title: Incidence of West Nile virus infection in the Dallas-Fort Worth metropolitan area during the 2012 epidemic.
abstract: The 2012 West Nile virus (WNV) epidemic was the largest since 2003 and the North Texas region was the most heavily impacted. We conducted a serosurvey of blood donors from four counties in the Dallas-Fort Worth area to characterize the epidemic. Blood donor specimens collected in November 2012 were tested for WNV-specific antibodies. Donors positive for WNV-specific IgG, IgM, and neutralizing antibodies were considered to have been infected in 2012. This number was adjusted using a multi-step process that accounted for timing of IgM seroreversion determined from previous longitudinal studies of WNV-infected donors. Of 4971 donations screened, 139 (2·8%) were confirmed WNV IgG positive, and 69 (1·4%) had IgM indicating infection in 2012. After adjusting for timing of sampling and potential seroreversion, we estimated that 1·8% [95% confidence interval (CI) 1·5-2·2] of the adult population in the Dallas-Fort Worth area were infected during 2012. The resulting overall estimate for the ratio of infections to reported WNV neuroinvasive disease (WNND) cases was 238:1 (95% CI 192-290), with significantly increased risk of WNND in older age groups. These findings were very similar to previous estimates of infections per WNND case, indicating no change in virulence as WNV evolved into an endemic infection in the United States.
authors.affiliation: Creative Testing Solutions,Tempe,AZ,USA.
authors.forename: P C
authors.initials: PC
authors.lastname: Williamson
authors.affiliation: Blood Systems Research Institute,San Francisco,CA,USA.
authors.forename: B
authors.initials: B
authors.lastname: Custer
authors.affiliation: Division of Vector-Borne Diseases,Centers for Disease Control and Prevention,Fort Collins,CO,USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Biggerstaff
authors.affiliation: Division of Vector-Borne Diseases,Centers for Disease Control and Prevention,Fort Collins,CO,USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Lanciotti
authors.affiliation: Carter BloodCare,Bedford,TX,USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Sayers
authors.affiliation: Carter BloodCare,Bedford,TX,USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Eason
authors.affiliation: Creative Testing Solutions,Bedford,TX,USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Dixon
authors.affiliation: Creative Testing Solutions,Tempe,AZ,USA.
authors.forename: V
authors.initials: V
authors.lastname: Winkelman
authors.affiliation: Blood Systems Research Institute,San Francisco,CA,USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Lanteri
authors.affiliation: Division of Vector-Borne Diseases,Centers for Disease Control and Prevention,Fort Collins,CO,USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Petersen
authors.affiliation: Blood Systems Research Institute,San Francisco,CA,USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Busch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057134:Antibodies, Neutralizing / Q000378:metabolism; D001782:Blood Donors / Q000706:statistics & numerical data; D058872:Epidemics; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D013781:Texas / Q000453:epidemiology; D014901:West Nile Fever / Q000097:blood / Q000453:epidemiology* / Q000821:virology; D014902:West Nile virus / Q000502:physiology*; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D007074:Immunoglobulin G; D007075:Immunoglobulin M
keywords: Blood transfusion-associated infections; West Nile virus; incidence
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