Tseren-Ochir Erdene-Ochir

Genetic analyses of H5N1 avian influenza virus in Mongolia, 2009 and its relationship with those of eastern Asia

In May and August 2009, 14 highly pathogenic H5N1 isolates were obtained from migratory birds in central Mongolia. To trace the genetic lineage of the isolates, nucleotide sequences of all eight genes were determined and phylogenetically analyzed. Hemagglutinin and nucleoprotein genes were clustered in clade 2.3.2. The polymerase acidic gene was related to the isolates of South Korea and Japan obtained in 2003 and 2004 outbreaks, and a migratory duck isolate from Jiangxi, China. The neuraminidase and other internal genes were closely related to those of clade 2.3.4 viruses. The results indicate evolving genetic diversity of the hemagglutinin gene and acquisition of different polymerase acidic gene in the 2009 Mongolian isolates, likely via bird migration. Prevention of potentially wider outbreak in domestic poultry and accurate monitoring of H5N1 genetic mutation will require continuous monitoring for H5N1 in both domestic and wild birds, and will necessitate international cooperation with neighboring countries sharing migratory flyways.

Highly Pathogenic Avian Influenza A(H5N8) Viruses Reintroduced into South Korea by Migratory Waterfowl, 2014-2015.

Highly pathogenic avian influenza A(H5N8) viruses were isolated from migratory waterfowl in South Korea during fall 2014–winter 2015, a recurrence after initial introduction in winter 2014. These reappeared viruses were phylogenetically distinct from isolates circulating in poultry farms in South Korea.

Sublingual administration of Lactobacillus rhamnosus affects respiratory immune responses and facilitates protection against influenza virus infection in mice.

The extensive morbidity and mortality caused by influenza A viruses worldwide prompts the need for a deeper understanding of the host immune response and novel therapeutic and/or prophylactic interventions. In this study, we assessed the sublingual route as an effective means of delivering probiotics against influenza virus in mice. In addition, IgA levels, NK cell activity, T cell activation, and cytokine profiles in the lungs were examined to understand the mechanism underlying this protective effect. Sublingual administration of Lactobacillus rhamnosus provided enhanced protection against influenza virus infection by enhancing mucosal secretory IgA production, and T and NK cell activity. Moreover, interleukin (IL)-12 levels in the lungs increased significantly. Conversely, IL-6 and tumor necrosis factor alpha levels in the lungs decreased significantly. On the basis of these promising findings, we propose that the sublingual mucosal route is an attractive alternative to mucosal routes for administering probiotics against influenza virus.

Reassortant Clade 2.3.4.4 Avian Influenza A(H5N6) Virus in a Wild Mandarin Duck, South Korea, 2016

A reassortant clade 2.3.4.4 avian influenza A(H5N6) virus was isolated from a fecal sample of a Mandarin duck (Aix galericulata) in South Korea during October 2016. This virus was genetically similar to H5N6 subtype virus isolates from China, Vietnam, Laos, and Hong Kong, including human isolates.

Complete genome sequence of a natural reassortant H9N2 avian influenza virus found in bean goose (Anser fabalis): direct evidence for virus exchange between Korea and China via wild birds.

In 2011, we isolated a natural recombinant H9N2 avian influenza virus from fecal droppings of bean goose (Anser fabalis) in Korea. Phylogenetic analyses showed that the A/bean goose/Korea/220/2011(H9N2) isolate is a reassortant of Eurasian and North American lineages of avian influenza virus. In addition, the complete genome sequence, including all 8 gene segments, was associated with Chinese H9N2 viruses isolated from wild birds in the Hunan East Dongting Lake National Nature Reserve. These data provide direct evidence for the exchange of avian influenza viruses between Korea and China via wild birds.

Pathogenicity of the Korean H5N8 highly pathogenic avian influenza virus in commercial domestic poultry species

ABSTRACT In 2014, the highly pathogenic avian influenza (HPAI) virus H5N8 triggered outbreaks in wild birds and poultry farms in South Korea. In the present study, we investigated the pathogenicity of the H5N8 HPAI virus, belonging to the clade 2.3.4.4, in different species of poultry. For this, we examined clinical signs and viral shedding levels following intranasal inoculation of the virus in 3-week-old commercial layer chickens and quails, 10-week-old Korean native chickens, and 8-week-old Muscovy ducks. Intranasal inoculation with 106.0 viruses at 50% egg-infective dose resulted in 100% mortality in the layer chickens (8/8) and quails (4/4), but 60% and 0% deaths in the Korean native chickens (3/5) and Muscovy ducks (0/4), respectively. In addition, transmission of the inoculated virus to contact-exposed birds was evident in all the species used in this study. Based on our results, we conclude that the H5N8 HPAI virus has lower pathogenicity and transmissibility in poultry species compared with previously reported H5N1 HPAI viruses.

Innate immune response gene expression profiles in specific pathogen-free chickens infected with avian influenza virus subtype H9N2

In poultry species, H9N2 low pathogenic avian influenza (LPAI) virus infections frequently lead to low to moderate mortality rates and morbidity characterized by depression, respiratory disease symptoms, and decreases in egg production. Since current knowledge on the avian immune response to H9N2 infection is limited, we used microarray analysis to examine global changes in immune-related gene expression induced by H9N2 LPAI infection in specific pathogen-free chickens. The expression profiles of approximately 800 genes, including those that influence cell differentiation, transcription, transport, immune responses, and signal transduction, were altered by H9N2 infection. A complete chicken genome microarray analysis identified a strong innate antiviral host response after infection in spleens. In particular, a significant number of immune response genes, including interferon genes and related immune response genes, were upregulated following H9N2 infection. The increased transcription of 2′-5′-oligoadenylate synthetase and myxovirus resistance genes was confirmed by real-time RT-PCR. These results suggest that the host response generated against H9N2 infection may contribute to protective effects by manipulating innate immune responses.

Pathogenicity in domestic ducks and mice of highly pathogenic H5N1 clade 2.3.2.1 influenza viruses recently circulating in Eastern Asia

Influenza virus A (H5N1) clade 2.3.2.1 has recently caused widespread outbreaks of disease in domestic poultry and wild birds in Eastern Asia. In the current study, the antigenicity and pathogenicity of three clade 2.3.2.1 viruses (Ck/Kr/Gimje/08, Ws/Mongolia/1/09, and Ws/Mongolia/7/10) were investigated in domestic ducks and mice. The H5N1 influenza viruses in this study were antigenically similar to each other (r-values of 0.35-1.4). The three viruses replicated systemically in all tissues tested in domestic ducks, indicating high pathogenicity. However, the viruses produced different clinical signs and mortality rates: Ck/Kr/Gimje/08 and Ws/Mongolia/1/09 resulted in 100% mortality with severe neurological signs, whereas Ws/Mongolia/7/10 resulted in 50% mortality with relatively mild neurological signs. In mice, infection with Ck/Kr/Gimje/08 and Ws/Mongolia/7/10 resulted in weight loss that peaked at 4 days post-infection (22.3% and 20.8%, respectively), same MLD50 (2.2 Log10 EID50) and systemic replication. The three viruses had K deletion at the -2 position of the HA1-connecting peptide (PQRERRRK-R), which is associated with increased virulence in domestic ducks and harbored NA stalk deletion, NS1 deletion and mutation of P42S in NS1, and full length (90aa) in PB1-F2, which confer increased virulence in mice. Our study shows that clade 2.3.2.1 viruses from Korea and Mongolia are antigenically similar and highly pathogenic in both domestic ducks and mice. Moreover, we provide molecular determinants of the clade 2.3.2.1 viruses associated with the pathogenicity in domestic ducks and mice, respectively.

Complete Genome Sequence of a Natural Recombinant H9N2 Influenza Virus from Wild Birds in Republic of Korea.

ABSTRACT We report the complete genome sequence of a natural recombinant H9N2 avian influenza virus (AIV) that was isolated from a wild bird in the Republic of Korea in 2005. The genomic sequence and phylogenetic analyses showed that this virus contains six genes of North American lineage AIV and two genes of Eurasian lineage AIV. These data are beneficial for investigating the ecology and epidemiology of AIVs.

Complete Genome Sequence of a Natural Recombinant H9N2 Influenza Virus Isolated from a White-Fronted Goose (Anser albifrons) in South Korea.

ABSTRACT In 2007, we isolated a natural recombinant H9N2 avian influenza virus (AIV) from the fecal droppings of a white-fronted goose (Anser albifrons) in South Korea. Phylogenetic analyses of the complete genome sequence showed that polymerase acidic (PA) and neuraminidase (NA) genes belonged to the Eurasian lineage AIV, but polymerase basic 2 (PB2), PB1, hemagglutinin (HA), nucleoprotein (NP), matrix (M), and nonstructural (NS) genes belonged to the North-American lineage AIV. These data are beneficial for understanding the ecology and epidemiology of AIVs.