Why are cats such a medical black box?

Over the last few decades, veterinary medicine has made enormous strides. But feline medicine has lagged behind its canine counterpart, and it is not always easy to provide evidence-based medicine for cats.

When my husband and I took our cat to the vet early last year, we were hoping to hear that we had nothing to worry about. Olive, a longhaired tortoiseshell kitten who had been the runt of her litter, was naturally quiet and skittish, prone to hiding in closets and napping behind the shower curtain. That made her hard to read -- and sometimes simply to find.

But days earlier, we had started wondering whether she might be sick. Did she seem even more reserved than usual? It was hard to say, but we decided to ask her vet just to be safe. The vet immediately noticed that Olive's gums were pale and that her heart was racing. A quick blood test revealed that she was severely anemic, with a blood-cell volume so low, the vet said, it was "incompatible with life."

So began a monthslong ordeal featuring repeated visits to the veterinary ICU, more than a dozen blood transfusions and few solid answers.

"Cats have been so understudied," said Elinor Karlsson, a geneticist at UMass Chan Medical School and the Broad Institute. "They're going to remain a black box unless something changes on the research side."

Dogs as the default

Over the last few decades, veterinary medicine has made enormous strides, allowing pets like Olive to receive highly advanced care. But feline medicine has lagged behind its canine counterpart, and it is not always easy to provide evidence-based medicine for cats. "It's still considered a bit of a niche interest," said Dr. Karen Perry, a veterinary orthopedic surgeon with a focus on feline health at Michigan State University.

Historically, many veterinarians essentially treated cats as small dogs, borrowing tests and treatments developed for canine patients to care for feline ones. Even in veterinary school, where students train for all sorts of specialties, dogs have long been the default.

"My anatomy book was 'Anatomy of the Dog,'" said Dr. Maggie Placer, the veterinary science programs manager at EveryCat Health Foundation. "We had PowerPoints and supplements for the cats."

Over time, however, it has become increasingly clear that what works for Rover may be worthless, or worse, for Tigger. Dogs and cats metabolize drugs differently, for instance, and some common canine drugs are toxic in cats. "It's not reasonable to assume that everything that works in a dog will work in a cat," said Dr. Bruce Kornreich, who directs the Cornell Feline Health Center. "There's a lot that we still need to learn."

On some level, the long-standing focus on dogs was practical. Studies have shown that pet owners take dogs to the vet more often than they take cats.

Is that because society simply places less value on the lives of cats than on dogs? Cats, after all, are far less likely to be working animals, and they're generally viewed as more independent and less sociable than dogs. "Maybe there are biases against cats," Kornreich said.

As a dog person who married a cat person and now has pets of both kinds, I do think that cats (and the people who keep them) tend to be derided or dismissed in ways that dogs aren't. But I don't think that fully explains why doting pet owners are less likely to seek care for their feline charges.

Over the years, my husband and I have gone to great lengths to help all of our ailing pets. But taking the cats to the vet was absolutely more stressful, for them and for us, than taking the dogs. And the cats simply didn't seem to need as much medical care.

Maybe that was a true reflection of reality. Our dogs regularly romped through Prospect Park in Brooklyn, swapped germs with playmates and scarfed down rogue chicken bones, while our cats lived cosseted, indoor lives.

Now I suspect that we may have missed signs of illness in our cats. I had worried that we were overreacting when we took Olive to the vet for seeming maybe, slightly, sort of not herself. In fact, she was critically ill.

Cats are talented at masking their symptoms, which may also present differently from those in dogs, experts told me. Arthritic dogs often develop noticeable limps, which are easily spotted on walks, while many arthritic cats show no obvious signs of lameness, Perry said. They might just jump onto the couch less often or seem crankier when being handled.

"Given that cats are sleeping so many hours a day, and owners are generally only around them for a few of those hours, it's much easier to not realize that your cat is gradually changing over time," Perry said.

In retrospect, it seemed likely that Olive had been quietly declining for weeks.

Eventually, vets concluded that her immune system was destroying her red blood cells. But they couldn't say what had triggered it or find a medication that helped. Finally, as something of a last resort, an internist suggested that we could consider removing Olive's enormous spleen, which was probably where her red blood cells were being destroyed.

I emailed another veterinarian for a second opinion. "Splenectomy is not the worst option," she wrote back, noting that it was an established treatment for human patients with similar conditions. "We just don't have data in vet med," she added, "especially in cats."

Getting curious about cats

The situation does seem to be improving, albeit slowly, experts said. Some vet schools are increasing their investment in feline health, and clinicians are trying to build stress-reducing, feline-friendly practices. And more scientists are probing the genetic and environmental causes of diseases in cats.

Karlsson has become known for her research on the dog genome, but she has always been a cat person at heart. Last year, she unveiled Darwin's Cats, a global community science project that aims to learn more about the genetic underpinnings of feline health and behavior.

Focusing on cats did require some tweaks to the DNA collection process: Unlike dogs, cats tend to be highly reluctant saliva donors. Karlsson and her colleagues have been investigating whether they could sequence a cat's genome using just a few strands of fur collected by a comb. So far, Karlsson said in an email, "the fur sequencing is working beautifully, and both the owners and the cats vastly prefer it!" The resulting data could pave the way for a better understanding of how cats' bodies work and what to do when things go haywire.

Karlsson had firsthand experience with feline medical mysteries. Nearly a decade ago, she had a kitten who died after developing a rare autoimmune condition that caused anemia. Karlsson still has the kitten's littermate, Lacey, who has some severe environmental allergies.

"I've always wondered if they both might have inherited a predisposition to immune disorders," Karlsson said. "The vets can't really say much because there is so little information."

Her story turned out to be eerily similar to our own. Olive, too, died just a few months after first falling ill. We never had the chance to weigh the pros and cons of an untested surgery. And we had no real explanation for Olive's decline.

But we did have Olive's littermate, Juniper, who seemed healthy and vigorous, although she, too, seemed to have environmental allergies. We jumped at the chance to enroll her in Darwin's Cats.

We also had a little clump of Olive's fur. A veterinarian had put it in a tiny glass jar after Olive died and given it to us as a keepsake. At the time, I hadn't known what to do with it or whether I even wanted to keep it. But I was too emotionally drained to protest and tucked it away in a drawer.

Months later, I learned that Karlsson's team was trying to extract DNA from feline fur samples, and I knew where the jar belonged. In October, I handed it over to the researchers. There was a good chance Olive's fur would never yield anything interesting or, perhaps, even usable. But it was also possible that there were answers in there, if only someone would look.