You can do many things to protect your dog from something that may cause your dog to get sick. You need to be aware of contagious canine diseases and have a plan and ongoing effort to protect them from disease-causing bacteria, viruses, fungi, and parasites.

Contagious Canine Diseases

These canine diseases can spread from one dog to another and from other animals to your dog.

Here are the ten most common contagious canine diseases:

  1. Parvovirus: Also known as CPV, this highly contagious virus affects the intestinal tract of dogs and can be deadly. It is spread through contact with the feces of an infected dog and passes between animals through contact with contaminated objects, surfaces, or people.
  2. Distemper: This virus affects dogs’ respiratory, gastrointestinal, and nervous systems and can be deadly if untreated. It spreads through contact with an infected animal’s saliva, urine or feces and contact with contaminated objects.
  3. Influenza: This is dog flu caused by a highly contagious virus that affects the respiratory system of dogs. It spreads through contact with an infected dog or contaminated objects.
  4. Kennel Cough: Various bacteria and viruses cause this infection, and it spreads through contact with an infected dog. It can cause a severe cough and can be very contagious.
  5. Canine Coronavirus: This virus affects the gastrointestinal system of dogs and spreads through contact with infected feces. It can cause vomiting, diarrhea and dehydration.
  6. Filariasis: This disease is also known as heartworm disease. The roundworm parasite causes it. The worm larvae spread from the blood of an infected animal to another through the bites of blood-sucking insects, such as black flies or mosquitos.
  7. Giardia: This parasite can cause gastrointestinal issues and spreads through contact with contaminated water or objects.
  8. Rabies: This fatal virus spreads through contact with the saliva of an infected animal. It affects the central nervous system and can be deadly if untreated.
  9. Lyme Disease: A tick-borne bacteria causes this disease with various symptoms. It spreads from a bite of an infected tick.
  10. Leptospirosis: This bacterial infection can cause various symptoms and spreads through contact with the urine of an infected animal.

Dog infected with canine diseases

Disease-Causing Bacteria

The best practice for protecting your dog from bacterial infections is to keep your dog up to date on its vaccinations. Keep your dog away from contact with wild animals and their waste. Do not allow contact with other animals that may be carriers. Do not let your dog swim in contaminated water or drink from stagnant water. Make sure to feed your dog only cooked food (never raw meat) and keep its environment clean. Practice good hygiene when handling your pet’s food and water.

Antibiotics are the preferred treatment for bacterial infections. However, use caution with antibiotics and only use them when necessary. Be sure to complete the full course of antibiotics as your veterinarian prescribes to avoid creating antibiotic-resistant strains of bacteria.


Vaccinations are the most effective way to prevent your dog from getting sick from viruses. Additionally, if your dog has exposure to other pets who are ill from a virus, the disease can pass to your dog. At the first sign of illness in one pet in a multi-pet household, isolate the sick one to separate it from the others as soon as possible. Thoroughly clean the common areas with disinfectant and sanitize dog toys and bedding. Clean up any waste, and do not let your healthy dogs have contact with the waste from a sick animal. Consider hiring an exterminator to treat outside areas if used by more than one pet.

Treatment for viruses is not always effective. You may also have to deal with secondary bacterial infections requiring antibiotic treatment. For example, it is common for a dog who has distemper caused by a virus also to get pneumonia caused by bacteria.


Common diseases caused by fungus include ringworm (caused by a mold-like parasite), aspergillosis, and blastomycosis. To protect your dog from these canine diseases and others caused by a fungus, practice good hygiene by cleaning and vacuuming your dog’s living area and bedding frequently. Keep your vaccinations up to date. Do not allow standing water to collect or bedding to get damp since the dampness can cause mold to grow.

Dogs can get Candida overgrowth, commonly called a yeast infection. Candida is a fungus. It is normally in the bodies of dogs and humans but kept in balance. Too much Candida may cause skin problems, itchy ears, and vaginal problems in females that may contribute to urinary tract infections.

Treatment with anti-fungal drugs may not be effective. Some strains of fungus are drug resistant. If you suspect a fungal infection, work with your veterinarian on a targeted treatment depending on where the infection presents itself in your dog.


The most common parasites are fleas, ticks, ear mites, intestinal worms, and heartworms. The best practice is to use a broad-spectrum preventative medication you give your dog monthly. You want to get rid of these parasites and prevent them from spreading.

Left untreated and not prevented, parasites carry disease vectors that can kill your dog. For example, treating a heartworm infestation is costly and dangerous for your dog, and your dog may not survive the treatment. It is far better to give preventative medicine. Start early and use a “de-wormer” for puppies. Once a puppy is at least four to five pounds, it can take the adult version. Every dog (not lactating) should take the parasite-preventative medicine monthly unless there are some contradictions.

Prevention is the Best Practice

It is not easy to deal with some of these serious canine diseases. When treatment is possible, the treatment may not work successfully. Your dog may get ill.  Some of these diseases can kill your dog. Keeping your dog from getting life-threatening canine diseases is best done by taking prevention seriously. Talk to your veterinarian to make a plan and follow a strong preventative strategy for keeping your dog safe from disease.