• Korean Journal of Veterinary Research
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• v.53 no.4
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• pp.193-197
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• 2013

Avian influenza viruses (AIV) have been isolated from a wide range of domestic and wild birds. Wild birds, predominantly ducks, geese and gulls form the reservoir of AIV in nature. The viruses in wild bird populations are a potential source of widespread infections in poultry. Active surveillance for AIV infection provides information regarding AIV distribution, and global AIV surveillance can play a key role in the early recognition of highly pathogenic avian influenza (HPAI). Since 2003 in Korea, there have been four H5N1 HPAI outbreaks caused by clade 2.5, 2.2 and 2.3.2. Therefore, improvement of AIV surveillance strategy is required to detect HPAI viruses effectively. This article deals with the major events establishing the role of wild birds in the natural history of influenza in Korea. We highlighted the need for continuous surveillance in wild birds and characterization of these viruses to understand AIV epidemiology and host ecology in Korea.

• 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 Veterinary Service
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• v.45 no.4
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• pp.285-292
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• 2022

Avian influenza viruses (AIVs) cause contagious diseases and have the potential to infect not only birds but also mammals. Wild birds are the natural reservoir of AIVs and spread them worldwide while migrating. Here we collected active AIV surveillance data from wild bird habitats during the 2019 to 2022 winter seasons (from September to March of the following year) in South Korea. We isolated 97 AIVs from a total of 7,590 fecal samples and found the yearly prevalence of AIVs was 0.83, 1.48, and 1.27, respectively. The prevalence of AIVs were generally higher from September to November. These findings demonstrate that a high number of wild birds that carry AIVs migrate into South Korea during the autumn season. The highest virus numbers were isolated from the species Anas platyrhynchos (72%; n=70), followed by Anas poecilorhyncha (15.4%; n=15), suggesting that each is an important host for these pathogens. Twenty-five hemagglutinin-neuraminidase subtypes were isolated, and all AIVs except the H5N8 subtype were found to be low-pathogenic avian influenza viruses (LPAIVs). Active surveillance of AIVs in wild birds could benefit public health because it could help to estimate their risk for introduction into animals and humans. Moreover, considering that 132 cases of human AIV infections have been reported worldwide within the last 5 years, active surveillance of AIVs is necessary to avoid outbreaks.

• 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.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1130-1135
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• 2009

Avian Influenza is an infectious desease of birds. The infection can cause a wide spectrum of symptoms in birds, ranging from mild illness to a rapidly fatal diseases which might bring a tremendous economic loss to poultry farms[1]. It can also give fatal diseases to human. Therefore it is important to surveil wildbirds that are primary transportation of avian influenza. This report showed a relationship between avian influenza and a habitat of wildbirds using system dynamics, and concluded with suggestion for surveilance.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.239-252
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• 2012

The circulation and infection of avian influenza virus (AIV) in zoos and backyard flocks has not been systematically investigated. In the present study, we surveyed the birds including those in live bird markets (LBMs) and evaluated co-circulation of AIVs among them. Overall, 26 H9N2 AIVs and one H6N2 AIV were isolated from backyard flocks and LBMs, but no AIVs were isolated from zoo birds. Genetic analysis of the HA and NA genes indicated that most of the H9N2 AIVs showed higher similarities to AIVs circulating in domestic poultry than to those in wild birds, while the H6N2 AIV isolate from an LBM did to AIVs circulating in migratory wild birds. In serological tests, 15% (391/2619) of the collected sera tested positive for AIVs by competitive-ELISA. Among them, 34% (131/391) of the sera tested positive for AIV H9 antigen by HI test, but only one zoo sample was H9 positive. Although AIVs were not isolated from zoo birds, the serological results indicated that infection of AIVs might occur in zoos. It was also confirmed that H9N2 AIVs continue to circulate and evolve between backyard flocks and LBMs. Therefore, continuous surveillance and monitoring of these flocks should be conducted to control further epidemics.

• Korean Journal of Poultry Science
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• v.31 no.2
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• pp.109-118
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• 2004

Avian influenza(AI) is an epizootic disease of variable severity caused by type A influenza viruses of the orthomyxovirus group. Chickens were the most frequently affected avian species with AI viruses. There were many outbreaks of fowl plague, now known as highly pathogenic AI(HP AI), throughout the world since Perroncito described the fowl plague in 1978 in Italy. In recent years HPAI viruses of different serotypes such as H5, H7 and H9 has been isolated from humans on several occasions either related with outbreak of HPAI in birds or not. In 1997, one of the most noteworthy events in AI history was the human mortality with H5N1 HPAI virus infection in Hong Kong. Six persons of total 18 persons with clinical signs of influenza were died. Recently the human cases with mortality related with HP AI outbreaks in poultry industry has been increased such as outbreaks of HP AI throughout Asia countries including Korea, Japan, China, Vietnam, Thailand and others in 2003. Although these outbreaks revealed the capable of spreading from birds to human, the capability for transmission between people was not clear. Therefore, this report will review the possibility of HP AI infection in human associated with HPAI outbreak in poultry industry.

• Journal of Multimedia Information System
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• v.6 no.4
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• pp.293-302
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• 2019

In the past, there was a theory that influenza wasn't transmitted directly from birds but was infected to humans via swains. Recently, molecular level research has progressed, and it was confirmed that the avian influenza virus can directly infected to human lung and intestinal epithelial cells. Three pandemicsin the past 100 years were also infected to humans directly from birds. In view of such scientific background, we are developing a method for screening sick birds by monitoring the physiological characteristics of birds in a contactless manner with sensors. Here, the movement of respiratory muscles and abdominal muscles under autonomic innervation was monitored using a magnet and Hall sensor sewn on the thoracic wall, and other multimedia devices. This paper presents and discusses the results of experiments involving continuous periodic noise discovered during flight experiments with a data logger mounted on a Japanese pheasant from 2012 to 2015. A brief summary is given as the below: 1. Magnet and Hall sensor sewn to the left and right chest walls, bipolar electrocardiograms between the thoracic walls, posterior thoracic air sac pressure, angular velocity sensors sewn on the back and hips, and optical reflection of LEDs (blue and green) from the skin of the hips allow observation of periodic vibrations(fasciculations) in the waves. No such analysis has been reported before. 2. These fasciculations are presumed to be derived from muscle to maintain and control air sac pressure. 3. Since each muscle fiber is spatially Gaussian distributed from the sympathetic nerve, the envelope is assumed to plot a Gaussian curve. 4. Since avian trunk muscles contract periodically at all time, we assume that the sympathetic nerve dominates in their control. 5. The technique of sewing a magnet to the thoracic wall and measuring the strength of the magnetic field with a Hall sensor can be applied to screen for early stage of avian influenza, with a sensor attached to the chicken enclosure.

• Journal of Veterinary Science
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• v.19 no.6
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• pp.850-854
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• 2018

Novel H5N6 highly pathogenic avian influenza viruses (HPAIVs) were isolated from duck farms and migratory bird habitats in South Korea in November to December 2017. Genetic analysis demonstrated that at least two genotypes of H5N6 were generated through reassortment between clade 2.3.4.4 H5N8 HPAIVs and Eurasian low pathogenic avian influenza virus in migratory birds in late 2017, suggesting frequent reassortment of clade 2.3.4.4 H5 HPAIVs and highlighting the need for systematic surveillance in Eurasian breeding grounds.

• Journal of Veterinary Science
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• v.23 no.3
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• pp.36.1-36.14
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• 2022

Background: Since 2003, the H5 highly pathogenic avian influenza (HPAI) subtype has caused massive economic losses in the poultry industry in South Korea. The role of inland water bodies in avian influenza (AI) outbreaks has not been investigated. Identifying water bodies that facilitate risk pathways leading to the incursion of the HPAI virus (HPAIV) into poultry farms is essential for implementing specific precautionary measures to prevent viral transmission. Objectives: This matched case-control study (1:4) examined whether inland waters were associated with a higher risk of AI outbreaks in the neighboring poultry farms. Methods: Rivers, irrigation canals, lakes, and ponds were considered inland water bodies. The cases and controls were chosen based on the matching criteria. The nearest possible farms located within a radius of 3 km of the case farms were chosen as the control farms. The poultry farms were selected randomly, and two HPAI epidemics (H5N8 [2014-2016] and H5N6 [2016-2017]) were studied. Conditional logistic regression analysis was applied. Results: Statistical analysis revealed that inland waters near poultry farms were significant risk factors for AI outbreaks. The study speculated that freely wandering wild waterfowl and small animals contaminate areas surrounding poultry farms. Conclusions: Pet birds and animals raised alongside poultry birds on farm premises may wander easily to nearby waters, potentially increasing the risk of AI infection in poultry farms. Mechanical transmission of the AI virus occurs when poultry farm workers or visitors come into contact with infected water bodies or their surroundings. To prevent AI outbreaks in the future, poultry farms should adopt strict precautions to avoid contact with nearby water bodies and their surroundings.