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Mosquito-borne Diseases Western equine encephalitis and St. Louis encephalitis Both have occurred in Washington but no reported cases since early 1980’s West Nile virus – Detected in 1999 in New York City – Detected in Washington and 43 other states in 2003 – Continued surveillance effort in Washington 2

Mosquito-borne Disease Surveillance Pre-1960’sNo record of state activity 1960’sFirst statewide mosquito survey published in ’sMosquito Control Districts formed in Eastern Washington 1970’sSentinel flocks used in Benton County and Grant County 3

Mosquito-borne Disease Surveillance 1980’sLast confirmed human and horse cases of mosquito-borne encephalitis 1990’sZoonotic Disease program established in DOH 2001 DOH initiates WNV surveillance 4

Yakima Valley Encephalitis Outbreaks cases cases13 fatal cases 3 fatal cases 2 fatal (Reported in August 1945 Journal of American Medical Association) 5

Spokane San Juan Island Pierce King Snohomish Skagit Whatcom Clallam Jefferson Grays Harbor Thurston Kitsap Clark Cowlitz Lewis Skamania Wahkiakum Mason Yakima 7 Cases ( 6 WEE, 1 SLE) Chelan Okanogan Ferr y Stevens Pend Oreille Lincoln Kittitas Whitman Klickitat Benton Walla Columbia Garfield Asotin Franklin Adams Grant Douglas Pacific Reported Human Cases of Mosquito-borne Disease ( ) Western Equine Encephalitis St. Louis Encephalitis Total cases = 12 6

Spokane San Juan Island Pierce King Snohomish Skagit Whatcom Clallam Jefferson Grays Harbor Thurston Kitsap Clark Cowlitz Lewis Skamania Wahkiakum Mason Yakima Chelan Okanogan Ferry Stevens Pend Oreille Lincoln Kittita s Whitman Klickitat Benton Walla Columbi a Garfield Asotin Franklin Adams Grant Douglas Pacific Western Equine Encephalitis Horse Cases ( ) Suspect cases Confirmed cases 7

West Nile Virus In the United States 8

WNV Background First isolated 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” 9

West Nile Outbreaks Israel , 1957, France 1962, 2000 South Africa 1974 Romania Italy 1997 Czech Republic 1998 Republic of the Congo 1998 Russia 1999 United States

Outbreak Timeline Israel 1957 Uganda 1937 Israel France 1962 South Africa 1974 Romania 1996 Italy 1997 Czech Rep Congo 1998 Russia 1999 US Israel France 2000 Encephalitis Condition Identified Equine Disease Identified 11

Incidental infections Bird reservoir hosts Incidental infections West Nile Virus Transmission Cycle Mosquito vector 12

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WNV in the US Speculated Pathways of Introduction Human-transported birdHuman-transported bird LegalLegal IllegalIllegal Human-transported mosquitoesHuman-transported mosquitoes Storm-transported birdStorm-transported bird Intentional introduction (terrorist event)- not likelyIntentional introduction (terrorist event)- not likely Infected human traveler-not likelyInfected human traveler-not likely 14

The incubation period for West Nile Virus is generally 3-14 days following a bite from an infected mosquito. WNV Symptoms High Fever Headache and body aches Skin rash Swollen lymph glands Neck stiffness Disorientation Convulsions 15

States with WNV (0) Distribution of WNV Before

States with WNV (4) Distribution of WNV as of November

States with WNV (12 + DC) Distribution of WNV as of November

States with WNV (27 + DC) Distribution of WNV as of November

States with WNV (44 + DC) Distribution of WNV as of November

WNV by County 21

Distribution by County December 7, 2002 Source: Dr. Henry Huang, Washington U. School of Medicine 22

San JuanIsland Clallam Jefferson Grays Harbor Kitsap Lewis Skamania Pacific Mason Ferry Stevens Lincoln Kittitas Klickitat Columbia Garfield Asotin Okanogan Snohomish Douglas Chelan Spokane Yakima Whatcom Pierce Franklin Benton Whitman Walla Clark Cowlitz Thurston Wahkiakum Pend Oreille Grant Adams King Counties Detecting West Nile Virus 2002 Skagit 23

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Case Summary Year Humans (deaths) Horses (deaths) 20024,161 (277)14, (9)470 (156) (2)60 (23) (7)25 (8) 27

*As of Dec 19 WNV Case-Patient Demographics & Mortality United States, * 28

Date of Symptom Onset, West Nile Virus United States, /78/49/1 9/29 10/2711/2412/23 Week ending Number of cases

Protecting Public Health Surveillance Personal Protection and Education Mosquito Control 30

WNV Surveillance Mosquitoes Dead birds (especially crows, jays, ravens and magpies) Veterinary surveillance Human surveillance 31

Mosquito Surveillance Review information on species in your jurisdiction Establish system for recording “mosquito complaints” Identify and map breeding locations Conduct larval/adult surveillance (May- Sep) 32

Dead Bird Surveillance Establish system for recording dead bird reports Message to public on reporting sightings Submit corvids for analysis (May-Oct) Response protocol for positive birds 33

Horse Case Surveillance Encourage reporting by local veterinarians Identify major stables, training facilities and establish contact Track cases as they occur Response protocol for sick, dead horses 34

Human Case Surveillance Enhanced passive surveillance May- Sep Active surveillance when cases result Case investigation to help define probable exposure Response protocol for illness or death in humans 35

Mosquito Control Assessment of local capability Designation of lead agency, person (where, when, how) Develop local action plan Training and licensing of personnel to use mosquito control compounds Keep community involved and informed in the decision process, especially if adulticiding is considered 36

WNV Mosquito Species in Washington Aedes cinereus Aedes vexans Culex pipiens Culex restuans Culex tarsalis Anopheles punctipennis Coquilletidia perturbans Ochlerotatus canadensis Ochlerotatus japonicus Counties (39)

Human cases Veterinary cases Mosquitoes Dead birds Time Disease Activity Sentinel hosts Estimated Sensitivity of WNV Surveillance Methods 38

Personal Protection Wear long sleeves & pants in mosquito- infested areas Use repellant containing DEET (N,N- diethyl-3-methylbenzamide) and follow directions carefully Limit outdoor activities at dawn and early evening Repair holes in door & window screens 39

Habitat Reduction Eliminate standing water (flower pots; tires; wheelbarrows; wading pools) Change the water in birdbaths at least weekly Aerate and chlorinate swimming pools and hot tubs; cover if possible Consider mosquito-eating fish for your pond Keep gutters clean to prevent standing water Spread the word: educate your friends and neighbors 40

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Want More? Your local health department 42