
Hi,
Like Jackie I can only speak with any knowledge on the snakes here in the UK, although with the pet passport it might be interesting to have some input from those living overseas.
My dog was bitten by a grass snake. Usually a grass snake will play dead to escape a potential predator, but it will bite if it thinks there is no other escape. I assume my old girl stood on it either when digging for mice or when she crouched to pee.
Grass snake bites should be treated with piriton and antibiotics, adder bites need immediate attention from a vet, so if you you know your dog has been bitten by an adder go to the vets as fast as possible.
My Rosebud was bitten on her vulva! OUCH! The first sign was a swollen look as though she was coming into season, but being spayed this was not possible. On closer examination the area was swollen and red around the bite area, but no punture wounds were visible at this point due to the amount of swelling. The piriton stops the swelling and might have to be given for a few days as the bite area irritates the dog. When the swelling went down two very visible puncture marks could be seen leaving no doubt at all what had bitten her. Antibiotics are a good idea as it covers the dog against any infection from the bite.
I had a dog which until summer of 1995, I used to show, he got bitten on his face, but I didn't notice the swelling so quickly. He got an infection in the bite and the result was his skin died back from around the area of the bite. Muck and pus seeped from under the skin for almost a month! In the end we were going back to the vets almost daily to have black dead skin cut back and he lost skin from nearly half his face, obviously not all at once but for a long time afterwards he had no hair on that side of his face, so needless to say I stopped showing him, and then never got round to going to shows with him again. He was bitten working on our little shoot, in late spring/early summer, when we were walking the deer off the crops. I don't know what type of snake bit him.
Where I live we have a lot of ponds streams, leets for mills (now vanished), and natural springs, which is grass snake heaven. We see quite lot every year. My village was a center for the duck and goose rearing trade for London. There was a disease the locals used to suffer from called "Duck Fever" this was because they used to live with their ducks in the houses and often crates of birds would kept under beds!