Just have to speak up-I am a veterinary technician,and high fever is NOT a symptom of parvo. If anything, many parvo infected dogs have a LOW body temperature. A dog can most certainly have parvo and not have broken with vomiting yet-though most will have both diarrhea and vomiting at some point. Given the listed symptoms of bloody diarrhea and lethargy, parvo is high on the list of possibilities. You do not mention your dog's age, whether or not he has ever been vaccinated (if he hasn't had shots, or got one shot as a puppy but not the full series of puppy shots he is not protected) and whether or not he is on heartworm prevention. These things all factor into the probability of his having parvo vs. Intestinal parasites or something else. In any case, your dog definitely could have parvo,among other things. Parvo is treatable,and treatment is much more successful than it was years ago. The earlier treatment is started,the better the chance of recovery. Parvo is highly contagious to other dogs, but not to other types of animals or people. Also,the anus may swell with prolonged diarrhea but the colon does not. In any case, what you are describing is a very sick dog that needs to see a veterinarian. Go soon-whether it is parvo or not,this dog is sick,and the longer you sit on it the sicker he'll get,which means more treatment needed and more cost to you.
