ABSTRACT
A real-time reverse transcription PCR (RRT-PCR) targeting a highly conserved HA2 H7 region was developed for the detection of all H7 subtype avian influenza viruses (PanH7). The wide phylogenetic scope and analytical sensitivity and specificity were validated with the use of a panel of 56 diverse influenza A viruses. The detection limit was determined with the use of serial dilutions of Eurasian isolates A/Ck/BE/06775/2003 and A/Ck/It/1067/v99 and North American isolates A/CK/PA/ 143586/2001 and A/Quail/PA/20304/1998, to be 1 log10 higher than the detection limit of the generic influenza A matrix RRT-PCR (about 2.5 EID50/reaction compared to 0.25 EID50/reaction for matrix). Diagnostic test properties of PanH7 were determined with the use of 102 swabs from A/Ck/It/1067/v99 experimentally infected chickens, and were not affected by the increased detection limit of PanH7. In comparison to matrix RRT-PCR and virus isolation in embryonated chicken eggs (VI), the PanH7 detected more weakly positive oropharyngeal swabs at the onset of the infection. PanH7 diagnostic sensitivity compared to virus isolation (VI) was 83.3% (compared to 72.2% for matrix RRT-PCR); and diagnostic specificity was 88.1% (94.0% for matrix). The PanH7 test can also be tailored to detect only American (AmH7) or only Eurasian (EurH7) strains by changing the mix of forward and reverse primers used in combination with the unique probe. Overall, this new test is a valuable tool for the detection and identification of H7 subtype influenza A.
Subject(s)
Hemagglutinin Glycoproteins, Influenza Virus/metabolism , Influenza A virus/classification , Influenza A virus/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/veterinary , Americas/epidemiology , Animals , Asia/epidemiology , Chickens , Cloaca/virology , Europe/epidemiology , Influenza in Birds/epidemiology , Influenza in Birds/virology , Oropharynx/virology , Reverse Transcriptase Polymerase Chain Reaction/methods , Specific Pathogen-Free OrganismsABSTRACT
The continuous outbreaks of fatal Newcastle disease (ND) in commercial poultry flocks demonstrate that current vaccination strategies are not fully efficacious and should be improved by new generation of vaccines. In this context, maternally immune conventional layer chickens were vaccinated in ovo with a turkey herpesvirus recombinant expressing the fusion (F) gene of NDV (rHVT-ND) and/or at day-old with an apathogenic enterotropic live ND vaccine co-administrated or not with chitosan by oculo-nasal route. The induced vaccinal immune responses and conferred protection against a challenge with a circulating NDV velogenic viscerotropic strain were evaluated. The innovative rHVT-ND/live ND-chitosan vaccination regimen provided the best protection against mortality and morbidity as well as the strongest reduction of virus shedding that could be related to the higher measured cellular immune response and digestive antibody-mediated immunity.
Subject(s)
Adjuvants, Immunologic/administration & dosage , Chitosan/administration & dosage , Genetic Vectors , Herpesvirus 1, Meleagrid/genetics , Newcastle Disease/prevention & control , Viral Fusion Proteins/immunology , Viral Vaccines/immunology , Adjuvants, Immunologic/pharmacology , Administration, Intranasal , Animals , Antibodies, Viral/blood , Chickens , Chitosan/pharmacology , Cloaca/virology , Newcastle Disease/immunology , Ovum/immunology , Spleen/immunology , Survival Analysis , T-Lymphocytes/immunology , Vaccination/methods , Vaccines, Attenuated/administration & dosage , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunology , Viral Fusion Proteins/genetics , Viral Vaccines/administration & dosage , Viral Vaccines/genetics , Virus Shedding/immunologyABSTRACT
We report the isolation and characterization of a highly pathogenic avian influenza A/H5N1 virus from Crested Hawk-Eagles smuggled into Europe by air travel. A screening performed in human and avian contacts indicated no dissemination occurred. Illegal movements of birds are a major threat for the introduction of highly pathogenic avian influenza.
Subject(s)
Influenza in Birds/epidemiology , Raptors/virology , Acetamides/pharmacology , Animals , Antiviral Agents/pharmacology , Belgium/epidemiology , Bird Diseases/epidemiology , Crime , Influenza A Virus, H5N1 Subtype , Influenza A virus/genetics , Influenza in Birds/drug therapy , Oseltamivir , Phylogeny , ThailandABSTRACT
The sequences of the L1 loop of the hexon protein from representative fowl adenovirus (FAdV) strains of the different European and American collections were determined and compared. This study highlighted the lack of consensus in the numbering of the individual serotypes between the American and the European classifications. An identification system is proposed based on restriction fragment length polymorphism of the hexonA/hexonB polymerase chain reaction product. In addition, new insights into the relationships among FAdV strains are presented and discussed on the basis of phylogenetic analysis of the L1 loops sequences. Six clusters of strains that are supported by high bootstrap values were identified. Three of them are clearly independent, forming groups A, B and C, whereas the three others are clustered in a single 'supergroup', denominated D. Interestingly, the Japanese strain TR22 that is presently classified as European type 5 (species B) could not be assigned to any of the aforementioned clusters and might therefore constitute the sole representative of a seventh cluster.
