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Avian Influenza Massi Paola Sezione di Forlì IZSLER Santa Sofia,26.10.2006.

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Presentazione sul tema: "Avian Influenza Massi Paola Sezione di Forlì IZSLER Santa Sofia,26.10.2006."— Transcript della presentazione:

1 Avian Influenza Massi Paola Sezione di Forlì IZSLER Santa Sofia,

2

3 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Dal 2003 a giugno 2006 registrati presso l’OMS 205 casi di infezione con 113 decessi

4 La letalità media del virus dell’influenza aviaria H5N1 (OMS) L’OIE segnala focolai epizootici negli uccelli domestici e selvatici in una cinquantina di Paesi

5 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Per il 50% i casi di contaminazione sono stati registrati nei soggetti con meno di 20 anni, il 90%in quelli con meno di 40 anni

6 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Quanto ai bambini colpiti dall’infezione, 21 avevano meno di 5 anni e 32 tra 5 e 9 anni.

7 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Il fatto che la maggior parte dei casi interessa soggetti di età compresa tra i 10 e i 29 anni potrebbe spiegare la loro presenza nei Paesi dove la popolazione è giovane

8 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Per esempio, Egitto e Indonesia, nel 2005, dove rispettivamente il 34 e il 28% della popolazione ha meno di 15 anni.

9 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Inoltre, i comportamenti legati all’età o al sesso (es.lo spiumaggio,la macellazione e la preparazione degli alimenti vengono effettuati dalle giovani donne e i bambini giocano con volatili infetti) aumentano il rischio di esposizione prolungata e di stretto contatto con i volatili infetti.

10 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Tuttavia, nessuna differenza statisticamente significativa è stata evidenziata fra gli uomini e le donne quanto al rischio dell’infezione

11 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Il livello generale di mortalità si assesta al 56%.E’ elevato per tutte le età anche se raggiunge il 73% dai 10 ai 39 anni Il livello più basso (18%) si registra negli over 50. Il livello di letalità differisce da quello dell’influenza stagionale”tradizionale”per la quale la mortalità più elevata si registra nelle persone più anziane.

12 La letalità media del virus dell’influenza aviaria H5N1 (OMS) Il livello generale più elevato di mortalità si è raggiunto nel 2004 con il 73% Durante gli ultimi tre anni, l’incidenza di mortalità ha raggiunto il picco nel corso del periodo inverno-primavera dell’emisfero nord

13 DIAGNOSIS Clinical, gross amd microscopic findings Laboratory diagnosis

14 Meat-type and breeder turkeys

15 Before 1999 We known H6 and H9 in turkeys Respiratory signs Inactivated vaccines

16 H7N1 LPAI 1999 Year

17 Low pathogenicity avian influenza (LPAI) Clinical findings Mortality rates ranging from 5 to 97% Depending of the age, on a series of environmental factors (temperature,ventilation,hygienic conditions) and the presence of infectious agents

18 Low pathogenicity avian influenza (LPAI) During the fase acute of the disease, depression,ruffled feathers and congiuntivitis Swelling of infraorbital sinuses with caseous clots Egg production dropped from 30 to 80% 3dispnea

19 3Swelling of infraorbital sinuses

20

21 Low pathogenicity avian influenza (LPAI Swelling of infraorbital sinuses with caseous clots

22 Low pathogenicity avian influenza (LPAI Haemorrhagic tracheitis

23

24 Lungs congested and haemorragic

25 H7N1 HPAI 2000 Year

26 Severe depression in preagonic phase and dead birds on their back due to nervous signs and spastic contractions prior to death

27 Highly pathogenic avian influenza (HPAI) In meat-type and breeder turkeys, 100% mortality hours from the onset of the first clinical signs. Drop in food consumption and nervous signs

28 Highly pathogenic avian influenza (HPAI) Post mortem findings

29 Haemorrhagic tracheitis with caseus clots

30 Pancreatitis and duodenitis

31 Necrosis of pancreas

32 Haemorrhages on the caecal tonsils

33 3Polmonite acuta

34 Chicken

35 LPAI Broilers and broilers breeders Clinical findings In the majority of flocks, LPAI did not cause any clinical signs In a limited number of outbreaks was characterised by anorexia and mild respiratory signs, with low mortality, in the order of 2-3%

36 LPAI Post mortem findings Polmonary and tracheal congestion with cattarrhal tracheitis Ovarian follicles haemorrhagic and oedematous

37 LPAI Caged layers Clinical findings Only 10-20%of the birds with loss of appetite and depression, with very mild respiratory signs and congestion of combs Drop in egg from 2 to 10% until 30% Mortality between 0.5 and 2%

38 LPAI Post mortem findings The lungs and tracheas were congested The ovary and oviduct edematous and haemorrhagic

39 Lungs and trachea congested

40 HPAI Chickens reared on litter Clinical findings 100% mortality h.from the onset of the first clinical signs Anorexia, depression and cessation of egg- laying were followed by complete reluctance to move and tremors of the head and paralysis of the wing and legs

41

42

43 HPAI Caged layers Clinical findings The disease moved more slowly within the flock Sonnolence, cessation of egg-laying and feed consumption. Cianotic coombs with tremors of the head

44

45 HPAI Post-mortem findings Pancreatitis, caecal tonsils haemorrhagic Internal organs appeared congested Urate deposits in the kidney

46

47 Duck and goose

48 HPAI Clinical findings Incoordination and tremors and mortality % Post mortem findings Pancreatic lesions Heart congested Duodenum congested

49

50

51

52 Japanese quail (coturnix coturnix japonica)

53 HPAI Severe respiratory condition, prostration and diarrhoa Nervous signs with torticollis and opistothonus High mortality

54 Ostrich (struthio camelus)

55 Clinical signs were observed only in juvenile (7-9 months of age) anorexia, depression Feed consuption dropped Nervous signs haemorrhagic faeces Mortality 1-20%

56 H7N3 LHAI 2002 year

57

58

59 Laboratory diagnosis

60 A presumptive diagnosis can be made by Detecting antibodies

61 A definitive diagnosis of AI is established by: 1.Direct detection of AI viral proteins or genes in specimens such as tissues, swab, cellculture or embryonating eggs 2.Isolation and identification of AI virus

62 Sample selection and storage Tracheal and cloacal swabs or tissues collected If the samples can be tested within 48h. After collection they may be kept at 4°C; if over h., storage at -70°C

63 Direct detection of AI viral protein or Nucleic acid Antigen capture ELISA to detect viral antigens in samples Elisa sandwich virologica Con Mab anti NPA (HB65)

64 Direct detection of AI viral protein or Nucleic acid a human influenza test (Directigen Becton- Dickinsos) used to detect influenza viral antigen This antigen capture enzyme immunoassay was found to be specific and sensitive in tracheal swabs

65 KIT IMMUNOENZIMATICO

66 3Kit immunoenzimatico

67

68 3Tamponi ed estratti d’organo per kit rapido

69

70 Commercial Rapid Ag Tests Advantages 1. Rapid 2. User-friendly 3. On farm test Disadvantages 1. Very high cost 2. Poor sensitivity

71 Direct detection of AI viral protein or Nucleic acid Polymerase chain reaction methods used are more sensitive than virus isolation procedures

72 RT-PCR H7 H5 M M ctrl Ctrl- H5+ H7+ Metodo identificativo del genoma virale

73 3PCR-Real Time

74

75 Quantitative real time PCR 3Allows detection of the amplicon as it accumulates by measuring light emission via a specific probe. This light emission is linked to amplicon production

76 PCR Advantages 3Sensitivity/ specifity 3Rapid test Disadvantages High cost

77 Virus isolation Chicken embryos,10-11 days old,inoculated via the allantoic cavity

78

79 Virus isolation The presence of virus is demostrated by chicken erythrocyte haemagglutinating activity (HA) in the allantoic fluid

80 Virus isolation Plaque assay on cell monolayers (MDCK) MDCK Madin Darby Canine Kidney Cells

81 Virus identification 1) H.I. assay against NDV and other paramixo

82 Virus identification 2) Double immunodiffusion test AGP to dectect the type- specific NP and matrix proteins

83 Virus identification 3) ELISA with monoclonal antibodies reacts with the nucleoprotein or matrix proteins

84 Virus identification 4) The next spet is to determine the antigenic subtype of the surface antigens: HA and NA The HA is identified in the HI test using a panel of antisera prepared against the distinct HAs

85 VIRUS ISOLATION Disadvantages 3No rapid 3Cost Advantages Virus isolation is important for patogenicity studies

86 Serology Specific antibodies detect as earlyas seven days after infection

87 Serology In serological surveillance programs: A) AGP test is used for the detection of anti-NP antibodies Group specific

88 Serology B) ELISA assays have been developed to detect antibodies AI virus

89 Serology C ) Once influenza is detected by AGP or ELISA, HI test and ELISA with Mabs can be used to determine the HA subtype Subtype specific Paolo Cordioli

90


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