Why cats are such a medical black box

UNITED STATES – When my husband and I took our cat to the vet in early 2024, 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 anaemic, with a blood-cell volume so low, the vet said, it was “incompatible with life”.

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

“Cats have been so understudied,” said Dr 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 orthopaedic 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 specialities, dogs have long been the default.

Over time, however, it has become increasingly clear that what works for dogs may be worthless, or worse, for cats. Dogs and cats metabolise 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 Centre. “There’s a lot 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 are generally viewed as more independent and less sociable than dogs.

Cats are talented at masking their symptoms, which may also present differently from those in dogs, experts said.

Arthritic dogs often develop noticeable limps, which are easily spotted on walks, while many arthritic cats show no obvious signs of lameness, Dr 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 around them for only a few of those hours, it’s much easier to not realise that your cat is gradually changing over time,” Dr 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 could not 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 e-mailed 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.

Dr Karlsson has become known for her research on the dog genome, but she has always been a cat person at heart. In 2024, she unveiled Darwin’s Cats, a global community science project that aims to learn more about the genetic underpinnings of feline health and behaviour.

Focusing on cats did require some tweaks to the DNA collection process. Unlike dogs, cats tend to be highly reluctant saliva donors.

Dr Karlsson and her colleagues have been investigating whether they could sequence a cat’s genome using strands of fur collected with a comb. So far, she said in an e-mail: “The fur sequencing is working beautifully, and the owners and cats vastly prefer it.”

The resulting data could pave the way for a better understanding of how cats’ bodies work.

Dr Karlsson had first-hand experience with feline medical mysteries. Nearly a decade ago, she had a kitten who died after developing a rare autoimmune condition that caused anaemia. She 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,” Dr 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 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 enrol 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 had not known what to do with it or whether I even wanted to keep it.

Months later, I learnt that Dr Karlsson’s team was trying to extract DNA from feline fur samples, and I knew where the jar belonged.

In October 2024, 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. NYTIMES