title: Increasing incidence of Ehrlichia chaffeensis and Anaplasma phagocytophilum in the United States, 2000-2007.
abstract: Ehrlichia chaffeensis causes human monocytic ehrlichiosis, and Anaplasma phagocytophilum causes human granulocytic anaplasmosis. These related tick-borne rickettsial organisms can cause severe and fatal illness. During 2000-2007, the reported incidence rate of E. chaffeensis increased from 0.80 to 3.0 cases/million persons/year. The case-fatality rate was 1.9%, and the hospitalization rate was 49%. During 2000-2007, the reported incidence of A. phagocytophilum increased from 1.4 to 3.0 cases/million persons/year. The case-fatality rate was 0.6%, and the hospitalization rate was 36%. Rates among female patients were lower than among male patients for ehrlichiosis (rate ratio = 0.68) and anaplasmosis (rate ratio = 0.70). Most (80%) ehrlichiosis and anaplasmosis cases met only a probable case definition, although, use of a polymerase chain reaction to confirm infections increased during 2000-2007. Heightened reporting of these diseases will likely continue with improving recognition, changing surveillance practices, and appropriate application of diagnostic assays.
authors: Division of Vectorborne Infectious Diseases, National Center for Enteric, Zoonotic, and Infectious Disease, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
authors: F Scott
authors: FS
authors: Dahlgren
authors: Eric J
authors: EJ
authors: Mandel
authors: John W
authors: JW
authors: Krebs
authors: Robert F
authors: RF
authors: Massung
authors: Jennifer H
authors: JH
authors: McQuiston
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D041081:Anaplasma phagocytophilum / Q000302:isolation & purification*; D000712:Anaplasmosis / Q000453:epidemiology* / Q000382:microbiology; D002487:Centers for Disease Control and Prevention, U.S.; D002648:Child; D002675:Child, Preschool; D018469:Ehrlichia chaffeensis / Q000302:isolation & purification*; D016873:Ehrlichiosis / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D017282:Tick-Borne Diseases / Q000453:epidemiology* / Q000382:microbiology; D014481:United States / Q000453:epidemiology; D055815:Young Adult