The time between infection and disease is 14 to 18 days, although there can be a fever from three to six days postinfection. So you're pup probably had it before you got him.
The dog should be treated by a veterinarian, usually with antibiotics for secondary bacterial infections, intravenous fluids, and nutritional supplements. The prognosis is poor.
The virus is destroyed in the environment by routine cleaning with disinfectants, detergents, or drying. It does not survive in the environment for more than a few hours at room temperature (20-25 °C), but can survive for a few weeks at temperatures slightly above freezing.
Young puppies between 3 and 6 months old are most susceptible to infection and disease and are more likely to die than infected adults.
Many diseases can cause symptoms resembling canine distemper and should be ruled out during diagnosis. Respiratory symptoms (e.g., cough and labored breathing) could be caused by bacterial pneumonia. Intestinal symptoms (e.g., vomiting and diarrhea) could be caused by gastroenteritis (an inflammatory bowel disease). Seizures and other neurological symptoms could be caused by toxoplasmosis (a protozoan infection) or epilepsy.
Treatment -
Since there's no cure for distemper, treatment is supportive.
Provide a clean, warm, draft-free environment.
Keep eyes and nose clear of discharge.
Give antiemetics (anti-nausea and anti-vomiting drugs) if there is vomiting.
Give antidiarrheals for diarrhea.
Monitor closely for dehydration. Dogs without an appetite that are experiencing vomiting and diarrhea may require intravenous rehydration therapy.
Antibiotics or bronchodilators are prescribed for pneumonia.
Anticonvulsants may partially control seizures. Many veterinarians prescribe them before seizures start.
Myoclonus is untreatable (and irreversible).
Puppies who recover but have hypoplasia (unenameled teeth that erode quickly) can have the enamel restored to prevent further tooth decay.
Glucocorticoid therapy can sometimes help blindness due to optic neuritis (inflammation of the optic nerve). This may help in the short term, but glucocorticoids weaken the immune system and may make symptoms worse.
Prognosis depends on the strain of canine distemper virus and the dog's immune response. After the initial fever subsides, the disease can progress in a number of ways.
More than half of all dogs die between 2 weeks and 3 months after infection, usually from central nervous system complications. Most veterinarians recommend euthanasia for dogs that suffer progressive, severe neurological complications.
Dogs that appear to recover may develop chronic or fatal central nervous system problems. Dogs with mild symptoms (e.g., myoclonus) may recover, though the symptoms can persist for several months or longer. Dogs with a strong immune response may never show any signs of infection. Once a dog has fully recovered, it no longer sheds the virus and is not contagious