The adder is the UK’s only naturally occurring venomous snake and is most commonly found in heaths and woodlands in the spring and summer months. Although typically non-aggressive, they may bite if provoked, stepped on or disturbed by an inquisitive dog, although this is a relatively rare occurrence. Severe pain and localised swelling are the most common clinical signs but, if left untreated, symptoms can include muscle tremors, seizures, collapse and, very occasionally, death.
If you do suspect your dog has been bitten by an adder, you should minimise their movement by carrying them (if possible), keep them warm and quiet, and get to the nearest vets as quickly as possible. If treated promptly, the prognosis is very good in the vast majority of cases.