What we know about the horse virus that’s killing people and horses

The vaccines that cause colds aren’t going away, and there’s a class of drugs that may offer little protection to people but can improve life for horses. The products, developed to treat or prevent…

What we know about the horse virus that’s killing people and horses

The vaccines that cause colds aren’t going away, and there’s a class of drugs that may offer little protection to people but can improve life for horses. The products, developed to treat or prevent respiratory tract infections in humans, were largely developed during the Holocaust. Initially developed to help save people from infections brought on by the other side of the “Iron Curtain,” the drugs were quickly used on suffering Holocaust victims.

For both humans and horses, treating the virus has included a slew of therapies — gout, an antiviral, a nasal spray, a probiotic and in one case, a synthetic version of a radioactive isotope. Scientists are developing vaccines for influenza as well. They haven’t found much effectiveness, but many believe one day they will find vaccines that protect against a major horse virus that’s causing catastrophic spread in the United States.

This week, an outbreak in California is blamed for infecting more than 2,500 people, so far killing about 70 of them, including dozens of people who suffered from health complications.

Horses often travel, when they’re not swimming in, say, the Sierra Nevada. For human horses, viral outbreaks in the U.S. almost always get a name. This virus is the “California Equine Cold,” a name that’s consistent across the Western states. Though it has a history of killing tens of thousands of horses in Eastern Europe, it hadn’t been seen in the U.S. in years before the California outbreak. This year is the first year the virus has made its way to states all the way up the West Coast — New Mexico and Colorado, for example, where the virus has infected 30 horses in 13 states. Scientists believe the virus entered the horses by crossing Interstate 10 on trailer trucks, though that’s not clear from the available data.

The disease is specific to horses that are coming from and going to Europe. If you’re not living there, not riding on a European horse trailer, you’re not likely to catch it, though horses that have a higher risk of being transferred are more at risk than their usual owners. The European horse virus is unpredictable and has no known treatment.

There’s been a little bit of hope in the developing days since the outbreak. Early last week, the Southern Equine and Mental Health Association in California reported that an experimental treatment for the virus is keeping the equine cold from becoming acute, preventing the horses from sinking into low temperatures and spreading to humans or other horses. The experimental treatment is made up of three substances that form a protective atmosphere for the virus — a small growth of the proteins that help the virus grow. The horse often infects itself with the virus when it allows its environment to become too warm, but it stops infecting itself when its environment is too cool.

“Just when you think it can’t get any worse, it does,” said Agnes Beharry, a veterinarian with the association. “But if you’re lucky enough to recover and you do get better, it just takes a while to be able to fly.”

The horse virus has at least four names, but experts and veterinarians know it by the euphemism, Pac3. The name is distinctive because there’s only one known person in the world who can identify the virus: Dr. Salvatore Marcaioli, a pediatrician who is fluent in Italian and who works in a children’s hospital near Milan. Marcaioli is widely considered to be the world’s foremost authority on human and equine respiratory infections, and is an active researcher in the fields of vaccines and antiviral drugs.

In an interview, Marcaioli said he always says he can trace the horse virus to Switzerland in 1942 when the first animals infected came to the U.S. he said: “This is not just about a European virus. This is about the time of the Second World War, and humanity at a low point.”

Marcaioli said he wishes he could offer a more definitive answer to how the horse virus came to America, but he says he can’t be blamed for responding to his emotions and not solving the problem: “I’m working with what I’ve got.”

Marcaioli noted that the equine cold virus is often transmitted from person to person, something that appears to be happening as the U.S. horse outbreak continues. “It’s like one of these children,” he said. “The child cries and another brother or sister tries to comfort it, and eventually it breaks.”

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