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

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

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

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

Animals ; Birds ; Humans ; Influenza A virus ; classification ; pathogenicity ; Influenza in Birds ; complications ; prevention & control ; virology ; Influenza, Human ; etiology ; prevention & control

Since the first human case of influenza A virus subtype H7N9 was reported in Shanghai, China in March 2013, there have been two H7N9-infected children and one healthy H7N9 carrier. With a brief introduction to the basic information of the three children, this paper discusses the variation of Avian influenza virus by referring to the literature, suggests that human-to-human transmission is not confirmed in the small outbreak, and reviews the measures for preventing and treating H7N9 infection in humans. In addition, this paper talks about the use of tamiflu in early stage of infection and the use of peramivir when the patient's condition is severe.
Animals ; Birds ; Child ; Child, Preschool ; Humans ; Influenza A virus ; genetics ; Influenza in Birds ; virology ; Influenza, Human ; drug therapy ; prevention & control ; transmission

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

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

Animals ; China ; Influenza A virus ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Nucleic Acids ; genetics ; Poultry ; virology

Animals ; Birds ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; immunology ; Humans ; Influenza A virus ; genetics ; immunology ; pathogenicity ; Influenza in Birds ; immunology ; pathology ; virology ; Influenza, Human ; immunology ; pathology ; virology ; Virulence ; genetics