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• [email protected]@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• [email protected]@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
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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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