An Ounce of Prevention Is Worth a Pound of Cure: Core Vaccines for Dogs and Cats

Whether you want to provide a healthy foundation for your new puppy or kitten, or you want to maintain your adult dog or cat’s health throughout the years, vaccinations are an important part of your animal’s overall well-being. Giving vaccinations on a regular schedule can help prevent serious and often life-threatening diseases in dogs and cats.

Throughout the last few years, vaccination guidelines have been revised for dogs and cats by several task forces including the American Animal Hospital Association (AAHA) and the American Association of Feline Practitioners (AAFP) to ensure dogs and cats are appropriately vaccinated across the United States. Immunization schedules have been tailored to fit your dog or cat’s specific needs and risk factors. In general, vaccinations for dogs and cats have been categorized into core and non-core vaccines.

What are core vaccines?

Core vaccines are recommended for ALL dogs and cats. These vaccines are used to protect against diseases that infect dogs and cats of all life stages and lifestyles. These diseases have high rates of infection, are usually severe and life-threatening, and have the potential to be transmitted from animals to people.

The core vaccines for dogs are rabies, canine distemper, hepatitis (adenovirus), parvovirus, and parainfluenza. Distemper, hepatitis, parvovirus, and parainfluenza are often given in combination vaccines such as DHPP or DHLPP (DHPP plus leptospirosis).

The core vaccines for cats are rabies, herpesvirus (rhinotracheitis), calicivirus, and panleukopenia (feline distemper). Herpesvirus, calicivirus, and panleukopenia are usually given in a combination vaccine referred to as HCP or FVRCP.

What diseases do core vaccines protect against?

Rabies: Rabies is a viral infection that affects both dogs and cats. The virus is transmitted through a bite wound from infected wildlife (raccoon, skunk, bat, and fox) or a domestic dog or cat through their saliva. This virus affects neurons, traveling up the nervous system to the brain. By the time symptoms are evident, the disease is fatal in animals and humans.

The rabies vaccine is required by law in the state of Wisconsin. If an unvaccinated pet bites a human, the pet may be confined to isolation or even euthanized. The earliest age for pets to receive the rabies vaccine is 12 weeks, but we recommend they receive it at 16 weeks. After the first rabies vaccine is given, an animal must be boostered one year later and then every three years thereafter.

Distemper in Dogs: Canine distemper is a highly contagious and fatal virus that attacks the gastrointestinal, respiratory, and nervous systems of dogs. In dogs, the virus is mostly spread through airborne exposure to the virus (through sneezing or coughing) from an infected dog or wild animal. The virus can also be spread through shared contact of food and water bowls and equipment.

Initial signs of distemper in dogs can include fever, coughing, sneezing, pus-like discharge from eyes/nose, lethargy, reduced appetite, and vomiting. When the virus attacks the nervous system, infected dogs often develop a head tilt, circling behavior, muscle switches, convulsions, seizures, and partial or complete paralysis.

Canine Hepatitis (Adenovirus): Canine hepatitis is an acute liver infection that is caused by canine adenovirus type-1. The virus is spread through bodily fluids including feces, urine, blood, saliva, and nasal discharge from infected dogs. Clinical signs of canine hepatitis include fever, lethargy, loss of appetite, coughing, and signs of liver disease such as jaundice (yellow pigmentation of the skin, whites of the eyes, and other mucous membranes), vomiting, and hepatic encephalopathy (decline in brain function that occurs as a result of severe liver disease).

Canine Parvovirus: Canine parvovirus is a highly contagious virus that can affect dogs of all ages, but unvaccinated dogs and puppies younger than 4 months are at the greatest risk. Parvovirus affects the gastrointestinal tract and is spread through contact with infected dogs and contact with contaminated feces, environments, people, or fomites (inanimate objects). Clinical signs of parvovirus include lethargy, fever or low body temperature, loss of appetite, abdominal pain, bloating, vomiting, and severe, often bloody, diarrhea.

Parvovirus can be very dangerous since the persistent vomiting and diarrhea can rapidly lead to dehydration, and damage to the intestines and immune system can cause septic shock. Most deaths from parvovirus occur within 48-72 hours after the onset of the above clinical signs if aggressive and intensive treatment is not started. Treatment can be very expensive and many infected dogs will die despite aggressive treatment.

Canine Parainfluenza: Canine parainfluenza virus is a highly contagious respiratory disease and is one of the most common pathogens associated with canine tracheobronchitis, also known as canine cough. Canine parainfluenza virus is transmitted through contact with nasal secretions of infected dogs. Clinical signs include coughing (dry or moist), low-grade fever, nasal discharge, lethargy, and loss of appetite. Dogs that are at greatest risk for this virus are dogs that are often in contact with other dogs such as:

  • Dogs that come from shelters, pet stores, and breeding kennels
  • Dogs that are boarded, go to doggie daycare, go to dog parks, or visit groomers

  • Dogs that participate in events and competitions

Feline Herpesvirus (Feline Viral Rhinotracheitis): Herpesvirus is a highly contagious infectious disease that affects cats. As with other herpes viruses, the virus is very species-specific and is only known to infect domestic and wild cats of all ages. Feline herpesvirus is one of the major causes of upper respiratory disease in cats and is spread though the saliva and eye and nose discharge from an infected cat or through inanimate objects (fomites) that have been contaminated with the viral particles. Clinical signs of feline herpesvirus include upper respiratory signs such as sneezing, nasal congestion, conjunctivitis (inflammation of the thin transparent layer of tissue that lines the inner surface of the eyelid and covers the white part of the eye), excessive squinting, and discharge from the eyes and/or nose that ranges from clear and watery to thick and contains pus.

Once a cat is infected with feline herpesvirus, it will become a carrier of the virus. Most carriers will become latent, which means the virus will survive in an inactive form within the cat’s body. Stress can cause the virus to reactivate and when this happens, the cat is again infectious. In most cases, the cat will show symptoms of an upper respiratory infection when the virus is reactivated. In some cases, however, cats with a reactivated feline herpesvirus infection will show no symptoms. They still will, however, be actively shedding the virus and present a risk to other cats.  

Feline Calicivirus: This virus is also an important cause of upper respiratory infections and oral disease in cats. Similar to feline herpesvirus, calicivirus is also spread through the saliva and eye/nose discharge from infected cats or through fomites with the viral particles. Clinical signs of calicivirus infection include upper respiratory signs similar to those caused by feline herpesvirus mentioned above. In addition to these upper respiratory signs, cats will calicivirus may also develop ulcers on the tongue, hard palate, gums, lips, or nose. In addition, the virus can cause anorexia, lethargy, and fever.

Feline Panleukopenia (also referred to as feline distemper or feline parvovirus): Panleukopenia is also a highly contagious and fatal virus that attacks actively dividing cells in the bone marrow and lymphoid tissue. In cats, the virus is transmitted primarily by the fecal-oral route (including through exposure to contaminated objects, clothing, hands, etc). Clinical signs of feline distemper include fever, anorexia, vomiting, diarrhea, dehydration, lethargy, and even sudden death.

When should we vaccinate?

Initially, neonatal animals have passive immunity from their mother. This means that puppies and kittens are temporarily protected from diseases by their mother’s antibodies. When these maternal antibodies are present, vaccination does not provide protection. When puppies and kittens are about 4-6 weeks of age, these antibody levels begin to decrease. There is a period of time in which the levels of maternal antibodies are too low to protect against disease but too high to allow the vaccines to work.

Unfortunately, it is impossible to know exactly when this “window of susceptibility” occurs in each puppy and kitten. Research shows that less than 50 percent of puppies and kittens will respond at 6 weeks, 75 percent at 9 weeks, 90 percent at 12 weeks and by 16 weeks, close to 100 percent will respond. Therefore, the typical puppy/kitten vaccine starts around 6-8 weeks of age and boosters are administered every 2-4 weeks until around 16 weeks of age, with the hope of narrowing the window of opportunity for infection. After a puppy or kitten receives its vaccines at 16 weeks, a booster one year later is recommended, then every three years thereafter.

All adult dogs and cats without medical records are treated as if they are unvaccinated. The core vaccines are administered, repeated one year later, and then every three years thereafter.

My cat is indoor only. Does it need vaccinations?

Yes. Cats should, at the very least, receive the core vaccines. At some point in a cat’s life, it will likely need to be boarded, transported, or taken to a hospital for treatment. Also, many indoor-only cats manage to sneak out of the house for periods of time. If your cat is not current on vaccines, it will be at a greater risk for contracting disease in these situations. In addition, as previously mentioned, the rabies vaccine is required by law in the state of Wisconsin, even for indoor-only cats.

Can vaccinations harm my pet?  

It is possible that your pet may have an adverse reaction to a vaccine. Fortunately, the benefits of the core vaccines far outweigh the risks. Typical mild vaccine reactions include swelling and tenderness at the injection site, mild lethargy for a day or two, a low-grade fever, and mild bouts of vomiting and/or diarrhea. More serious but far less common reactions include prolonged periods of vomiting and/or diarrhea, extreme lethargy, hives, difficulty breathing, cancer at the injection site (cats), and very rarely, death.

If your pet has a serious adverse reaction to a vaccine, you should speak to your veterinarian immediately and your pet may need to be treated promptly with injectable medications. For future vaccinations, pre-treating your pet with an anti-histamine can help to decrease the likelihood of these serious reactions. Vaccines may also need to be split and separated by 3-4 week intervals to avoid over-stimulating their immune systems. In rare cases, vaccine titers may be performed on pets if they have had extreme reactions to vaccines or have diseases that may be worsened by vaccinating (such as immune-mediated hemolytic anemia). In general, however, titer testing is not currently recommended for the general population of animals.  

In conclusion, vaccines help to prevent several diseases that affect pets. Taking your pet in to be examined and vaccinated by a veterinarian regularly has been considered one of the best and easiest ways to help your pet live a long and healthy life. In short, prevention really is the best medicine.

Is your dog or cat due for their vaccinations? Contact Badger Veterinary Hospital to schedule your pet's appointment today!