Marion County Environmental Health’s Vector Control Program Marion County Environmental Health’s Vector Control Program West Nile Virus 1

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Mosquito Surveillance 2005 Vector Control Districts Mosquito Surveillance 2005 Vector Control Districts Existing VCD Proposed VCD 3

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Trends in Human Cases Year# of Cases# of Deaths# of States* states + DC states + DC states + DC * with human cases 7

Spectrum of Illness - West Nile Fever Most people who get sick from WNV infection have WNV fever Time from exposure (usually by mosquito bite): 3-14 days Fever, chills, headache, fatigue Can be severe Nausea, vomiting (can be severe) Rash, usually not itchy, lasting a few days, mainly on chest, back, abdomen, and/or arms Usually better within a week, though persistent headache, fatigue common -- reports of weeks, even longer among otherwise healthy persons 8

9 What Can You Do?

10 Wear repellent when outdoors. Avoid being outdoors from dusk to dawn. Wear long sleeve shirts and pants. Clean your roof gutters, empty buckets and kiddy pools. Properly dispose of tires or drill holes in them. Change the water in birdbaths and pet waterers at least weekly. Keep ponds free of vegetation

Source Reduction 11

Source Reduction 12

Other Ways to Protect Yourself 13

DEET Effectiveness 14 % DEET~Hours of Protection *1.5* * with 2% soybean oil

Gambusia affinis Mosquito Fish 15 Native to Southern US Effective in small ponds, ornamental pools Effective in livestock water troughs Eat the mosquito larvae Available in pet stores at very low cost

Gambusia affinis Mosquito Fish 16 Can not be used in rivers, creeks, lakes Can not be taken across county borders without ODFW Transport Permit Do not use where they can escape into open waters Fish are live-bearers and reproduce rapidly Effective in shallow water with vegetation Concerns about predation of native species

17 What Can Marion County DO?

18 Marion County will collect dead crows and jays for WNV testing Marion County will identify and survey adult mosquitoes for WNV Marion County will speak to civic organizations, schools, etc. Marion County will provide information to the public through pamphlets, handouts and the internet Marion County will cooperate with cities on controlling mosquito larvae

Marion County will survey property for owners and consult with them on control measures. Marion County will do limited larvaciding in areas of the county where high-risk populations are located. Marion County will use the safest most efficient pesticide for larvae control. Marion County will use Bacillus thurengiensis (bacteria) and Methoprene (growth regulator) Marion County will provide information on where to obtain Gambusia affinis 19

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22 Marion County Environmental Health

West Nile Virus 2005 West Nile in the West and U.S.

West Nile Virus in 2005 in the U.S.

Birds with WNV in California As of July 22, 2005 Positive Human Cases Positive Equine Cases Positive Dead Birds Positive Mosquito Pools 21 Cases*27 Cases** 619 Positive Out of 4380 Tested*** 386 Positive Pools**** * 6 are Neuroinvasive ** 12 New Cases *** Week of July 22, Positive Birds **** Also 2 Cases of WEE Western Equine Encephalitis