West Nile VirusApril 2003

West Nile VirusApril 2003

Emi Kate Saito, VMD, Emi Kate Saito, VMD, MSPHMSPH

National Wildlife Health CenterNational Wildlife Health Center

Madison, WIMadison, WI

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Emi Kate SaitoEmi Kate SaitoEmi Kate SaitoEmi Kate Saito• 1993: BS – Zoology and 1993: BS – Zoology and

Biological Aspects of Biological Aspects of Conservation, Univ. of Conservation, Univ. of Wisconsin-MadisonWisconsin-Madison

• 1997: VMD – Veterinary 1997: VMD – Veterinary Medicine, Univ. of Penn.Medicine, Univ. of Penn.

• 1997-1998- Dept. of Biology, 1997-1998- Dept. of Biology, Emory University Graduate Emory University Graduate School (Population Biology, School (Population Biology, Ecology and Evolution)Ecology and Evolution)

• 1998-2000 – Small animal 1998-2000 – Small animal Practice, Atlanta & AnnapolisPractice, Atlanta & Annapolis

• 2000-2001- MSPH- 2000-2001- MSPH- Epidemiology, Emory Epidemiology, Emory UniversityUniversity

• 2001 WNV Season: DeKalb 2001 WNV Season: DeKalb Co. Board of Health, Atlanta Co. Board of Health, Atlanta GAGA

• 2002: USGS NWHC2002: USGS NWHC• 608-270-2456608-270-2456• esaito@usgs.govesaito@usgs.gov• www.nwhc.usgs.govwww.nwhc.usgs.gov

• 1993: BS – Zoology and 1993: BS – Zoology and Biological Aspects of Biological Aspects of Conservation, Univ. of Conservation, Univ. of Wisconsin-MadisonWisconsin-Madison

• 1997: VMD – Veterinary 1997: VMD – Veterinary Medicine, Univ. of Penn.Medicine, Univ. of Penn.

• 1997-1998- Dept. of Biology, 1997-1998- Dept. of Biology, Emory University Graduate Emory University Graduate School (Population Biology, School (Population Biology, Ecology and Evolution)Ecology and Evolution)

• 1998-2000 – Small animal 1998-2000 – Small animal Practice, Atlanta & AnnapolisPractice, Atlanta & Annapolis

• 2000-2001- MSPH- 2000-2001- MSPH- Epidemiology, Emory Epidemiology, Emory UniversityUniversity

• 2001 WNV Season: DeKalb 2001 WNV Season: DeKalb Co. Board of Health, Atlanta Co. Board of Health, Atlanta GAGA

• 2002: USGS NWHC2002: USGS NWHC• 608-270-2456608-270-2456• esaito@usgs.govesaito@usgs.gov• www.nwhc.usgs.govwww.nwhc.usgs.gov

(New Hire picture – not my most flattering picture)

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ClassificationClassificationClassificationClassification• Family: Flaviviridae • Genus: Flavivirus

Japanese Encephalitis Antigenic Complex

• Complex includes: Alfuy Cacipacore Japanese Encephalitis Koutango Murray Valley

Encephalitis St. Louis Encephalitis Rocio Stratford Usutu West Nile Yaounde

• Family: Flaviviridae • Genus: Flavivirus

Japanese Encephalitis Antigenic Complex

• Complex includes: Alfuy Cacipacore Japanese Encephalitis Koutango Murray Valley

Encephalitis St. Louis Encephalitis Rocio Stratford Usutu West Nile Yaounde

(www.niaid.nih.gov/newsroom/focuson/bugborne01/wnile.htm)

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Transmission CycleTransmission CycleTransmission CycleTransmission Cycle

http://www.cdc.gov/ncidod/dvbid/westnile/misc/slides/nasci/slide13.htm

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Vector Control/Disease PreventionVector Control/Disease PreventionVector Control/Disease PreventionVector Control/Disease Prevention

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U.S. and WNVU.S. and WNVU.S. and WNVU.S. and WNV

• NY99 strain closely related to Isr98NY99 strain closely related to Isr98• High avian mortality associated High avian mortality associated

with human caseswith human cases• Increased sensitivity of crowsIncreased sensitivity of crows

• NY99 strain closely related to Isr98NY99 strain closely related to Isr98• High avian mortality associated High avian mortality associated

with human caseswith human cases• Increased sensitivity of crowsIncreased sensitivity of crows

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• 124,854 dead birds reported

• 31,514 tested (25%)

• 15,745 WNV-positive (50%)• 8,420 crows (53%)• 7,325 birds of other spp. (47%)

WNV Surveillance, United States: Dead Bird Data,

2002(as of January 2003)

77

U.S. counties reporting any WNV-infectedbirdsbirds in 19991999 (N = 28 counties)

88

U.S. counties reporting any WNV-infectedbirdsbirdsin20002000(N = 136 counties)

99

U.S. counties reporting any WNV-infectedbirdsbirds in 20012001 (N = 328 counties)

1010

U.S. Counties Reporting WNV-Positive Dead Birds, 2002*

15,745 birds1,888 counties42 states & D.C.

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NWHC Submissions tested NWHC Submissions tested for WNV, 2002for WNV, 2002

NWHC Submissions tested NWHC Submissions tested for WNV, 2002for WNV, 2002

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Frequency of Positive Frequency of Positive Submissions, NWHC 1999-Submissions, NWHC 1999-

20022002

Frequency of Positive Frequency of Positive Submissions, NWHC 1999-Submissions, NWHC 1999-

20022002  1999 2000 2001 2002

# Teste

d

%Positiv

e

# Teste

d

%Positiv

e

# Teste

d

%Positiv

e

# Teste

d

%Positiv

e

American Crow

235 12.8 558 13.3 1011 34.6 686 32.9

Other Corvidae

19 10.5 93 10.8 761 9.6 1030 29.2

Birds of Prey

34 5.9 159 4.4 222 4.1 155 20.6

Other Birds

216 0.5 1117 0.1 597 1.0 584 7.2

Mammals

259 0 76 0 3 0 13 7.7

Herps 0 0 3 0 0 0 0 0

Total 763 4.6 2006

4.6 2594

16.9

2468

24.41313

Species found with WNV Species found with WNV infectioninfection

Species found with WNV Species found with WNV infectioninfection

• 167 (dead) bird species167 (dead) bird species• 18 mammal species18 mammal species

– wolfwolf– squirrels (grey, fox)squirrels (grey, fox)– reindeerreindeer– sheepsheep– harbor sealharbor seal

• Farm-raised alligatorsFarm-raised alligators

• SerologySerology

• 167 (dead) bird species167 (dead) bird species• 18 mammal species18 mammal species

– wolfwolf– squirrels (grey, fox)squirrels (grey, fox)– reindeerreindeer– sheepsheep– harbor sealharbor seal

• Farm-raised alligatorsFarm-raised alligators

• SerologySerology

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* Reported as of 01/21/2003 – 36 species

WNV-Positive Mosquito Species Reported,United States, 1999-2002*

Orthopodomyia signiferatriseriatusterritans

Uranotaenia sapphirinatrivittatus

Ps. feroxtaeniorhynchuserraticus

Ps. ciliatawalkerisollicitansnigripalpus

Ps. columbiaequadrimac.japonicussalinarius

Deinocerites cancerpuncitpenniscantatorvexansrestuans

Cq. perturbanscrucianscanadensiscinereustarsalis

Cs. inornatabarberiatropalpusaegyptiquinq.

Cs. melanuraatroposatlanticusalbopictuspipiens

OtherAnophelesOchlerotatusAedesCulex

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Research projectsResearch projects

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Ae. albopictus Ae. aegypti Ps. feroxAe. vexans

Cx. salinarius Cq. perturbansCx. tarsalis Cx. nigripalpus

Cx. pipiens Oc. canadensisOc. atropalpus Cx. quinquefasciatus Oc.

cantatorOc. j. japonicus Cx. restuans Oc. sollicitans

Oc. taeniorhynchus

Oc. triseriatus

Efficient Moderate Inefficient

Potential vectors of West Nile virus (based on laboratory vector competence studies)

(Turrell et al., 2001, 2002)1717

Bird Reservoir Competency Study

(laboratory-based)

Bird Reservoir Competency Study

(laboratory-based)

Blue Jay (4)Blue Jay (4)Common Common Grackle Grackle

(6)(6)House Finch House Finch

(2)(2)Am. Crow (8)Am. Crow (8)House House

Sparrow (6)Sparrow (6)

Blue Jay (4)Blue Jay (4)Common Common Grackle Grackle

(6)(6)House Finch House Finch

(2)(2)Am. Crow (8)Am. Crow (8)House House

Sparrow (6)Sparrow (6)

Ring-billed Ring-billed gull (2)gull (2)

Black-billed Black-billed Magpie (3)Magpie (3)Am. Robin (2)Am. Robin (2)Red-winged Red-winged Blackbird Blackbird

(3)(3)Killdeer (2)Killdeer (2)GHO (1)GHO (1)Am. Kestrel Am. Kestrel

(2)(2)Fish Crow (8)Fish Crow (8)

Ring-billed Ring-billed gull (2)gull (2)

Black-billed Black-billed Magpie (3)Magpie (3)Am. Robin (2)Am. Robin (2)Red-winged Red-winged Blackbird Blackbird

(3)(3)Killdeer (2)Killdeer (2)GHO (1)GHO (1)Am. Kestrel Am. Kestrel

(2)(2)Fish Crow (8)Fish Crow (8)

Mallard (2)Mallard (2)European European Starling (6)Starling (6)Mourning Dove Mourning Dove

(3)(3)Northern Northern

Flicker (1)Flicker (1)Canada Goose Canada Goose

(3)(3)

Mallard (2)Mallard (2)European European Starling (6)Starling (6)Mourning Dove Mourning Dove

(3)(3)Northern Northern

Flicker (1)Flicker (1)Canada Goose Canada Goose

(3)(3)

Am. Coot (1)Am. Coot (1)Rock Dove (6)Rock Dove (6)Chicken (11)Chicken (11)Northern Northern

Bobwhite Bobwhite (3)(3)

Ring-necked Ring-necked Pheasant Pheasant (3)(3)

Budgerigar (3)Budgerigar (3)Monk Monk

Parakeet Parakeet (3)(3)

Japanese Quail Japanese Quail (3)(3)

Am. Coot (1)Am. Coot (1)Rock Dove (6)Rock Dove (6)Chicken (11)Chicken (11)Northern Northern

Bobwhite Bobwhite (3)(3)

Ring-necked Ring-necked Pheasant Pheasant (3)(3)

Budgerigar (3)Budgerigar (3)Monk Monk

Parakeet Parakeet (3)(3)

Japanese Quail Japanese Quail (3)(3)

Very Moderate Weak Not

Komar et al., 2003, EID 9(3): 311-322; www.cdc.gov/ncidod/eid/vol9no3/02-0628.htm

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Experimental WNV Mortality

Species n mortality rate

American Crow 20 100Black-billed Magpie 5 100Blue Jay 6 83House Finch 3 67Fish Crow 11 64

Ring-billed Gull 2 50Common Grackle 10 40

House Sparrow 12 25

NO mortality in Eur. Starlings (6), Rock Doves (6), Chicken (18), Ring-necked Pheasant (3), Canada Goose (3), Am. Robin (3), Red-winged Blackbird (3), Mourning Dove (3), Budgerigar (3), Monk Parakeet (3), Japanese Quail (3), Northern Bobwhite (3)

Komar et al., 2003, EID 9(3): 311-322; www.cdc.gov/ncidod/eid/vol9no3/02-0628.htm

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Alternative modes of Transmission

Alternative modes of Transmission

• Cage mate transmission– Am. Crow (4)– Black-billed Magpie (2)– Blue Jay (2)– Ring-billed Gull (1)– Chicken (1)

• Oral transmission– Am. Crow (3, susp.; 6, bird)– House Finch (1, mosq.)– House Sparrow (6, susp.)– Common Grackle (4, susp.)– GHO (1, mouse)

• Cloacal Shedding (crows)

• Cage mate transmission– Am. Crow (4)– Black-billed Magpie (2)– Blue Jay (2)– Ring-billed Gull (1)– Chicken (1)

• Oral transmission– Am. Crow (3, susp.; 6, bird)– House Finch (1, mosq.)– House Sparrow (6, susp.)– Common Grackle (4, susp.)– GHO (1, mouse)

• Cloacal Shedding (crows)

Komar et al., 2003, EID 9(3): 311-322; www.cdc.gov/ncidod/eid/vol9no3/02-0628.htm

2020

NWHC ProjectsNWHC Projects

• Crow StudyCrow Study• 20002000• OKOK

• Mallard StudyMallard Study• Crane Vaccination StudyCrane Vaccination Study• RaptorsRaptors• Red-cockaded WoodpeckerRed-cockaded Woodpecker• AmikihiAmikihi• WaterfowlWaterfowl

• Crow StudyCrow Study• 20002000• OKOK

• Mallard StudyMallard Study• Crane Vaccination StudyCrane Vaccination Study• RaptorsRaptors• Red-cockaded WoodpeckerRed-cockaded Woodpecker• AmikihiAmikihi• WaterfowlWaterfowl

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Migratory Bird Migratory Bird SamplingSampling

Migratory Bird Migratory Bird SamplingSampling

http://migratorybirds.pacific.fws.gov/flyways_map.htm

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• General weakness, lethargy

• Emaciation

• Sedentary

• Difficulty maintaining balance, trembling

• Inability to walk, perch, stand, or fly

• Do not respond normally to danger

Symptoms of WNV Symptoms of WNV Infection?Infection?

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• NWHC received 56 raptorsNWHC received 56 raptors

• Diagnostic Testing doneDiagnostic Testing done

• FindingsFindings

• Significance?Significance?

• NWHC received 56 raptorsNWHC received 56 raptors

• Diagnostic Testing doneDiagnostic Testing done

• FindingsFindings

• Significance?Significance?

NWHC Raptor Cases, NWHC Raptor Cases, 20022002

NWHC Raptor Cases, NWHC Raptor Cases, 20022002

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Other reports:Other reports:Other reports:Other reports:

• Raptor Center at U. of Raptor Center at U. of MinnesotaMinnesota

• SCWDSSCWDS• Other diagnostic laboratoriesOther diagnostic laboratories• New York & New JerseyNew York & New Jersey• Raptor rehabilitatorsRaptor rehabilitators

• Raptor Center at U. of Raptor Center at U. of MinnesotaMinnesota

• SCWDSSCWDS• Other diagnostic laboratoriesOther diagnostic laboratories• New York & New JerseyNew York & New Jersey• Raptor rehabilitatorsRaptor rehabilitators

I’ve gone blind?!Help!!

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Other avian Other avian morbidity/mortality:morbidity/mortality:

Other avian Other avian morbidity/mortality:morbidity/mortality:

• Lack of birds/rapid disappearance

• Finches • Pelicans, cranes• Blue Jays….• Recrudescence of raptor cases?

• Lack of birds/rapid disappearance

• Finches • Pelicans, cranes• Blue Jays….• Recrudescence of raptor cases?

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Questions still to be answered…

Questions still to be answered…

• Why the high avian mortality associated with NY99 Strain?• What impact has WNV had on the bird populations?• What other species are being significantly affected?• What impact will WNV have on endangered/threatened

bird species?• Do migratory birds really play an important role in the

spread of the virus? • Are there other modes of transmission among bird

populations? • What birds are the important reservoirs for maintaining

natural transmission? • How is the virus over-wintering?

• Many, many more….

• Why the high avian mortality associated with NY99 Strain?• What impact has WNV had on the bird populations?• What other species are being significantly affected?• What impact will WNV have on endangered/threatened

bird species?• Do migratory birds really play an important role in the

spread of the virus? • Are there other modes of transmission among bird

populations? • What birds are the important reservoirs for maintaining

natural transmission? • How is the virus over-wintering?

• Many, many more….

??!??!?

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