• Korean Journal of Poultry Science
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• v.46 no.3
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• pp.173-183
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• 2019

Based on their virulence, the avian influenza viruses (AIVs) are classified into two pathotypes: low pathogenic avian influenza (LPAI) virus and highly pathogenic avian influenza (HPAI) virus. Among the 16 HA subtypes of AIV, only the H5 and H7 subtypes are classified as HPAI. Some AIVs, including H5 and H7 viruses, can infect humans directly. Six H7 subtype isolates from wild birds of the H7N7 (n=4) and H7N1 (n=2) subtypes were characterized in this study. Phylogenetic analysis showed that eight viral genes (HA, NA, PB2, PB1, PA, NP, M, and NS) of the H7 isolates clustered in the Eurasian lineage, the genetic diversity of which is indicated by its division into several sublineages. The Korean H7 isolates had two motifs, PEIPKGR and PELPKGR, at the HA cleavage site, which have been associated with LPAI viruses. Six H7 isolates encoded glutamine (Q) and glycine (G) at positions 226 (H3 numbering) and 228 of HA, suggesting avian-type receptor-binding specificity. None of the Korean H7 isolates had the amino acid substitutions E627K in PB2 and I368V in PB1, which are critical for efficient replication in human cells. The Korean H7 isolates showed no deletions in the NA stalk region and in NS. These results suggest that the Korean H7 isolates from wild birds are different from the H7N9 influenza viruses isolated in China in 2013, which are capable of infecting humans.

• Journal of Life Science
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• v.33 no.8
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• pp.605-611
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• 2023

Recently, sporadic cases of human infection by genetic reassortants of H7Nx influenza A viruses have been reported; such viruses have also been continuously isolated from avian species. In this study, A/wild bird/South Korea/sw-anu/2023, a novel reassortant of the H7N1 avian influenza virus, was analyzed using full-genome sequencing and molecular characterization. Phylogenetic analysis showed that A/wild bird/South Korea/sw-anu/2023 belonged to the Eurasian lineage of H7Nx viruses. The polymerase basic (PB)2, PB1, polymerase acidic (PA), and nucleoprotein (NP) genes of these viruses were found to be closely related to those of avian influenza viruses isolated from wild birds, while the hemagglutinin (HA), neuraminidase (NA), matrix (M), and nonstructural (NS) genes were similar to those of avian influenza viruses isolated from domestic ducks. In addition, A/wild bird/South Korea/sw-anu/2023 also had a high binding preference for avian-specific glycans in the solid-phase direct binding assay. These results suggest the presence of a new generation of H7N1 avian influenza viruses in wild birds and highlight the reassortment of avian influenza viruses found along the East Asian-Australasian flyway. Overall, H7Nx viruses circulate worldwide, and mutated H7N1 avian viruses may infect humans, which emphasizes the requirement for continued surveillance of the H7N1 avian influenza virus in wild birds and poultry.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.523-528
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• 2016

The migratory locust Locusta migratoria, one of the world's most notorious insect pests, has polyphenic (gregarious or solitarious) characteristics. Although this species is known to have several morphological variants, it is genetically divided into two different lineages using mitochondrial genome analysis: Southern (Africa, Southern Europe, Southern Asia, and Australia) and Northern (East Asia and the Eurasian continent). In 2014, a large number of orange black-colored gregarious L. migratoria nymphs suddenly appeared at Haenamgun, Jeollanamdo in the south of Korea. This is the first report of gregarious phase locusts occurring in Korea. In this study, mitochondrial COI sequences of one nymph and 11 adults of L. migratoria were analyzed to examine the genetic lineage of the gregarious nymphs of L. migratoria. Our results showed that all 12 individuals belong to the Northern linage and have low intraspecific genetic divergences (0.0% - 0.9%).

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.4
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• pp.457-466
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• 2015

Taoyuan pig is a native Taiwan breed. According to the historical record, the breed was first introduced to Taiwan from Guangdong province, Southern China, around 1877. The breed played an important role in Taiwan's early swine industry. It was classified as an indigenous breed in 1986. After 1987, a conserved population of Taoyuan pig was collected and reared in isolation. In this study, mitochondrial DNA sequences and 18 microsatellite markers were used to investigate maternal lineage and genetic diversity within the Taoyuan pig population. Population differentiation among Taoyuan, Asian type, and European type pig breeds was also evaluated using differentiation indices. Only one D-loop haplotype of the Taoyuan pig was found. It clustered with Lower Changjiang River Basin and Central China Type pig breeds. Based on the polymorphism of microsatellite markers, a positive fixation index value ($F_{IS}$) indicates that the conserved Taoyuan population suffers from inbreeding. In addition, high $F_{ST}$ values (>0.2105) were obtained, revealing high differentiation among these breeds. Non-metric multi-dimensional scaling showed a clear geometric structure among 7 breeds. Together these results indicate that maternally Taoyuan pig originated in the Lower Changjiang River Basin and Central China; however, since being introduced to Taiwan differentiation has occurred. In addition, Taoyuan pig has lost genetic diversity in both its mitochondrial and nuclear genomes.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.243-252
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• 2013

Among the 16 hemagglutinin (HA) subtypes of avian influenza virus (AIV), only the H5 and H7 subtypes have caused highly pathogenic avian influenza (HPAI) in poultry. However, most H5 or H7 subtype viruses are categorized as low pathogenic avian influenza (LPAI). Some AIVs, including the H5 and H7 HPAI viruses, have shown the ability to infect humans directly. In this study, we describe the biological and molecular characterization of an H5N3 AIV (SBD/KR/KNU SYG06/06) isolated from spot-billed duck (Anas poecilorhyncha) in Korea. A phylogenetic analysis of the eight viral genes showed that the SBD/KR/KNU SYG06/06 isolate belongs to the Eurasian lineage and that the SBD/KR/KNU SYG06/06 isolate was clearly different from HPAI H5N1 strains, including human isolates and the Italian HPAI H5N2 strains. Additionally, no relationship was found between SBD/KR/KNU SYG06/06 and the Korean HPAI H5N1 isolates. The SBD/KR/ KNU SYG06/06 isolate had avian specific receptor binding site residues in the HA protein and the four C-terminal amino acids in the NS1 protein. The HA protein of the SBD/KR/KNU SYG06/06 isolate exhibited the typical LPAI motif at the cleavage site and this virus produced no cytopathic effects in MDCK cells without trypsin. Given these results, we suggest that the H5N3 AIV isolated from the spot-billed duck should be considered an LPAI virus and should have no pathogenic effect in humans.

• Journal of Life Science
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• v.28 no.8
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• pp.962-968
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• 2018

Type A influenza virus is circulating in wild birds and can infect wide ranges of hosts such as humans, pigs, domestic birds, and other mammals. Many subtypes of avian influenza viruses are circulating in aquatic birds. Most avian influenza viruses found in aquatic birds are low pathogenic avian influenza viruses. Highly pathogenic avian influenza viruses have been found in waterfowls since 2005. It is known that H5 and H7 subtypes of avian influenza viruses can be mutated into highly pathogenic avian influenza viruses in domestic poultry. In this study, we isolated novel reassortant H7N7 avian influenza virus from the fecal materials of migratory birds in the Western part of South Korea in 2016, and analyzed the sequences of all its eight genes. The genetic analysis of our isolate, A/waterfowl/Korea/S017/2016 (H7N7) indicates that it was reassortant avian influenza virus containing genes of both avian influenza viruses of wild birds and domestic ducks. Phylogenetic analysis showed that our isolate belongs to Eurasian lineage of avian influenza virus. Since avian influenza viruses continue to evolve, and H7-subtype avian influenza virus can mutate into the highly pathogenic avian influenza viruses, which cause the great threat to humans and animals, we closely survey the infections in both wild birds, and domestic poultry, and mammals.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.459-464
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• 2016

An outbreak of the migratory locust, Locusta migratoria, in the environment-friendly reclaimed plantations of forage crops in Sanyimyeon, Haenam-gun, Jellanam-do, Korea in August 2014 caused severe damages to various crops. Owing to its first occurrence in the Korean history, the causes underlying the outbreak and phase-transition of the migratory locust were not known. It is critical to establish the genetic relationship of the migratory locust in Sanyimyeon, Haenam-gun with the other previously reported strains in the world in order to understand the mechanisms responsible for its outbreak. The gene sequences of the 16S ribosomal RNA (rRNA) and displacement-loop (D-loop) of the mitochondria of various regional species of the migratory locust were used to perform the phylogenetic analysis. Our results suggested that the migratory locusts in Sanyimyeon, Haenam-gun are closely related with the Eurasian strains of the northern lineage. In future, these two mitochondrial genes can be used for elucidating the genetic population structures in migratory locusts in various regions. In addition, the sequence information of these genes can be used to enhance our understanding of the genetic basis of the outbreak of migratory locusts.