Serologic evidence for exposure to Rickettsia rickettsii in eastern Arizona and recent emergence of Rocky Mountain spotted fever in this region.
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.
Demma
Linda J
LJ
Centers for Disease Control and Prevention, National Center for Infectious Diseases, Division of Viral and Rickettsial Diseases, Atlanta, Georgia, USA. ldemma@cdc.gov
Traeger
Marc
M
Blau
Dianna
D
Gordon
Rondeen
R
Johnson
Brian
B
Dickson
Jeff
J
Ethelbah
Rudy
R
Piontkowski
Stephen
S
Levy
Craig
C
Nicholson
William L
WL
Duncan
Christopher
C
Heath
Karen
K
Cheek
James
J
Swerdlow
David L
DL
McQuiston
Jennifer H
JH
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
D000907:Antibodies, Bacterial