This article is from the Canine Medical Information FAQ, by Cindy Tittle Moore with numerous contributions by others.
In most cases the disease is mild. Primary symptoms are fever,
listlessness, loss of appetite and depression. Other symptoms involve
the kidneys: a "hunched up" look due to kidney pain, ulcers on the
mucus membranes of the mouth and tongue, thick brown coating on the
tongue, bleeding from the mouth or bloody stools, severe thirst with
increased urination. The whites of the eyes may turn yellow.
Persistent vomiting and diarrhea are common. This disease is more
prevalent in some areas than others. (Summarized From Carlson &
Many dogs seem to be allergic to the leptospirosis vaccination. If
your dog is vaccination against lepto for the first time, keep a close
eye on it for a few hours afterwards. If the dog goes into
anaphylactic shock, get him back to the vet immediately.
Leptospirosis is a zoonotic disease, so if you come into contact with
a dog that has Lepto, consult with your own doctor.