title: Diagnostic and epidemiologic analysis of the 2008-2010 investigation of a multi-year outbreak of contagious equine metritis in the United States.
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.
authors.affiliation: USDA, Animal and Plant Health Inspection Service, Veterinary Services, National Veterinary Services Laboratories, 1920 Dayton Ave, Ames, IA 50010, USA. matthew.m.erdman@aphis.usda.gov
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Erdman
authors.forename: Lynn H
authors.initials: LH
authors.lastname: Creekmore
authors.forename: Patricia E
authors.initials: PE
authors.lastname: Fox
authors.forename: Angela M
authors.initials: AM
authors.lastname: Pelzel
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Porter-Spalding
authors.forename: Alan M
authors.initials: AM
authors.lastname: Aalsburg
authors.forename: Linda K
authors.initials: LK
authors.lastname: Cox
authors.forename: Brenda R
authors.initials: BR
authors.lastname: Morningstar-Shaw
authors.forename: Randall L
authors.initials: RL
authors.lastname: Crom
mesh_terms: D000818:Animals; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004196:Disease Outbreaks / Q000662:veterinary*; D005260:Female; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D006734:Horse Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology* / Q000635:transmission; D006736:Horses; D007841:Latex Fixation Tests / Q000662:veterinary; D008297:Male; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011247:Pregnancy; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics; D012749:Sexually Transmitted Diseases / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D020625:Taylorella equigenitalis / Q000235:genetics / Q000302:isolation & purification*; D014481:United States / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S