- Количество слайдов: 97
(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
Hulimangala-Hosakote Lingareddy Shivaprasad
California Animal Health & Food Safety Laboratory System School of Veterinary Medicine University of California Mission To provide the citizens of California with the highest quality diagnostic laboratory support for:
CAHFS Mission Disease Control Health Managemen t Food Safety Public Health Equine Health New Knowledge
California Animal Health & Food Safety Laboratory System Davis Turlock - Avian Fresno - Avian Tulare Livestock San Bernardino
Tests Essential for Disease Diagnosis ü Clinical signs ü ü ü History Necropsy (autopsy) Serology Immunology (tissues) Bacteriology Virology
Tests Essential for Disease Diagnosis ü ü ü ü Histopathology Parasitology Toxicology Electron microscopy Biotechnology Hematology, chemistry, cytology Pathogenicity tests
West Nile Virus ØFirst isolated from a woman in West Nile province of Uganda in 1937 ØEndemic in Africa and Middle East – France (1962 -65), Eastern Europe (1996 -1999), Israel (2000) ØUS: 1999 to present
West Nile Virus and Birds Ø…‘bulk of public concern is focused on the risk of West Nile to people, ’… Ø. . . ‘owls with glazed eyes, truckloads of dead crows, eagles struggling for their lives’…. . Ø…‘potential harm to the ecological balance could have lasting ramifications’
West Nile Virus and Birds Ø…. ‘taking care of raptors is not a high priority for the state, ’…. Ø…. . ‘raptors, including owls, eagles and hawks, are being devastated by the disease’ Ø… ‘has led people to dump pesticides in rivers, to demand mass chemical spraying and even to poison bird feeders’….
West Nile Virus ØFlavivirus (Family: Flaviviridae) –RNA virus, positive sense, 45 - 50 nm diameter –Has an integral membrane glycoproteins, E and pr. M in the envelope • E; most immunologically important structural protein • E; is the virus hemagglutinin, mediates virushost cell binding
West Nile Virus ØEcology of WNV in humans, mosquitos and birds worked out in Egypt in 1950’s üMortality in pigeons – involvement of crows ØRole of birds in Romanian outbreak (1996) üpasseriformes and domestic fowl/turkeys/goose Ø Migrating White Storks, captive White- eyed Gull and geese in Israel (1998 -99) – domestic geese, 40 % mortality (1998)
West Nile Virus and Birds v. Dr. Tracey S. Mc. Namara (Pathologist) v. Wild Crow die-off, NY city, August 1999 –Hemorrhage in calvarium, myocarditis, encephalitis q. Wildlife 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
2008 August 20 th
2004 6 1 Humans Horses Dead birds Mosquito pools Sentinel chickens 10 3 7 1 1 3 3 1 58 counties 15 3 1 60 197 2 331 WNV activity (no human cases) 830 / 28 540 / 230 3232 1136 805 64 WNV activity (number of human infections) 116 2 1
1 WNV Activity in California 2005 1 4 2 1 12 177 4 5 2 36 11 1 92 5 28 19 1, 242 Sentinel chickens 1 3, 046 Mosquito pools 4 35 9 6 456 Dead birds 25 928 Horse cases 1 13 2 Humans infections 790 63 32 N = 40 counties with human infection 60 68 2 WNV activity (no human cases) 34 1 47 104 17 WNV activity (number of human infections) 1 1
West Nile Virus - Transmission Cycle Ø birds are primary vertebrate hosts –Crows can amplify WNV to very high titers Ø 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 üHumans, equine and other animals are incidental hosts üOthers: more than 20 mammals; bat, cat, dog, chipmunk, squirrel, rabbit, reindeer, raccoon, skunk, seal, etc. üAlligator, snake
West Nile Virus Transmission Cycle Mosquito vector Incidental infections West Nile virus Incidental infections Bird reservoir hosts
Onset of Human WNV Disease, United States 1999 -2005* *Reported as of 2/14/2006
West Nile Virus and Birds Transmission ØPrimarily through mosquito bites ØOral ØContact ØRespiratory? ØOthers?
West Nile Virus and Birds Diagnosis ØEpidemiology, clinical signs, pathology ØSerology; antigen and Ig. M capture ELISA, PRNT, etc. ØRT – PCR ØImmunohistochemistry ØVirus isolation
WNV in Humans - Symptoms Ø Risks - People over 50, outside activity, mosquitoes üWest Nile fever, Neuroinvasive disease, others Ø No symptoms - 80 % Ø Up to 20 % - fever, headache, skin rash Ø One in 150 - high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis Ø Death (1999 -2007): 1, 060/27, 337 = 4 %
West Nile Virus and Birds ØMost striking feature of US outbreak üis the involvement of birds, high avian deaths üAmerican crows (Corvus brachrynchos) and other corvids üVirulent WNV or susceptible population? üMutation favoring replication (Dr. A. Brault) ØMore than 320 species of birds ØChicken, turkey, Ring Neck pheasant, Rock Dove, Northern Bob White, etc. resistant
West Nile Virus and Birds Øcorvids (Crow, raven, blue jay, magpie), grackle, house sparrow and finch, gulls, domestic geese - highly susceptible ØRaptors; hawks, owls, eagles, falcon, osprey, kestrel ØPsittacines; Rosella, lorikeets and others (budgerigar, cockatiel, Amazon, macaw) ØOthers; Impeyan pheasant, flamingo, BW duck, etc.
2005: 92 species of WNV positive dead birds Other Corvids (4 species) 1% Non-Corvids (85 species)16% Yellow-billed Magpie 12% American Crow 44% Number reported = 109, 375 Western Scrub Jay 27% Number tested = 9, 263 Number WNV pos = 3, 046
West Nile Virus and Birds Clinical signs Ønone, sudden death Øanorexia, ruffled feathers, depression, weakness, lethargy Øinability to walk or perch or stand or fly, droopy wings, do not respond to danger Øneurological signs such as ataxia, torticollis, opisthotonus, tremors, circling, convulsions Øloss of weight, anisocoria
WNV in Psittacines 2004 -06 ØMost common species affected; Australian Parakeets ØMost from out door aviaries, evidence of mosquitos and dead crows in the vicinity ØMost birds were mature (1 – 15 years) ØSeveral young (6 weeks to 4 months) ØMacaws, Amazons, Budgies, Cockatiels not affected
WNV in Psittacines 2004 -2006 Species Rosella S. C. Parakeet Conure Lorikeet Cockatoo Caique Princess of Wales Others (one each) Total 2004 6 0 4 2 2 1 1 3 19 2005 7 3 2 5 0 1 0 4 20 2006 4 5 2 0 1 1 14 total 17 8 8 7 3 2 2 8 53
West Nile Virus - Surveillance ØAvian morbidity/mortality – testing –Most sensitive early indicator of WNV –Not a mass die-off –Toll free # 877 -WNV-BIRD (877 -968 -2743) – E-mail: [email protected] ca. gov – http: //westnile. ca. gov ØSentinel chickens ØMosquito testing ØHuman cases and equine cases ØRatites (Emu and Ostrich)
West Nile Virus - Control ØMosquito control üMinimize standing water üSpray for mosquitos üRepellents ØVaccination üAvailable for equine üBirds?
West Nile Virus and Birds v…. ‘nature will ultimately take its course, as it has for centuries’ v… ‘the birds that survive the epidemic will pass on their West Nile-resistant traits to future generations’. … v…. ‘over time, breeds will become resilient in the face of the disease’ v…‘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 Ø 1918 - 19 (Spanish Flu) – H 1 N 1 Ø 1957 - 58 (Asian Flu) - H 2 N 2 Ø 1968 - 69 (Hong Kong Flu) - H 3 N 2 Ø 1977 - H 1 N 1 Ø 1997 - Hong Kong, H 5 N 1 Ø 2003 - China/Hong Kong, H 5 N 1 Ø 2004 - Present. S. E. Asia, china and others, H 5 N 1
Great Pandemic (1918 -1919)
20 -50 Million Deaths
Avian Influenza - Bird Flu ØAcute systemic lethal disease of poultry caused by type A Avian Influenza (AI) virus, Orthomyxovirus ØAI viruses are divided in to subtypes – based on Hemagglutinin (H) and Neuraminidase (N) antigens – 16 H (H 1 – H 16) and 9 N (N 1 – N 9) distinct types, all found in avian species – H 1 N 1, H 5 N 1, H 7 N 2, H 6 N 2, etc.
Avian influenza virus 100 nm
AI and Bird Flu (H 5 N 1) Ø Disease of economic significance in poultry Ø Migratory waterfowl are primary reservoirs ü pigs also serve as reservoirs ØH 5 N 1 infections in > 40 countries since December 2003 Ø>500 million birds ØApproximately 383 people (241 fatal) –human infections a result of direct contact with birds (except 2 clusters – Turkey and Indonesia)
Poultry FAD 2005
Bird Flu üSignificance: virus could evolve in to a form that is easily spread between people üHow: human flu virus and bird flu virus could recombine producing a hybrid üTransmission to humans: direct contact with chickens and their secretions üOutbreak: has spread rapidly to various countries in poultry üControl: kill infected poultry, anti flu drugs, vaccination?
Avian Influenza – H 5 N 1 Ø 1997 Hong Kong Ø 2003 -2004 South East Asia (China, Korea, Vietnam, Indonesia, Thailand, Japan, Cambodia, Laos, Malaysia) Ø 2005 (Russia, Kazakhstan, Mongolia, Romania, Turkey, Croatia) Ø 2006 – 2008 more than 40 countries in Asia, Africa, Europe including India
Country Cases Deaths Azerbaijan Cambodia China Egypt Indonesia Iraq Laos Nigeria Thailand Turkey Vietnam Total 8 7 30 50 133 3 2 1 25 12 106 383 5 7 20 32 108 2 2 1 17 4 52 241
Bird Flu - Species Susceptible ØGallinaceous birds; chickens, turkeys, quail, pheasants, partridges ØZebra finches (*), geese, emus, House finches, budgerigars, ostriches ØDucks, gulls, swans, starlings, pigeons ØEgrets, herons, flamingos, magpie, falcon, owl, sparrow, etc. ØMammals; humans, tigers, leopards, cats, civets, pigs, ferrets
Bird Flu - Transmission ØContact ØRespiratory secretions ØFeces ØContaminated feed and water ØCarcasses ØEquipment, fomites (shoes, clothes, hands, etc. ) Øothers
Pathogenicity ØVaries with the strain (H 5 and H 7) üHigh (HPAI) or low path (LPAI) ? üHPAI arise from LPAI circulating in birds ØPresence of concurrent infections ØAge and species of birds, nutritional and environmental factors ØDefinition of HPAI üIVPI > 1. 2 (lethal for 75 % of chickens) üAmino acid sequence at the Haemagglut cleavage site compatible with HPAI
Bird Flu- Diagnosis Ø Clinical signs, pathology Ø Serology: AGID, ELISA, HI, NI Ø Virus isolation (trachea, lung, intestine, feces, others) üPathogenicity studies (IVPI) in chickens ØRRT – PCR ØSequencing ØDirectigen, Bionex– Type A influenza ØImmunohistochemistry
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”