The number of horses testing positive for the equine herpesvirus at Sunland Park in New Mexico continues to climb, but Turf Paradise in Arizona has announced that it plans to lift its quarantine at the end of next week after reporting to health officials that no horses there have exhibited symptoms of the disease since a horse was euthanized nearly two weeks ago. The Equine Disease Communications Center said on Monday that 56 horses at Sunland Park have now tested positive for equine herpesvirus, a highly contagious disease that can sometimes prove fatal. The center had reported on Saturday that 51 horses had tested positive at Sunland, which has ceased racing as it tries to get the disease under control. Sunland Park has not raced since Jan. 22, after the first batch of horses began testing positive at the track. The EDCC said on Monday that the virus is affecting 20 barns at the track. The track’s biggest race is the $800,000 Sunland Park Derby, scheduled for March 20. The EDCC said that the quarantine at Turf Paradise will be lifted on Feb. 18. A notice from the center said that no horses at Turf Paradise have shown any indications of the disease since the track closed its backstretch on Jan. 27, shortly after a horse that had shipped in from Sunland began exhibiting neurological symptoms consistent with the herpesvirus while in quarantine. Turf Paradise has continued to race while under quarantine. A number of tracks across the Southwest and South have imposed bans on horses shipping in from both Turf Paradise and Sunland.