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1.
Avian Dis ; 63(sp1): 219-229, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31713400

RESUMO

In late 2016, a highly pathogenic avian influenza (HPAI) virus subtype H5N8 clade 2.3.4.4 was reported in Egypt in migratory birds; subsequently, the virus spread to backyard and commercial poultry in several Egyptian governorates, causing severe economic losses to the poultry industry. Here, a recombinant subunit commercial H5 vaccine prepared from the clade 2.3.2 H5 segment on baculovirus was evaluated in Pekin ducks (Anasplatyrhynchos domesticus) and Muscovy ducks (Cairina moschata) in Biosafety Level 3 isolators by using two vaccination regimes: either a single dose on day 10 and a challenge on day 31 or a double dose on days 10 and 28 and a challenge on day 49. The protection parameters were evaluated after experimental infection with the Egyptian HPAI H5N8 isolate clade 2.3.4.4b (A/common-coot/Egypt/CA285/2016) based on mortality rate, clinical signs, gross lesions, seroconversion, virus shedding, and histopathologic changes. In the single-dose vaccination regime, the mortality rate in Muscovy and Pekin ducks was 10% and 0% vs. 40% and 0% in nonvaccinated challenged ducks, respectively. In the double-dose vaccination regime, the mortality rates in Muscovy and Pekin ducks were 0% and 0% vs. 60% and 40% in nonvaccinated challenged ducks, respectively. Muscovy ducks developed more severe clinical signs and gross lesions than Pekin ducks. In addition, tracheal viral shedding in challenged Muscovy ducks, in the single-dose vaccination regime, was 50%, 22%, and 0% at 3, 5, and 7 days postchallenge (DPC), respectively, and was 0% in all Pekin ducks vs. 100% in all challenged nonvaccinated Muscovy and Pekin ducks at 3, 5, and 7 DPC. The viral shedding in challenged Muscovy and Pekin ducks, in the double-dose vaccination regime, was 0% at 3, 5, and 7 DPC vs. 100% in nonvaccinated challenged Muscovy and Pekin ducks, respectively. The results of this study indicate that the H5 baculovirus-based vaccine can be used in ducks with better vaccination regime based on double-dose vaccination at 10 and 28 days of age. In addition, they highlight the need to evaluate the efficacy of currently used commercial vaccines against challenge with the newly emerged HPAI H5N8 clade 2.3.4.4 in the field in Egypt to ensure proper control strategy in ducks.

2.
Front Vet Sci ; 6: 341, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31649942

RESUMO

Six vaccination regimes using classical (Mass-type) and variant (IB-VAR2 and IB-793B) live vaccines were evaluated against Middle Eastern variant-2 infectious bronchitis virus challenge. Six groups of SPF chicks (30 birds/group) were vaccinated using prime-boost regimes at day-1 and day-14 using; IB-M41:IB-VAR2, IB-VAR2:IB-VAR2, IB-VAR2:IB-M41, IB-Ma5:IB-793B, IB-793B:IB-793B, and IB-793B:IB-Ma5, respectively. Ciliostasis and lesion scores were evaluated at day-5 after each vaccination. Birds were challenged intranasally at 14-day post 2nd vaccination using 105EID50/0.1 ml/bird of wild-type IBV (Eg/1212B/2012). At 3, 5, and 7-day post challenge (DPC) virus shedding was monitored by real-time RT-PCR. Five chicks/group were euthanized at 7DPC for ciliostasis and lesion scoring and histopathology was conducted on 3 chicks/group. Seroconversion was evaluated at 14 DPC. All groups primed with the 793B vaccine showed relatively higher ciliostasis scores compared to other groups. The IB-VAR2 vaccinated groups showed the highest protection rates (80-100%) and high protection score (67.6-73.2%) compared to the 793B vaccine groups (50-60%). The virus shedding was significantly reduced at 3 and 5DPC in groups received the IBV-VAR2 (prime or booster) compared to those received the 793B vaccine. In conclusion, the homologous IBV-VAR2 vaccine showed superior results compared to 793B or Mass-type vaccines confirming the importance of IBV vaccine seed homology to the circulating IBV strains.

3.
Vet Ital ; 55(3): 231-239, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31599547

RESUMO

Egypt has a large traditional and exotic poultry sector which is challenged regularly by poultry diseases in endemic and epidemic proportions. The household poultry in particular is a source of livelihoods and employment for millions of low income citizens. Highly pathogenic avian influenza (HPAI) H5N1 and Newcastle disease are the most important poultry diseases in this sector. Whereas poultry vaccines are available to reduce the incidence of disease in Egypt, their effectiveness is doubtful. We conducted a biological evaluation of selected viral vaccines of poultry in three governorates in Egypt. Fifty­four percent of the vaccines had reduced vaccine titres and the effect of secondary vaccine distributions was associated with the observed vaccine titres. External contamination was observed in some vaccines and break in cold chain was reported. Whereas no vaccine distributor used purpose­built vaccine refrigerator, none also had prescribed protocol for vaccine handling or kept record of vaccine. There is a need to review vaccine handling procedure, monitor of vaccine cold chain more critically and review the whole chain that support vaccine distributions in Egypt.


Assuntos
Galinhas , Doenças das Aves Domésticas/prevenção & controle , Vacinação/veterinária , Vacinas Virais/uso terapêutico , Animais , Egito , Doenças das Aves Domésticas/virologia , Vacinação/métodos
4.
Vet World ; 12(1): 97-105, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30936661

RESUMO

Aim: The aim of the current study was to evaluate the efficacy of a trivalent-inactivated oil-emulsion vaccine against challenge by different clades highly pathogenic avian influenza (HPAI) viruses including HPAI-H5N8 and the virulent genotype VII Newcastle disease virus (NDV) (vNDV). Materials and Methods: The vaccine studied herein is composed of reassortant AI viruses rgA/Chicken/Egypt/ME1010/2016 (clade 2.2.1.1), H5N1 rgA/Chicken/Egypt/RG-173CAL/2017 (clade 2.2.1.2), and "NDV" (LaSota NDV/CK/Egypt/11478AF/11); all used at a concentration of 108 EID50/bird and mixed with Montanide-ISA70 oil adjuvant. Two-week-old specific pathogen free (SPF) chickens were immunized subcutaneously with 0.5 ml of the vaccine, and hemagglutination inhibition (HI) antibody titers were monitored weekly. The intranasal challenge was conducted 4 weeks post-vaccination (PV) using 106 EID50/0.1 ml of the different virulent HPAI-H5N1 viruses representing clades 2.2.1, 2.2.1.1, 2.2.1.2, 2.3.4.4b-H5N8, and the vNDV. Results: The vaccine induced HI antibody titers of >6log2 against both H5N1 and NDV viruses at 2 weeks PV. Clinical protection against all HPAI H5N1 viruses and vNDV was 100%, except for HPAI H5N1 clade-2.2.1 and HPAI H5N8 clade-2.3.4.4b viruses that showed 93.3% protection. Challenged SPF chickens showed significant decreases in the virus shedding titers up to <3log10 compared to challenge control chickens. No virus shedding was detected 6 "days post-challenge" in all vaccinated challenged groups. Conclusion: Our results indicate that the trivalent H5ND vaccine provides significant clinical protection against different clades of the HPAI viruses including the newly emerging H5N8 HPAI virus. Availability of such potent multivalent oil-emulsion vaccine offers an effective tool against HPAI control in endemic countries and promises simpler vaccination programs.

5.
Poult Sci ; 98(6): 2371-2379, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30668795

RESUMO

A total of 50 poultry farms of commercial broilers (N = 39) and commercial layers (N = 11) suffered from respiratory problems and mortality during the period from January 2016 to December 2017 were investigated. Also, samples were collected from quail (N = 4), Bluebird (Sialis, N = 1), and Greenfinch (Chloris chloris, N = 1) for analysis. Respiratory viral pathogens were screened by PCR and positive samples were subjected to virus isolation and genetic identification. Antigenic relatedness of isolated avian influenza (AI) H5 subtype was evaluated using cross-hemagglutination inhibition. Results revealed that the incidence of single virus infections in commercial broilers was 64.1% (25/39), with the highest incidence for ND (33.3%) and H9N2 (20.5%), followed by H5N1 (7.7%) and H5N8 (2.7). Meanwhile, H9N2/ND mixed infection was the most observed case (7.7%). Other mixed infections H5N1/ND, H5N1/H9N2/ND, H5N1/H9N2/ND/IB, H9N2/IB, and H9N2/ILT were also observed (2.6% each). In commercial layers, H5N1 and ILT were the only detected single infections (18.1% each). Mixed H9N2/ND was the most predominant infection in layers (27.3%). Other mixed infections of H9N2/IB, H5N1/H5N8/H9N2, and H9N2/ND/IB were observed in 3 separate farms (9.1% each). The H5N8 virus was detected in one quail farm and 2 out of 3 wild bird's samples. Partial HA gene sequence analysis showed the clustering of the selected AI H5N8 within the 2.3.4.4 clade, while H5N1 clustered with the clade 2.2.1.2. Interestingly, the H5N8 isolated from chickens possessed 6 amino acids substitutions at HA1 compared to those isolated from wild birds with low antigenic relatedness to AI H5N1 clades 2.2.1 or 2.2.1.2. In conclusion, mixed viral infections were observed in both broiler and layer chickens in Egypt. The detected triple H5N1, H9N2, and H5N8 influenza co-infection raises the concern of potential AI epidemic strain emergence. The low genetic and antigenic relatedness between AI H5N1 and H5N8 viruses suggest the need for modification of vaccination strategies of avian influenza in Egypt along with strict biosecurity measures.


Assuntos
Doenças das Aves/epidemiologia , Coinfecção/veterinária , Influenza Aviária/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Animais , Animais Selvagens , Doenças das Aves/virologia , Galinhas , Coinfecção/epidemiologia , Coinfecção/virologia , Coturnix , Egito/epidemiologia , Tentilhões , Incidência , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/imunologia , Virus da Influenza A Subtipo H5N1/fisiologia , Vírus da Influenza A Subtipo H5N8/genética , Vírus da Influenza A Subtipo H5N8/imunologia , Vírus da Influenza A Subtipo H5N8/fisiologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Prevalência , Aves Canoras
6.
Poult Sci ; 97(12): 4238-4244, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30085298

RESUMO

Vaccination programs against infectious bronchitis virus (IBV) in Egypt depend on both classical and/or imported variant IBV strain vaccines. However, many IBV outbreaks associated with respiratory distress, nephropathy, and high mortalities were attributed to the circulation of both classical and new nephropathogenic IBV variant 2 strains. In the present study, we report the development of attenuated IBV candidate vaccines using the classic IBV strains (IBM41 and IB2) and a nephropathogenic strain (IBvar2). The wild-type (WT) viruses were attenuated through serial passages in embryonated specific pathogen free (SPF) chicken eggs. Virulence of the attenuated viruses was then tested via the ocular route inoculation and the in vivo back passage in day-old SPF chickens. Efficacy against homologous challenge was investigated also in day-old SPF chickens. Results showed that the viruses were successfully adapted to the embryo by the 100th (IBM41 and IB2) and 110th passages (IBvar2). The attenuated viruses were safe and showed no change of virulence in day-old SPF chickens up to the 10th back passages. The efficacy experiment showed that the attenuated vaccines showed 90 to 100% protection against the homologous challenge based on ciliostasis score and protection percent. The att-IBM41 and att-IB2 vaccines were able to reduce the shedding of the challenge at 3 days post-infection (DPI) and no virus shedding was detected in both vaccinated groups by 5 DPI. In the att-IBvar2 vaccinated birds, only 20% of vaccinated birds shed the challenge virus with low titers (102.10±0.3 EID50/mL) at 3 DPI. In conclusion, the attenuated strains IBM41, IB2, and IBvar2 are efficient vaccine candidates against currently circulating classic and variant IB viruses, respectively. Further studies to evaluate the field efficacy and combining these attenuated IBV strains to induce a wider protection against heterologous IBV challenge are suggested.


Assuntos
Galinhas , Infecções por Coronavirus/veterinária , Vírus da Bronquite Infecciosa/imunologia , Vírus da Bronquite Infecciosa/patogenicidade , Doenças das Aves Domésticas/prevenção & controle , Vacinação/veterinária , Vacinas Virais/imunologia , Animais , Embrião de Galinha , Infecções por Coronavirus/prevenção & controle , Egito , Distribuição Aleatória , Organismos Livres de Patógenos Específicos , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/imunologia , Vacinas Virais/administração & dosagem , Virulência
7.
Vet Sci ; 5(2)2018 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-29747397

RESUMO

Egyptian poultry suffer from frequent respiratory disease outbreaks associated with Infectious Bronchitis Virus (IBV) variant 2 strains (Egy/VarII). Different vaccination programs using imported vaccines have failed to protect the flocks from field challenge. Recent studies confirmed a successful protection using homologous strains as live attenuated vaccines. In this study, a newly developed live attenuated IB-VAR2 vaccine representing the GI-23 Middle East IBV lineage was evaluated in day-old commercial broilers in an IBV-endemic area. A commercial broiler flock was vaccinated with the IB-VAR2 vaccine at day-old age followed by IB-H120 at day 16. The vaccinated flock was monitored on a weekly basis till the slaughter age. The health status and growth performance were monitored, and selected viral pathogen real-time RT-PCR (rRT-PCR) detection was conducted on a weekly basis. Finally, the flock was compared to a nearby farm with only the classical IB-H120 vaccination program. Results showed that the IB-VAR2 vaccine was tolerable in day-old broiler chicks. The IBV virus rRT-PCR detection was limited to the trachea as compared to its nephropathogenic parent virus. Respiratory disease problems and high mortalities were reported in the IB-H120-only vaccinated flock. An exposure to a wild-type Egy/VarII strain was confirmed in both flocks as indicated by partial IBV S1 gene sequence. Even though the IB-VAR2-vaccinated flock performance was better than the flock that received only IB-H120, the IBV ELISA (enzyme-linked immunosorbent assay) and log2 Haemagglutination inhibition (HI) antibody mean titers remained high (3128 ± 2713 and ≥9 log2, respectively) until the 28th day of age. The current study demonstrates the safety and effectiveness of IB-VAR2 as a live attenuated vaccine in day-old commercial broilers. Also, the combination of IB-VAR2 and classical IBV vaccines confers a broader protective immune response against IBV in endemic areas.

8.
PLoS One ; 11(6): e0156747, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27304069

RESUMO

In Egypt, ducks kept for commercial purposes constitute the second highest poultry population, at 150 million ducks/year. Hence, ducks play an important role in the introduction and transmission of avian influenza (AI) in the Egyptian poultry population. Attempts to control outbreaks include the use of vaccines, which have varying levels of efficacy and failure. To date, the effects of vaccine efficacy has rarely been determined in ducks. In this study, we evaluated the protective efficacy of a live recombinant vector vaccine based on a turkey Herpes Virus (HVT) expressing the H5 gene from a clade 2.2 H5N1 HPAIV strain (A/Swan/Hungary/499/2006) (rHVT-H5) and a bivalent inactivated H5N1 vaccine prepared from clade 2.2.1 and 2.2.1.1 H5N1 seeds in Mulard ducks. A 0.3ml/dose subcutaneous injection of rHVT-H5 vaccine was administered to one-day-old ducklings (D1) and another 0.5ml/dose subcutaneous injection of the inactivated MEFLUVAC was administered at 7 days (D7). Four separate challenge experiments were conducted at Days 21, 28, 35 and 42, in which all the vaccinated ducks were challenged with 106EID50/duck of H5N1 HPAI virus (A/chicken/Egypt/128s/2012(H5N1) (clade 2.2.1) via intranasal inoculation. Maternal-derived antibody regression and post-vaccination antibody immune responses were monitored weekly. Ducks vaccinated at 21, 28, 35 and 42 days with the rHVT-H5 and MEFLUVAC vaccines were protected against mortality (80%, 80%, 90% and 90%) and (50%, 70%, 80% and 90%) respectively, against challenges with the H5N1 HPAI virus. The amount of viral shedding and shedding rates were lower in the rHVT-H5 vaccine groups than in the MEFLUVAC groups only in the first two challenge experiments. However, the non-vaccinated groups shed significantly more of the virus than the vaccinated groups. Both rHVT-H5 and MEFLUVAC provide early protection, and rHVT-H5 vaccine in particular provides protection against HPAI challenge.


Assuntos
Patos/imunologia , Herpesvirus Meleagrídeo 1/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Doenças das Aves Domésticas/prevenção & controle , Vacinas Virais/imunologia , Animais , Patos/virologia , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/imunologia , Virus da Influenza A Subtipo H5N1/fisiologia , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/imunologia , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Substâncias Protetoras/administração & dosagem , Fatores de Tempo , Resultado do Tratamento , Perus/virologia , Vacinação/métodos , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia , Vacinas Virais/administração & dosagem , Eliminação de Partículas Virais/efeitos dos fármacos , Eliminação de Partículas Virais/imunologia
9.
Avian Dis ; 60(1 Suppl): 226-31, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27309059

RESUMO

Low pathogenic avian influenza H9N2 virus infection has been an important risk to the Egyptian poultry industry since 2011. Economic losses have occurred from early infection and co-infection with other pathogens. Therefore, H9N2 vaccination of broiler chicks as young as 7 days old was recommended. The current inactivated H9N2 vaccines (0.5 ml/bird) administered at a reduced dose (0.25 ml/bird) do not guarantee the delivery of an effective dose for broilers. In this study, the efficacy of the reduced-dose volume (0.3 ml/bird), compared with the regular vaccine dose (0.5 ml/bird) of inactivated H9N2 vaccines using two different commercially available adjuvants, was investigated. The vaccines were prepared from the local H9N2 virus (Ck/EG/114940v/NLQP/11) using the same antigen content: 300 hemagglutinating units. Postvaccination (PV) immune response was monitored using the hemagglutination inhibition test. At 4 wk PV, both vaccinated groups were challenged using the homologous H9N2 strain at a 50% egg infective dose (EID50) of 10(6) EID50/bird via the intranasal route. Clinical signs, mortality, and virus shedding in oropharyngeal swabs were monitored at 2, 4, 6, and 10 days postchallenge (DPC). The reduced-dose volume of vaccine induced a significantly faster and higher immune response than the regular volume of vaccine at 2 and 3 wk PV. No significant difference in virus shedding between the two vaccine formulas was found (P ≥ 0.05), and both vaccines were able to stop virus shedding by 6 DPC. The reduced-dose volume of vaccine using a suitable oil adjuvant and proper antigen content can be used effectively for early immunization of broiler chicks.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Vírus da Influenza A Subtipo H9N2/imunologia , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Adjuvantes Imunológicos/química , Animais , Galinhas , Composição de Medicamentos , Vírus da Influenza A Subtipo H9N2/genética , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/química , Vacinas contra Influenza/genética , Vacinas contra Influenza/imunologia , Influenza Aviária/imunologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Vacinação , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/química , Vacinas de Produtos Inativados/genética , Vacinas de Produtos Inativados/imunologia
10.
Avian Dis ; 60(1 Suppl): 245-52, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27309063

RESUMO

The immunity profile against H5N1 highly pathogenic avian influenza (HPAI) in the commercial poultry value chain network in Egypt was modeled with the use of different vaccination scenarios. The model estimated the vaccination coverage, the protective seroconversion level, and the duration of immunity for each node of the network and vaccination scenario. Partial budget analysis was used to compare the benefit-cost of the different vaccination scenarios. The model predicted that targeting day-old chick avian influenza (AI) vaccination in industrial and large hatcheries would increase immunity levels in the overall poultry population in Egypt and especially in small commercial poultry farms (from <30% to >60%). This strategy was shown to be more efficient than the current strategy of using inactivated vaccines. Improving HPAI control in the commercial poultry sector in Egypt would have a positive impact to improve disease control.


Assuntos
Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Animais , Galinhas , Egito , Virus da Influenza A Subtipo H5N1/genética , Vacinas contra Influenza/genética , Vacinas contra Influenza/imunologia , Influenza Aviária/embriologia , Influenza Aviária/imunologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Vacinação , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/genética , Vacinas de Produtos Inativados/imunologia
11.
Avian Dis ; 60(1 Suppl): 256-61, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27309065

RESUMO

Since the first report of low pathogenic avian influenza (LPAI) H9N2 virus in Egypt in 2011, the Egyptian poultry industry has suffered from unexpected economic losses as a result of the wide spread of LPAI H9N2. Hence, inactivated H9N2 vaccines have been included in the vaccination programs of different poultry production sectors. The optimal antigen content of avian influenza virus vaccines is essential to reach protective antibody titers. In this study, the correlation between antigen content (based on hemagglutinating units [HAU]) and postvaccination (PV) antibody response of H9N2 inactivated vaccine was studied. Five different vaccine antigen loads (128, 200, 250, 300, and 350 HAU formulas/dose) were investigated in commercial broiler and specific-pathogen-free (SPF) chickens. Vaccine safety and PV antibody responses were monitored. At the fourth week PV only SPF vaccinated groups (128, 200, 250, and 300 HAU/dose) were challenged using LPAI H9N2 (A/Ck/EG/114940v/NLQP/11) virus with 10(6) EID50/bird. Oropharyngeal swabs were used to monitor virus shedding at 2, 4, 6, and 10 days postchallenge. Results showed that all vaccine formulations were well tolerated, and the highest antibody titers were observed in birds vaccinated with higher HAU. Vaccines containing 128 and 200 HAU/dose did not induce the required protective HI titers by 3 wk PV. Meanwhile, the challenge experiment in SPF chickens showed that 250 and 300 HAU vaccine doses were required to reduce the level and duration of virus shedding. Study results thus suggest that inactivated H9N2 vaccines containing at least 250 HAU/dose will induce the optimal protective titers and minimize virus shedding in SPF chickens.


Assuntos
Vírus da Influenza A Subtipo H9N2/imunologia , Vacinas contra Influenza/imunologia , Influenza Aviária/imunologia , Doenças das Aves Domésticas/prevenção & controle , Animais , Anticorpos Antivirais/imunologia , Galinhas , Relação Dose-Resposta Imunológica , Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/fisiologia , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Organismos Livres de Patógenos Específicos , Vacinação , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia , Eliminação de Partículas Virais
12.
Avian Pathol ; 44(5): 333-41, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26023824

RESUMO

Vaccination is the main tool implemented in Egypt since 2007 to control H5N1 avian influenza. The present study aimed at comparing the effectiveness of three avian influenza vaccination regimes in commercial broiler chickens carrying high levels of maternally derived antibodies (MDAs). Day-old chicks were divided into four experimental groups. Group I received only the rHVT-H5 vaccine (recombinant turkey herpesvirus (HVT) which carries a H5 clade 2.2 insert) administered at D1. Group II received only the KV-H5 (an oil emulsion killed vaccine prepared from reassortant HPAI virus (A/duck/Anhui/1/06)) vaccine (inactivated reverse genetic H5N1 clade 2.3.4 virus) administered at D8. Group III received rHVT-H5 and KV-H5 as prime/boost. Group IV served as unvaccinated control. Weekly serological monitoring was conducted using the haemagglutination inhibition test. Two challenge experiments were conducted at D28 and D35 using HPAI H5N1 clade 2.2.1 virus. Birds were monitored daily 14 days post-challenge for morbidity and mortality, and oropharyngeal swabs were collected for virological monitoring. Initially, day-old chicks had high mean MDA titres (9 + 0.9 log2). The MDA half-life was >7 and <7 days, respectively, for unvaccinated and vaccinated birds. Group III showed the highest post-vaccination humoral immune response and seroconversion rate. The highest protection rate against morbidity (80-90%) and mortality (90-90%) was obtained in Group III after challenge at D28 and D35, respectively, as compared to Group I (70-70%) and (80-90%) and Group II (0-0%) and (30-30%). Groups I and III had lower number of shedder birds. The vaccination regime with prime/boost conferred the highest and earliest protection, and can hence be recommended for the broiler production sector in endemic and high HPAI H5N1 challenge areas.


Assuntos
Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Vacinação , Animais , Galinhas , Egito , Testes de Inibição da Hemaglutinação , Vacinas contra Influenza/imunologia , Influenza Aviária/epidemiologia , Influenza Aviária/imunologia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/imunologia , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia
13.
Virol J ; 10: 203, 2013 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-23799999

RESUMO

BACKGROUND: The endemic H5N1 high pathogenicity avian influenza virus (A/H5N1) in poultry in Egypt continues to cause heavy losses in poultry and poses a significant threat to human health. METHODS: Here we describe results of A/H5N1 surveillance in domestic poultry in 2009 and wild birds in 2009-2010. Tracheal and cloacal swabs were collected from domestic poultry from 22024 commercial farms, 1435 backyards and 944 live bird markets (LBMs) as well as from 1297 wild birds representing 28 different types of migratory birds. Viral RNA was extracted from a mix of tracheal and cloacal swabs media. Matrix gene of avian influenza type A virus was detected using specific real-time reverse-transcription polymerase chain reaction (RT-qPCR) and positive samples were tested by RT-qPCR for simultaneous detection of the H5 and N1 genes. RESULTS: In this surveillance, A/H5N1 was detected from 0.1% (n = 23/) of examined commercial poultry farms, 10.5% (n = 151) of backyard birds and 11.4% (n = 108) of LBMs but no wild bird tested positive for A/H5N1. The virus was detected from domestic poultry year-round with higher incidence in the warmer months of summer and spring particularly in backyard birds. Outbreaks were recorded mostly in Lower Egypt where 95.7% (n = 22), 68.9% (n = 104) and 52.8% (n = 57) of positive commercial farms, backyards and LBMs were detected, respectively. Higher prevalence (56%, n = 85) was reported in backyards that had mixed chickens and waterfowl together in the same vicinity and LBMs that had waterfowl (76%, n = 82). CONCLUSION: Our findings indicated broad circulation of the endemic A/H5N1 among poultry in 2009 in Egypt. In addition, the epidemiology of A/H5N1 has changed over time with outbreaks occurring in the warmer months of the year. Backyard waterfowl may play a role as a reservoir and/or source of A/H5N1 particularly in LBMs. The virus has been established in poultry in the Nile Delta where major metropolitan areas, dense human population and poultry stocks are concentrated. Continuous surveillance, tracing the source of live birds in the markets and integration of multifaceted strategies and global collaboration are needed to control the spread of the virus in Egypt.


Assuntos
Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Animais , Aves , Cloaca/virologia , Surtos de Doenças , Egito/epidemiologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Virus da Influenza A Subtipo H5N1/genética , Neuraminidase/genética , Aves Domésticas , Prevalência , Reação em Cadeia da Polimerase em Tempo Real , Estações do Ano , Traqueia/virologia , Proteínas da Matriz Viral/genética , Proteínas Virais/genética
14.
Virol J ; 9: 294, 2012 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-23185975

RESUMO

BACKGROUND: Uninterrupted transmission of highly pathogenic avian influenza virus (HPAIV) H5N1 of clade 2.2.1 in Egypt since 2006 resulted in establishment of two main genetic clusters. The 2.2.1/C group where all recent human and majority of backyard origin viruses clustered together, meanwhile the majority of viruses derived from vaccinated poultry in commercial farms grouped in 2.2.1.1 clade. FINDINGS: In the present investigation, an HPAIV H5N1 was isolated from twenty weeks old layers chickens that were vaccinated with a homologous H5N1 vaccine at 1, 7 and 16 weeks old. At twenty weeks of age, birds showed cyanosis of comb and wattle, decrease in egg production and up to 27% mortality. Examined serum samples showed low antibody titer in HI test (Log2 3.2 ± 4.2). The hemagglutinin (HA) and neuraminidase (NA) genes of the isolated virus were closely related to viruses in 2.2.1/C group isolated from poultry in live bird market (LBM) and backyards or from infected people. Conspicuous mutations in the HA and NA genes including a deletion within the receptor binding domain in the HA globular head region were observed. CONCLUSIONS: Despite repeated vaccination of layer chickens using a homologous H5N1 vaccine, infection with HPAIV H5N1 resulted in significant morbidity and mortality. In endemic countries like Egypt, rigorous control measures including enforcement of biosecurity, culling of infected birds and constant update of vaccine virus strains are highly required to prevent circulation of HPAIV H5N1 between backyard birds, commercial poultry, LBM and humans.


Assuntos
Virus da Influenza A Subtipo H5N1/genética , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Animais , Galinhas , Egito , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Virus da Influenza A Subtipo H5N1/classificação , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Vacinas contra Influenza/imunologia , Influenza Aviária/imunologia , Dados de Sequência Molecular , Neuraminidase/genética , Filogenia , Doenças das Aves Domésticas/imunologia
15.
Arch Virol ; 157(6): 1167-72, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22426861

RESUMO

This study describes the first isolation of H9N2 avian influenza virus (AIV) from commercial bobwhite quail (Colinus virginianus) in Egypt. Infected birds showed neither clinical signs nor mortality. Virus isolation and real-time reverse transcription polymerase chain reaction confirmed the presence of the H9N2 virus in cloacal swab samples collected at 35 days of age and the absence of other AIV subtypes, including H5 and H7. The hemagglutinin and neuraminidase genes of the isolated virus showed 99.1% and 98.2% nucleotide identity and 97.3% and 100% amino acid identity, respectively, to those of H9N2 viruses currently circulating in poultry in the Middle East. Phylogenetically, the Egyptian H9N2 virus was closely related to viruses of the G1-like lineage isolated from neighbouring countries, indicating possible epidemiological links.


Assuntos
Vírus da Influenza A Subtipo H9N2/isolamento & purificação , Influenza Aviária/virologia , Codorniz/virologia , Animais , Egito , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A Subtipo H9N2/classificação , Vírus da Influenza A Subtipo H9N2/genética , Dados de Sequência Molecular , Neuraminidase/genética , Filogenia , Proteínas Virais/genética
16.
Arch Virol ; 157(5): 951-9, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22350650

RESUMO

Avian influenza due to highly pathogenic avian influenza (HPAIV) H5N1 virus is not a food-borne illness but a serious panzootic disease with the potential to be pandemic. In this study, broiler chickens were vaccinated with commercial H5N1 or H5N2 inactivated vaccines prior to being challenged with an HPAIV H5N1 (clade 2.2.1 classic) virus. Challenged and non-challenged vaccinated chickens were kept together, and unvaccinated chickens served as contact groups. Post-challenge samples from skin and edible internal organs were collected from dead and sacrificed (after a 14-day observation period) birds and tested using qRT-PCR for virus detection and quantification. H5N1 vaccine protected chickens against morbidity, mortality and transmission. Virus RNA was not detected in the meat or edible organs of chickens vaccinated with H5N1 vaccine. Conversely, H5N2 vaccine did not confer clinical protection, and a significant virus load was detected in the meat and internal organs. Phylogenetic analysis showed that the H5N1 virus vaccine and challenge virus strains are closely related. The results of the present study strongly suggest a need for proper selection of vaccines and their routine evaluation against newly emergent field viruses. These actions will help to reduce human exposure to HPAIV H5N1 virus from both infected live birds and slaughtered poultry. In addition, rigorous preventive measures should be put in place in order to minimize the public-health risks of avian influenza at the human-animal interface.


Assuntos
Virus da Influenza A Subtipo H5N1/imunologia , Influenza Aviária/imunologia , RNA Viral/genética , Animais , Galinhas , Humanos , Virus da Influenza A Subtipo H5N1/classificação , Virus da Influenza A Subtipo H5N1/genética , Vírus da Influenza A Subtipo H5N2/classificação , Vírus da Influenza A Subtipo H5N2/genética , Vírus da Influenza A Subtipo H5N2/imunologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Influenza Aviária/transmissão , Influenza Aviária/virologia , Influenza Humana/prevenção & controle , Influenza Humana/transmissão , Influenza Humana/virologia , Carne/análise , Carne/virologia , Dados de Sequência Molecular , Filogenia , RNA Viral/imunologia , Vacinação
17.
Vet Microbiol ; 150(1-2): 28-34, 2011 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-21236607

RESUMO

In contrast to chickens, there is a paucity of information on the potency of H5 vaccines to protect turkeys against the highly pathogenic avian influenza (HPAI) H5N1 virus infections. In this study, 4 groups, 10 turkey poults each, were vaccinated at seven days old with one of H5N2 or H5N1 commercial vaccines or one of two prepared H5N1 vaccines from a local Egyptian variant HPAI H5N1 (EGYvar/H5N1) strain. At 35 days age, all vaccinated and 10 non vaccinated birds were challenged intranasal with 10(6) EID(50)/0.1 ml of EGYvar/H5N1. All vaccines used in this study were immunogenic in turkeys. There was no cross reaction between the commercial vaccines and the Egyptian variant H5N1 antigen as obtained by the hemagglutination inhibition test. Birds vaccinated with H5N2 vaccine were died, while other H5N1 vaccinated groups have had 20-40% mortality. The highest virus excretion was found in non-vaccinated infected and H5N2 vaccinated birds. Eleven peculiar amino acid substitutions in H5 protein of the variant strain were existed neither in the vaccine strains nor in the earliest H5N1 virus introduced into Egypt in 2006. In conclusion, single vaccination at seven days old is inadequate for protection of meat turkeys against variant HPAI H5N1 challenge and multi-dose vaccination at older age is recommended. For the foreseeable future, continuous evaluation of the current vaccines in H5N1 endemic countries in the face of virus evolution is a paramount challenge to mitigate the socio-economic impact of the virus.


Assuntos
Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Perus/virologia , Vacinação/veterinária , Adjuvantes Imunológicos/administração & dosagem , Administração Intranasal , Substituição de Aminoácidos , Animais , Egito , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Virus da Influenza A Subtipo H5N1/imunologia , Vírus da Influenza A Subtipo H5N2/imunologia , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/imunologia , Influenza Aviária/virologia , Perus/imunologia , Vacinas de Produtos Inativados/imunologia , Eliminação de Partículas Virais
18.
Virol J ; 7: 330, 2010 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-21092081

RESUMO

BACKGROUND: Avian influenza A (H5N1) virus is one of the most important public health concerns worldwide. The antiviral activity of native and esterified whey proteins fractions (α- lactalbumin, ß- lactoglobulin, and lactoferrin) was evaluated against A/chicken/Egypt/086Q-NLQP/2008 HPAI (H5N1) strain of clade 2.2.1 (for multiplicity of infection (1 MOI) after 72 h of incubation at 37 °C in the presence of 5% CO2) using MDCK cell lines. RESULT: Both the native and esterified lactoferrin seem to be the most active antiviral protein among the tested samples, followed by ß- lactoglobulin. α-Lactalbumin had less antiviral activity even after esterification. CONCLUSION: Esterification of whey proteins fractions especially lactoferrin and ß-lactoglobulin enhanced their antiviral activity against H5N1 in a concentration dependent manner.


Assuntos
Antivirais/farmacologia , Virus da Influenza A Subtipo H5N1/efeitos dos fármacos , Proteínas do Leite/farmacologia , Animais , Antivirais/química , Aves , Linhagem Celular , Cães , Egito , Esterificação , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/virologia , Testes de Sensibilidade Microbiana , Proteínas do Leite/química , Proteínas do Soro do Leite
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