Deadly caterpillars that can kill dogs 'expanding massively' in Brit holiday hotspots

The deadly caterpillars are well-known pests in the UK and further afield, with the insects having first been discovered on British shores nearly two decades ago

Deadly caterpillars known for the dangers they pose to dogs have been spotted in holiday hotspots frequented by Britons.

Processionary caterpillars are "expanding massively" in Spain, and tend to thrive in the particularly warm, sunny areas holidaymakers love. The caterpillars, famed for their furry bodies, are laden with hundreds of toxic barbs that, if touched, can cause reactions in both humans and animals.

Humans who touch the insects experience skin irritation, eye pain, coughing fits, and allergic reactions. Repeated exposure can have even more severe effects, including loss of consciousness or rapid drops in blood pressure. Dogs, which experience a range of different symptoms, can die from exposure to the processionary toxin.

The Huffington Post reports that the caterpillars usually hatch in October and spend autumn and winter hibernating, but the recent run of balmy weather in Spain has seen them emerge from the trees in which they usually stay. They have been sighted in significant numbers in Ibiza, Formentera, Menorca and Murcia.

Active processionary caterpillars can be spotted while they make a procession on the floor or in the trees, and their large, silk adorned nests are often visible in tree tops. While holidaymakers themselves are unlikely to experience severe ill effects from contact with the insects, they will need to keep any dogs strictly on their leash and under close eye when walking through infested areas.

Dogs that come into contact with the caterpillars' bristles can develop a host of gruesome symptoms that can prove deadly without treatment. They will usually display the following symptoms:

• Excessive drooling and salivating
• Gagging and vomiting
• Drowsiness or lethargy
• Irritation
• Mouth, tongue and face swelling
• Breathing difficulties
• Eye irritation and conjunctivitis

Without prompt treatment, the toxic barbs can cause necrosis, a condition in which tissue dies and falls off the body. Dogs that come into contact with processionary caterpillars will need washing with warm water within the first two hours of people suspecting they have been affected.

Processionary caterpillars do not exclusively live in Spain, as the UK has its own breed, the oak processionary moth (OPM) caterpillar, which is just as dangerous. They were first discovered on British shores in 2006, and, while they tend to stick to the south of the country, climate change has seen them spread further afield.