Common Dog Diseases, Illnesses & Conditions 

Three Minutes
Oct 31, 2022

As a dog owner, it’s important to know the clinical signs of different diseases in dogs so you can catch them early. Caring for a sick dog can be a challenge, but understanding the symptoms and treatment for different puppy diseases and dog illnesses, including those that may be transmitted from humans, can help.

Here are nine common dog viruses and conditions all pet parents should know to watch out for.


Cancer in dogs is the leading cause of canine deaths. However, a cancer diagnosis doesn’t immediately spell out a death sentence. Your pet’s prognosis can depend on the type of cancer and how soon you caught it. Treatment generally varies from surgery to different therapies (immunotherapy, chemotherapy, radiation therapy) or a combination of treatments.

Cancer is more prominent in older dogs, but can affect dogs of any age. Here are the top clinical symptoms of cancer in dogs pet owners should watch out for:

  • Lumps or bumps (tumors)
  • Weight loss
  • Muscle weakness or collapse
  • Blood in the urine
  • Seizures
  • Difficulty breathing or swallowing


Canine diabetes is when a dog’s body either cannot produce insulin or produces it, but cannot regulate it. This affects the glucose levels in dogs’ blood, causing them to either spike or drop, both of which can be dangerous. Diabetes primarily affects older dogs, but all dogs are susceptible. Diabetes treatment includes giving your dog insulin shots to maintain their blood sugar levels and managing their diet.3 Work with your veterinarian to decide how to best treat and care for your dog with diabetes.

A diabetes diagnosis may be intimidating, but many dogs live long and healthy lives with diabetes. Catching diabetes early is crucial to giving your dog the best quality of life possible. There are a few key symptoms to watch for:

  • Cloudy eyes
  • Drinking and urinating excessively
  • Lack of appetite
  • Constant infections
  • Breath that smells sweet


Canine distemper is a highly contagious dog virus that affects the nervous system. This viral disease is transmitted through both air and contact with infected dog’s dishes or other surfaces. There’s no treatment for distemper; instead, a vet will administer supportive care to help fight secondary dog infections, dehydration, and neurological damage. Whether your dog recovers fully or not ultimately depends on how strong their immune system is and what strain of distemper they get.4

The symptoms of distemper vary depending on the stage your pup has reached. But these are the signs to watch out for:4

  • Watery eyes
  • Runny nose
  • Cough
  • Fever
  • Vomiting
  • Diarrhea
  • Seizures
  • Twitching
  • Muscle weakness
  • Balance problems
  • Pneumonia

Canine Flu

The canine flu is highly contagious and appears similar to the human flu. While it’s not deadly, some canine influenza cases do become serious and may cause your dog to develop pneumonia. The best way to protect your dog from contracting the disease is to get them vaccinated with the canine flu shot. It’s often required by doggy daycares and boarding facilities, so your dog may already be getting one as part of their annual vaccinations, but it doesn’t hurt to double-check.5

  • Canine flu symptoms are pretty intuitive and include:
  • Cough
  • Runny nose and sneezing
  • Fever
  • Fatigue
  • Loss of appetite

If your dog has a persistent cough, it’s a good sign you should take them to the vet, though it may actually be a sign of kennel cough, rather than the flu.

Kennel Cough

Kennel cough, or Canine Infectious Respiratory Disease Complex (CIRDC), affects a dog's respiratory system. It is very contagious and can be caused by many different bacterias, though one bacteria known as Bordetella bronchiseptica is the most common cause. That’s why you may also see kennel cough referred to as Bordetella and vice versa.

Because of how infectious it is, kennel cough is prevalent in shelters or other spaces where lots of dogs are kept in confined spaces. That’s why it’s key to isolate sick dogs from their peers.

Kennel cough isn’t a fatal sickness, so dogs usually recover on their own in 7 – 10 days, but with severe infections, dogs are at risk for pneumonia. The symptoms of kennel cough are pretty straightforward:

  • A strong, hacking cough
  • Runny nose and sneezing
  • Lethargy
  • Loss of appetite

Vaccines can help prevent kennel cough caused by Bordetella, distemper, parainfluenza, and canine adenovirus-2.

Canine Parvovirus

Canine parvovirus (CPV or parvo) is an infectious disease that compromises puppies’ digestive systems. A rare strain also attacks puppies’ hearts. It’s transmitted through the feces of infected dogs and can live on surfaces for months. Parvo can be deadly unless it’s caught and treated quickly with hospitalization, intravenous fluids, and antibiotics.

The parvo vaccine is considered one of the core vaccines for puppies. Parvo is primarily a puppy sickness, but it can affect unvaccinated dogs of any age. Here are some symptoms to keep an eye out for:

  • Loss of appetite
  • Vomiting and diarrhea (sometimes bloody diarrhea)
  • Abdominal pain
  • Weight loss
  • Lethargy or depression

Lyme Disease

Lyme disease in dogs is a bacteria that’s transmitted through tick bites. This tick-borne bacteria attacks dogs’ kidneys and joints. You can help protect your dog from Lyme disease by vaccinating them and using a tick prevention program. But ultimately, be vigilant when walking your dog in wooded or grassy areas, where ticks thrive. Lyme disease can be treated with antibiotics.

If your dog has been bitten by a tick and is experiencing any of these symptoms, it’s time to see a veterinarian:

  • Bull’s-eye rash on the bite
  • High fever
  • Limping
  • Vomiting
  • Weight loss
  • Loss of appetite


Heartworm in dogs is a dangerous disease where worms clog a dog’s heart and major blood vessels. However, there are heartworm prevention programs to help protect your dog. Heartworm treatment depends on what stage of infection your dog has. But diagnosis and treatment can include X-rays, bloodwork, drug treatments, and antibiotics.

Dogs usually don’t show symptoms of heartworm for many years after they’ve been infected. During this time, the worms build up in their heart and blood vessels, eventually causing congestive heart failure. Early symptoms are mild, but should still be checked by a veterinarian. Here’s what to look out for:

  • Soft cough
  • Weakness
  • Shortness of breath
  • Lack of energy
  • Swelling of legs


Rabies in dogs is incurable, but mostly preventable with a vaccine. If it’s caught early, your dog has a chance at surviving, but as the symptoms progress, it becomes fatal. Rabies primarily affects the nervous system, causing erratic behavior and seizures.

If you suspect your dog has been bitten by wildlife or your dog exhibits any of the symptoms below, take them to see a vet:

  • Fever
  • Seizures
  • Difficulty swallowing
  • Excessive drooling or foaming at the mouth
  • Staggering
  • Odd behavior (restlessness, aggression, confusion, being easily overwhelmed or overly affectionate)

Protect Your Dog With Pet Insurance

Whether your dog is a young puppy or an adult dog, they’ll likely need healthcare throughout their life. In a perfect world, we would vaccinate our pups and protect them from all dog illnesses and diseases. But we can’t protect them from everything.

If your dog is diagnosed with any of the above dog diseases, they’ll need medical attention, and possibly even hospitalization. This is where dog insurance comes in. A pet insurance policy helps cover medical expenses over the life of your pet.2 This way you can focus less on the cost of treatment and more on the care.

Get started today with a free quote from MetLife Pet Insurance, winner of the “Pet Insurance of the Year” Award in the 2023 Pet Independent Innovation Awards Program.1

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Nothing in this article should be construed as financial, legal, or veterinary advice. Please consult your own advisors for questions relating to your and your pet’s specific circumstances.

1 Pet Insurance offered by MetLife Pet Insurance Solutions LLC is underwritten by Independence American Insurance Company (“IAIC”), a Delaware insurance company, headquartered at 485 Madison Avenue, NY, NY 10022, and Metropolitan General Insurance Company (“MetGen”), a Rhode Island insurance company, headquartered at 700 Quaker Lane, Warwick, RI 02886, in those states where MetGen’s policies are available. MetLife Pet Insurance Solutions LLC is the policy administrator authorized by IAIC and MetGen to offer and administer pet insurance policies. MetLife Pet Insurance Solutions LLC was previously known as PetFirst Healthcare, LLC and in some states continues to operate under that name pending approval of its application for a name change. The entity may operate under an alternate, assumed, and/or fictitious name in certain jurisdictions as approved, including MetLife Pet Insurance Services LLC (New York and Minnesota), MetLife Pet Insurance Solutions Agency LLC (Illinois), and such other alternate, assumed, or fictitious names approved by certain jurisdictions.

2 Provided all terms of the policy are met. Application is subject to underwriting review and approval. Like most insurance policies, insurance policies issued by IAIC and MetGen contain certain deductibles, co-insurance, exclusions, exceptions, reductions, limitations, and terms for keeping them in force. For costs, complete details of coverage and exclusions, and a listing of approved states, please contact MetLife Pet Insurance Solutions LLC.

3 “Diabetes in Pets,” AVMA

“Distemper in Dogs - Causes, Symptoms, & Treatment,” AKC

5 “Do Dogs Need a Flu Shot? Facts About the Canine Influenza Vaccine,” AKC

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