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10 Common Infectious Diseases in Dogs

Written by: Nicole Cosgrove

Last Updated on May 1, 2024 by Dogster Team

white golden puppy with a cold and nose discharge

10 Common Infectious Diseases in Dogs

As the parent of a pet, you hope to never see them in distress. When your dog is sick, it can be stressful and worrisome, to wonder whether your dog will be ok or not. As much as we might try to prevent negative health conditions from ever occurring, there’s no way to truly put a stop to the possibility of infectious disease.

Like humans, dogs are susceptible to a myriad of illnesses, but the following 10 infectious diseases are the most common. Read about each of these diseases and learn to identify the symptoms. That way, if your beloved dog starts to display symptoms related to any of these illnesses, you’ll be able to identify it right away and provide treatment early to increase the chances of your dog making a full recovery.

divider-dog paw

The 10 Canine Infectious Diseases

1. Canine Influenza

Though similar to the influenza virus that affects humans, canine influenza is a separate strain and has never been reported to infect a human.

Common signs of canine influenza include:
  • Runny nose
  • Loss of energy
  • Lack of appetite
  • Discharge from the eyes
  • Fever
  • Persistent cough

Not all dogs will show symptoms of canine influenza. Severity can range from practically symptom-free to fatal. A majority of dogs will recover on their own in just a few weeks, though sometimes a secondary bacterial infection could develop. If this happens, pneumonia is likely to occur, which will greatly increase the chances of death.

dog with eye problem
Image Credit: Alexandr Jitarev, Shutterstock

2. Canine Parainfluenza

Canine parainfluenza is extremely contagious and presents similar symptoms to canine influenza, though the two are distinctly different viruses that require separate vaccinations and treatments. Canine parainfluenza will break down the immune system, making additional infections more likely, which will also increase the severity of illness.

Common symptoms to look out for include:
  • Persistent harsh cough for up to a week
  • Fever
  • Nasal discharge

3. Parvovirus

Canine parvovirus is a rather common disease. It’s highly contagious and often fatal. Many dogs contract it by sniffing, eating, or licking feces from an infected dog. Transmission can also occur indirectly by a person who’s been exposed to an infected dog recently. Even contaminated water bowls, clothes, and leashes can lead to parvovirus infection. This disease targets the stomach and small intestines, destroying cells, disrupting the gut barrier, and preventing proper absorption. From six weeks to six months of age, puppies are most likely to contract parvo. Vaccines are administered at six, eight, and 12 weeks old.

Some breeds are more likely to contract parvo than others, including German Shepherds, Labrador Retrievers, and English Springer Spaniels.

The most common symptoms of parvovirus are:
  • Lethargy
  • Weight loss
  • Weakness
  • Bloody diarrhea
  • Vomiting
  • Depression
  • Dehydration
  • Anorexia
  • Fever
dog vomiting
Image Credit: Mumemories, Shutterstock

4. Canine Distemper

Canine distemper affects more than just dogs. It can affect many mammals, including foxes, ferrets, felines, pandas, skunks, and more. This is a dangerous and extremely contagious disease that attacks multiple bodily systems simultaneously, including the respiratory, gastrointestinal, and nervous systems. Airborne exposure is the most common way that canine distemper is spread, though it can also be contracted by contact with contaminated items.

In wildlife, the symptoms of canine distemper are very similar to those of rabies.

For domesticated canines, the most common symptoms to look for are:
  • Discharge from the eyes
  • Nasal discharge
  • Persistent coughing
  • Loss of energy
  • Lack of appetite
  • Fever
  • Vomiting
  • Walking in circles
  • Tilted head
  • Muscle twitches
  • Seizures
  • Paralysis

5. Canine Coronavirus

This highly contagious infectious disease attacks the intestines. It doesn’t generally last very long, but it can result in serious discomfort for your dog. After the pandemic of 2020, most people are rightly terrified of anything with coronavirus in the name, but canine coronavirus is a completely separate strain that is not related to COVID-19.

Canine coronavirus is most commonly contracted by contact with infected feces, dogs, or other contaminated items. This disease takes one to four days for incubation and usually lasts just two to 10 days, though dogs can still carry the disease for 180 days following infection.

Common signs of canine coronavirus include:
  • Diarrhea
  • Lethargy
  • Loss of appetite
  • Loose stools with a foul odor and orange coloration
  • Blood or mucus in the stool
Jack Russell dog pooping
Image By: Kiadtisak-Khwanyu, Shutterstock

6. Rabies

There are few infectious diseases your dog could contract that are worse than rabies. This disease is incurable once symptoms start to present, though it’s treatable if caught early and can even be prevented by a vaccine. Rabies attacks the brain and spinal cord and it can affect any mammal, even humans. It’s most often spread through a bite from a wild animal, as rabies is present in saliva. Luckily, most dogs are vaccinated against rabies, so you shouldn’t have to deal with this disease.

Still, symptoms include:
  • Restlessness
  • Irritability
  • Aggression
  • Uncharacteristic affection
  • Behavior changes
  • Fever
  • Difficulty swallowing
  • Staggering
  • Seizures
  • Excessive drooling
  • Paralysis

7. Ringworm

Ironically, ringworm is actually a fungus, not a worm. This fungus can infect practically any domestic animal species. Luckily, ringworm infection is superficial and usually affects only a few parts of a dog’s body. It’s spread through direct contact with either an infected person or animal or a contaminated item. Unfortunately, ringworm spores can live for up to 18 months, which is why it’s such a common infection.

Thankfully, ringworm isn’t a fatal disease, though it’s still highly contagious. You’ll need a vet’s help to cure your dog of ringworm and prevent passing the infection to other animals or people.

Signs to look for include:
  • Circles of hair loss
  • Inflamed or scabbed skin patches
  • Brittle and easy to break hairs
  • Increased shedding
  • Brittle, rough claws
yeast infection on dog
Image Credit: ThamKC, Shutterstock

8. Kennel Cough

Kennel cough is easily spread through airborne contamination when your dog breathes in particular bacteria. Infections are common in places where multiple dogs gather, such as kennels, boarding facilities, dog training facilities, dog parks, and other similar places. It will usually heal on its own in a few weeks, though the symptoms can be worrisome to watch.

Look for:
  • Persistent honking cough
  • Discharge from the eyes
  • Excessive sneezing
  • Runny nose

9. Canine Hepatitis

Canine hepatitis has the potential to be deadly, with 10%-30% of affected dogs dying from the disease. If the dog is simultaneously infected with parvo or distemper, then the outlook looks even worse. Thankfully, this disease is rather rare in places where it’s vaccinated against.

Keep an eye out for these symptoms:
  • Fever greater than 104 degrees Fahrenheit
  • Leukopenia
  • Anorexia
  • Excessive thirst
  • Discharge from the eyes and nose
  • Abdominal pain
  • Enlarged tonsils
  • Apathy
  • Vomiting
Black dog vomiting
Image Credit: Mumemories, Shutterstock

10. Giardia

Giardia is a parasite that lives in the small intestine causing cysts. These cysts are then released into the world through feces, where they can live for weeks until they’re eaten by a new host, restarting the life cycle again. Giardia must be ingested for infection, so drinking contaminated water or eating contaminated food or feces are the only ways for your dogs to contract it.

Giardia is rather easy to avoid by ensuring your dog doesn’t have access to contaminated food and water sources.

Even so, accidents happen, so look for the following symptoms to determine possible giardia infection:
  • Vomiting
  • Dehydration
  • Worsening appearance of the coat
  • Loss of weight
  • Diarrhea



No matter what you do, you can’t eradicate the possibility of infectious disease. Diseases can be caused by simply breathing in airborne bacterium, and even with proper prevention, it’s always going to be a possibility. But knowing the signs and symptoms of common canine diseases can help you to diagnose them early on, giving your dog the best chance of a speedy recovery without any lasting effects.

Next on your reading list:

Featured Image Credit: Cassiohabib, Shutterstock

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