title: Rocky mountain spotted fever in the United States, 2000-2007: interpreting contemporary increases in incidence.
abstract: Rocky Mountain spotted fever (RMSF), a potentially fatal tick-borne infection caused by Rickettsia rickettsii, is considered a notifiable condition in the United States. During 2000 to 2007, the annual reported incidence of RMSF increased from 1.7 to 7 cases per million persons from 2000 to 2007, the highest rate ever recorded. American Indians had a significantly higher incidence than other race groups. Children 5-9 years of age appeared at highest risk for fatal outcome. Enzyme-linked immunosorbent assays became more widely available beginning in 2004 and were used to diagnose 38% of cases during 2005-2007. The proportion of cases classified as confirmed RMSF decreased from 15% in 2000 to 4% in 2007. Concomitantly, case fatality decreased from 2.2% to 0.3%. The decreasing proportion of confirmed cases and cases with fatal outcome suggests that changes in diagnostic and surveillance practices may be influencing the observed increase in reported incidence rates.
authors.affiliation: Division of Viral and Rickettsial Diseases, National Center of Zoonotic, Vector-Borne, and Enteric Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Openshaw
authors.forename: David L
authors.initials: DL
authors.lastname: Swerdlow
authors.forename: John W
authors.initials: JW
authors.lastname: Krebs
authors.forename: Robert C
authors.initials: RC
authors.lastname: Holman
authors.forename: Eric
authors.initials: E
authors.lastname: Mandel
authors.forename: Alexis
authors.initials: A
authors.lastname: Harvey
authors.forename: Dana
authors.initials: D
authors.lastname: Haberling
authors.forename: Robert F
authors.initials: RF
authors.lastname: Massung
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: McQuiston
mesh_terms: D000818:Animals; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000639:trends; D006801:Humans; D015994:Incidence; D012284:Rickettsia rickettsii; D012373:Rocky Mountain Spotted Fever / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology