01/15/2017 8:16PM

Fair Grounds: No further horses test positive for equine herpesvirus

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NEW ORLEANS – There were no new cases of the equine herpesvirus reported over the weekend at Fair Grounds, but the track and Louisiana state officials still were grappling with the logistics of managing the viral outbreak here.

Thirty horses that tested positive last week for the virus, known as EHV-1, still were stabled in their regular stalls as of Sunday, although the protocol put in place by the Louisiana Department of Agriculture and Forestry for managing the disease event at Fair Grounds requires horses that test positive to be isolated.

“Some of the horses are still in their barns,” said Dr. Jonathan Roberts, a Louisiana state veterinarian who started working on the Fair Grounds EHV-1 situation last week. “We’re trying to find room to isolate the animals.”  

Fair Grounds already has erected temporary tents that house nine EHV-1 positive horses, and several trainers on Sunday said the track and state officials had decided to set up another large tent to accommodate the latest round of horses with positive tests. The tentative plan, the trainers said, calls for the tent to be set up in a parking lot that runs parallel to the homestretch

There had been discussions about moving EHV-1 positive horses to a farm in nearby Chalmette, but that plan reportedly has been scrapped.

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None of the 30 horses with positive tests displayed any symptoms. They were tested as part of a change in protocol last week whereby all horses, ill or not, in barns with an EHV-1 positive horse had to be tested for the virus. A barn can clear quarantine after all its occupants twice test negative. The previous protocol had been only to test horses in quarantined barns that showed symptoms of illness.

All but two of the EHV-1 positives at Fair Grounds have been for the wild subtype of the virus that is common among horse populations and does not usually produce serious illness, though it can. But the first case of EHV-1 reported here in late December involved a horse that had the much more serious neuropathogenic strain of EHV-1. That horse, which was stabled in barn 14, had to be euthanized, and a second horse in the barn tested positive for the same strain Dec. 31.

That was the last known case of the neuropathogenic strain here, but regulators have been forced to treat the subsequent wild type EHV-1 cases as though they were part of the same outbreak, though that is not the case. The two strains are not interchangeable, and most cases of wild type EHV-1 would go undetected because horses rarely are tested for it.

Trainers whose horses are in quarantined barns are not permitted to race, and they have been growing ever more frustrated with their situation. Most believe that they are dealing with an everyday illness that, had the neuropathogenic case never happened, would have come and gone from the Fair Grounds backstretch with little notice. There is concern over the nature of the tests themselves, which produced a surprisingly high number of positives last week, and about the management of the quarantine.

Barns 4 and 30 each had a single horse test for wild-type EHV-1 last week, and the two barns were quarantined Tuesday. Horsemen in those barns were told the rest of their stock would be tested within a day or two, but as of Sunday, no samples had yet been taken from any of the horses in those barns. The lab to which the EHV-1 tests had been sent was closed over the weekend, and because of Martin Luther King Day wasn’t scheduled to open again until Tuesday.

The delay in testing means a delay in the start of those barns’ 14-day quarantine if more EHV-1 positive horses are found, and given the rate of positive tests last week, that seems extremely likely. It also allows horses carrying the virus a greater opportunity to infect horses that might otherwise test negative, which could further prolong the quarantine.

Fair Grounds has three training sessions now; the first for the general population, the second for horses in quarantined barns other than barn 14, and the third for barn 14. Apparently healthy horses that have tested positive are not permitted to train.

Dr. Roberts also said that a horse in barn 20 that ran a fever had tested negative for EHV-1 late last week. The horse was to be re-tested 72 hours after the initial test.