In a separate and unrelated incident, a second contagious equine metritis (CEM)-like organism was recovered from a jack in Kentucky which has no known association or relation to the California jack. Two Standardbred mares which had no clinical signs and which were not suspected of the disease were undergoing examination to qualify as post-import breeding test mares. These mares were part of a group of five which were used as nurse mares and which were domestic horses with no known exposure to imported horses. On Jan. 12, 1998, when both mares were unexpectedly diagnosed positive for CEM by complement fixation (CF) tests at the Kentucky Animal Disease Diagnostic Center in Lexington, the serologic tests were repeated to rule out tasting error and bacteriologic specimens were additionally collected. A donkey jack which had recently been used to cover the mares was also cultured. On Jan. 20, 1998, the second serologic tests were positive and were supported by microbiologic isolation of a CEM-like organism from the mares and the jack. The Kentucky CEM-like organism, in similarity to the California isolate, displayed cultural characteristics and biochemical reactions which resembled but were not identical to reactions of the CEM organism associated with the 1978 incident in Thoroughbred horses in Central Kentucky. The National Veterinary Services Laboratory confirmed the isolation of a CEM-like organism on Jan. 21.

Epidemiologic Survey and Action (Kentucky)

The jack arrived on the Fayette County, Kentucky, premises on Dec. 12, 1997, from Rowan County, Kentucky, for the purpose of breeding three nurse mares. A fourth mare on the Rowan County premises is pregnant by the jack and is scheduled to foal in March 1998. Examination of the four mares revealed no visible vaginal discharge or other signs of CEM. The premises was additionally populated by 39 breeding-age mares, 34 broodmares, 22 yearlings, and five horses which had recently arrived from training. No stallions were present since all breeding was performed by artificial insemination. On Jan. 21, the premise was quarantined and broodmares on the original premises underwent blood collection for CF testing. The premise on which the jack was located prior to Dec. 12, 1997, also was quarantined and blood was drawn for CF testing from those horses as well. Currently, 211 animals in addition to the four original nurse mares, have been identified, quarantined, and tested. Of these, 213 are CF negative, but the jack is culture positive and one of the four original broodmares was positive by culture as reported by NVSL on Feb. 4, 1998.

Current Areas of Activity: Epidemiologic action In both California and Kentucky, efforts to locate additional or potential contacts (tracebacks) of the affected jacks continues. Jacks and mares with positive CF or culture results are under quarantine, as are premises containing high and low risk exposed animals