Fairfax County West Nile virus Control and Mosquito

Management Program,

2003 Season

Fairfax County West Nile Virus Statistics, 2003

Human cases 3

Birds 15

Mosquito pools 149

Horses 2

Avian Surveillance

0

5

10

15

20

25

30Dead Birds Called in to Fairfax County Health Department, 2003

Date

Frequency of Birds Reported by Day to the Health Department Phone Line 2003

Crow poisoning 1st + bird

Last bird

Distribution of Dead Birds Reported by the Community

1,259 dead birds called in

Distribution of Dead Crows & Blue Jays Reported by the Community,

2003

367 Crows

457 total

90 Blue jays

Distribution of WNV Positive Birds in Fairfax County, 2003

The decision was made to stop at 15

Climate

Silent Partners

0

10

20

30

40

50

60

70

80

90

100

1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361

2002 2003

Daily Temperature Recorded for Fairfax County

(Regan National Airport), 2002 and 2003.

Days of the year

OF

0

100

200

300

400

500

600

700

1 18 35 52 69 86 103 120 137 154 171 188 205 222 239 256 273 290 307 324 341 358

sum >75-02 sum >75-03

Cumulative Day Degrees above 75oC Recorded for Fairfax County

(Regan National Airport), 2002 and 2003.

Days of the year

298 day degrees

Date

Daily Precipitation Recorded for Fairfax County

(Regan National Airport), 2002 and 2003.

0

0.5

1

1.5

2

2.5

1 15 29 12 26 12 26 9 23 7 21 4 18 2 16 30 13 27 10 24 8 22 5 19 3 17 31

2002 2003

Inch

es

Attachment 16.- Cumulative Daily Precipitation Recorded for Fairfax County (Regan National Airport), 2002 and 2003.

Days of the year

0

10

20

30

40

50

60

70

1 16 31 46 61 76 91 106 121 136 151 166 181 196 211 226 241 256 271 286 301 316 331 346 361

Cumulative 2002 Cumulative 2003

inch

es

Almost 2X previous yr.

0:00

2:24

4:48

7:12

9:36

12:00

14:24

16:48

1 20 8 27 18 6 25 14 2 21 10 29 17 5 24 13 1 20 9 28

May 22nd, Epi. week 21

14½ daylight hours

Daylight Hours in Fairfax County

Little vector borne transmission

Sporadic transmission

Endemic transmission

Sustained endemic transmission

Outbreaks

Principal factors implicated in West Nile virus transmission by Culex pipiens

Average temperature

>25OC 20 - 25ºC 15 - 19ºC <15ºC

Altitude (m)

2,.500

1,.200

900

600

Sea level

Rai

nfa

ll

Solid waste, water management (CB’s), community participation (behavior)

Daylight hours (Photoperiod)

596877

Epidemic

Mosquito Surveillance

Traps set by the Health Department to complement the Mosquito Surveillance done by Clarke

Distribution of WNV Positive Mosquito Pools in Fairfax County,

2003.

21,335 mosquitoes1,836 pools149 positive pools

FAIRFAX COUNTY

Species # of pools tested

# of pools

positive

# of specimens

Infection rate (%)

Aedes albopictus 169 3 1,211 0.25%Aedes vexans 79 0 671 ------

Anopheles punctipennis 117 0 1,661 ------

Coquilletidia perturbans 27 0 316 ------

Culex erraticus 3 0 11 ------

Culex pipiens 514 119 6,224 1.91%

CDC trap 178 11 1,127 0.98%

Gravid trap 336 108 5,079 2.13%

Culex restuans 360 24 3,916 0.61%

CDC trap 204 0 2,103 ------

Gravid trap 156 24 1,718 1.40%

Culex salinarius 172 2 1,453 0.14%

CDC trap 164 2 1,437 0.14%

Gravid trap 8 0 16 ------

Ochlerotatus canadensis 11 0 168 ------

Ochlerotatus japonicus 32 0 84 ------

Ochlerotatus triseriatus 7 0 47 ------

Ochlerotatus trivitattus 4 0 50 ------

Psorophora ferox 24 0 807 ------

Others 298 0 4,180 ------

TOTAL 1,836 148 21,335 ------

Mosquitoes tested for West Nile virus, 2003

FAIRFAX COUNTY

Species # of pools tested

# of pools

positive

# of specimens

Infection rate (%)

Aedes albopictus 169 3 1,211 0.25%

Aedes vexans 79 0 671 ------

Anopheles punctipennis 117 0 1,661 ------

Coquilletidia perturbans 27 0 316 ------

Culex erraticus 3 0 11 ------

Culex pipiens 514 119 6,224 1.91%

CDC trap 178 11 1,127 0.98%

Gravid trap 336 108 5,079 2.13%Culex restuans 360 24 3,916 0.61%

CDC trap 204 0 2,103 ------

Gravid trap 156 24 1,718 1.40%

Culex salinarius 172 2 1,453 0.14%

CDC trap 164 2 1,437 0.14%

Gravid trap 8 0 16 ------

Ochlerotatus canadensis 11 0 168 ------

Ochlerotatus japonicus 32 0 84 ------

Ochlerotatus triseriatus 7 0 47 ------

Ochlerotatus trivitattus 4 0 50 ------

Psorophora ferox 24 0 807 ------

Others 298 0 4,180 ------

TOTAL 1,836 148 21,335 ------

Mosquitoes tested for West Nile virus, 2003

FAIRFAX COUNTY

Species # of pools tested

# of pools

positive

# of specimens

Infection rate (%)

Aedes albopictus 169 3 1,211 0.25%

Aedes vexans 79 0 671 ------

Anopheles punctipennis 117 0 1,661 ------

Coquilletidia perturbans 27 0 316 ------

Culex erraticus 3 0 11 ------

Culex pipiens 514 119 6,224 1.91%

CDC trap 178 11 1,127 0.98%

Gravid trap 336 108 5,079 2.13%

Culex restuans 360 24 3,916 0.61%

CDC trap 204 0 2,103 ------

Gravid trap 156 24 1,718 1.40%Culex salinarius 172 2 1,453 0.14%

CDC trap 164 2 1,437 0.14%

Gravid trap 8 0 16 ------

Ochlerotatus canadensis 11 0 168 ------

Ochlerotatus japonicus 32 0 84 ------

Ochlerotatus triseriatus 7 0 47 ------

Ochlerotatus trivitattus 4 0 50 ------

Psorophora ferox 24 0 807 ------

Others 298 0 4,180 ------

TOTAL 1,836 148 21,335 ------

Mosquitoes tested for West Nile virus, 2003

FAIRFAX COUNTY

Species # of pools tested

# of pools

positive

# of specimens

Infection rate (%)

Aedes albopictus 169 3 1,211 0.25%

Aedes vexans 79 0 671 ------

Anopheles punctipennis 117 0 1,661 ------

Coquilletidia perturbans 27 0 316 ------

Culex erraticus 3 0 11 ------

Culex pipiens 514 119 6,224 1.91%

CDC trap 178 11 1,127 0.98%

Gravid trap 336 108 5,079 2.13%

Culex restuans 360 24 3,916 0.61%

CDC trap 204 0 2,103 ------

Gravid trap 156 24 1,718 1.40%

Culex salinarius 172 2 1,453 0.14%

CDC trap 164 2 1,437 0.14%

Gravid trap 8 0 16 ------Ochlerotatus canadensis 11 0 168 ------

Ochlerotatus japonicus 32 0 84 ------

Ochlerotatus triseriatus 7 0 47 ------

Ochlerotatus trivitattus 4 0 50 ------

Psorophora ferox 24 0 807 ------

Others 298 0 4,180 ------

TOTAL 1,836 148 21,335 ------

Mosquitoes tested for West Nile virus, 2003

FAIRFAX COUNTY

Species # of pools tested

# of pools positive

# of specimens

Infection rate (%)

Aedes albopictus 169 3 1,211 0.25%

Aedes vexans 79 0 671 ------

Anopheles punctipennis 117 0 1,661 ------

Coquilletidia perturbans 27 0 316 ------

Culex erraticus 3 0 11 ------

Culex pipiens 514 119 6,224 1.91%

CDC trap 178 11 1,127 0.98%

Gravid trap 336 108 5,079 2.13%

Culex restuans 360 24 3,916 0.61%

CDC trap 204 0 2,103 ------

Gravid trap 156 24 1,718 1.40%

Culex salinarius 172 2 1,453 0.14%

CDC trap 164 2 1,437 0.14%

Gravid trap 8 0 16 ------

Ochlerotatus canadensis 11 0 168 ------

Ochlerotatus japonicus 32 0 84 ------Ochlerotatus triseriatus 7 0 47 ------

Ochlerotatus trivitattus 4 0 50 ------

Psorophora ferox 24 0 807 ------

Others 298 0 4,180 ------

TOTAL 1,836 148 21,335 ------

Mosquitoes tested for West Nile virus, 2003

Number and Percentage of Positive Mosquito Poolsper Epidemiological Week, Fairfax County, 2003 WNV Season

0

20

40

60

80

100

120

24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

% Positive Pools

# of Pools Tested

Epidemiological week

149 positive pools1,836 pools tested

Moments at the First Detection of WNV in Birds, Mosquitoes and Humans with Relation to Cumulative Day Degrees Above 75oF

0

100

200

300

400

500

600

1 18 35 52 69 86 103 120 137 154 171 188 205 222 239 256 273 290 307 324 341 358

sum >75oF- 02 sum >75oF- 03

H H

M

M

B

B

H

H

Days

B = BirdM = MosquitoH = Human

B

B

M

M

Larval surveillance

Cx. restuans82%

Cx. pipiens6%

An. punctipennis5%

Cx. territans3%

Ae. vexans2%

Cx. salinarius1%

Oc. japonicus1%

Mosquito Larval Surveillance, Percentage of Mosquitoes Sampled, 2003 WNV Season

0

1020

30

4050

60

70

8090

100

23 24 25 28 31 32 33 37Culex restuans

Culex pipiens

Epi week

% o

f m

osqu

itoes

sam

pled

Percentage of Culex restuans and Cx. pipiens Larvae Sampled,

Fairfax County, 2003

0

1

2

3

4

5

6

20 22 24 26 28 30 32 34 36 38 40 42 44

Distribution of Culex pipiens Captured in CO2 Baited CDC Light Traps*,

Fairfax County, VA. 2003

# F

emal

es p

er L

ight

Tra

p

Epidemiological Week

1st 14½ hr. day

1st week avrg >75oF

1ST pos. Cx. pipiens

1st pos crow

last pos. Cx. pipiens

*total of 915 trap nights

1st human case

1st day <50oF

0

10

20

30

40

21 23 25 27 29 31 33 35 37 39 41 43 45

Distribution of Culex pipiens Captured in Hay Infusion Baited Gravid Traps*,

Fairfax County, VA. 2003

# F

emal

es p

er G

ravi

d T

rap

Epidemiological Week

1st 14½ hr. day

1st week avrg >75oF

1ST pos. Cx. pipiens1st pos crow

last pos. Cx. pipiens

*total of 527 trap nights

1st human case

1st day <50oF

County trapping

Education & Outreach MaterialPrepared by Fairfax County for WNV

Education & Outreach Material Translated by Fairfax County for WNV

NH.NG ÐI.U B.N CÓ TH.N.u có v.n .. v. mu.i t.i n.i b.n s.ng, thì ph.i ch.cch.n là b.n không t.o n.i sanh s.n cho chúng t.i khu..t c.a mình..NG MÁNG TRÊN MÁI NHÀ - th..ng xuyên d.ns.ch lá và các v.n vãi.CÁC LON Ð. H.P VÀ CÁC V.T Ð.NG KHÁC -v.t .i, c.t gi. bên trong nhà, ho.c l.t úp xu.ng.CÁC L.P XE C. - c.t các l.p xe này d..i t.ng h.mho.c nhà kho n.i không b. n..c m.a ..ng vào.CH.U CHO CHIM DÙNG - r.a s.ch và thay n..cvài ngày m.t l.n.CH.U N..C L.N CHO TR. EM CH.I - thayn..c ít nh.t m.t vài ngày m.t l.n và l.p úp l.i khikhông dùng t.i.THUY.N CHÈO, TÀU - che l.i b.ng m.t t.m b.t l.pv.a khít ho.c l.t úp xu.ngCÁC AO LÀM C.NH - cho nhi.u con cá nh. vàoCÁC V.NG N..C VÀ NH.NG N.I ..T VÀS.NG N..C - Tháo n..c hay l.p ..t ho.c các v.tli.u khác. Ph..ng cách h.u hi.u nh.t .. ki.m ch.mu.i là lo.i b. ho.c x. lý n..c ..ng n.i có các .utrùng sinh s.ng. M.t khi xu.t hi.n mu.i tr..ng thành,ki.m soát b.ng hóa ch.t ch. có b.t .i m.t cách t.mth.i.

CONOZCA LOS ZANCUDOS Y EL VIRUS DEL NILO OCCIDENTALLos zancudos son algo más que molestos; hoy existen numerosas enfermedades causadas por sus picaduras. Una de ellas, el virus de Nilo Occidental, es relativamente nueva en los Estados Unidos. El virus del Nilo fue identificado originalmente en 1937 en Uganda. Hoy se ha extendido por toda África y Medio Oriente, parte de Europa, Rusia, India, Indonesia y Australia. En los Estados Unidos apareció por primera vez en la ciudad de Nueva York en 1999. Desde allí se propagó rápidamente a todo el país. En la mayoría de los casos, el Virus del Nilo no presenta síntomas, o bien, puede causar sólo una leve afección con síntomas similares a los de la gripe. Con menor frecuencia, el virus puede causar encefalitis o meningitis que constituyen una grave amenaza para la salud.

Vietnamese Spanish

Education & Outreach Material Translated by Fairfax County for WNV

FIGHT THE BITE페어펙스 카운티 (Fairfax County Health Department) 에서는 가정에서 행할 수 있는 모기 퇴치 방법을 다음과 같이 안내하고 있습니다 . 다 함께 참여하여 우리의 건강을 지키도록 합시다 .현재의 모기는 내성이 강해서 가정에서 쉽게 접할 수 있는 살충제로는 일시적 구제효과 만을 가져 올 수 있습니다 . 따라서 모기를 통제할 수 있는 가장 효과적 방법은 유충이 부화하고 성충이 자랄 수 있는 환경을 제거 하는 것인데 , 가정에서 유충을 없애는 가장 확실한 방법은 물이 고일 수 있는 모든 것을 사전에 차단 하는 것입니다 .만일 여러분께서 생활 하시는 곳에 모기가 있다면 , 그것은 여러분의 집안 내 어느 곳엔 가 모기가 자랄 수 있는 곳이 있다는 것을 의미하며 , 이를 찾아 내어 제거하여야 할 것 입니다 . 특히 모기가 자라기 위해서는 단지 몇 스푼의 물만을 필요하므로 모든 종류의 용기에 고인 물 ( 흐르는 물은 모기가 자라기에 적합치 않음 ) 에서는 모기가 자랄 수 있고 , 또 번식력이 강하므로 , 모기의 발생원을 제거 하는 것이 모기를 가장 효과적으로 구제 하는 방법이라 하겠습니다 .

了解蚊子及西尼罗病蚊子不单是令人讨厌，还有不少的疾病是由蚊子的叮咬造成。其中一种名为西尼罗病毒的疾病，在美国属于一种较新的疾病。西尼罗病毒于 1937年首次在乌干达发现，现在在整个非洲及中东、部分欧洲国家、俄国、印度、印尼及澳洲都有这种疾病。在美国，此疾病首次在 1999年在纽约市发现，从该处迅速蔓延至全国。在大部分情况下西尼罗病毒可能不会造成任何症状或只会造成轻微不适、如感冒的症状。在少数情况下，此病毒可造成脑炎或脑膜炎，严重危及健康。让我们一起合作西尼罗病毒现有在费尔法克斯县出现。为确保公共卫生及健康，本县已采取措施以减少蚊子的数目。蚊子在静止的浅水中繁殖。几乎在任何地方，包括排水沟、污水池、小水潭、屋顶的边沟、轮胎等，都可以经常见到蚊子的繁殖。本县已尽力以杀虫剂处理排水沟、水池及其它蚊子可以繁殖的地方，以抑制牠们的繁殖。卫生部也会在全县进行监察，以确保您的安全。

Korean Chinese

Arbor Day

County Fair

4H Fair

Mosquito Dunks

KAP Study

Radio, Television and Newspaper Interviews (Spanish & Korean)

Web Page – URL

Homeowners associations

Board Members

Outreach & Education Efforts

http://www.fairfa

xcounty.gov/fightthebite