• 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.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.62-69
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• 2018

This study investigate the patent trend of natural feed additives for avian influenza prevention and immunity enhancement. The search scope is Korean and Chinese patents published before December 31, 2017. As a result, I found 53 Korean patents and 105 Chinese patents. Korea and China has increased the number of patent applications since late 2000. In particular, China filed the most patent applications in 2016. Both Korea and China, the oriental medicine materials were mainly used in patent claims. Korea has many patent applications that are submitted by universities, research institutes and bio companies, but China has a high proportion of individual patent applicants.

• Korean Journal of Veterinary Service
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• v.27 no.1
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• pp.81-87
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• 2004

This study was conducted to investigate the similarity between hemagglutination inhibition (HI) test and enzyme-linked immunosorbent assay(ELISA), the HI titer and mean ratio S/P ratio) of avian influenza virus. To perform this study, the 1,457 sera of layers 21 farms in May, July and September, respectively. As a result of HI test, positive rates were 480 to 422 (92.1%) in May, 494 to 394(79.8%) in July and 483 to 402(83.2%) in September, and the mean antibody titer were 4.6, 4.3, 4.0 to 0.3 decreased, respectively. The positive rates by ELISA, 480 to 475(99.0%) in May, 494 to 485(98.2%) in July, 483 to 472(97.7%) in September, and the mean S/P ratio were 2.319, 2.557 and 2.380, respectively. The result of HI test and ELISA positive 480 to 422(92.1%), 475(99.0%), 494 to 394(79.8%), 485(98.2%) and 483 to 402(83.2%), 472(97.7%). Therefore, ELISA was shown more sensitive compare the HI titers.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.465-470
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• 2009

The chicken Mx gene has been regarded as a candidate gene for resistance to avian influenza virus (AIV). In this study, three groups of chickens with homozygotes (AA, GG) and heterozygotes (AG) of the resistant (A) and susceptible alleles (G) to AIV of the Mx gene were constructed from a line of dwarf egg-type chickens. These chickens were not examined for their resistant activities to AIV because the differential resistance had only been detected in vitro. The birds of the three groups were vaccinated with inactivated H5N2 AIV vaccine and the level of hemagglutination inhibition (HI) antibody to AIV was detected. The association between disease resistant activity to AIV and antibody response to AIV vaccination in the three groups was analyzed. The chickens with homozygous resistant allele A showed the lowest antibody levels, whereas the heterozygous chickens (AG) presented the highest antibody level after the boosting vaccination, which indicates that the efficiency of artificial selection on the resistant allele of Mx gene will be compromised since the homozygotes of the allele presented the weakest antibody response to the corresponding vaccine.

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.392-397
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• 2009

We designed a wavelength interrogation-based surface plasmon resonance (SPR) biosensor to detect avian influenza DNA (AI-DNA). Hybridization reactions between target AI-DNA probes and capture probes immobilized on a gold surface were monitored quantitatively by measuring the resonance wavelength in the visible waveband. The experimental results were consistent with numerical calculations. Although the SPR detection technique does not require the DNA to be labeled, we also evaluated fluorescently-labeled targets to verify the hybridization behavior of the AI-DNA. Changes in resonance were found to be linearly proportional to the amount of bound analyte. A wavelength interrogation-type SPR biosensor can be used for rapid measurement and high-throughput detection of highly pathogenic AI viruses.

• Korean Journal of Veterinary Research
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• v.59 no.2
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• pp.101-104
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• 2019

This study examined the disinfection conditions (exposure time, 0-30 min; exposure temperature, $4^{\circ}C-65^{\circ}C$) of hypochlorous acid water (HOCl) in automobile disinfection equipment. The study tested poliovirus type 1 (PV1), low pathogenic avian influenza virus (AIV, H9N2), and foot and mouth disease virus (FMDV, O type). As a result, the PV1 and FMD viruses were inactivated easily (virus titer 4 log value) by HOCl (> 100 ppm) but the AIV required higher exposure temperatures (> $55^{\circ}C$). In conclusion, the exposure temperature and time are important factors in deactivating AIV and FMDV.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.207-218
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• 2023

Duck farming restriction refers to a program in which duck farms suspend their operations for a certain period at times when the risk of avian influenza (AI) is high and receive compensation from the Korean government. This study analyzed the effect of this duck farming restriction on the incidence of AI using data on regional AI incidence rates, the program participation rate, and characteristics of poultry farming in 2016 (before the implementation of the restriction), as well as data from 2020 and 2021 (when new AI outbreaks occurred). In this study, the treatment group was divided into five subgroups according to the policy participation rate and a difference-in-difference (DID) estimation was conducted using certain covariates, in this case the average number of ducks raised, the land area, the number of high-susceptibility farms, the number of low-susceptibility farms, the average number of farms within a 3 km radius, the average distance to the nearest farm, and a year dummy. The results showed that when more than 30% of all duck farms in a region participated in the farming restriction, it had a statistically significant effect on the incidence of AI. Specifically, when more than 30, 40, 50, and 60% of all duck farms participated in the farming restriction, the AI incidence rate decreased by 0.7184, 1.0025, 1.5844, and 1.5843%p, respectively.

• Korean Journal of Poultry Science
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• v.41 no.3
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• pp.173-179
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• 2014

While use of mass rearing systems improved poultry production, chances of exposing to contagious diseases have been increased, making flocks more vulnerable to diseases. Diseases of interest which affects egg production adversely include Low pathogenic avian influenza (LPAI), Infectious bronchitis (IB), Avian meta-pneumoviral infection (aMPV) and Egg drop syndrome'76 (EDS'76). This report collected and analyzed 5,385 serum samples, which were collected from 1,330 different chicken flock, provided by Chungbuk National University, Avian Disease Laboratory at 2009. Serums were analyzed based on rearing stages; 0~1.3weeks (wks) (maternal antibody period), >1.3~3 wks (starting period), >3~10 wks (growing period), >10~22 wks (developing period), >22~40 wks (peak laying period), >40~60 wks (late laying period) and over 60 wks (post-molting period). Results showed the 99.7% of the tested flocks were immunized against ND and73.8%, 97.1%, 78,2% and 78% of the flocks were immunized against other 4 agents (LPAI, IB, EDS'76, aMPV). Maternal antibody was transferred to enough quantity for NDV. Generally, antibody titers which were developed at 22 weeks were stabilized permanently for life. In case of IB and aMPV, infection titer emerged as early as 10 weeks and the titer was increased from 99.4% to 100% for life. EDS76 showed increase in titers, reflecting decreased frequency of vaccination programs. Overall, this study displayed general trends of major viral disease in layers, but considering the trend of development of preventive measures and evolution of pathogens, conducting serological surveys on a regular basis is important.

• 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.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.189.1-189
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• 2002