The feline panleukopenia virus, often shortened to FPL or FPV, is known by several other names, including feline infectious enteritis, feline parvo, and most commonly, feline distemper. The disease doesn’t occur in dogs.
Despite what these different names indicate, the organism that causes FPV isn’t related to the viruses that cause canine distemper or parvovirus. However, just to add to the confusion, feline panleukopenia is actually caused by a parvovirus and much of the information on canine parvovirus can be applied to FPV.
According to the Morris Animal Foundation, the feline panleukopenia virus (FPV) has come “roaring back” in the last 15 years following a sharp decline after the FPV vaccine (now part of the “kitten shots” series) was introduced in the late 1960s.1 “Roaring back” isn’t quantified in the Foundation’s article, nor does it mention where the spread of the disease is occurring.
A new strain of FPV has apparently been ruled out, but interestingly, researchers at the University of Sydney are investigating the resurgence of the disease by studying the intestinal virome (collection of gut viruses) of FPV-infected cats. This would seem to indicate the disease is occurring in vaccinated cats, but that’s just an educated guess on my part. Hopefully, more detailed information will be released in the near future.
How the Virus Is Transmitted and Cats at Highest Risk
FPV is ubiquitous and extremely stable in the environment. The organism can live for years in contaminated environments and can survive freezing temperatures as well as treatment with common disinfectants such as alcohol and iodine. Thankfully, a mixture of 1 part bleach to 32 parts water effectively kills it.
The virus is highly contagious and potentially life-threatening. It attacks rapidly, dividing cells in the body — especially those found in the gastrointestinal (GI) tract, bone marrow and the stem cells of kittens in the womb. Because the virus affects blood cells, FPV can lead to anemia. It can also make the bodies of infected kitties more susceptible to other viral and bacterial infections.
Severe cases of panleukopenia are most commonly seen in kittens between 2 and 6 months of age, pregnant females and immunocompromised cats. Kitties living in groups, for example, barn cats and feral cats, and those living in stressful shelter and rescue situations are at highest risk for outbreaks of the disease.
In healthy adult cats, FPV is usually mild and can even go undetected because there are no observable symptoms. Kitties who survive the infection are immune to further infection with the virus. Panleukopenia can also infect wild cats, as well as minks, raccoons and ferrets.
The virus is shed in the bodily secretions of infected animals for up to six months following exposure. Cats can become infected through direct exposure to infected feces, saliva or viral particles left behind on food and water dishes, towels, bedding or surfaces around the home or shelter. FPV can also be transmitted in utero from an infected mother cat to her kittens, as well as to newborn kittens when mom grooms them.
Symptoms of an FPV Infection
The virus enters through a cat’s mouth or nose. The lymph nodes in the throat are affected first, and then over the next two to seven days, the infection moves quickly to the bone marrow and intestine. In the bone marrow, the virus suppresses production of all white blood cells (“panleukopenia” means “all white shortage”), which are the immune cells required to fight the infection. Without white blood cells, the cat’s body can’t stop the progression of the virus.
In the intestine, the virus causes ulcers that lead to diarrhea, life-threatening dehydration and overwhelming secondary bacterial infections. Death is usually caused by either dehydration or a bacterial infection that spreads from the gut to a kitty’s systemic circulation. In infected cats, FPV causes symptoms similar to those seen in canine parvovirus, including:
Vomiting |
Depression |
Diarrhea (sometimes bloody) |
Hiding |
Refusal to eat |
Anemia |
High fever |
Significant weight loss |
Profound dehydration |
Neurologic signs if the virus attacks the brain |
How Panleukopenia Is Diagnosed
Your veterinarian will take a complete history, including your cat’s general health and whether she may have recently come in contact with other cats or spends time outside. Since the virus causes symptoms also seen in several other conditions, including poisonings, feline leukemia (FeLV), feline immunodeficiency virus (FIV) and pancreatitis, your veterinarian will want to rule those things out first.
Routine laboratory tests include a complete blood count (CBC), a biochemistry panel and urinalysis. In cats with FPV, bloodwork will typically show a dramatic decrease in white blood cells, and a low red blood cell count as well, indicating anemia. A fecal sample may also be taken to check for viral shedding.
Specific tests for FPV include immunofluorescent antibody testing, the polymerase chain reaction test and virus isolation — however, they aren’t commonly used. Generally speaking, kittens with severe GI symptoms plus an extremely low white blood cell count plus anemia are considered probably infected with the panleukopenia virus.
FPV Treatment Options
Unfortunately, there are no antiviral protocols specific for FPV, so the only way a cat can survive is if she can be kept alive until her immune system is able to throw off the infection. At a minimum, this requires aggressive intravenous (IV) fluid therapy to prevent dehydration, and control of opportunistic intestinal bacteria.
Depending on the kitty’s symptoms, other medications may be required, including expectorants to help manage bronchitis or pneumonia, anti-emetics to help control nausea and vomiting, and whole blood transfusions for severely anemic patients. Sometimes nutritional support is required as well because the cat isn’t eating, and often pain management is necessary.
Cats with FPV must be hospitalized during this critical period and remain isolated from other felines. Integrative veterinarians may also use IV vitamin C therapy, homeopathic FPV nosodes, as well as microbiome restorative therapy during this time to assist in rapidly stimulating a cat’s immune system in a race to save her life.
Unfortunately, even with aggressive supportive therapy, FPV is almost always fatal in very young or immunocompromised kittens. Older cats with stronger immune systems have a much better prognosis, but even their chances of survival are not great. Veterinary vaccine expert Dr. Ronald Schultz believes two well-timed panleukopenia vaccines given to kittens is the best way to protect most cats from the disease. Dr. Richard Pitcairn advocates the use of FPV nosodes instead.
Home Care
For cats lucky enough to survive FPV, the good news is they’ll never catch it again. The less good news is it can take weeks or even months to fully recover.
Once an FPV kitty is able to go home, ongoing excellent supportive care will be necessary. Your cat will need plenty of rest in a quiet, warm area of your home, away from stressful situations and the daily household hustle and bustle. She’ll also need to be isolated from other cats until she’s fully recovered.
It’s important to pet and cuddle your cat, because this disease has a particularly depressing effect both physically and mentally, and your kitty will need attention and affection while she recovers. But with that said, you’ll need to practice very strict hygiene during your cat’s recovery from the infection.
It’s important to keep in mind that viral particles can remain around your home and on surfaces in the home for many months. Be sure you’re cleaning especially well anything that comes in contact with your kitty and her belongings to avoid unintentionally spreading the virus to other cats in the household.
Anyone coming into your home should use every precaution to prevent spreading the disease, including through contaminated shoes and clothing. It’s also important to thoroughly disinfect hands and arms before coming in contact with non-infected animals.
Household bleach can be used as an effective disinfectant. However, the best way to ensure you’ve truly eradicated the virus from your home is to replace all your cat’s belongings with new ones, including bedding, toys, dishes, towels and litterboxes, once she’s recovered.