title: Epidemiology of a Salmonella enterica subsp. enterica serovar Typhimurium strain associated with a songbird outbreak.
abstract: Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.
authors.affiliation: Departments of Population Health, University of Georgia, Athens, Georgia, USA.
authors.forename: Sonia M
authors.initials: SM
authors.lastname: Hernandez
authors.forename: Kevin
authors.initials: K
authors.lastname: Keel
authors.forename: Susan
authors.initials: S
authors.lastname: Sanchez
authors.forename: Eija
authors.initials: E
authors.lastname: Trees
authors.forename: Peter
authors.initials: P
authors.lastname: Gerner-Smidt
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Adams
authors.forename: Ying
authors.initials: Y
authors.lastname: Cheng
authors.forename: Al
authors.initials: A
authors.lastname: Ray
authors.forename: Gordon
authors.initials: G
authors.lastname: Martin
authors.forename: Andrea
authors.initials: A
authors.lastname: Presotto
authors.forename: Mark G
authors.initials: MG
authors.lastname: Ruder
authors.forename: Justin
authors.initials: J
authors.lastname: Brown
authors.forename: David S
authors.initials: DS
authors.lastname: Blehert
authors.forename: Walter
authors.initials: W
authors.lastname: Cottrell
authors.forename: John J
authors.initials: JJ
authors.lastname: Maurer
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology* / Q000382:microbiology*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D018598:Minisatellite Repeats; D017720:Molecular Epidemiology; D058889:Molecular Typing; D012481:Salmonella Infections, Animal / Q000453:epidemiology* / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D020308:Songbirds / Q000382:microbiology*; D014481:United States / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial