Cytauxzoon Felis: Why Ticks Are a Cat Killer and How to Stop Them

I’ve got to share something heavy that’s been on my mind. This past year, I lost no less than five cat patients to Cytauxzoon felis, a nasty tick-borne disease we call Bobcat Fever. Losing those patients hit hard, and it’s why I’m here to talk about why tick control isn’t just a good idea—it’s a must to keep your cats safe.

So, what’s Cytauxzoon felis? It’s a parasite ticks carry, mostly the Lone Star tick, though others like the American dog tick can spread it too. Bobcats handle it fine and are carriers of the parasite, but for our house cats, it’s a different story. A tick bites, and within a week or two, your cat’s burning up—fever as high as 106°F—barely eating, looking wiped out, with pale or yellow gums and struggling to breathe. That parasite gums up their blood vessels, hitting organs like the spleen, liver, and lungs hard. It’s a terrible disease and moves so fast, there is virtually nothing the pet parent (or myself) can do once we suspect it. All five of my patients—cats full of life—couldn’t pull through, even with everything I threw at it. It’s a race against time, and too often, we lose. That’s why I want to share this real threat with you, so you can take action to PREVENT, because a cure is often just not possible.

Why’s it so bad? Cytauxzoon triggers what I call a body-wide meltdown—protozoal sepsis, where inflammation goes haywire. Spotting it early with blood tests is tough because the disease progresses so fast, with loss of life often within 1 week of clinical signs. If we catch it, we hit it with drugs like atovaquone and azithromycin, plus fluids, oxygen, maybe transfusions, but even then the prognosis is still poor. A study from 2013 gave a 60% survival shot with this mix, but I’ve never seen that in practice.

Here’s the deal: you can stop this with tick control. Those Lone Star ticks love woods and grass—think Southeast, South-Central, Mid-Atlantic, and they’re spreading as the climate shifts. Outdoor cats are sitting ducks, but even indoor ones aren’t safe—ticks sneak in on you, your dog, or socks. I’m all about year-round protection. Products like Bravecto drops, Frontline, or Seresto collars work—kill ticks fast, before they get a chance to spread the disease. Run your hands over your cat daily—check the belly, ears, tail base. Indoor life’s the safest bet, but I know that’s not every cat’s cup of tea, so keep your yard trimmed and your yard treated if possible.

I know that many of the flea/tick preventatives get a bad wrap. People worry about the chemicals and toxins, but remember it’s a risk/reward equation. I always recommend sticking with name brand products with known safety margins. Skip products like Hartz or Sentry, and ask your vet for suggestions. Prescription products are often the best, safest, and efficacious, but there are some decent OTC options. ALWAYS use products as they are labeled, taking special care never to apply a dog product to a cat.

Want to know more? I’ve got a video on flea and tick prevention below—it’s a quick rundown on keeping your pets tick-free. Losing five patients drives me to make sure you never face that pain. We have the tools to prevent this, so lets use them!