A potential economic disaster in the U.S. horse industry was averted by the work of veterinary microbiologists at the UC Davis Center for Equine Health. Using the latest genetic diagnostic techniques, the scientists tested a California donkey that appeared to be carrying a serious venereal disease known as contagious equine metritis (CEM). They discovered, however, that the donkey was infected with a previously unknown organism that mimics CEM, but does not cause disease. "Providing accurate diagnoses for animal disease is what we do routinely, but it's particularly gratifying to be able to deliver good news in a situation that had the potential to devastate the horse industry," says Dr. Gregory Ferraro, director of the UC Davis Center for Equine Health. CEM is a bacterial disease that can easily be treated with antibiotics, but spreads readily during breeding. Until diagnosed and cured, it causes infertility or abortions in infected mares and can wreak havoc in a horse-breeding program. Because the disease has been reported in 25 European countries, all foreign breeding-age horses must be quarantined and tested before they are allowed to enter the United States. The disease has been found only twice in this country. Had the UC Davis tests proved positive for CEM, the $78 million U.S. equine export trade would have been in jeopardy. With funding from the U.S. Department of Agriculture, UC Davis scientists are now working to develop a rapid diagnostic test that will differentiate between CEM and its newly discovered look-alike.