An equine flu has killed over a dozen wild burros in the Inland Empire

As humans continue to contend with COVID-19, herds of wild burros in the Inland Empire are facing their own outbreak of a deadly equine influenza that has killed more than a dozen donkeys since June.

The burros, which roam around 30 to 40 square miles in the mountains and hills east of Riverside and south of San Bernardino, began showing up sick around a month ago, said Chad Cheatham, vice president of the nonprofit DonkeyLand sanctuary in Colton.

While serving as a sanctuary for injured burros, DonkeyLand has also been responding to reports of sick donkeys and taking them to equine veterinarians for treatment.

However, the illnesses have often been too severe for veterinarians to intervene.

"Several herds in different jurisdictions have been dropping dead without any time to help save them," the sanctuary wrote on Facebook last week. "Their symptoms have all been the same, from foaming or bubbles from the mouth, dripping noses, coughing or showing severe symptoms of heavy labored breathing."

By the time the donkeys are transported for treatment, it is often too late.

"They actually were coming in pretty sick … almost on their last legs," said equine veterinarian Dr. Paul Wan of the SoCal Equine Hospital in Norco, where DonkeyLand takes many of its sick and injured burros.

"They were just breathing so hard and really easily caught," Wan said. "Unfortunately, a lot of them just passed as soon as they got in the hospital — within, I would say, a 24-hour period."

About 17 burros have died as of Thursday, Wan said. Multiple donkeys have been sent to state laboratories for necropsies.

DonkeyLand attempted to save a 2-week-old burro that had been found sick, taking her to a veterinarian, said DonkeyLand founder and vice president Amber-LeVonne Cheatham. But the foal died in the veterinarian's arms.

This is not the first time that the herds of wild burros have faced an outbreak of equine influenza — in the fall of 2020, an outbreak killed about 40 burros — but the current outbreak has caught the DonkeyLand operators off guard.

Equine influenza usually doesn't spread until the cooler months, and an outbreak isn't expected every year, said Chad Cheatham. This early summer outbreak came as a surprise, he said.

And in the 2020 outbreak, veterinarians were able to treat many of the burros that showed symptoms.

Wan said donkeys coming into contact with domesticated horses, which are often vaccinated, could have started the outbreak. Equine influenza cannot be passed from burros to humans.

The wild burros are unvaccinated and have no immunity to the virus, Wan said.

Additionally, Amber-LeVonne Cheatham is concerned about the water that area residents have been putting out for the burros.

The water is often neglected and not changed out for fresh water, Cheatham said.

With the equine influenza virus spreading, animal rescuers and veterinarians have a plan that resembles the steps taken to combat the COVID-19 pandemic.

"What we're trying to do is … establish some sort of herd immunity with vaccine," Wan said. "Hopefully we can vaccinate approximately 200 and it'll probably stop the outbreak."

The same plan was successful in 2020.

"In 2020 it was running pretty hard and then we vaccinated approximately 200," Wan said. "After we got the vaccines done within a week or two, I think we only saw one or two more [cases] after that time."

Wan and DonkeyLand advised people in the area to report sick donkeys to the local animal services department.

This story originally appeared in Los Angeles Times.