Like all pets, dogs are also prone to many diseases. For dogs to remain disease-free, you must understand them first and treat them well with the help of the veterinarian. Some of the common diseases in dogs are discussed below: 
Rabies:
Rabies is a very common disease in dogs caused by a virus that affects the dog’s central nervous system. We know that rabies is transmitted by saliva. There are several stages observed in dogs. In the first stage, the dogs are perceived with a change of behavior, in the second stage, the dogs become very violent and in the third stage, the parts of the dogs’ bodies stop coordinating. There is no cure so far for this deadly disease.
Bloat:
This is a serious condition of the dog. The dog’s stomach twists, which is due to overeating. The symptoms of bloating are agitation and depression, associated with dry heaves.
Distemper:
It is considered the worst dog disease in the world. This leads to a lethal condition in puppies up to 80% and in adult dogs up to 50%. The usual symptoms of this disease are chest congestion, cough, diarrhea, wobbly eyes, runny nose, and so on. In more advanced stages, they affect the nervous system of dogs causing paralysis. It is a very contagious dog disease. It can be transmitted by the feces of the infected dog. This dog disease also has no treatment.
Parvovirus:
It is a very contagious disease that affects the intestinal tract of dogs. It is also said to affect the hearts of dogs. The symptoms of this disease are severe diarrhea, depression, decreased appetite. The dog’s material happens to be of a different color with blood stains. Symptoms appear within hours of infestation and can even kill the dog within 2 to 3 days of infection. Therefore, it is considered a deadly disease.
Kennel Cough:
It is very common in dogs. It’s a kind of respiratory disease. This can be easily treated.
Canine Viral Hepatitis:
This disease affects the liver, kidneys and blood vessels of dogs. The usual symptoms are heavy thirst, vomiting, haemorrhage, loss of appetite, etc. This virus is also spread in dog feces.
Leptospirosis:
This disease is caused by bacteria and even humans are affected by the bacteria. There are several species of bacteria responsible for the disease in dogs. Common symptoms include lethargy, fever, kidney inflammation, blood clotting and conjunctivitis. In more chronic conditions, it can cause pneumonia, intestinal inflammation and jaundice.
Heartworm:
Heartworms are a kind of parasite that multiplies and develops, causing an infection in the cavities of the heart and arteries of the lungs. Symptoms may begin with mild cough, fatigue and lethargy. If left untreated, this can lead to congestive heart failure.
Retinal Dysplasia:
The abnormal development of the retina is disorder. This is very common in most breeds of dogs. The minor forms cause vision problems and the acute forms lead to total blindness in the dog. Cataracts can also accompany this disorder.