Infectious viruses and bacteria are dangerous threats to dog and cat health. Your pet needs a strong internal defense to protect themselves against contagious diseases. Routine vaccinations educate and strengthen your pet’s immune system against the most common and deadly pathogens.
To help you understand the power and potential in your pet’s core (i.e., essential) vaccines, Island Animal Hospital has rounded up the five greatest viral threats to dog and cat health.
Rabies virus in pets
Rabies is a merciless and unforgiving virus found worldwide. Rabies infects mammals and humans, and is a zoonotic disease and a public health threat. Once clinical signs appear the virus is always fatal. Because rabies is a human health risk, state and local laws require that dogs and cats be vaccinated every one to three years.
- Known locations — Rabies is present on every continent, except Antarctica.
- Transmission — Rabies can infect any mammal, although bats, skunks, raccoons, and foxes are most commonly affected in North America. Rabies is transmitted through direct contact with infected saliva, generally via a penetrating bite wound. Although less common, contact through mucous membranes (e.g., nasal passages, gums) is possible.
- Clinical signs — Rabies attacks the central nervous system and causes sudden behavior changes (e.g., dullness or aggression) and progressive paralysis. Infected wildlife may display abnormal wake and sleep patterns, or appear to lose their fear of humans.
- Prognosis — Rabies is always fatal in animals. Post-exposure vaccines are available for humans, but are effective only if administered before clinical signs appear.
Distemper virus in dogs
Canine distemper virus is also found worldwide, but widespread vaccination efforts have successfully decreased its U.S. prevalence. Distemper virus is most commonly diagnosed in puppies and unvaccinated or incompletely vaccinated dogs.
- Known locations — Distemper outbreaks most commonly occur in areas with large or mixed canine populations, such as animal shelters, breeding facilities, pet stores, and dog parks.
- Transmission — The virus is transmitted by direct contact with aerosol secretions (e.g., saliva, nasal discharge from sneezing).
- Signs — Distemper virus affects several body systems, including the respiratory, digestive, and nervous systems. Infected puppies and dogs may experience fever, lethargy, appetite loss, nasal discharge, gastrointestinal signs, muscle tremors or twitching, and seizures.
- Prognosis — Hospitalized treatment is required to manage illness-related signs and provide supportive care (e.g., anticonvulsants, anti-fever medication, fluid therapy, antibiotics, nutrition therapy). Sadly, distemper is often fatal in severely affected puppies and dogs.
Parvovirus in dogs
Canine parvovirus is a highly contagious virus that causes rapid and life-threatening illness by attacking quickly dividing cells in the bone marrow and gastrointestinal tract. Puppies and incompletely vaccinated young adult dogs are the most vulnerable.
- Known locations — Parvovirus can survive on objects and in soil for prolonged periods and can resist many cleaning agents. Virus particles (i.e., fomites) can be carried on clothing, shoes, pet care items, and skin. Because the virus is shed in infected pet feces, infected dogs must be strictly isolated to prevent viral spread.
- Transmission — Vulnerable puppies and dogs may contract parvovirus through direct contact with infected body fluids or contaminated objects.
- Clinical signs — Classic signs include persistent vomiting, diarrhea, lethargy, and inappetence. Because dehydration is rapid and can be life-threatening, puppies with suspected parvovirus require immediate veterinary attention.
- Prognosis — Early diagnosis and aggressive supportive care (e.g., hospitalization, fluid therapy, medications, and nutrition) are critical for survival. Severe cases may suffer intestinal complications or fail to recover.
Panleukopenia in cats
Panleukopenia, which is sometimes referred to as feline distemper, is actually caused by the highly contagious feline parvovirus that most commonly occurs in kittens and immunocompromised cats, and attacks rapidly multiplying cells in the bone marrow and intestinal lining.
- Known locations — Feline panleukopenia is found in the environment, most commonly in high cat population areas (e.g., shelters, catteries, unvaccinated colonies, and boarding facilities).
- Transmission — Virus particles are shed in infected cat secretions, including urine, feces, and saliva. Direct contact is unnecessary, because the virus can survive for up to a year in the environment.
- Clinical signs — Infected cats and kittens display weakness, lethargy, appetite loss, vomiting, dehydration, fever, and diarrhea.
- Prognosis — Without veterinary intervention, as many as 90% of affected cats may die from panleukopenia. Kittens younger than 8 weeks generally have a poor prognosis, while older cats can fully recover with aggressive supportive care.
Feline respiratory complex in cats
Cats are susceptible to several highly contagious respiratory viruses, including calicivirus, chlamydia, and feline viral rhinotracheitis (caused by feline herpes virus), that can progress to serious health problems (e.g., pneumonia, eye problems, systemic illness), and may re-emerge later during periods of high stress.
- Known locations — Respiratory diseases are often found in areas with high cat populations, including shelters, catteries, feral colonies, and boarding facilities.
- Transmission — These diseases are transmitted through close contact with infected cats and aerosolized droplets (e.g., sneezing, coughing).
- Clinical signs — Infected cats generally display upper respiratory signs (e.g., sneezing, coughing, respiratory difficulty) nasal discharge, fever, and eye or mouth ulcers, and may stop eating because of discomfort or breathing trouble.
- Prognosis — Mild cases may resolve on their own, or with antibiotics for secondary infections. Cats with severe signs or complications may require hospitalization and experience a prolonged recovery.
This list highlights only the top five most threatening diseases that we routinely vaccinate against at Island Animal Hospital and does not necessarily reflect your pet’s unique vaccine protocol. Based on your pet’s age, species, health history, and lifestyle (e.g., attending boarding, grooming, or training services), your veterinarian may recommend additional vaccines to protect them from contagious diseases.
Strengthen your pet’s defense against these common threats by scheduling your pet’s next preventive care appointment at Island Animal Hospital.