LONGMONT — Shiners Dun Juan is decked neck to tail in mesh to protect the champion reining horse from black flies buzzing around his stable. Owner Janiejill Tointon has sprayed the horse with insecticide and spread diatomaceous earth around his stable to keep the stinging pests away.
But she can only hope that her six-figure purse winner won’t get sick. The flies are believed responsible for the rapid spread of vesicular stomatitis, or VS, which has sickened more than 200 horses and cows in Colorado and put more than 130 farm and ranch properties under quarantine.
Out in the pasture at Tointon’s Diamond Double T Ranch west of Niwot is Mia, a chestnut mare whose muzzle is spotted white with healed VS sores. Though Mia and two other horses that contracted the virus are well, the ranch will stay quarantined for about three more weeks — unless more of Tointon’s 45 horses show symptoms.
Infected animals — usually horses and cattle but sometimes sheep, goats, alpaca and swine — mostly get blisters on the mouth, tongue and sometimes hooves, though dairy cows can get sores on their udders.
Though rarely fatal, the virus makes eating and drinking tough, so the animals lose weight. In serious cases, horses can slough off skin and even hooves, or need feeding tubes and IVs. Treatment can cost owners thousands of dollars.
Tointon, a breeder, said the shutdown is costing her money and customers. She is paying to feed and care for five sold horses, which, with veterinary bills, she figures is costing her a few thousand dollars.
As the virus spreads, owners’ fears of facing similar losses have spread with it. Would-be customers are scared to visit Tointon’s ranch, she said, because they fear they’ll carry infected flies home.
The outbreak was first reported July 14 in Boulder County and has led to the cancellation of horse shows from Loveland to Grand Junction, though the state veterinarian’s office hasn’t recommended doing so. It has stirred concern in the cattle ranching community, too, although only three cows have been diagnosed.
The number of quarantines is rising steadily, said state veterinarian Keith Roehr. His office has gotten 10 to 15 reports every day for weeks.
As of Friday, there were 133 quarantines, by Tuesday at 7 a.m. there were 175, mostly in Boulder and Weld counties. The week before had 69.
The timing of the outbreak is particularly harmful. Now is a peak time for horse shows and sales, meaning owners have fewer shots to win purses and add to their horses’ reputations.
“It’s just a huge time of year,” said Bub Poplin, president of the Western Slope Reining Horse Association, which canceled its August show in Grand Junction. “Money earnings (from competitions) go on the horse’s record, and that’s how you help sell horses.”
It’s the worst outbreak Colorado has seen since 2004. Roehr said he expects this year’s quarantine tally to exceed the 199 logged that year, mostly along the Front Range and the Arkansas River in southeastern Colorado. In 2004, another 95 properties were quarantined in New Mexico and Texas, according to the U.S. Department of Agriculture.
The virus, detected so far this year only in Texas and Colorado, is thought to be spread by gnats and black flies that migrate north from Mexico, Roehr said.
The spread won’t be stemmed until the first hard freeze — usually the end of September or start of October — when the flies die off.
Roehr said cattle are less vulnerable, but ranchers have ramped up prevention and pulled out of shows. The Colorado State Fair might cancel its cattle show this year because of falling registration, general manager Chris Wiseman said.
Mary Kraft, a Western Dairy Association board member who owns 5,500 head in Fort Morgan, said she has doubled her spending on spraying, introduced wasps to eat fly larvae and is tilling to expose manure to sunlight.
If her cows lose weight, she said, they might stop producing milk.
So while she and the cattle industry haven’t had widespread issues, Kraft said she’s eager for the year’s first frost to snuff out the risk.
“You’ve got your flowers out in the box,” Kraft said, “but now, I’m hoping those little guys die.”
Colorado’s vesicular stomatitis outbreak has been most severe in the northern part of the Front Range so far, but has begun to spread south. Here are the counties where the virus has been detected and the number of properties under quarantine as of Tuesday morning:
Weld: 66
Boulder: 58
Larimer: 33
Adams: 9
Jefferson: 6
Broomfield: 1
Douglas: 1
El Paso: 1