Another six wild horses horses at a Wheatland facility have died of a contagious equine disease commonly known as “strangles” and at least half of the 2,750 horses at the facility are showing signs of the illness, according to the U.S. Bureau of Land Management.
The agency announced that the deaths at the facility it maintains to hold wild horses collected from the plans of Wyoming brings to 11 the number of horses killed by the upper respiratory illness known as streptococcus equi or “strangles.”
In addition, about half of the 2,750 animals at the facility are showing some observable signs of strangles, the agency said.
“It’s possible that it could spread further just due to contagiousness of strangles,” BLM spokesman Tyson Finnicum told Cowboy State Daily on Thursday. “It’s also possible that more horses either have been infected and recovered without showing visible signs of the infection or they were unaffected because of immunity.
“All of the animals at the facility have received the vaccine and we are starting to give annual boosters,” he continued. “We’re mitigating the infection by treating affected horses, segregating animals, and are also implementing biosecurity measures, like bleaching equipment and work areas, to stop or reduce transmission.”
The mortality rate of strangles is typically under 10% but can be as high as 40%. In comparison, 0.8% of the horses affected by strangles at the Wheatland facility have died.
BLM has again stopped a wild horse and burro adoption event due to the strangles outbreak, which has been going on since late March. The cause of the infection has not yet been determined.
“The primary reason why we’ve closed the facility and are pausing adoptions is to keep the disease from spreading outside of the facility,” Finnicum said. “Holding off on adoptions also helps the horses recover. Not until we are confident that horses can leave the facility without risk of transmission will we lift the closure and resume adoptions.”
The horses are currently under quarantine and being treated for the disease.
“Strangles” is the most common infectious illness found in horses between 6 and 10 years old. Horses can catch the disease through inhalation or ingestion of the bacteria, such as through horse-to-horse contact, drinking contaminated water or making contact with infected material.
According to the Equine Disease Communication Center, most horses will be exposed to or infected with strangles at a young age.
No animals, including domestic saddle horses, have been shipped or received at the facility since the last load of horses gathered last fall were delivered in January.
No foals have died due to the infection.
Foaling mares and newborn foals have shown to be the least impacted by the infection, according to BLM. Additionally, all of the mares at the facility have been vaccinated for strangles, which means their foals are born with some immunity.
