Cyprus is house to one million or so free-roaming cats that wander its streets, parks, or even luxurious motels. They’re about as a large number of as other folks. So when a dangerous cat outbreak started sweeping around the Mediterranean island this yr, the people temporarily spotted one thing was once extraordinarily fallacious.

Stray and feral cats died by way of the 1000’s. Puppy cats died, too. Their bellies was swollen like bowling balls, a symptom function of the illness pussycat infectious peritonitis, or FIP, this is nearly 100% deadly left untreated. FIP is brought about by way of a coronavirus that infects cats however no longer people. (It’s associated with however distinct from SARS-CoV-2.) The illness can fester in small, indoor outbreaks, nevertheless it had by no means raced throughout a complete island, leaving 1000’s of lifeless out of doors cats in its trail. In early 2023, lab-confirmed FIP instances in Cyprus shot up 20-fold. The unusualness of this outbreak apprehensive cat house owners at the island and confounded veterinarians around the globe.

It gave the look of one thing about FIP should have modified, however what? Had a brand new pressure seemed? Or, professionals puzzled, may just the outbreak have one thing to do with the unfold of COVID, additionally brought about by way of a coronavirus and in addition identified to contaminate cats?

Both means, the pandemic got here with a silver lining for FIP: It made treating the cat illness so much more uncomplicated. The 2 coronaviruses proportion sufficient similarities that COVID antivirals also are efficient towards FIP—actually, they’re downright miracle remedies. “It’s like bringing those cats again from the lifeless,” says Gary Whittaker, a virologist at Cornell who research FIP.

The primary FIP remedy seemed a pair years earlier than the pandemic, however for a very long time cat house owners’ may just simplest purchase black-market variations on-line. The reaction to COVID supercharged analysis into antivirals towards coronaviruses, increasing the arsenal of gear and making them extra broadly to be had. So Cyprus was once oddly ready for this new viral scourge. This summer season, the federal government started freeing leftover stockpiles of the COVID antiviral molnupiravir for cats with FIP. If this outbreak had took place even a couple of years previous, Cyprus would have needed to watch helplessly as its cats died one at a time.

In January, veterinarians on Cyprus started noticing an bizarre collection of FIP instances. Demetris Epaminondas, the vice chairman of the Pancyprian Veterinary Affiliation, instructed me that his spouse, additionally a veterinarian, hadn’t observed any instances of FIP the yr earlier than. This yr, she’s observed greater than 50. The earliest instances clustered within the capital town of Nicosia, however they quickly started radiating outward, attaining essentially the most rural, far off areas of Cyprus ultimate—as though a unique pathogen was once spreading from an preliminary epicenter.

The pussycat coronavirus is a perplexing virus that moves other cats in radically alternative ways. In maximum cats, it infects the intestine, inflicting simplest transient diarrhea, if any signs in any respect. However in a small minority—possibly the ones already underneath tension or with a genetic predisposition—the virus mutates into a brand new and distinctive pressure throughout the cat, infecting white blood cells that shuttle all the way through the frame inflicting irritation. Significantly, those mutated traces infrequently unfold to different cats. When the virus beneficial properties the power to purpose serious illness, it kind of feels to lose the power to contaminate new hosts. It assists in keeping operating smack into an evolutionary trade-off.

However in uncommon instances, the virus turns right into a “sizzling pressure,” says Danielle Gunn-Moore, a pussycat medication specialist on the College of Edinburgh. Those traces have simply the precise mutations to sicken cats with FIP and unfold to new ones. Scientists intently documented one such outbreak in a refuge in Taiwan, the place the similar pressure of FIP seemed to kill 8 cats. Gunn-Moore and her colleagues in Edinburgh—together with Charalampos Attipa, a vet at first from Cyprus who accumulated one of the vital preliminary outbreak knowledge—at the moment are sequencing viruses to peer if a in particular sizzling pressure has evolved the power to unfold on a large scale. Piecing the genomes in combination has been technically difficult, she instructed me, as a result of not like with COVID, researchers have few absolutely sequenced pussycat coronaviruses to make use of as reference. They hope to investigate the consequences from about 100 samples quickly. An bizarre “sizzling pressure”—possibly blended with some genetic disposition in Cyprus’s cats—is the workforce’s most sensible speculation.

It didn’t get away their consideration, regardless that, that this bizarre outbreak comes at the heels of an epidemic of every other coronavirus: SARS-CoV-2, after all. The workforce puzzled if the pussycat coronavirus can have recombined with SARS-CoV-2 to create a virulent new coronavirus, regardless that the 2 are divergent sufficient that this situation could be bizarre. Or would possibly SARS-CoV-2 be concerned however not directly? FIP shows an bizarre development the place earlier immunity from a vaccine can perversely make the illness even worse, Gunn-Moore instructed me. (This has foiled FIP vaccines for cats, regardless that the development doesn’t display up with COVID vaccines for people.) COVID has most probably inflamed a few of these cats lately, and he or she wonders if having had COVID would possibly aggravate FIP in a similar fashion—an surprising outcome of the worldwide pandemic.

Till reasonably lately, vets had no technique to deal with FIP. The turning level got here in 2018, when a researcher at UC Davis examined a brand new drug chemically very similar to the antiviral drug remdesivir in 10 cats with FIP. All 10 had been cured. This was once unprecedented. Information of the miracle remedy started spreading by way of phrase of mouth, however for the reason that corporate that patented the drug refused to license it, Chinese language producers started making very a success black-market variations. Remdesivir, which additionally works towards FIP, has since grow to be to be had thru quite a lot of way too.

In past due 2020, as new COVID antivirals akin to molnupiravir started producing buzz, Chinese language producers as soon as once more noticed the possibility of FIP. An organization started promoting unlicensed molnupiravir to in another country cat house owners, touting an unpublished find out about by which 286 cats had been all absolutely cured. Who is aware of how a lot inventory to soak up this, however remarkably, peer-reviewed analysis has since validated the effectiveness of the drug. In 5 years time, FIP has long past from the “worst analysis it’s good to get” for cats to a illness absolutely curable with no longer one however 3 other medicine, says Nicole Jacque, a cat-rescue volunteer who has helped behavior analysis on molnupiravir. The pastime that the pandemic spurred in coronavirus antivirals has been a boon for FIP. (Vets instructed me that Paxlovid can be a promising antiviral for FIP too, regardless that no person turns out to have examined it but.)

When the FIP outbreak hit Cyprus, other folks there additionally started purchasing black-market medicine. The fee is extremely top, operating into 1000’s of U.S. greenbacks according to cat relying at the actual drug. And there’s no ensure that the goods in reality include the drug on the purity and the doses claimed. “We can’t depend at the black marketplace,” Epaminondas says. Vets in Cyprus started asking the federal government for lend a hand previous this yr. Through then, molnupiravir have been falling out of fashion globally as a human drug, as Paxlovid had proved simpler. The Cypriot executive had a variety of molnupiravir left over, and it agreed to unlock the primary doses to veterinarians this summer season.

Even supposing molnupiravir can for sure deal with FIP, it might not be the “perfect” drug for it. In lab research, it kind of feels poisonous at decrease quantities than the opposite choices, so it might be more uncomplicated to by chance overdose. And since molnupiravir works by way of inducing plenty of mutations within the virus—to the purpose the place it will have to prevent operating—professionals have puzzled if it will accelerate the emergence of latest variants, a worry that in the past dogged its human use.

However molnupiravir has giant sensible benefits too: It’s the least expensive of the FIP medicine. And within the U.S., it’s the perhaps to be readily to be had, says Drew Weigner, a former president of the EveryCat Well being Basis, which has funded a number of FIP drug research underneath his tenure. The drug is lately approved for emergency use for COVID, but when it’s formally authorized, vets may just additionally prescribe it off-label to cats. After which The united states, too, would possibly in spite of everything have a criminal drug to regard FIP—in case the outbreak spreads globally, and even though no longer, for the numerous cats that also automatically get FIP yearly.