrow underground, what should you do? I suggest you move away from them, and if you have a dog do not let it anywhere near. The worst thing you can do is to tread on them. All that does is release the hairs into the air, and that means you could easily breathe them in. Pulling the nests down from the trees in order to burn them is something that only the professionals should do.