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Transfusion medicine

Tranfusion-transmitted disease

West Nile virus and transfusions

Reviewer: Huy Phu Pham, M.D. (see Reviewers page)
Revised: 1 November 2011, last major update November 2011
Copyright: (c) 2007-2011, PathologyOutlines.com, Inc.


● West Nile virus is a flavivirus primarily transmitted through mosquitoes, with birds as immediate hosts (Wikipedia)
● Entered North America in 1999; still epidemic in North America due to mosquito and bird vectors
● First appeared in NY in 1999, and rapidly expanded its geographical area within 3 years
● Symptoms: headache, new rash, generalized weakness (Transfusion 2006;46:272)
● May cause meningoencephalitis (Am J Clin Pathol 2003;119:749)
● Transfusion transmission resulted in 23 infections in 2002 during an outbreak
● Detected by nucleic acid based testing, although virus adheres to human red blood cells in whole blood (Clin Infect Dis 2007;45:181)
● NAT testing was implemented in 2003
● Use of only minipool NAT testing resulted in 7 transfusion-transmission cases in 2003-2004

Cost effectiveness models:
● In areas with high levels of transmission, seasonal screening of individual samples and restricting screening to blood donations designated for immunocompromised recipients is cost effective
● In areas with low levels of infection, using a standard questionnaire is cost-effective (PLoS Med 2006;3:e21, PLoS Med 2006;3:e99; see also Ann Intern Med 2005;143:486 and Ann Intern Med 2005;143:537)

● In 2003-2005, 1425 infected blood donors were identified in US (Transfusion 2006;46:2038)
● In 2003, only 6 cases of transfusion-transmitted WNV were documented in US from 12.6 million blood units donated and 23 million blood transfusions; fewer since strategy changed from minipool to individual nucleic acid testing method in epidemic areas (Dev Biol [Basel] 2007;127:43, N Engl J Med 2005;353:460)
● Viral inactivation systems may be useful (Vox Sang 2006;91:345, Antiviral Res 2005;68:84)
● Donor prevalence rates: Mexico-0.03% (Transfusion 2006;46:111), Netherlands-0% (Vox Sang 2006;90:166)
● Epidemiologic reports from Centers for Disease Control (2002-2007): MMWR 2002;51:790, MMWR 2002;51:823, MMWR 2002;51:884, MMWR 2002;51:973, MMWR 2003;52:769, MMWR 2003;52:916, MMWR 2004;53:281, MMWR 2004;53:842, Emerg Infect Dis 2005;11:1167, MMWR 2007;56:76

End of Transfusion Medicine > Tranfusion-transmitted disease > West Nile virus and transfusions

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