title: West Nile virus infections projected from blood donor screening data, United States, 2003.
abstract: National blood donor screening for West Nile virus (WNV) RNA using minipool nucleic acid amplification testing (MP-NAT) was implemented in the United States in July 2003. We compiled national NAT yield data and performed WNV immunoglobulin M (IgM) testing in 1 WNV-epidemic region (North Dakota). State-specific MP-NAT yield, antibody seroprevalence, and the average time RNA is detectable by MP-NAT were used to estimate incident infections in 2003. WNV donor screening yielded 944 confirmed viremic donors. MP-NAT yield peaked in August with >0.5% of donations positive for WNV RNA in 4 states. Peak IgM seroprevalence for North Dakota was 5.2% in late September. The average time viremia is detectable by MP-NAT was 6.9 days (95% confidence interval [CI] 3.0-10.7). An estimated 735,000 (95% CI 322,000-1,147,000) infections occurred in 2003, with 256 (95% CI 112-401) infections per neuroinvasive case. In addition to preventing transfusion-transmitted WNV infection, donor screening can serve as a tool to monitor seasonal incidence in the general population.
authors.affiliation: Blood Systems Research Institute, San Francisco, California 94118, USA. mbusch@bloodsystems.org
authors.forename: Michael P
authors.initials: MP
authors.lastname: Busch
authors.forename: David J
authors.initials: DJ
authors.lastname: Wright
authors.forename: Brian
authors.initials: B
authors.lastname: Custer
authors.forename: Leslie H
authors.initials: LH
authors.lastname: Tobler
authors.forename: Susan L
authors.initials: SL
authors.lastname: Stramer
authors.forename: Steven H
authors.initials: SH
authors.lastname: Kleinman
authors.forename: Harry E
authors.initials: HE
authors.lastname: Prince
authors.forename: Celso
authors.initials: C
authors.lastname: Bianco
authors.forename: Gregory
authors.initials: G
authors.lastname: Foster
authors.forename: Lyle R
authors.initials: LR
authors.lastname: Petersen
authors.forename: George
authors.initials: G
authors.lastname: Nemo
authors.forename: Simone A
authors.initials: SA
authors.lastname: Glynn
mesh_terms: D001782:Blood Donors; D006801:Humans; D015994:Incidence; D008403:Mass Screening; D012367:RNA, Viral / Q000097:blood; D012621:Seasons; D012680:Sensitivity and Specificity; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D014901:West Nile Fever / Q000097:blood* / Q000453:epidemiology*; D014902:West Nile virus / Q000302:isolation & purification
chemical_list: D012367:RNA, Viral