10ish Things I Learned About Feline Panleukopenia

Feline panleukopenia aka panleuk is a jerk of a virus that attacks mostly young or at-risk cats. Before I dive into all things panleuk, please understand: Your cat is low-risk as long as he or she is vaccinated at annual vet visits. Adult cats and older vaccinated kittens (6+ months) have strong immune systems, and with vaccinations, typically conquer the virus with little difficulty. I’ll cover high-risk cat populations, like small non-vaccinated kittens (1 lb. and under) in this post. I don’t want you to worry that your indoor-only, vaccinated cat has feline panleukopenia because they puked up a hairball. Panleuk has symptoms that are extremely common in other illnesses too, and it’s more likely your vaccinated cat has another illness over panleuk. But, as I always say, if your cat is sick in any way, please talk to your vet.

The Silent Killer Who Took JR

One morning in August 2019, I walked into the bathroom to find my little foster kitten, JR, limp and cold on the floor. His blue eyes were glazed over, even though they had twinkled the night before.

I picked him up, crying and screaming, “JR! Don’t do this to me! You’re not going to die on me! JR!”

Then, I saw him take a breath. Then another. Although I knew in my heart they were likely his last breaths, I rushed him to the ER while giving CPR, hoping against all hope they could save his tiny, precious life.

Unfortunately, my gut was correct.

My heart was literally in my feet, and I was totally devastated. I am a foster and my responsibility is to prevent this exact thing from happening. I went right to the shelter with his body in a cardboard coffin. Tears streaming down my face, I confessed how I failed him as I handed him over to my friend and fellow cat boss babe Tammy, who worked there at the time.

Tammy said, “You didn’t fail him. If something was clearly wrong, you would have known and done something. I’m so sorry this happened.”

Dr. Morgan Shafer, another cat boss babe, examined his body. The results? Positive for panleuk.

What?! I’d heard all this stuff about how awful panleuk presented (like explosive diarrhea and vomit everywhere), and JR didn’t have that, so what the heck happened? How did I miss this?

The answer is, it’s easy to miss, most small kittens lose the battle and early detection doesn’t mean survival. Let’s take a look at this jerk of a virus.

1. Feline panleukopenia has many names.

According to PetMD, feline parvovirus (FPV) is also called feline panleukopenia (aka panleuk) because it causes a low white blood cell count (pan = all, leuko = white blood cells, penia = lack of).

Although it’s sometimes referred to as feline distemper, many sources I’ve read say that’s a misnomer because it’s more closely related to the canine parvovirus.

2. Feline panleukopenia is a vicious virus.

Panleuk is a virus that attacks all of the body’s rapidly growing and dividing cells, specifically the intestinal tract, bone marrow, skin, and a developing fetus. It can lead to anemia, but also leave the body vulnerable to other viral and bacterial illnesses. If a pregnant cat contracts panleuk early in pregnancy, the fetuses will likely die. Contracting it late in pregnancy could lead to kittens being born with cerebellar hypoplasia (CH) aka Wobbly Kitten Syndrome, which we’ll discuss below.

3. Feline panleukopenia has a mortality rate as high as 90%.

Without supportive care, AVMA reports up to 90% of cats with panleuk may die. And with supportive care, there is no guarantee the cat will survive.

High-risk cats include:

• Kittens under 6 months
• Pregnant cats
• Immune-compromised cats
• Non-vaccinated cats

4. Feline panleukopenia is easily spread and likes to stick around.

Panleuk is spread through urine, stool, and nasal secretions. Like your ex, panleuk can hang around in the environment for as long as a year, waiting for it’s next opportunity. The virus can also be shed in a recovered cat’s #1 and #2 for up to 6 weeks, per PetMD.

To disinfect, many shelters or vet offices use Rescue, which kills a lot of pathogens. Another method is to dilute 1 part bleach in 32 parts water.

5. Feline panleukopenia can’t decide: Lots of symptoms or silent killer?

When you look at this list of symptoms, you’ll see even more why panleuk is one sneaky SOB – these symptoms could be, and are more often than not, a million other illnesses. Some kittens and cats display one or two symptoms, and they may even seem mild (JR had mild diarrhea). And, sometimes cats display zero symptoms. That’s why this virus is such a jerk.

Health Symptoms:

• Vomiting
• Diarrhea/bloody diarrhea
• Dehydration
• Weight loss
• High fever
• Anemia
• Rough hair coat

Behavioral Changes:

• Depression
• Complete loss of interest in food
• Hiding
• Neurological symptoms, like lack of coordination

Symptoms taken directly from PetMD.

Remember: Cats are reeeeeeeally good at hiding illness and injury. You can only act on the information you have, so it’s important to be observant, but accept the fact that you could still suddenly lose a kitten to panleuk, and that is not your fault.

6. Feline panleukopenia often wins because of dehydration.

Dehydration is typically what causes a kitten or cat to die from panleuk, even if they are drinking water or getting fluids, because they can’t stay hydrated. A secondary bacterial infection is the 2nd most common reason cats and kittens don’t survive panleuk.

Source: Pet Revival Health

7. There are a variety of ways to test for feline panleukopenia.

Metropolitan Veterinary Associates explains that blood work indicating dehydration and low white blood cell counts combined with vaccination history and living conditions (i.e. being in a shelter or another space with a lot of animals) can point to panleuk. Many private vets confirm panleuk with a positive fecal ELISA test. Although designed to test for canine parvovirus, ELISA is often used for cats too. False negative can happen early or late in the virus’ presentation.

8. You can treat feline panleukopenia, but you won’t always be successful.

Although the outcome for kittens under eight weeks is poor, the treatment for kittens and cats is the same: focus on hydration, replace nutrients, and prevent a secondary infection. Most often, cants and kittens need hospitalization because they require round-the-clock care:

• Intravenous fluids
• Anti-nausea meds
• Broad spectrum antibiotic

If a cat survives 5 days fighting the virus, the chance for survival significantly increases. Once a cat beats the virus, he or she will be immune forever.

Sources: PetMD, AVMA, and Metropolitan Veterinary Associates.

9. Feline panleukopenia can cause Wobbly Kitten Syndrome.

Have you ever seen a cat or kitten online that walks like it’s drunk? These kittens have cerebellar hypoplasia or CH, an underdeveloped cerebellum. Since the cerebellum controls motor skills, CH causes mobility issues, like jerky movements and tremors (kinda like me at 1 a.m. on a Sat night – haha).

As iCatCare.org explains, kittens born with CH is usually because their mom contracted panleuk late in pregnancy. The cerebellum develops late in pregnancy and continues to grow the first few weeks after birth. The virus attacks the cerebellum, causing issues with motor skills, balance, and coordination. There is no treatment for CH, but these cats aren’t in any pain and live full and wonderful lives.

Although panleuk is the most common cause, CH can also be caused by poisoning, malnutrition, or trauma.

10. Vaccination is the key to preventing feline panleukopenia.

Vaccines give cats and kittens the best protection. Adult cats should receive the FVRCP vaccine (“P” = panleukopenia) every 1-3 years.

There are different opinions on when kittens should start getting their vaccines. At the shelter where I foster, kittens get their first booster at 1 lb., then every 3 weeks until they hit 4 lbs. (16 weeks). Some vets may recommend boosters at 8, 12 and 16 weeks. New kitten parents: Talk to your vet and follow his or her recommendation. Kitten fosters: Ask your organization for their kitten vaccination policy.

Anecdotally, I’ve heard that kittens receiving boosters are still vulnerable. Please do everything you can disinfect areas where you have very small kittens.

Could JR Have Been Saved?

We’ll never know, but the odds were stacked against JR, especially with his young age. Even with early detection, the outcome would have likely been the same. Given he was alert, purring, and had mild diarrhea, he probably wouldn’t have been tested for panleuk. I would’ve been sent home with anti-diarrhea meds, maybe one bag of fluids, and he still would have crossed the rainbow bridge. Trust me, I’m not trying to let myself off the hook. It’s taken months of reflection and research to get me to this point of forgiving myself and understanding I could only work with the info I had.

The Skinny: Feline Panleukopenia Is a Giant, Selfish Jerk

While nearly every cat gets exposed to panleuk at some point in their lives, the average indoor cat will likely never get sick from it. You will probably only see this virus if you foster or deal with outdoor, non-vaccinated colonies (if you care for a colony, contact local shelters and rescue groups to see if you can trap your colony and bring them in for spay/neuter and vaccines). Like anything else, keep a close eye on the young, old and immune-compromised. And, please, don’t be a moron: Vaccinate your cat.

If something seems off – call your vet. Most likely, it’s not panleuk, but better to cover all your bases and let a professional determine next steps.

I miss you JR. You’ll forever be mine. I’m sorry your life was so short, but I hope you felt loved.