West Nile virus infections projected from blood donor screening data, United States, 2003.
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.
Busch
Michael P
MP
Blood Systems Research Institute, San Francisco, California 94118, USA. mbusch@bloodsystems.org
Wright
David J
DJ
Custer
Brian
B
Tobler
Leslie H
LH
Stramer
Susan L
SL
Kleinman
Steven H
SH
Prince
Harry E
HE
Bianco
Celso
C
Foster
Gregory
G
Petersen
Lyle R
LR
Nemo
George
G
Glynn
Simone A
SA
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
D012367:RNA, Viral