Can you possibly post what the vet says. I posted on here that Indie was very sick the other night, she is fine now but we think it might have been from a frog. Another thing that is freaking me out is with all this wet humid weather, we are getting tiny mushrooms growing in the garden and the dogs are hoovering them up.... which is not good either. I don't know these dogs are a worry 
Chatted with the vet about this yesterday, and she said that although it is true that she could catch lungworm from the snails, one of the wormers that are available (she was confused as to which one) does guard against lungworm. Also she said that in this part of the country, Cambridgeshire, it is very rare - but is much more common in the South West of the country.
She asked me to keep an eye on her, and remove them from her as soon as possible, but not to spray anything in the garden as she is so young.
