Theresa L. Smith, MD, MPH Division of Vector-Borne Infectious Diseases Centers for Disease Control and Prevention Fort Collins, CO West Nile Virus Epidemiology & Surveillance Update 2005 Blood Product Advisory Committee Gaithersburg, MD November 3, 2005

West Nile Virus (WNV) Update* VirologyVirology Epidemiology of WNV in US 1999 – 2005Epidemiology of WNV in US 1999 – surveillance update2005 surveillance update Blood donation surveillance eventsBlood donation surveillance events *Unless marked, all data including 2005 was in ArboNET as of 11/1/05

WNV: Virology Flavivirus in the Japanese encephalitis serogroup WNV & St. Louis encephalitis in the US Primarily bird pathogen Bird – mosquito – bird transmission cycle Mammals are dead-end hosts in natural cycle Low-level viremia before illness onset

WNV Update VirologyVirology Epidemiology of WNV in US 1999 – 2005Epidemiology of WNV in US 1999 – surveillance update2005 surveillance update Blood donation surveillance eventsBlood donation surveillance events

ArboNET: A National Arbovirus Surveillance System Web-based passive system begun in area health departments to DVBID Mosquito, bird, horse, other animal surveillance Year, state, county, date of collection Human cases Age, sex, race/ethnicity Residence Clinical illness, onset date and outcome Blood or organ donation/receipt

First Reported WNV Activity, by State, Human

2,539 human cases 1,142 WNND 100 deaths 40 states + DC 523 counties

2005 2,581 human cases 1,053 WNND 83 deaths 40 states 563 counties

WNV Update VirologyVirology Epidemiology of WNV in US 1999 – 2005Epidemiology of WNV in US 1999 – surveillance update2005 surveillance update Blood donation surveillance eventsBlood donation surveillance events

Human WNV Disease Cases by week of illness onset and date reported to ArboNET United States, 2004

Reported Human WNV disease cases, United States, YearCasesStates/District , DC 20039, DC 20042, DC 20052,58142

Human WNV Disease, ArboNET ,581 case reports 42 states Neuroinvasive – 1,053 Fever – 1,363 Deaths – 83* Median age: 78 yrs Age range: 36 – 98 yrs States with > 100 case reports California824 Illinois 241 South Dakota235 Texas139 Louisiana111 Arizona102 64% of all reports * 78 fatalities had age available

WNV Update VirologyVirology Epidemiology of WNV in US 1999 – 2005Epidemiology of WNV in US 1999 – surveillance update2005 surveillance update Blood donation surveillance eventsBlood donation surveillance events

WNV Blood Screening, US, YearScreened*PVDsWNNDWNFTAT NA *In millions

Data unavailable

Reported PVDs to ArboNET, 2004 vs in 29 states Top four states: California66 Arizona36 Colorado 24 Texas in 30 states Top four states: California87 Texas57 Nebraska 53 Louisiana22

Implicated Donation Viral Concentrations implicated donations had virus titers ranging from 0.8 to 75.1 pfu/mL with a of median of 10.5 pfu/mL 2003 Four implicated donations had virus titers ranging from 0.06 to 0.5 pfu/mL with a median of 0.11 pfu/mL 2004 One implicated donation had a viral titer of 0.12 pfu/mL

2005 Investigations Blood Transmission 6 investigations 3 negative 3 pending plasma return from Switzerland Organ Transplantation Transmission Likely mosquito-borne infection in donor Possible febrile illness IgM positive, PCR negative before donation Three of four organ recipients PCR positive Two became ill

Organ Donor Timeline August 2005 Serum, Plasma PCR (-) IgM, IgG (+) 28 WNV + Mosquitoes In Nearby Park Injury and Surgery Organ Recovery Brain Death Febrile Illness? 27

2005 Summary WNV activity over most of the continental US Continued westward expansion Full season of transmission in CA Human cases reported from all states except Alaska, Hawaii, Maine, & Washington Risk of WNV TAT unknown Continue to investigate possible TAT TAT less likely to cause organ transplant related WNV transmission