west_nile_virus_72505

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					Marion County Environmental Health’s
       Vector Control Program
           503-588-5346




West Nile Virus
                   1
             West Nile Virus Oregon Map 2004
           CLATSOP
                  COLUMBIA


                                         HOOD                                           UMATILLA
             WASHINGTON        MULTNOMAH RIVER           SHERMAN                                               WALLOWA
                                                                           MORROW
   TILLAMOOK        YAMHILL      CLACKAMAS
                                                                                                   UNION
              YAMHILL
                                                 WASCO           GILLIAM

              POLK      MARION
                                                                   WHEELER

        LINCOLN
                                                 JEFFERSON                                             BAKER
                                                                                                                         County      Human   Birds   Horse
                              LINNLINN

            BENTON                                                                   GRANT
                                                                                                                                                     s

                                                                CROOK
                                                                                                                         Benton          0       1           0
                               LANE
                                             DESCHUTES                                                                   Crook           0       1           0
                                                                                                                         Grant           0       0           1
 COOS
                     DOUGLAS                                                                           MALHEUR
                                                                                                                         Jackson         1      11           4
                                                         LAKE                       HARNEY

                                                                                                                         Josephine       0       5           4

        JOSEPHINE
                                                                                                                         Lane            0       2           0
                       JACKSON           KLAMATH
CURRY
                                                                                                                         Linn            0       0           1
                                                                                                                         Malheur         4       3      22
                                                                                                                         Total           5      23      32


                                                                                               2
                                      Mosquito Surveillance 2005
                                         Vector Control Districts                                                                .

                      COLUMBIA
           CLATSOP

                                                                                                                                     Existing VCD
                      W ASHINGTON
                                         HOOD                                                 UMATILLA
                               MULTNOMAH RIVER               SHERMAN                                                 W ALLOW A

   TILLAMOOK        YAMHILL
                                                                               MORROW                                                Proposed VCD
                                 CLACKAMAS
                                                                                                         UNION
              YAMHILL
                                      MARION        W ASCO           GILLIAM

              POLK      MARION
                                                                       W HEELER
                                                    JEFFERSON                                                BAKER
        LINCOLN                   LINN
                              LINN

            BENTON                                                                          GRANT



                                                                    CROOK
                               LANE
                                                DESCHUTES




 COOS                                                                                                        MALHEUR
                     DOUGLAS
                                                             LAKE                       HARNEY




        JOSEPHINE      JACKSON                 KLAMATH
CURRY




                                                                                        3
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         WNV Human Infection ŅIcebergÓ

  For every case of illness         <1%          ~10% fatal
involving the brain or spinal       CNS          (<0.1% of total infections)
           cord,                  disease
    ~150 total infections                                  Very crude
                                 ~20%                      estimates
                            ŅWest Nile Fever Ó




                                    ~80%
                                Asymptomatic




                                     6
       Trends in Human Cases
Year     # of Cases # of Deaths # of States*

1999        62           7              1

2000        21           2              3

2001        66           9             10

2002       4071         279      39 states + DC

2003       9862         264      45 states + DC

2004       2470         88       40 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
What Can You Do?



       9
   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

                        10
Source Reduction




       11
Source Reduction




       12
Other Ways to Protect
      Yourself




         13
 DEET Effectiveness

% DEET        ~Hours of Protection

 23.8                     5

  20                      4

 6.65                     2

 4.75*                  1.5*

                 * with 2% soybean oil
         14
            Gambusia affinis
             Mosquito Fish




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




                     15
          Gambusia affinis
                  Mosquito Fish




  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


                       16
What Can Marion County
        DO?



          17
 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


                         18
   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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   Marion County
Environmental Health
   503-588-5346
          22
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    Positive   Positive Dead           Positive
Human Cases Equine Cases     Birds               Mosquito
                                                  Pools

                             619 Positive
 21 Cases*      27 Cases**   Out of 4380      386 Positive
                              Tested***        Pools****

   * 6 are      ** 12 New     *** Week of       **** Also 2
Neuroinvasive     Cases      July 22, 2005       Cases of
                             163 Positive          WEE
                                             Western Equine Encephalitis
                                  Birds