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West Nile Virus

Washington State Department of Health

The 2004 Picture

WestNileVirus

Washington State Department of Health 2

First isolated from in the West Nile District of Uganda, 1937

Recognized as a cause of inflammation of the spinal cord and brain with outbreak in elderly patients, Israel, 1957

Equine disease noted in Egypt and France in the early 1960s

1999 “Old World” virus arrives in the “New World”

WNV Background

Washington State Department of Health 3

Incidental infections

Bird reservoir hosts

Incidental infections

Mosquito vector

Transmission Cycle

Washington State Department of Health 4

Some Speculated Pathways of Introduction Human-transported birdHuman-transported mosquitoesStorm-transported birdIntentional introduction (terrorist event)

- not likelyInfected human traveler - not likely

WNV in the US

Washington State Department of Health 5

Human Human infectioninfection with WNV with WNV

~80%No symptoms

~20%West Nile fever

<1%WNND

Fatal WNV infection: <0.1% of all infections10% of WNND

1/150 of all infectionscause West Nileneuroinvasive

disease (WNND) Very rough estimates

Washington State Department of Health 6

Washington State Department of Health 7

Washington &WNV

2002 Washington goes positive...

Raven Pend Oreille CountyCrowSnohomish CountyHorse Island CountyHorse Whatcom County

Washington State Department of Health 8

A Tale of Two Years

2003 2004

US Total 9,862 2,313

“The West” 3,773 1,562

As of November 16

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2003 2004*

Arizona 13 389

California 3 737

Colorado 2,947 276

Idaho 1 2

Montana 222 6

Nevada 2 44

New Mexico 209 86

Oregon 0 3

Utah 1 11

Washington 0 0

Wyoming 375 9*As of Nov 23, 2004

A Tale of Two Years

Washington State Department of Health 10

2004 WNV Cases as of November 23

                                                                                                                

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The Northwest Experience

Washington State Department of Health

WestNileVirus

Washington State Department of Health 12

Idaho

2003 2004

Humans 1 2

Horses 0 23

Birds 0 6

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Idaho Human Case Locations 2004

Washington State Department of Health 14

Idaho Horse Case Locations 2004

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Idaho Bird Case Locations 2004

Washington State Department of Health 16

Oregon

2003 2004

Humans 0 3

Horses 0 31

Birds 0 19

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Oregon Human Case Locations 2004

Washington State Department of Health 18

Oregon Horse Case Locations 2004

Washington State Department of Health 19

Oregon Bird Case Locations 2004

Washington State Department of Health 20

Washington Bird Locations 2004

536 birds tested

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Washington Surveillance Testing 2004

Humans 23

Horses 53

Birds 551

Mosquito Pools 829

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Lasting Effects

47% required physical therapy after hospitalization

Only 37% fully recovered after 1 year

Cognitive loss reported = 41.2%

Functional loss reported = 42.9%

Physical loss reported = 45.7%Source: Emerging Infectious Diseases, Vol. 10, No. 8, August 2004 (http://www.cdc.gov/ncidod/EID/vol10no8/03-0879.htm)

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Thanks to Our Partners

• Mosquito Control Districts• Local Health Jurisdictions• USACHPPM-West• Veterinarians• Health Care Providers• State agencies and others

West Nile Virus Surveillance

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Only Time Will Tell

Washington State Department of Health

Washington State Update 2004

WestNileVirus