As loving pet owners, we naturally want to protect our furry companions. Unfortunately, the same way viruses and other pathogens plague people, our feline friends are susceptible to a variety of harmful organisms, too. Three particular viruses are especially worrisome for cats—feline leukemia, feline immunodeficiency virus, and feline infectious peritonitis, which is caused by a feline coronavirus. The good news? You can help prevent these potentially deadly viruses from infecting your pet. First, let’s learn a little more about these feline viruses and the diseases they cause.

Feline leukemia virus

Approximately 2 percent to 3 percent of all U.S. indoor cats are affected by this retrovirus, but the infection rate may be much higher (i.e., around 30 percent) for cats who spend time outdoors, or who are otherwise at risk. A leading cause of cancer and death, feline leukemia virus (FeLV) can be a devastating diagnosis for cats and their owners. FeLV was initially discovered and named because of its propensity to infect and kill feline white blood cells, but the virus can secondarily affect multiple body areas, and cause a variety of diseases. 

FeLV is shed in an infected cat’s urine, saliva, blood, feces, and milk. Transmission typically occurs through bite wounds, mutual grooming, and, rarely, shared litter spaces. Kittens may also become infected from the mother in utero, or through the mother’s milk. 

Feline immunodeficiency virus

Also known as feline acquired immune deficiency syndrome (AIDS), this virus has a similar effect on cats as the human immunodeficiency virus (HIV) on people. After infection occurs, the virus slowly attacks the immune system, putting affected cats at risk for secondary infections from bacteria, viruses, and other pathogens that a healthy immune system could normally fight off. While some affected cats eventually succumb to secondary disease, many FIV-positive felines enjoy average lifespans, although this may be hindered by co-infection with FeLV. 

FIV is most commonly transmitted via bite wounds. Unlike FeLV, FIV is rarely spread through grooming, or shared litter or food spaces. Therefore, FIV-positive cats can often safely live with FIV-negative cats, if fighting is not a concern. FIV is not typically transmitted from mother to kitten, although this can occur. 

Feline infectious peritonitis

This condition occurs when a common feline enteric coronavirus (FeCV) undergoes mutation, leading to systemic infection. The virus is common in the feline population but, for most healthy cats, poses no risk. The majority of infected cats will exhibit minimal or no signs, because their immune system mounts an appropriate response. However, a small percentage of cats will experience a viral mutation that leads to inflammation, often in the abdomen, brain, or kidney, known as feline infectious peritonitis (FIP). Once clinical disease signs are present, cats usually experience progressive signs that eventually prove fatal. 

FeCV, which is quite contagious, is spread through feces and saliva, and prevention is difficult, especially in high-density populations like shelters.  

Common signs of feline viral infection

While feline viral infection signs can vary widely among individual cats, most will initially exhibit common, non-specific signs, such as weight loss, decreased appetite, and depression. Other common signs include poor hair coat, enlarged lymph nodes, or pale gums. Since FeLV, FIV, and FIP can all lead to secondary infections, clinical signs may manifest related to the body area where the infection is occurring. Owners may observe seizures, behavioral changes, diarrhea, vomiting, urinary problems, or skin concerns as a result of these viral infections. Therefore, you must not ignore any abnormal signs in your cat. 

Protecting your cat from viral infection

There is no question that certain feline populations are at risk for these viral infections. Kittens have immature immune systems, making them particularly vulnerable to the virus’s effects, including serious disease. Cats who spend time outdoors are more likely to contract FeLV or FIV because of their propensity to fight and sustain bite wounds. Cats housed in shelters or other facilities where they are kept in close quarters are naturally more susceptible to infection. So, what can you do to protect your feline friends from these dangerous viruses?

  • Keep cats indoors — The more your cat ventures outdoors, the more likely they are to come in contact with an infected cat. 
  • Vaccinate — Fortunately, a safe, effective vaccine is available to prevent FeLV infection, and should be administered to all kittens, with boosters recommended annually for all adult cats who venture outdoors. No vaccine is available for FIV or FeCV. 
  • Test — If you’ll be welcoming a new cat into your home, ensure they are tested for FeLV and FIV prior to introducing them to other household cats. 

At Haskell Valley Veterinary Clinic, we care deeply about your feline companions. If you have questions about feline viruses, would like more information, or are concerned about your cat, don’t hesitate to contact us.