(Zoonotic Diseases of Birds) West Nile Virus and Bird Flu

H. L. Shivaprasad

California Animal Health and Food Safety Laboratory System – Fresno Branch

University of California, Davis

Prasad

Hulimangala-HosakoteLingareddyShivaprasad

School of Veterinary MedicineUniversity of California

To provide the citizens of California with the highest quality diagnostic

laboratory support for:

California Animal Health & Food SafetyLaboratory System

Mission

CAHFS Mission

Public Health

New Knowledge

Health Management

Equine Health

Food SafetyDisease Control

California Animal Health & Food Safety

Laboratory System

Davis

Turlock - Avian

Fresno - Avian

Tulare Livestock

San Bernardino

Tests Essential for Disease Diagnosis Clinical signs History Necropsy (autopsy) Serology Immunology (tissues) Bacteriology Virology

Tests Essential for Disease Diagnosis

Histopathology Parasitology Toxicology Electron microscopy Biotechnology Hematology, chemistry, cytology Pathogenicity tests

West Nile Virus

First isolated from a woman in West Nile province of Uganda in 1937Endemic in Africa and Middle East

– France (1962-65), Eastern Europe (1996-1999), Israel (2000)

US: 1999 to present

West Nile Virus and Birds

…‘bulk of public concern is focused on the risk of West Nile to people,’…...‘owls with glazed eyes, truckloads of dead crows, eagles struggling for their lives’…..…‘potential harm to the ecological balance could have lasting ramifications’

West Nile Virus and Birds

….‘taking care of raptors is not a high priority for the state,’….….. ‘raptors, including owls, eagles and hawks, are being devastated by the disease’… ‘has led people to dump pesticides in rivers, to demand mass chemical spraying and even to poison bird feeders’….

West Nile Virus

Flavivirus (Family:Flaviviridae)–RNA virus, positive sense, 45 - 50 nm diameter

–Has an integral membrane glycoproteins, E and prM in the envelope

•E; most immunologically important structural protein•E; is the virus hemagglutinin, mediates virus-host cell binding

West Nile Virus

Ecology of WNV in humans, mosquitos and birds worked out in Egypt in 1950’s

Mortality in pigeons– involvement of crows

Role of birds in Romanian outbreak (1996) passeriformes and domestic fowl/turkeys/goose

Migrating White Storks, captive White-eyed Gull and geese in Israel (1998-99)

– domestic geese, 40 % mortality (1998)

West Nile Virus and Birds

Dr. Tracey S. McNamara (Pathologist)Wild Crow die-off, NY city, August 1999

–Hemorrhage in calvarium, myocarditis, encephalitisWildlife Conservation Society (Bronx Zoo, NY city)

– Between August 10 and September 23, 27 wild or exotic birds died or were euthanized– included 8 orders and 14 species of birds

1999

2000

2001

2002

2003

2004

2005

20062006

20072007

2008 August 20th2008 August 20th

Humans 830 / 28

Horses 540 / 230

Dead birds 3232

Mosquito pools 1136

Sentinel chickens 805

2004

WNV activity (number of human infections)

WNV activity (no human cases)

58 counties15

1

197

116

331

60

7

1

6

3

64

2

2

1

1

10

1 1

3

3

1

1

3

WNV Activity in California 2005

WNV activity (number of human infections)

WNV activity (no human cases)

68

104

177

60

34

25

63

32

47

17

35

365

92

9

281

211

195

12

1

4

1

2

1

4

12

1

1

928

456

3,046

1,242

790

Humans infections

Horse cases

Dead birds

Mosquito pools

Sentinel chickens

N = 40 counties with human infection

4

13

1

1

2

1

1

6

West Nile Virus - Transmission Cycle

birds are primary vertebrate hosts–Crows can amplify WNV to very high titers

mosquitoes are vectors– more than 36 species identified

– Culex sp.; Cx pipiens, Cx restuans, Cx quinquefasciatus, Cx tarsalis, etc.

– others of Aedes sp, Anopheles sp, Ochlerotatus sp, etc.

West Nile Virus – Other Hosts

Humans, equine and other animals are incidental hostsOthers: more than 20 mammals; bat, cat, dog, chipmunk, squirrel, rabbit, reindeer, raccoon, skunk, seal, etc.Alligator, snake

West Nile Virus Transmission Cycle

West Nilevirus

West Nilevirus

Mosquito vector

Incidental infections

Bird reservoir hosts

Incidental infections

Onset of Human WNV Disease,United States 1999-2005*

*Reported as of 2/14/2006

1999

2000

2001

2002

2003

2004

2005

2006Jan

FebM

arApr

May

JunJul

AugSep

OctNov

Dec

Month

West Nile Virus and Birds Transmission

Primarily through mosquito bitesOralContactRespiratory?Others?

West Nile Virus and BirdsDiagnosis

Epidemiology, clinical signs, pathologySerology; antigen and IgM capture ELISA, PRNT, etc.RT – PCRImmunohistochemistryVirus isolation

WNV in Humans - Symptoms

Risks - People over 50, outside activity, mosquitoes

West Nile fever, Neuroinvasive disease, others No symptoms - 80 % Up to 20 % - fever, headache, skin rash One in 150 - high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis Death (1999-2007): 1,060/27,337 = 4 %

West Nile Virus and BirdsMost striking feature of US outbreak

is the involvement of birds, high avian deathsAmerican crows (Corvus brachrynchos) and other corvids

Virulent WNV or susceptible population?Mutation favoring replication (Dr. A. Brault)

More than 320 species of birds Chicken, turkey, Ring Neck pheasant, Rock Dove, Northern Bob White, etc. resistant

West Nile Virus and Birdscorvids (Crow, raven, blue jay, magpie), grackle, house sparrow and finch, gulls, domestic geese - highly susceptibleRaptors; hawks, owls, eagles, falcon, osprey, kestrel Psittacines; Rosella, lorikeets and others (budgerigar, cockatiel, Amazon, macaw)Others; Impeyan pheasant, flamingo, BW duck, etc.

2005: 92 species of WNV positive dead birds2005: 92 species of WNV positive dead birds

Other Corvids (4 species) 1%

Non-Corvids (85 species)16%

American Crow 44%

Western Scrub Jay 27%

Yellow-billed Magpie 12%

Number reported = 109,375

Number tested = 9,263

Number WNV pos = 3,046

West Nile Virus and Birds Clinical signs

none, sudden deathanorexia, ruffled feathers, depression, weakness, lethargyinability to walk or perch or stand or fly, droopy wings, do not respond to dangerneurological signs such as ataxia, torticollis, opisthotonus, tremors, circling, convulsionsloss of weight, anisocoria

WNV in Psittacines 2004-06

Most common species affected; Australian Parakeets Most from out door aviaries, evidence of mosquitos and dead crows in the vicinityMost birds were mature (1 – 15 years)Several young (6 weeks to 4 months)Macaws, Amazons, Budgies, Cockatiels not affected

WNV in Psittacines 2004-2006

Species 2004 2005 2006 total

Rosella 6 7 4 17

S. C. Parakeet 0 3 5 8

Conure 4 2 2 8

Lorikeet 2 5 0 7

Cockatoo 2 0 1 3

Caique 1 1 0 2

Princess of Wales 1 0 1 2

Others (one each) 3 4 1 8

Total 19 20 14 53

West Nile Virus - SurveillanceAvian morbidity/mortality – testing

–Most sensitive early indicator of WNV–Not a mass die-off–Toll free # 877-WNV-BIRD (877-968-2743)– E-mail: arbovirus@dhs.ca.gov – http://westnile.ca.gov

Sentinel chickensMosquito testingHuman cases and equine casesRatites (Emu and Ostrich)

West Nile Virus - Control

Mosquito controlMinimize standing waterSpray for mosquitosRepellents

VaccinationAvailable for equineBirds?

West Nile Virus and Birds

….‘nature will ultimately take its course, as it has for centuries’… ‘the birds that survive the epidemic will pass on their West Nile-resistant traits to future generations’.…….‘over time, breeds will become resilient in the face of the disease’…‘something like this will run its course in three or four years’

Crows at staging area Whittier Narrows Wildlife Area

Photo by Bill Reisen, UCD

Flu Pandemics in Humans

1918 - 19 (Spanish Flu) – H1 N1 1957 - 58 (Asian Flu) - H2 N2 1968 - 69 (Hong Kong Flu) - H3 N2 1977 - H1 N1 1997 - Hong Kong, H5 N1 2003 - China/Hong Kong, H5 N1 2004 - Present. S.E. Asia, china and others, H5 N1

Great Pandemic (1918-1919)

20-50 Million Deaths

Avian Influenza - Bird Flu

Acute systemic lethal disease of poultry caused by type A Avian Influenza (AI) virus, OrthomyxovirusAI viruses are divided in to subtypes

– based on Hemagglutinin (H) and Neuraminidase (N) antigens

– 16 H (H1 – H16) and 9 N (N1 – N9) distinct types, all found in avian species

– H1 N1, H5 N1, H7 N2, H6 N2, etc.

100 nm

Avian influenza virus

AI and Bird Flu (H5N1) Disease of economic significance in poultry Migratory waterfowl are primary reservoirs

pigs also serve as reservoirs

H5N1 infections in > 40 countries since December 2003>500 million birdsApproximately 383 people (241fatal)

–human infections a result of direct contact with birds (except 2 clusters – Turkey and Indonesia)

Poultry FAD 2005

Bird Flu

Significance: virus could evolve in to a form that is easily spread between peopleHow: human flu virus and bird flu virus could recombine producing a hybridTransmission to humans: direct contact with chickens and their secretionsOutbreak: has spread rapidly to various countries in poultryControl: kill infected poultry, anti flu drugs, vaccination?

Avian Influenza – H5N1

1997 Hong Kong2003 -2004 South East Asia (China, Korea, Vietnam, Indonesia, Thailand, Japan, Cambodia, Laos, Malaysia)2005 (Russia, Kazakhstan, Mongolia, Romania, Turkey, Croatia)2006 – 2008 more than 40 countries in Asia, Africa, Europe including India

Country Cases Deaths

Azerbaijan 8 5

Cambodia 7 7

China 30 20

Egypt 50 32

Indonesia 133 108

Iraq 3 2

Laos 2 2

Nigeria 1 1

Thailand 25 17

Turkey 12 4

Vietnam 106 52

Total 383 241

Bird Flu - Species Susceptible

Gallinaceous birds; chickens, turkeys, quail, pheasants, partridges Zebra finches (*), geese, emus, House finches, budgerigars, ostrichesDucks, gulls, swans, starlings, pigeons Egrets, herons, flamingos, magpie, falcon, owl, sparrow, etc.Mammals; humans, tigers, leopards, cats, civets, pigs, ferrets

Bird Flu - Transmission

ContactRespiratory secretionsFecesContaminated feed and waterCarcassesEquipment, fomites (shoes, clothes, hands, etc.)others

PathogenicityVaries with the strain (H5 and H7)

High (HPAI) or low path (LPAI) ?HPAI arise from LPAI circulating in birds

Presence of concurrent infectionsAge and species of birds, nutritional and environmental factorsDefinition of HPAI

IVPI > 1.2 (lethal for 75 % of chickens)Amino acid sequence at the Haemagglut cleavage site compatible with HPAI

Bird Flu- Diagnosis Clinical signs, pathology Serology: AGID, ELISA, HI, NI Virus isolation (trachea, lung, intestine, feces, others)

Pathogenicity studies (IVPI) in chickens

RRT – PCRSequencingDirectigen, Bionex– Type A influenza

Immunohistochemistry

Flyways and Central San Joaquin Valley

Pintail migration Russia Central San Joauin Valley

http://www.werc.usgs.gov/dixon/joe.asp

“Control of bird flu in birds will control bird flu

in humans”