If the bronchitis in dogs is chronic then it is not contagious. But if the bronchitis is due to viral infection then it can be contagious for other dogs. The affected dog will remain contagious until he is having sneezing, runny nose and hacking cough. Viral bronchitis don't require treatment because virus is self treated after completion of life cycle. Only cough suppressants can be helpful without killing virus. Bacterial bronchitis are treated by antibiotics.
If your dog is still coughing or sneezing then he is still contagious to other dogs, So, keep him separated from other dogs. If no symptoms then no more contagious.
If your dog is still coughing or sneezing then he is still contagious to other dogs, So, keep him separated from other dogs. If no symptoms then no more contagious.