Update on West Nile Virus – United States, Eileen C. Farnon, MD Arboviral Diseases Branch Division of Vector-Borne Infectious Diseases Centers for Disease Control and Prevention Fort Collins, Colorado Blood Products Advisory Committee 89 th Meeting April 27, 2007

WNV Transmission Cycle Enzootic (Maintenance/Amplification) Epizootic Epidemic Amplifying hosts Dead-end hosts (usually)

ArboNET Arboviral national electronic surveillance system Humans Ecologic Mosquitoes Birds Animals WNV, SLE, EEE, WEE, LAC, DEN, VEE All data current as of April 12, 2007

Human WNV Syndromes Reported to ArboNET WN fever (WNF) WN neuroinvasive disease (WNND) Meningitis Encephalitis Acute flaccid paralysis Other Unspecified illness

Incidence per million >=100 Any WNV Activity WNV Neuroinvasive Disease Incidence, by County, US, 1999 N=59

WNV Neuroinvasive Disease Incidence, by County, US, 2000 Incidence per million >=100 Any WNV Activity N=19

WNV Neuroinvasive Disease Incidence, by County, US, 2001 Incidence per million >=100 Any WNV Activity N=64

WNV Neuroinvasive Disease Incidence, by County, US, 2002 Incidence per million >=100 Any WNV Activity N=2,946

WNV Neuroinvasive Disease Incidence, by County, US, 2003 Incidence per million >=100 Any WNV Activity N=2,866

WNV Neuroinvasive Disease Incidence, by County, US, 2004 Incidence per million >=100 Any WNV Activity N=1,148

WNV Neuroinvasive Disease Incidence, by County, US, 2005 Incidence per million >=100 Any WNV Activity N=1,309

WNV Neuroinvasive Disease Incidence, by County, US, 2006 Incidence per million >=100 Any WNV Activity N=1,491 *Reported as of 4/12/2007

Onset of Human WNV Disease, United States * *Reported as of 4/12/2006

Cumulative WNND Incidence, by County, US, *Reported as of 11/14/06 Lindsey N, et al, in press

Median Annual WNND Incidence Rank versus Cumulative WNND Incidence Rank by County, *Reported as of 11/14/06 Lindsey N, et al, in press

Counties with Persistently High WNND Incidence,

Reported WNV Disease Cases in Humans – United States, * YearTotalWNNDWNF/otherDeaths ,1562,9461, ,8622,8666, ,5391,1481, ,0001,3091, ,2611,4912, Total23,9679,90214, *Reported as of 4/12/2007

WNV Blood Screening 2002 – 23 cases of transfusion-associated transmission (TAT) 2003 – Nucleic acid amplification tests (NAT) MP-NAT (6-16 units)  ID-NAT Blood banks report presumptively viremic donors (PVDs) to local public health department Remove infectious blood products from circulation Public health departments report to ArboNET Perform clinical follow-up Perform trace-back investigations

WNV PVDs by Year* YearPVDs Total1820 *Reported as of 4/12/2007

West Nile Viremic Blood Donors, by State of Residence, 2006* *Reported as of 4/12/2007

PVDs Reported to ArboNET*, 2006 Over 8 million donations screened 361 PVDs reported to ArboNET 84 (23%) WNF 4 (0.1%) WNND 2 (0.1%) other 118 (33%) reported from 3 states: NE, ID, TX *Reported as of 4/12/2007

WNV Transfusion-associated Transmission, 2006 – Case 1 82 y male resident of SD recently post-kidney transplant 4d post-transplant: 2U PRBC 21d post-transplant: encephalitis WNV IgM detected in serum and CSF Organ donor tested negative for WNV Blood donor tested positive for WNV IgM negative MP-NAT MMWR 2/2/07

WNV Transfusion-associated Transmission, 2006 – Case 2 60 y male resident of IA 5y post-kidney transplant Spinal fracture repair in SD: 15 blood products 6U FFP from blood donor 11d post-operatively: encephalomyelitis WNV IgM detected in CSF MMWR 2/2/07

Summary WNV occurs throughout the continental U.S. Western plains have highest incidence of WNND Dates of onset for WNV disease span the year 2 cases of transfusion-associated transmission despite MP-NAT testing New approaches to triggering ID-NAT considered

Acknowledgements The findings and conclusions in this presentation are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention. Jennifer Lehman Nicole Lindsey Stephanie Kuhn Margaret Collins Kate Ellingson Matt Kuehnert Mark Duffy Marc Fischer Edward Hayes John Jones Nicholas Komar Roger Nasci John Roehrig Janet McAllister Harry Savage James Sejvar Theresa Smith Grant Campbell Brad Biggerstaff Lyle Petersen All reporting states, jurisdictions, and local health departments

Photo: Meggan Gould

Cumulative Incidence of WNND by State – United States, * *Reported as of 11/14/06