95 Wild Horses Died. A Virus Is the Likely Cause, Officials Say.

The Bureau of Land Management said Thursday that the mysterious respiratory disease that has killed at least 95 wild horses and forced a federal holding facility in Colorado to go under quarantining may have been caused by an equine influenza virus.

The bureau said in a news release that the H3N8 strain of the virus was likely to be the cause of the outbreak and related horse deaths.

The strain of bird flu that has been identified in the United States is not related to this year's outbreak.

The bureau, which is in charge of caring for the nation's wild horses, said at least 57 horses had died in Colorado since the weekend. There were 95 deaths by Thursday.

It was the second time in recent weeks that the bureau had to shut down a facility because of a widespread illness among horses. An adoption event for wild horses was put off because some of the animals developed a disease similar to strep throat.

There is a struggle to manage wild horses and burros in the West. There are more animals on public lands than the bureau can support.

Thousands of horses are rounded up every year and offered for adoption by the bureau. The number of people willing to adopt an untrained mustang has almost never equaled the number of animals the government removes, so a surplus has built up year by year in a collection of corrals and pastures that the bureau calls the holding system.

The system costs about 72 million a year to hold more than 60,000 animals.

The holding system includes long-term ranches in the tall grass prairie where unwanted horses can spend decades, as well as short-term feedlots where crowded corrals temporarily hold horses fresh off the range.

The short-term facility is next to a Colorado state prison where inmates train horses. It is a potential breeding ground for disease because it is a way station where animals from different herds are brought together in corrals that cover only 50 acres. Horses stay for a long time in the holding system because of overcrowding.

The bureau said on Monday that there were 2,550 horses in the area, just a few hundred shy of the maximum.

Steven Hall, a spokesman for the bureau, said on Thursday that the facility would remain under quark as long as necessary to prevent the spread of the virus.

Most of the horses affected by the disease were removed from the West Douglas Herd Area in northwestern Colorado last year. The bureau said that the rounding up of excess horses was done to protect the health of the horses. A portion of the herd was tested for a potentially fatal virus that can be spread through fly bites. The West Douglas horses were kept separate from other horses after all the tests were negative.

Scott Beckstead, director of campaigns for the Center for a Humane Economy, a nonprofit animal welfare organization, said that this is the first situation that he knows of where so many horses died suddenly.

The conditions in the holding facilities were too crowded and filthy according to Mr. Beckstead. The horses are standing together. It is a perfect environment for disease to spread.

Suzanne Roy, executive director for the American Wild Horse Campaign, said in a statement on Wednesday that the bureau was putting the animals in harm's way.

Since 1971, the Bureau of Land Management has been protecting wild horses and burros on public lands.

Horse-advocacy groups and lawmakers have been pressing the bureau to shrink the holding system for decades. Thousands of protected wild horses ended up at slaughter houses after being adopted out of the system.

The bureau began paying people $1,000 a head to take animals off its hands. An investigation by The New York Times showed that a large number of horses were sold to slaughter buyers as soon as the checks cleared.

The number of horses stored in the holding system has only grown since 2020, partly because of an increase in the number of horses being rounded up.

The bureau wants to double the number of animals it rounds up each year, but the move would increase the number of horses in the system.

The United States government is trying to remove large numbers of protected animals to benefit the live stock industry. In the short term, the bureau should stop mass roundings until heathy and safe conditions can be guaranteed.

The cost of rounding up tens of thousands of wild horses is going to cost the American taxpayer tens of millions of dollars.