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H5N1 highly pathogenic avian influenza virus isolated from conjunctiva of a whooper swan with neurological signs
Get PDFAn H5N1 highly pathogenic avian influenza virus was isolated from conjunctiva of a whooper swan with neurological signs, which was captured during the latest H5N1 HPAI outbreak in Japan. The conjunctival swab contained a larger amount of the virus in comparison with the tracheal swab. This is the first report on H5N1 virus isolation from the conjunctiva of a wild bird, and the result may suggest the conjunctival swab to be a critical sample for H5N1 HPAIV detection in waterfowl. Phylogenetic analysis of the HA gene indicated that the virus falls into H5N1 clade 2.3.2.1.National Institute of Allergy and Infectious Diseases (U.S.) (NIAID contract HHSN266200700009C)National Institute of Allergy and Infectious Diseases (U.S.) (NIAID contract HHSN266200700007C
Genetic characterization of an H5N1 avian influenza virus from a vaccinated duck flock in Vietnam
Get PDFThis study reports the genetic characterization of a highly pathogenic avian influenza virus subtype H5N1 isolated from a moribund domestic duck in central Vietnam during 2012. In the moribund duck’s flock, within 6 days after vaccination with a commercial H5N1 vaccine (Re-5) to 59-day-old birds, 120 out of 2,000 ducks died. Genetic analysis revealed a substantial number of mutations in the HA gene of the isolate in comparison with the vaccine strains, Re-1 and Re-5. Similar mutations were also found in selected Vietnamese H5N1 strains isolated since 2009. Mutations in the HA gene involved positions at antigenic sites associated with antibody binding and also neutralizing epitopes, with some of the mutations resulting in the modification of N-linked glycosylation of the HA. Those mutations may be related to the escape of virus from antibody binding and the infection of poultry, interpretations which may be confirmed through a reverse genetics approach. The virus also carried an amino acid substitution in the M2, which conferred a reduced susceptibility to amantadine, but no neuraminidase inhibitor resistance markers were found in the viral NA gene. Additional information including vaccination history in the farm and the surrounding area is needed to fully understand the background of this outbreak. Such understanding and expanded monitoring of the H5N1 influenza viruses circulating in Vietnam is an urgent need to provide updated information to improve effective vaccine strain selection and vaccination protocols, aiding disease control, and biosecurity to prevent H5N1 infection in both poultry and humans.Japan Society for the Promotion of Science. Grant-in-Aid for the Bilateral Joint ProjectsHeiwa Nakajima FoundationNational Institute of Allergy and Infectious Diseases (U.S.) (Contract HHSN2662007000010C
Pathogenicity of an H5N1 avian influenza virus isolated in Vietnam in 2012 and reliability of conjunctival samples for diagnosis of infection
Get PDFThe continued spread of highly pathogenic avian influenza virus (HPAIV) subtype H5N1 among poultry in Vietnam poses a potential threat to animals and public health. To evaluate the pathogenicity of a 2012 H5N1 HPAIV isolate and to assess the utility of conjunctival swabs for viral detection and isolation in surveillance, an experimental infection with HPAIV subtype H5N1 was carried out in domestic ducks. Ducks were infected with 10[superscript 7.2] TCID[subscript 50] of A/duck/Vietnam/QB1207/2012 (H5N1), which was isolated from a moribund domestic duck. In the infected ducks, clinical signs of disease, including neurological disorder, were observed. Ducks started to die at 3 days-post-infection (dpi), and the study mortality reached 67%. Viruses were recovered from oropharyngeal and conjunctival swabs until 7 dpi and from cloacal swabs until 4 dpi. In the ducks that died or were sacrificed on 3, 5, or 6 dpi, viruses were recovered from lung, brain, heart, pancreas and intestine, among which the highest virus titers were in the lung, brain or heart. Results of virus titration were confirmed by real-time RT-PCR. Genetic and phylogenetic analysis of the HA gene revealed that the isolate belongs to clade 2.3.2.1 similarly to the H5N1 viruses isolated in Vietnam in 2012. The present study demonstrated that this recent HPAI H5N1 virus of clade 2.3.2.1 could replicate efficiently in the systemic organs, including the brain, and cause severe disease with neurological symptoms in domestic ducks. Therefore, this HPAI H5N1 virus seems to retain the neurotrophic feature and has further developed properties of shedding virus from the oropharynx and conjunctiva in addition to the cloaca, potentially posing a higher risk of virus spread through cross-contact and/or environmental transmission. Continued surveillance and diagnostic programs using conjunctival swabs in the field would further verify the apparent reliability of conjunctival samples for the detection of AIV.Japan Society for the Promotion of Science (Grant-in-Aid for Bilateral Joint Projects)Heiwa Nakajima FoundationNational Institute of Allergy and Infectious Diseases (U.S.) (Contract HHSN2662007000010C
Characterization of a genetic and antigenic variant of avian paramyxovirus 6 isolated from a migratory wild bird, the red-necked stint (Calidris ruficollis)
Get PDFA hemagglutinating virus (8KS0813) was isolated from a red-necked stint. Hemagglutination inhibition and neutralization tests indicated that 8KS0813 was antigenically related to a prototype strain, APMV-6/duck/Hong Kong/18/199/77, but with an 8- and 16-fold difference, respectively, in their titers. The full genome sequence of 8KS0813 showed 98.6 % nucleotide sequence identity to that of APMV-6/duck/Italy/4524-2/07, which has been reported to belong to an APMV-6 subgroup, and showed less similarity to that of the prototype strain (70.6 % similarity). The growth of 8KS0813 and the prototype strain in four different cell cultures was greatly enhanced by adding trypsin. Interestingly, this virus induced syncytia only in Vero cells. 8KS0813 was identified as APMV-6/red-necked stint/Japan/8KS0813/08, but it is antigenically and genetically distinguishable from the prototype strain, suggesting that variant APMV-6 is circulating in migratory birds.Program of Founding Research Centers for Emerging and Reemerging Infectious DiseasesJapan. Ministry of Education, Culture, Sports, Science and Technology (Grant-in-Aid for Exploratory Research (19659115))National Institute of Allergy and Infectious Diseases (U.S.) (NIAID contracts HHSN266200700009C and HHSN266200700007C
Rabies Virus In Arctic Fox (Vulpes Lagopus): A Study Of Pantropic Distribution
Get PDFThesis (M.S.) University of Alaska Fairbanks, 2010Rabies is endemic in Arctic foxes, in Alaska and other Arctic regions and cold temperatures may preserve the virus in Arctic climates in infected animal carcasses. These frozen carcasses may provide a source of infection throughout winters and thereby propagate the rabies virus within animal populations in the Arctic. It was hypothesized that rabies virus antigen is present in the soft tissues of naturally infected Arctic foxes, Vulpes lagopus. Using a direct rapid immunohistochemistry test (DRIT) and a fluorescent antibody test (FAT), thirteen organ tissues from twelve naturally infected and three experimentally infected Arctic foxes were tested. All tissues, except testes, tested positive for rabies virus antigen by the DRIT, the FAT, or both in at least one fox. Although the DRIT detected rabies virus antigen in non-neuronal tissues, it did not detect antigen in as many non-neuronal tissues as the FAT. Spleen and stomach tissues had the highest rate of rabies virus detection by the FAT and using a combination of non-neuronal tissues would be the best substitute for brain if brain were unavailable
Reticulate evolution is favored in influenza niche switching
No full textReticulate evolution is thought to accelerate the process of evolution beyond simple genetic drift and selection, helping to rapidly generate novel hybrids with combinations of adaptive traits. However, the long-standing dogma that reticulate evolutionary processes are likewise advantageous for switching ecological niches, as in microbial pathogen host switch events, has not been explicitly tested. We use data from the influenza genome sequencing project and a phylogenetic heuristic approach to show that reassortment, a reticulate evolutionary mechanism, predominates over mutational drift in transmission between different host species. Moreover, as host evolutionary distance increases, reassortment is increasingly favored. We conclude that the greater the quantitative difference between ecological niches, the greater the importance of reticulate evolutionary processes in overcoming niche barriers.National Institute of Allergy and Infectious Diseases. Centers of Excellence for Influenza Research and Surveillance Program (Contract HHSN272014000008C
Connecting the study of wild influenza with the potential for pandemic disease
Get PDFContinuing outbreaks of pathogenic (H5N1) and pandemic (SOIVH1N1) influenza have underscored the need to understand the origin, characteristics, and evolution of novel influenza A virus (IAV) variants that pose a threat to human health. In the last 4–5 years, focus has been placed on the organization of large-scale surveillance programs to examine the phylogenetics of avian influenza virus (AIV) and host–virus relationships in domestic and wild animals. Here we review the current gaps in wild animal and environmental surveillance and the current understanding of genetic signatures in potentially pandemic strains.National Institute of Allergy and Infectious Diseases (U.S.) (Contract HHSN266200700010C)Massachusetts Institute of Technolog
Genetic characterization of a rare H12N3 avian influenza virus isolated from a green-winged teal in Japan
Get PDFThis study reports on the genetic characterization of an avian influenza virus, subtype H12N3, isolated from an Eurasian green-winged teal (Anas crecca) in Japan in 2009. The entire genome sequence of the isolate was analyzed, and phylogenetic analyses were conducted to characterize the evolutionary history of the isolate. Phylogenetic analysis of the hemagglutinin and neuraminidase genes indicated that the virus belonged to the Eurasian-like avian lineage. Molecular dating indicated that this H12 virus is likely a multiple reassortant influenza A virus. This is the first reported characterization of influenza A virus subtype H12N3 isolated in Japan and these data contribute to the accumulation of knowledge on the genetic diversity and generation of novel influenza A viruses.National Institute of Allergy and Infectious Diseases (U.S.) (Contracts HHSN266200700009C and HHSN266200700007)Japan Society for the Promotion of Science. Grant-in-Aid for the Bilateral Joint ProjectsHeiwa Nakajima Foundatio
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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