Animals ; Birds ; Influenza A Virus, H5N1 Subtype ; Influenza in Birds ; virology

From February 2013, a novel avian influenza A H7N9 virus causing human infection with fatal outcomes has been identified in eastern China. This avian influenza A H7N9 virus is a triple reassortant of viruses that are avian-origin only and it is low pathogenic in poultry. Several characteristic amino acid mutations in HA and PB2 polymerase subunit (including G186V, Q226L and E627K substitution) have been found through sequence analysis, and these mutations probably facilitate binding to human-type receptors and efficient replication in mammals. Other mutations in NA, M2 and NS genes were also found. Although sustained human-to-human transmission has not been conclusively established, limited human-to-human transmission of the H7N9 virus remains possible. Intensified surveillance for the H7N9 virus in humans and animals is needed to answer questions about the viral origin, spread and potential threat.
Animals ; Birds ; virology ; China ; epidemiology ; Humans ; Influenza A virus ; genetics ; Influenza in Birds ; virology ; Influenza, Human ; transmission ; virology ; Mutation

Recently, avian viral diseases have become one of the main models to study mechanisms of viral infections and pathogenesis. The study of regulatory relationships and mechanisms between viruses and microRNAs has also become the focus. In this review, we briefly summarize the general situations of microRNAs encoded by avian herpesviruses. Also, we analyze the regulatory relationships between tumorigenicity of avian herpesviruses and microRNAs. Additionally, the possible applications for prevention and treatment of viral diseases (such as infectious bursal disease, avian influenza and avian leucosis) using the regulatory mechanisms of microRNAs are also discussed.
Animals ; Avian Leukosis ; Birds ; virology ; Birnaviridae Infections ; Herpesviridae ; genetics ; Influenza in Birds ; MicroRNAs ; genetics

In Taiwan, the first human-infecting H6N1 avian influenza virus was isolated in 2013. To better understand the origin, evolutionary relationship and pathogenesis of the H6N1 virus, we studied the adaptive evolution and evolutionary dynamics of the hemagglutinin (HA) genes of the H6N1 virus in Taiwan. We felt that such studies woud contribute to the further study and control of the virus. Datasets were gained from the Flu and Global Initiative on Sharing All Influenza Data (GISAID) databases. Then, phylogenetic trees and evolutionary dynamics were reconstructed. The evolutionary rate and characterization of adaptive evolution were analyzed by bioinformatic methods. Results indicated that the HA genes of H6N1 in Taiwan were divided into at least five types, and that the new types that the infected human H6N1 belonged to could be local advantage type at present. Evolutionary dynamics revealed the viral population expanded first at the end of 1971, reduced sharply in 2008, and then increased slightly. Three sites were identified under positive selection, suggesting that various sites might increase the adaptive ability of the virus. Eighty-nine sites were under negative selection, revealing that these sites might play an important role in the replication and epidemiology of the virus. Interestingly, site 329 upstream from the cleavage site was also under negative selection, suggesting that this site might be associated with the virulence of H6N1. These data suggest that the HA genes of the Taiwanese H6N1 virus have been undergoing adaptive evolution, and that an outbreak may occur again. Hence, more attention should be paid to the identified sites, to enable timely monitoring and control of a future epidemic.
Animals ; Birds ; Evolution, Molecular ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; Influenza A virus ; genetics ; Influenza in Birds ; virology ; Taiwan

Animals ; Birds ; China ; Humans ; Influenza A Virus, H7N9 Subtype ; pathogenicity ; Influenza in Birds ; epidemiology ; virology ; Influenza, Human ; epidemiology ; virology

OBJECTIVETo elucidate the variation in characterizations and genetic evolution of the matrix protein 2 or ion channel protein(M2) genes of avian influenza subtype H5N1 viruses in the boundary region of Yunnan province from 2008 to 2012.

METHODSA total of swab samples were collected from foreign poultry such as the junction between Yunnan and Vietnam, Laos,myanmar and wild birds in boundary region of Yunnan province from 2008 to 2012 and screened by H5N1 subtype-specific multiplex RT-PCR. The M genes of H5N1 virus from the positive samples were amplified by RT-PCR and cloned into pMD18-T vectors for sequencing. The alignment and phylogenetic analysis of M2 genes were performed with sequences of the known reference strains.

RESULTSA total of 71 positive samples were found out of 1240 samples and the positive rate was 5.72%. A total of 14 different M2 sequences were obtained from 30 positive samples and were divided into 3 distinct clades or sub-clades(1.2.1, 1.2.2 and 2) by phylogenetic analysis, 5, 7 and 2, respectively. The M2 genes and Hemagglutinin(HA) genes of H5N1 viruses from the boundary region of Yunnan province had showed different relationship of genetic evolution. The substitution or mutation of key amino acids sites had been found among the domains of epitope, adamantane-resistance, and poultry or human original viral strains.

CONCLUSIONThe M2 genes of H5N1 subtype viruses in boundary region of Yunnan province from 2008 to 2012 showed genetic divergence and the virus of clade 1.2.2 had become dominant epidemic strain in this region.

Animals ; Birds ; virology ; Chickens ; virology ; China ; Evolution, Molecular ; Influenza A Virus, H5N1 Subtype ; classification ; genetics ; Influenza in Birds ; virology ; Phylogeny ; Poultry ; virology ; Viral Matrix Proteins ; genetics

Wild birds (mainly Anseriformes and Charadriiformes) are recognized as the natural reservoir of avian influenza viruses (AIVs). The long-term surveillance of AIVs in wild birds has been conducted in North America and Europe since 1970s. More and more surveillance data revealed that all the HA and NA subtypes of AIVs were identified in the wild ducks, shorebirds, and gulls, and the AIVs circulating in wild birds were implicated in the outbreaks of AIVs in poultry and humans. Therefore, the AIVs in wild birds pose huge threat to poultry industry and human health. To gain a better understanding of the ecology and epidemiology of AIVs in wild birds, we summarize the transmission of AIVs between wild birds, poultry, and humans, the main results of surveillance of AIVs in wild birds worldwide and methods for surveillance, and the types of samples and detection methods for AIVs in wild birds, which would be vital for the effective control of avian influenza and response to possible influenza pandemic.
Animals ; Animals, Wild ; virology ; Birds ; virology ; Humans ; Influenza A virus ; genetics ; isolation & purification ; physiology ; Influenza in Birds ; epidemiology ; transmission ; virology ; Influenza, Human ; epidemiology ; transmission ; virology ; Sentinel Surveillance ; veterinary

influenza virus can infect humans and cause disease. The clinical presentation of human infection is usually mild, but the infection caused by A(H5N1) avian influenza virus occurring initially in Hongkong in 1997 or the A(H7N9) virus isolated first at the beginning of this year in China is severe and characterized by high mortality. The mortality rate of adolescents and children caused by H5N1 avian influenza is lower than that of adults and the younger the child the lower the mortality rate. A few pediatric H7N9 avian influenza cases recovered soon after treatment. A child was determined to be a H7N9 avian influenza virus carrier. These findings suggested that the pediatric H7N9 avian influenza infection was mild. It is very important to start anti-virus treatment with oseltamivir as early as possible in cases of avian influenza infection is considered. Combined therapy, including respiratory and circulatory support and inhibiting immunological reaction, is emphasized in the treatment of severe cases.
Animals ; Birds ; virology ; China ; epidemiology ; Disease Outbreaks ; Humans ; Influenza A Virus, H5N1 Subtype ; Influenza in Birds ; virology ; Influenza, Human ; diagnosis ; drug therapy ; epidemiology ; virology ; Time Factors

The annual seasonal epidemic of influenza caused serious disease burden around the world, and serious social panic and economic losses. Due to the high variability and uncertainty of influenza virus, prevention and control of influenza faces many challenges. Surveillance is a key strategy to prevent and control influenza, and influenza is the first infectious disease to be monitored globally. More than 60 years, influenza surveillance programs in China has made great contributions to the prevention and control of influenza in China and the world. Especially in the past 10 years, the influenza surveillance network has developed rapidly, the scale has been expanded significantly, the monitoring content and scope have been continuously improved, and the monitoring quality has been rapidly improved. The China Influenza Surveillance Network is one of the early detection systems for emerging infectious diseases in China and the world. It helps to improve the capacity of public health system in prevention and control and early warning of emerging infectious diseases.
Animals ; Birds ; China ; Communicable Diseases, Emerging/virology* ; Disease Outbreaks ; Global Health ; Humans ; Influenza in Birds/virology* ; Influenza, Human/virology* ; Population Surveillance/methods* ; Public Health ; Public Policy

OBJECTIVETo analyze the genetic composition of a novel H2N3 virus isolate identified from a duck cage swab in a live poultry market (LPM) in 2009 in Guangdong province of China.

METHODSPCR-positive specimens were inoculated into embryonated chicken eggs and subtyped by conventional RT-PCR. All segments of the virus A/environment/Guangdong/2/2009 were sequenced, and phylogenetic trees were constructed and analyzed.

RESULTSThe genes of this virus belong to Eurasian-lineage avian viruses. The virus is a reassortant with the HA gene from an H2N2 virus and the NA gene from an H5N3 virus. The PB1, PB2, and NP genes were from an H4N6 virus, the PA was from an H3N8 virus, the M gene was from an H1N3 virus, and the NS gene was from an H10N6 virus.

CONCLUSIONA novel avian-origin reassortant H2N3 influenza virus was detected in a live poultry market. Its potential impacts and evolution should be closely monitored.

Animals ; China ; Ducks ; virology ; Genome, Viral ; Influenza A virus ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Phylogeny