ABSTRACT
Aquatic birds are known to harbor all the known influenza A viruses. In the winter of January 2016, we surveyed influenza A virus in the feces of migratory birds in South Korea. The novel re-assorted H11N9 avian influenza virus, which contains genes from avian influenza viruses of poultry and wild birds, was isolated. The polymerase basic 2 (PB2), polymerase basic 1 (PB1), hemagglutinin (HA), and nucleoprotein (NP) genes were most closely related to those of domestic duck-origin avian influenza viruses, while the non-structural (NS) gene was closely related to that of domestic goose-origin avian influenza virus. The polymerase acidic (PA), neuraminidase (NA), and matrix (M) genes were most similar to those of wild bird-origin avian influenza viruses. Our results suggested that the interaction between wild birds and domestic poultry could possibly create novel re-assorted avian influenza viruses circulating in wild birds.
Subject(s)
Anseriformes/virology , Influenza A virus/genetics , Influenza A virus/isolation & purification , Influenza in Birds/virology , Reassortant Viruses/genetics , Reassortant Viruses/isolation & purification , Animals , Animals, Wild/virology , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Influenza A virus/classification , Influenza A virus/physiology , Phylogeny , Reassortant Viruses/classification , Republic of KoreaABSTRACT
Outbreaks of the highly pathogenic H5N1 virus in poultry and humans are ongoing. Vaccination is an efficient method for prevention of H5N1 infection. Using chickens and ducks, we assessed the efficacy of a vaccine comprising H5N1 hemagglutinin (HA) protein produced in a baculovirus expression system. The immunized chickens and ducks were protected against lethal infection by H5N1 in an antigen dose-dependent manner. Complete protection against homologous challenge and partial protection against heterologous challenge were achieved in chickens immunized with 5 µg HA protein and in ducks immunized with 10 µg HA protein. The IgG antibody subtype was mainly detected in the sera and tissues, including the lungs. The neuraminidase (NA) inhibition assay was negative in immunized chickens and ducks. Our results indicated that the expressed HA protein by baculovirus was immunogenic to both chickens and ducks, and the immunized chickens and ducks were protected from the lethal infections of highly pathogenic H5N1 influenza virus, though ducks required more HA protein than chickens to be protected. Also, baculovirus HA-vaccinated poultry can be differentiated from infected poultry by NA inhibition assay.
Subject(s)
Baculoviridae/genetics , Drug Carriers , Hemagglutinin Glycoproteins, Influenza Virus/immunology , Influenza A Virus, H5N1 Subtype/immunology , Influenza Vaccines/immunology , Influenza in Birds/prevention & control , Animals , Chickens , Ducks , Genetic Vectors , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Immunoglobulin G/analysis , Immunoglobulin G/blood , Influenza Vaccines/administration & dosage , Influenza Vaccines/genetics , Lung/immunology , Survival Analysis , Treatment Outcome , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunologySubject(s)
Anseriformes/virology , Influenza A Virus, H5N1 Subtype/isolation & purification , Influenza in Birds/epidemiology , Influenza in Birds/virology , Animals , Disease Outbreaks , History, 21st Century , Influenza A Virus, H5N1 Subtype/classification , Influenza A Virus, H5N1 Subtype/genetics , Influenza in Birds/history , Republic of Korea/epidemiologyABSTRACT
We studied the pathogenesis and transmissibility of a novel avian-origin H7N9 influenza virus in pigs. When pigs were infected with H7N9 influenza virus, they did not show any clear clinical signs (such as sneezing, fever and loss of body weight), and they shed viruses through their noses for 2 days after infection. No transmission occurred between infected and naïve pigs. Pigs suffered from mild pneumonia, which was accompanied by the induction of inflammatory cytokines and chemokines such as IL-8 and CCL1. Taken together, our results suggest that pigs may not play an active role in transmitting H7N9 influenza virus to mammals.
