ABSTRACT
Contagious equine metritis (CEM) is a highly contagious venereal disease of horses caused by Taylorella equigenitalis. During testing for semen export purposes, a stallion in Kentucky was found to be T. equigenitalis culture positive in December of 2008. This finding triggered an extensive regulatory investigation to search for additional positive horses, determine the extent of the outbreak, identify the potential source of the outbreak, and ultimately return the United States to CEM-free status. The investigation included over 1000 horses located in 48 states. Diagnostic testing found a total of 22 stallions, 1 gelding and 5 mares culture positive for T. equigenitalis. Epidemiologic analysis indicated that all of the positive horses were linked to a single common source, most likely a Fjord stallion imported into the United States in 2000. The T. equigenitalis strain subsequently spread to other stallions via undetermined indirect mechanisms at shared breeding facilities, and to mares via artificial insemination and live breeding. This CEM outbreak and investigation represent the largest ever in the United States based on the number of exposed horses tested and their geographic distribution.
Subject(s)
Disease Outbreaks/veterinary , Gram-Negative Bacterial Infections/veterinary , Horse Diseases/epidemiology , Horse Diseases/microbiology , Sexually Transmitted Diseases/veterinary , Taylorella equigenitalis/isolation & purification , Animals , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Female , Fluorescent Antibody Technique/veterinary , Gram-Negative Bacterial Infections/epidemiology , Gram-Negative Bacterial Infections/microbiology , Gram-Negative Bacterial Infections/transmission , Horse Diseases/diagnosis , Horse Diseases/transmission , Horses , Latex Fixation Tests/veterinary , Male , Polymerase Chain Reaction/veterinary , Pregnancy , RNA, Ribosomal, 16S/chemistry , RNA, Ribosomal, 16S/genetics , Sexually Transmitted Diseases/epidemiology , Sexually Transmitted Diseases/microbiology , Sexually Transmitted Diseases/transmission , Taylorella equigenitalis/genetics , United States/epidemiologyABSTRACT
OBJECTIVE: To identify factors associated with development of vesicular stomatitis (VS). DESIGN: Case-control study. SAMPLE POPULATION: 138 livestock premises and 118 horses suspected of having VS in Texas, New Mexico, and Colorado. PROCEDURES: Premises with >or= 1 animal with clinical signs and laboratory confirmation of infection were classified as case premises. Premises where laboratory confirmation results were negative were control premises. Among equine premises, case and control horses were selected on the basis of premises status. A survey was conducted to identify factors associated with VS for premises and specific horses. RESULTS: Control of insect populations in the 2 weeks before the VS investigation decreased the odds of disease for premises where vegetation coverage was grassland or pasture (odds ratio [OR], 0.08; 95% confidence interval [CI], 0.01 to 0.7). Odds of VS for premises covered with grassland or pasture increased when measures to control insect populations were not used (OR, 11; 95% CI, 0.8 to 156.3) and for premises that had a body of water (OR, 2.3; 95% CI, 1.0 to 5.6). Use of measures to prevent insect bites or harassment by insects (OR, 0.2; 95% CI, 0.1 to 0.8) and spending time in shelters (OR, 0.4; 95% CI, 0.2 to 1.1) in the 2 weeks prior to investigation decreased the odds of being a case horse. CONCLUSIONS AND CLINICAL RELEVANCE: Insect control and spending time in shelters decreased the odds for infection with VS. Premises covered with grassland or pasture or that had a body of water were at a higher risk.
