Dog diseases and effective ways to prevent

As someone who has worked in animal care for over 10 years, as well as being a passionate #doglover, I promise that this huge list can help you become a better pet parent. A dog can be a wonderful addition to any home, but whether you are a veteran pet parent or first-time adopter, it is essential that you make the health and happiness of your canine companion your highest priority. You and your dog should be comfortable with people who will give your dog preventive care and regular checkups. Regular visits to get shots, clean teeth, keep fleas and ticks at bay, and other medical needs are arguably some of the most important tips for taking care of a dog.

Common dog diseases

Canine distemper

Canine distemper is caused by a very contagious virus. Puppies and dogs usually become infected through virus particles in the air or in the respiratory secretions of infected dogs. Infected dogs typically develop runny eyes, fever, snotty nose, coughing, vomiting, diarrhea, seizures, and paralysis. It is often fatal.

Commonly observed signs are a runny nose, vomiting and diarrhea, dehydration, excessive salivation, coughing and/or labored breathing, loss of appetite, and weight loss. If neurological signs develop, incontinence may ensue. Central nervous system signs include a localized involuntary twitching of muscles or groups of muscles, seizures with salivation and jaw movements commonly described as “chewing-gum fits”, or more appropriately as “distemper myoclonus”

Fortunately, there is an effective vaccine to protect your dog from this deadly disease. The canine distemper vaccine is considered a “core” vaccine and is recommended for every dog.

No specific treatment for the CDV is known. As with measles, the treatment is symptomatic and supportive. Care is geared towards treating fluid/electrolyte imbalances, neurological symptoms, and preventing any secondary bacterial infections. Examples include administering fluids, electrolyte solutions, analgesics, anticonvulsants, broad-spectrum antibiotics, antipyretics, parenteral nutrition, and nursing care.


Warning signs of cancer in dogs include

  • Persistent or abnormal swelling.
  • Sores that do not heal.
  • Loss of weight and/or loss of appetite.
  • Bleeding or abnormal discharge from any body opening.
  • Difficulty eating or swallowing.
  • Lethargy or loss of stamina.
  • Persistent lameness or stiffness.
  • Difficulty urinating, defecating, or breathing.

Types of Cancer in Dogs

  • Anal Sac Cancer
  • Bladder Cancer
  • Hemangiosarcoma
  • Liver Cancer
  • Lymphoma
  • Breast Cancer
  • Mast Cell Tumors
  • Melanoma
  • Oral Melanoma
  • Stomach Cancer
  • Soft Tissue Sarcoma
  • Testicular Cancer
  • Thyroid Cancer


What Are the Symptoms of Diabetes in Dogs?

Early signs. The owner will sometimes notice certain symptoms that can be early signs of diabetes:

  • Excessive thirst. The dog may drink frequently and empty the water bowl more often.
  • Increased urination. The dog may ask to go outside frequently and may start having “accidents” in the house. Increased urination (and increased thirst) happens because the body is trying to get rid of excess sugar by sending it out through urine, along with water that bonds to the sugar.
  • Weight loss. The dog can lose weight despite eating normal portions. This is because the dog isn’t efficiently converting nutrients from its food.
  • Increased appetite. The dog can be very hungry all the time because the body’s cells aren’t getting all the glucose they need, even though the dog is eating a normal amount.

Advanced signs. In more advanced cases of diabetes, symptoms can become more pronounced and can include:

  • Loss of appetite
  • Lack of energy
  • Depressed attitude
  • Vomiting

Threats to health. Uncontrolled diabetes can lead to devastating effects on the dog’s body, which is why early detection and proper treatment are crucial. Effects of diabetes on the dog’s health can include:

  • Cataracts (leading to blindness)
  • Enlarged liver
  • Urinary tract infections
  • Seizures
  • Kidney failure
  • Ketoacidosis, a potentially life-threatening acute condition that can be accompanied by rapid breathing, dehydration, lethargy, vomiting, or sweet-smelling breath; can be triggered by factors such as stress, surgery, fasting, infection, or an underlying health condition combined with low insulin level. Owners of diabetic animals should always have on hand ketone testing sticks and should test their dog’s urine if any of the above occurs. If the dog’s urine tests positive for ketones, an emergency vet should be called immediately.

Canine influenza

What are signs of canine influenza in dogs?

The signs of this illness in dogs are cough, runny nose, fever, lethargy, eye discharge, and reduced appetite, but not all dogs will show signs of illness. The severity of illness associated with canine flu in dogs can range from no signs to severe illness resulting in pneumonia and sometimes death.

Most dogs recover within 2 to 3 weeks. However, some dogs may develop secondary bacterial infections which may lead to more severe illness and pneumonia. Anyone with concerns about their pet’s health, or whose pet is showing signs of canine influenza, should contact their veterinarian.


Heartworm disease is a serious disease that results in severe lung disease, heart failure, other organ damage, and death in pets, mainly dogs, cats, and ferrets. It is caused by a parasitic worm called Dirofilaria immitis.

What are the Symptoms of Heartworm Disease in a Dog?

The severity of heartworm disease is related to how many worms are living inside the dog (the worm burden), how long the dog has been infected, and how the dog’s body is responding to the presence of the heartworms.  The dog’s activity level also plays a role in the severity of the disease and in when symptoms are first seen.  Symptoms of heartworm disease may not be obvious in dogs that have low worm burdens, have been recently infected, or are not very active.  Dogs that have heavy worm burdens, have been infected for a long time, or are very active often show obvious symptoms of heartworm disease. 

There are four classes, or stages, of heartworm disease.  The higher the class, the worse the disease and the more obvious the symptoms.

  • Class 1:  No symptoms or mild symptoms such as an occasional cough.
  • Class 2:  Mild to moderate symptoms such as an occasional cough and tiredness after moderate activity.
  • Class 3:  More severe symptoms such as a sickly appearance, a persistent cough, and tiredness after mild activity.  Trouble breathing and signs of heart failure are common. For class 2 and 3 heartworm disease, heart and lung changes are usually seen on chest x-rays.
  • Class 4:  Also called caval syndrome.  There is such a heavy worm burden that blood flowing back to the heart is physically blocked by a large mass of worms.  Caval syndrome is life-threatening and quick surgical removal of the heartworms is the only treatment option.  The surgery is risky, and even with surgery, most dogs with caval syndrome die. 

Not all dogs with heartworm disease develop caval syndrome.  However, if left untreated, heartworm disease will progress and damage the dog’s heart, lungs, liver, and kidneys, eventually causing death. 

Kennel Cough

  • Kennel cough is a respiratory infection caused by a number of bacteria and viruses
  • It is not usually dangerous and normally clears up without treatment within a few weeks
  • Apart from your dog coughing, the infection is unlikely to make them feel ill
  • But puppies, elderly dogs and those with existing medical conditions can be susceptible to complications from kennel cough, such as pneumonia
  • Kennel cough has an incubation period of two to 14 days
  • A kennel cough vaccine is available and is often required for a stay in kennels where the highly-contagious infection can spread easily


Canine parvovirus (CPV) is a highly contagious viral disease of dogs that commonly causes acute gastrointestinal illness in puppies. The disease most often strikes in pups between six and 20 weeks old, but older animals are sometimes also affected. A rare variant of the disease may be seen in very young (neonatal) puppies is myocarditis (an inflammation of the heart muscle).

Symptoms of Parvo in Puppies

A puppy with parvo is a very sick dog. The sooner you catch the early signs of the virus in puppies, the sooner you can get your dog to the vet. Since parvo is common in young puppies, you should call your vet any time your puppy is feeling under the weather, but you should also be aware of the specific symptoms of parvo in puppies:

  • Bloody diarrhea
  • Vomiting
  • Fever
  • Lethargy
  • Anorexia
  • Weight loss
  • Weakness
  • Dehydration
  • Depression

All of these symptoms are serious by themselves and could be a sign of parvo or another serious illness. You should contact your vet immediately if you suspect your puppy has parvo, and be sure to notify the vet’s staff ahead of time of your suspicions and your puppy’s symptoms, so that they can take the appropriate quarantine procedures to prevent your puppy from infecting other dogs.


Rabies Transmission

There are several reported routes of transmission of the rabies virus.

  • Rabies is most often transmitted through a bite from an infected animal.
  • Less frequently, it can be passed on when the saliva of an infected animal enters another animal’s body through mucous membranes or an open, fresh wound.
  • The risk for contracting rabies runs highest if your dog is exposed to wild animals. Outbreaks can occur in populations of wild animals (most often raccoons, bats, skunks and foxes in this country) or in areas where there are significant numbers of unvaccinated, free-roaming dogs and cats.

Rabies Prevention

  • Vaccination is the key—and in many areas of the country, such as New York City, it’s the law.
  • Some local ordinances require lengthy quarantines—or euthanasia—of pets who have bitten someone if their owners do not have proof of current vaccination.
  • Vaccinating your dog doesn’t just protect him from rabies—it also protects your dog if he bites someone. Dogs who have bitten humans are required to be confined for at least 10 days to see if rabies develops.
  • Avoiding contact with wild animals is also necessary to prevention. Walk your dog on a leash and supervise him while he’s outsoodrs.

Symptoms of Rabies

Animals will not show signs immediately following exposure to a rabid animal. Symptoms can be varied and can take between two and eight weeks to incubate. Classic signs of rabies in dogs include:

  • Changes in behavior (including restlessness, apprehension, aggression or irritability)
  • Biting or snapping at any form of stimulus
  • Attacking other animals, humans and even inanimate objects
  • Licking, biting and chewing at the bite site
  • Fever
  • Hypersensitivity
  • Hiding in dark places
  • Eating unusual objects
  • Paralysis of the throat and jaw muscles
  • Foaming at the mouth
  • Disorientation, incoordination and staggering
  • Paralysis of the hind legs
  • Loss of appetite
  • Weakness
  • Seizures
  • Sudden death

Transmission of the virus through saliva can happen as early as ten days before symptoms appear.


Ringworm Symptoms

Classic symptoms of ringworm in dogs include:

  • Skin lesions that typically appear on the head, ears, paws and forelimbs.
  • Ringworm can patchy, crusted, circular bald spots that sometimes look red in the center
  • In mild cases, there may be just a few broken hairs, while bad cases can spread over most of a dog’s body.
  • It’s also possible for a pet to carry the fungus and not show any symptoms whatsoever.

Dogs More Prone to Ringworm.

  • Puppies less than a year old are most prone to infection
  • Malnourished, immunocompromised and stressed dogs are also at a greater risk.
  • Ringworm can quickly spread in kennels, shelters and other places where there are many dogs in a close environment.

Diagnosing Ringworm

Because infection can potentially spread over a dog’s body and infect other animals and people, it is important that you see your vet for an accurate diagnosis if your pet is showing any signs of a skin problem.

  • A veterinarian may use an ultraviolet light to diagnose ringworm, or may examine a fungal culture taken from the affected area.

Intestinal parasites

Intestinal parasites such as roundworms, hookworms, whipworms and tapeworms lay eggs that are passed in the dog’s stool and infect other dogs when they eat contaminated soil, lick contaminated fur or paws, or drink water contaminated with the stool from infected dogs. Tapeworms are spread when dogs eat fleas, lice, or rodents infected with tapeworms.

These worms can cause malnutrition (because they steal nutrients as food is being digested) and diarrhea, and hookworms can cause blood loss. There are many products available to treat worms, and you should consult their veterinarian for the appropriate products for your pets.

How To Care And Treat A Sick Dog

Some cases of illness can be carefully cared for at home, others require immediate veterinary supervision. Anytime you’re not sure, don’t be afraid to call your doctor.

Know the symptoms of the disease

Monitor your dog’s daily activity

Keep a record of when your dog goes to the bathroom, when symptoms occur, when they eat, and so on. This will help shape the symptoms. It is also a useful tool for doctors to diagnose dog diseases.

Some symptoms require immediate medical attention

  • Comatose
  • Excessive bleeding
  • Ingesting toxic substances
  • Vomiting and diarrhea that doesn’t stop
  • Fracture
  • Shortness of breath
  • Convulsions continuously within 1 minute
  • Urinary retention or not passing urine
  • New or repeated symptoms in an existing dog (eg: diabetes, etc.)
  • Large swellings on the face, eyes, or throat.

Treatment at home

Do not feed if your dog is vomiting or has diarrhea

With puppies and dogs over 6 months old are healthy. The way to care for a puppy at this time is that it can be without food for up to 24 hours if the initial symptom is vomiting or diarrhea.

Make sure your dog is drinking water

Never restrict your dog from drinking water unless he or she vomits while drinking. If this happens, consult your veterinarian.

Feed your dog bland food for 1-2 days

After not feeding for 24 hours and your dog becoming more normal, you can slowly introduce a bland diet for 1-2 days. A bland dog diet consists of 1 part protein and 2 parts easily digestible starch.

Commonly used protein sources include cottage cheese or chicken (without the skin and fat) or boiled meatballs.
The best type of starch for dogs is white rice.
Feed a dog weighing 5kg 1 cup per day (divided into 4 servings, every 6 hours).
Restricting dogs from exercising and running
Make sure your dog gets plenty of rest by limiting their exercise and play time. Take your dog outside for comfort, but don’t let him run around if he’s tired. This is especially important when your dog has leg pain.

Control your dog’s feces and urine

Pay attention to the amount of feces and urine your dog has when he is sick. If you usually let your dog go to the bathroom on his own, when he’s sick, take him away so you can observe his poop and urine output.

Don’t punish your dog if he accidentally goes to the bathroom or vomits in the house. They are uncontrollable because they are sick and can avoid you if punished.

Monitor your dog’s symptoms closely

Make sure you keep a close eye on your dog in case his symptoms worsen. Don’t leave your dog alone during the day or on weekends. If you have to go somewhere (e.g. to work), check your dog every 2 hours.

If you can’t make an arrangement, call a pet hospital to see if they can take care of your dog at the hospital. Symptoms may worsen rapidly, new or more serious symptoms may occur immediately.

Don’t be afraid to call the vet

If you’re not sure what your dog’s symptoms are, or if they seem to be getting weaker, call your doctor.

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