title: Serologic evidence for exposure to Rickettsia rickettsii in eastern Arizona and recent emergence of Rocky Mountain spotted fever in this region.
abstract: During 2002 through 2004, 15 patients with Rocky Mountain spotted fever (RMSF) were identified in a rural community in Arizona where the disease had not been previously reported. The outbreak was associated with Rickettsia rickettsii in an unexpected tick vector, the brown dog tick (Rhipicephalus sanguineus), which had not been previously associated with RMSF transmission in the United States. We investigated the extent of exposure to R. rickettsii in the local area through serologic evaluations of children and dogs in 2003-2004, and in canine sera from 1996. Antibodies to R. rickettsii at titers > or = 32 were detected in 10% of children and 70% of dogs in the outbreak community and 16% of children and 57% of dogs in a neighboring community. In comparison, only 5% of canine samples from 1996 had anti-R. rickettsii antibodies at titers > or = 32. These results suggest that exposures to RMSF have increased over the past 9 years, and that RMSF may now be endemic in this region.
authors.affiliation: Centers for Disease Control and Prevention, National Center for Infectious Diseases, Division of Viral and Rickettsial Diseases, Atlanta, Georgia, USA. ldemma@cdc.gov
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Demma
authors.forename: Marc
authors.initials: M
authors.lastname: Traeger
authors.forename: Dianna
authors.initials: D
authors.lastname: Blau
authors.forename: Rondeen
authors.initials: R
authors.lastname: Gordon
authors.forename: Brian
authors.initials: B
authors.lastname: Johnson
authors.forename: Jeff
authors.initials: J
authors.lastname: Dickson
authors.forename: Rudy
authors.initials: R
authors.lastname: Ethelbah
authors.forename: Stephen
authors.initials: S
authors.lastname: Piontkowski
authors.forename: Craig
authors.initials: C
authors.lastname: Levy
authors.forename: William L
authors.initials: WL
authors.lastname: Nicholson
authors.forename: Christopher
authors.initials: C
authors.lastname: Duncan
authors.forename: Karen
authors.initials: K
authors.lastname: Heath
authors.forename: James
authors.initials: J
authors.lastname: Cheek
authors.forename: David L
authors.initials: DL
authors.lastname: Swerdlow
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: McQuiston
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001096:Arachnid Vectors / Q000382:microbiology*; D001130:Arizona / Q000453:epidemiology; D002648:Child; D004196:Disease Outbreaks; D004283:Dog Diseases / Q000453:epidemiology* / Q000635:transmission; D004285:Dogs; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D048508:Rhipicephalus sanguineus / Q000382:microbiology*; D012284:Rickettsia rickettsii / Q000276:immunology*; D012373:Rocky Mountain Spotted Fever / Q000453:epidemiology* / Q000635:transmission; D016036:Seroepidemiologic Studies; D013984:Tick Infestations / Q000453:epidemiology / Q000662:veterinary
chemical_list: D000907:Antibodies, Bacterial