Canine distemper is a contagious and serious disease caused by a virus that attacks the respiratory, gastrointestinal and nervous systems of puppies and dogs.

The virus can also be found in wildlife such as foxes, wolves, coyotes, raccoons, skunks, mink and ferrets and has been reported in lions, tigers, leopards and other wild cats as well as seals.

How is Canine Distemper spread?

Puppies and dogs most often become infected through airborne exposure (through sneezing or coughing) to the virus from an infected dog or wild animal. The virus can also be transmitted by shared food and water bowls and equipment. Infected dogs can shed the virus for months, and mother dogs can pass the virus through the placenta to their puppies.

Because canine distemper also impacts wildlife populations, contact between wild animals and domestic dogs can facilitate the spread of the virus. Canine distemper outbreaks in local raccoon populations can signal increased risk for pet dogs in the area.

how can Canine Distemper be prevented?

Vaccination is crucial in preventing canine distemper.

  • A series of vaccinations is administered to puppies to increase the likelihood of building immunity when the immune system has not yet fully matured.

  • Avoid gaps in the immunization schedule and make sure distemper vaccinations are up to date.

  • Avoid contact with infected animals and wildlife

  • Use caution when socializing puppies or unvaccinated dogs at parks, puppy classes, obedience classes, doggy day care and other places where dogs can congregate.

  • Pet ferrets should be vaccinated against canine distemper using a USDA-approved ferret vaccine.


Canine parvovirus is a highly contagious virus that can affect all dogs, but unvaccinated dogs and puppies younger than four months old are the most at risk. Dogs that are ill from canine parvovirus infection are often said to have "parvo." The virus affects dogs' gastrointestinal tracts and is spread by direct dog-to-dog contact and contact with contaminated feces (stool), environments, or people. The virus can also contaminate kennel surfaces, food and water bowls, collars and leashes, and the hands and clothing of people who handle infected dogs. It is resistant to heat, cold, humidity, and drying, and can survive in the environment for long periods of time. Even trace amounts of feces from an infected dog may harbor the virus and infect other dogs that come into the infected environment. The virus is readily transmitted from place to place on the hair or feet of dogs or via contaminated cages, shoes, or other objects.

How to prevent Canine Parvovirus:

Vaccination and good hygiene are critical components of prevention.

Young puppies are very susceptible to infection, particularly because the natural immunity provided in their mothers' milk may wear off before the puppies' own immune systems are mature enough to fight off infection. If a puppy is exposed to canine parvovirus during this gap in protection, it may become ill. An additional concern is that immunity provided by a mother's milk may interfere with an effective response to vaccination. This means even vaccinated puppies may occasionally be infected by parvovirus and develop disease. To reduce gaps in protection and provide the best protection against parvovirus during the first few months of life, a series of puppy vaccinations are administered. Puppies should receive a dose of canine parvovirus vaccine between 14 and 16 weeks of age, regardless of how many doses they received earlier, to develop adequate protection.

To protect their adult dogs, pet owners should be sure that their dog's parvovirus vaccination is up-to-date. There are titers available that measure the dog's level of antibodies against the canine parvovirus, but the antibody level may not directly translate to protection if the dog is exposed to the virus. Ask your veterinarian about a recommended prevention program for your dog.

Until a puppy has received its complete series of vaccinations, pet owners should use caution when bringing their pet to places where young puppies congregate (e.g. pet shops, parks, puppy classes, obedience classes, doggy daycare, kennels, and grooming establishments). Reputable establishments and training programs reduce exposure risk by requiring vaccinations, health examinations, good hygiene, and isolation of ill puppies and dogs. Contact with known infected dogs and their premises should always be avoided.

In spite of proper vaccination, a small percentage of dogs do not develop protective immunity and remain susceptible to infection.

Finally, do not let your puppy or adult dog to come into contact with the fecal waste of other dogs while walking or playing outdoors. Prompt and proper disposal of waste material is always advisable as a way to limit spread of canine parvovirus infection as well as other diseases that can infect humans and animals.

Dogs with vomiting or diarrhea or other dogs which have been exposed to ill dogs should not be taken to kennels, show grounds, dog parks, or other areas where they will come into contact with other dogs. Similarly, unvaccinated dogs should not be exposed to ill dogs or those with unknown vaccination histories. People who are in contact with sick or exposed dogs should avoid handling of other dogs or at least wash their hands and change their clothes before doing so.


Canine heartworm disease develops when a dog is bitten by a mosquito carrying microscopic larvae of a parasite called Dirofilaria immitis. As a mosquito feeds, these microscopic larvae infect and begin their migration into the dog’s bloodstream, where they grow into adult worms. Adult female heartworms are larger than male heartworms and can grow 10 to 12 inches in length. They make their home in the right side of the heart and vessels of the lungs (pulmonary arteries), often causing lung disease and heart failure. Although easy to prevent, heartworm disease continues to be a major health problem for dogs living in the United States and wherever mosquitoes live. If you ever see or get bitten by mosquitoes, your dog is at risk!

Heartworm Lifecycle:

When a dog has a mature heartworm infection, female worms release their young (microfilariae) directly into the dog’s bloodstream. When a mosquito bites a dog with microfilariae in the blood, it ingests the microfilariae along with the blood. Over the following 10 to 14 days, these microfilariae develop and mature into infective larvae inside the mosquito. When the mosquito bites another dog, the larvae are left behind to enter the fresh wound. In 6 to 7 months, these infective larvae migrate inside the dog, eventually reaching the heart and vessels of the lungs, where they continue to grow to full maturity. The mature adult worms produce microfilariae of their own, which are available in the dog’s blood to infect other mosquitoes. Because heartworms may live for 5 to 7 years in the dog, each mosquito season can lead to increasing numbers of worms as they accumulate in unprotected dogs.

Heartworm Prevention:

Heartworm preventive medications are very effective when given properly on the prescribed schedule. It is important to monitor your pet’s weight to ensure your pet falls within the weight range listed on the package. All approved heartworm preventives are safe, very easy to use, relatively inexpensive, and some provide treatment for additional parasites. Prevention is always safer and more affordable than treating adult heartworm infections. It is your responsibility to faithfully give your dog the preventive medication as prescribed. The best way to reduce the risk of heartworm infection in your dog is to give preventive medication year-round. In addition, you can take steps to minimize mosquito exposure by limiting outdoor activity during peak mosquito times and by utilizing approved mosquito repellants. Be certain to have all dogs tested prior to initiating or restarting any heartworm prevention program as administration of preventives can cause life-threatening reactions when given to heartworm-infected pets. Routine testing is critical to avoid a delay in detecting early infection and starting life-saving therapy.

Some examples of prevention include:

  • Heartgard

  • Heartgard Plus

  • Interceptor

  • Interceptor Plus

  • Triheart Plus

  • Trifexis

  • Sentinel

  • Sentinel Spectrum

  • Revolution

  • Advantage Multi

  • Iverhart Plus Multi

  • Simparica Trio

  • Proheart 6

  • Proheart 12

  • Selarid

Heartworm Treatment:

  • Confirm the diagnosis. Once a dog tests positive on an antigen test, the diagnosis should be confirmed with an additional—and different—test. Because the treatment regimen for heartworm is both expensive and complex, your veterinarian will want to be absolutely sure that treatment is necessary.

  • Restrict exercise. This requirement might be difficult to adhere to, especially if your dog is accustomed to being active. But your dog’s normal physical activities must be restricted as soon as the diagnosis is confirmed, because physical exertion increases the rate at which the heartworms cause damage in the heart and lungs. The more severe the symptoms, the less activity your dog should have.

  • Stabilize your dog's disease. Before actual heartworm treatment can begin, your dog’s condition may need to be stabilized with appropriate therapy. In severe cases of heartworm disease, or when a dog has another serious condition, the process can take several months.

  • Administer treatment. Once your veterinarian has determined your dog is stable and ready for heartworm treatment, he or she will recommend a treatment protocol involving several steps. The American Heartworm Society has guidelines for developing this plan of attack. Dogs with no signs or mild signs of heartworm disease, such as cough or exercise intolerance, have a high success rate with treatment. More severe disease can also be successfully treated, but the possibility of complications is greater. The severity of heartworm disease does not always correlate with the severity of symptoms, and dogs with many worms may have few or no symptoms early in the course of the disease.

  • Test (and prevent) for success. Approximately 6 months after treatment is completed, your veterinarian will perform a heartworm test to confirm that all heartworms have been eliminated. To avoid the possibility of your dog contracting heartworm disease again, you will want to administer heartworm prevention year-round for the rest of his life.           


--American Heartworm Society