title: Rocky mountain spotted fever characterization and comparison to similar illnesses in a highly endemic area-Arizona, 2002-2011.
abstract: BACKGROUND
  Rocky Mountain spotted fever (RMSF) has emerged as a significant cause of morbidity and mortality since 2002 on tribal lands in Arizona. The explosive nature of this outbreak and the recognition of an unexpected tick vector, Rhipicephalus sanguineus, prompted an investigation to characterize RMSF in this unique setting and compare RMSF cases to similar illnesses.
  
  
  METHODS
  We compared medical records of 205 patients with RMSF and 175 with non-RMSF illnesses that prompted RMSF testing during 2002-2011 from 2 Indian reservations in Arizona.
  
  
  RESULTS
  RMSF cases in Arizona occurred year-round and peaked later (July-September) than RMSF cases reported from other US regions. Cases were younger (median age, 11 years) and reported fever and rash less frequently, compared to cases from other US regions. Fever was present in 81% of cases but not significantly different from that in patients with non-RMSF illnesses. Classic laboratory abnormalities such as low sodium and platelet counts had small and subtle differences between cases and patients with non-RMSF illnesses. Imaging studies reflected the variability and complexity of the illness but proved unhelpful in clarifying the early diagnosis.
  
  
  CONCLUSIONS
  RMSF epidemiology in this region appears different than RMSF elsewhere in the United States. No specific pattern of signs, symptoms, or laboratory findings occurred with enough frequency to consistently differentiate RMSF from other illnesses. Due to the nonspecific and variable nature of RMSF presentations, clinicians in this region should aggressively treat febrile illnesses and sepsis with doxycycline for suspected RMSF.
authors.affiliation: Indian Health Service Hospital, Whiteriver, Arizona.
authors.forename: Marc S
authors.initials: MS
authors.lastname: Traeger
authors.affiliation: Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).
authors.forename: Joanna J
authors.initials: JJ
authors.lastname: Regan
authors.affiliation: Indian Health Service Hospital, Whiteriver, Arizona.
authors.forename: Dwight
authors.initials: D
authors.lastname: Humpherys
authors.affiliation: Indian Health Service Hospital, Whiteriver, Arizona.
authors.forename: Dianna L
authors.initials: DL
authors.lastname: Mahoney
authors.affiliation: Indian Health Service Hospital, Whiteriver, Arizona.
authors.forename: Michelle
authors.initials: M
authors.lastname: Martinez
authors.affiliation: Poxvirus and Rabies Branch, Division of High-Consequence Pathogens and Pathogenicity, NCEZID.
authors.forename: Ginny L
authors.initials: GL
authors.lastname: Emerson
authors.affiliation: Poxvirus and Rabies Branch, Division of High-Consequence Pathogens and Pathogenicity, NCEZID Epidemic Intelligence Service, Division of Applied Public Health Training, Epidemiology Program Office, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Tack
authors.affiliation: Bacterial Diseases Branch, Division of Vector-Borne Diseases, NCEZID, CDC, Fort Collins, Colorado.
authors.forename: Aimee
authors.initials: A
authors.lastname: Geissler
authors.affiliation: Epidemic Intelligence Service, Division of Applied Public Health Training, Epidemiology Program Office, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia.
authors.forename: Seema
authors.initials: S
authors.lastname: Yasmin
authors.affiliation: Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh.
authors.forename: Regina
authors.initials: R
authors.lastname: Lawson
authors.affiliation: Division of Health Programs, Community A.
authors.forename: Charlene
authors.initials: C
authors.lastname: Hamilton
authors.affiliation: Department of Health and Human Services, Community B.
authors.forename: Velda
authors.initials: V
authors.lastname: Williams
authors.affiliation: Bureau of Epidemiology and Disease Control, Division of Public Health Services, Arizona Department of Health Services, Phoenix.
authors.forename: Craig
authors.initials: C
authors.lastname: Levy
authors.affiliation: Bureau of Epidemiology and Disease Control, Division of Public Health Services, Arizona Department of Health Services, Phoenix.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Komatsu
authors.affiliation: Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: McQuiston
authors.affiliation: Indian Health Service Hospital, Whiteriver, Arizona.
authors.forename: David A
authors.initials: DA
authors.lastname: Yost
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001130:Arizona / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D003955:Diagnostic Tests, Routine; D004318:Doxycycline / Q000627:therapeutic use; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012373:Rocky Mountain Spotted Fever / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D004318:Doxycycline
keywords: AIAN; American Indians; Rhipicephalus sanguineus; Rocky Mountain spotted fever; tick-borne