I have a 5 year old Saint Bernard and back in September 2012 he came down with lameness, couldn't walk, 108 fever and had to be rushed to an animal er. After tests and follow up with family vet - it was diagnosed as a fever of unknown origin. It all cleared up and no problems until July of this year - same thing high fever, lameness, fluid buildup. Tested positive for lymes - was treated. Medicine made horribly sick - thought maybe a bleeding ulcer - treated. Still relapsing so we are doing cortison therapy. THe vet has done many blood tests - he did have very low proteins which have improved, however last night we had another relapse. Fluid builds up in his hind leg, it's painful to him, fever of 103.8 and lameness - won't eat or drink. Our family vet is stumped. We are going to a referral clinic this weekend but just looking to see if anyone else has ever had this with a pet, especially a large breed like a Saint.