• Korean Journal of Poultry Science
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• v.27 no.2
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• pp.109-114
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• 2000

The objective of these experiments was to develop an attenuated thermostable Newcastle disease virus(NDV), CBP-1 strain isolated from infected pheasants. Safety, pathogenicity and protective effects against velogenic NDV were also investigated to evaluate if the attenuated NDV, CBP-1 strain could be a candidate for a new NDV vaccine strain. CBP-1 strain was passaged up to the 173 times by nine days old embryonated eggs and chicken embryo fibroblast(CEF) cell cultures. Its sensitivitly to lipid solvents and low pH, thermostability, mean death time(MDT), intracerebral pathogenicity index(ICPI) of one day old chicks and intravenous pathogenicity index(IVPI) of four weeks old chicks were examined. Safety, boosting and protective effects were tested by chicks mortality. CBP-1 NDV strain had significant thermostability at 56$\^{C}$ for 30 minutes. by hemagglutinin activity and egg infectivity test, but was not resistant to lipid solvent. It showed possibility to use as a feed or water vaccine because of the resistance to low pH. MDT, ICPI and IVPI of CBP-1 were attenuated from 51.5, 1.96, 2.60 to 112.4, 1.12, 1.45. These results implied that the 173rd passages in embryonated egg and CEF cell cultures induced a substantial attenuation of the pathogenicity of the parent virus, changing the virulence from velogenic to intermediate between mesogenic and lentogenic. After vaccination with CBP-1 at one day old by drinking water mortality was 17.5%. However, spray vaccination with B1 at one day old, CBP-1 at two weeks ild and challenge with velogenic Kyojeongwon strain at four weeks old showed 93.5% survival rate. Mortality of chicks, vaccination with 173rd passaged CBP-1 strain at one day old, two weeks old and challenge with Kyokeongwon strain at four weeks old, was 20.0%. The results of these studies indicated that partial attenuated CBP-1 strain tended to be a low safety for ND of broiler chicks and would need to be more successive attenuation.

• Korean Journal of Veterinary Service
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• v.28 no.4
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• pp.367-373
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• 2005

Coccidiosis of domestic fowl is a parasitic disease that infects poultry drastically and can cost the pastured poultry producer much in the course of a year. Two hundred forty, day-old-broiler chicks were purchased and were randomly divided in eight groups, containing thirty birds in each group. Decoquinate $6\%$, maduramicin ammonium $2\%$, monensin sodium $13.2\%$, salinomycin sodium $12\%$, a live attenuated vaccine, and trivalent live attenuated vaccine, was provided to the day chicks of six groups, respectively. The chicks of last two groups served as infected non-medicated and uninfected non-medicated, respectively. Feed consumption, weight gain, feed conversion ratio, mortality and oocyst count per gram feces were recorded during the conduction of the experiment. Among treated groups, performance of salinomycin group was significantly better (p<0.05) in all aspects. Salinomycin acts against the sporozoites, trophozoites and first generation schizonts and is highly effective against the economically important species of Eimeria. The present study confirms that use of salinomycin, as an anticoccidial, is a drug of choice.

• Environmental Engineering Research
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• v.20 no.4
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• pp.356-362
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• 2015

Many burial sites were constructed in a short time to prevent the rapid spread of foot and mouth disease in infected livestock carcasses in Korea. More than 4,700 carcass burial sites were constructed in 2011. Approximately seven million poultry and 3.5 million livestock, including cattle and swine, were buried on farmland. Some burial sites were suspected of leachate leakage and were excavated and carcasses redisposed in a bioaugmentation process. This study performed interviews in order to understand the economic issues related to carcass burial and redisposal. The internal data from local government and the assumption data from online sites were analyzed to evaluate the costs; the focus was on burial site construction. The results showed that the local government paid $4.7 and $10.9 per carcass for traditional burial and redisposal. The comparable costs shown online were $4.5. This study found that the standard operating procedures should be carried out to reduce environmental impact and avoid additional costs. We estimated that the cost could be reduced by the advance preparations of materials against the emergency situations such as catastrophe of epidemics. In addition, the innovative technology for the stabilization of carcasses should be established through a future study.

• Korean Journal of Veterinary Service
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• v.39 no.1
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• pp.21-28
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• 2016

Protozoan parasite, the genus Eimeria, causes an intestinal disease, coccidiosis, in young broilers. Coccidiosis induces significant economic loss in poultry production. This study was designed to identify the prevalence of Eimeria spp. in broilers in Gyeonggi province, Korea. Fecal samples from broilers at 94 farms were collected in two chicken slaughterhouses between March and June 2015. Eimeria infection was determined by microscopic examination and PCR using ITS-1 region. The prevalence of Eimeria was 58.5% (55 of 94). E. acervulina was identified in 96.4% of samples, E. tenella in 81.8%, E. maxima in 12.7%, E. praecox in 12.7%, E. brunetti in 5.5%, E. necatrix in 1.8%, and E. mitis in 1.8%. Body weight (BW) of broilers infected with both E. tenella and E. acervulina ($mean=1.53{\pm}0.19^Bkg$) was significantly lower than broilers with E. acervulina positive/E. tenalla negative ($mean=1.74{\pm}0.07^Akg$) or Eimeria negative ($mean=1.65{\pm}0.15^Akg$) (Duncan's multiple range test, P<0.01). High prevalence of Eimeria tenella and the impact on the broiler body weight shows the importance of this protozoa in broiler industry. Development of the periodic monitoring strategy and systemic management for the purpose of the prevention/eradication of Eimeria infection among broilers is required.

• Korean Journal of Veterinary Service
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• v.38 no.1
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• pp.51-56
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• 2015

Infectious bronchitis virus (IBV) causes an acute and highly contagious viral disease of chicken that is great economic losses to the poultry industry worldwide. Among the IBV structural proteins, the high rate spike glycoprotein S1 gene mutation and antigenic variant strains have been reported in many countries. During the years 2012~2014, 10 IBV strains were isolated from infected chicken farms distributed in provinces of Jeonbuk. Analysis of the S1 gene sequences amplified from 10 isolated strains with QX strains showed nucleotide homologies ranging from 96.5 to 95.4%. Phylogenetic analysis revealed that all strains were clustered into QX-like groups. This study suggests that QX-like IBVs are circulating in commercial chicken farms in Jeonbuk. Therefore, the continuing survellance is significantly important for prevention and control of BIV infection.

• Journal of Veterinary Science
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• v.22 no.2
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• pp.21.1-21.6
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• 2021

In this study, we describe the isolation and characterization of previously unreported Y280-lineage H9N2 viruses from two live bird markets in Korea in June 2020. Genetic analysis revealed that they were distinct from previous H9N2 viruses circulating in Korea and had highest homology to A/chicken/Shandong/1844/2019(H9N2) viruses. Their genetic constellation showed they belonged to genotype S, which is the predominant genotype in China since 2010, where genotype S viruses have infected humans and acted as internal gene donors to H5 and H7 zoonotic influenza viruses. Active surveillance and control measures need to be enhanced to protect the poultry industry and public health.

• Korean Journal of Poultry Science
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• v.37 no.3
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• pp.283-287
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• 2010

In the present study we report in vivo inhibitory potential of single strain of bacteriophage ($CJ{\phi}07$) in day-old SPF chicks experimentally infected with Salmonella enteritidis (SE). The bacteriophages prepared by feed additives and drinking water were given to chicks for 20 days starting prior 10 days before challenge with SE. Chicks were euthanized at 10 days after challenge for quantitative salmonella isolation from intestine and determination of environmental contamination level of salmonella. Bacteriophage therapy as additives in feed and drinking water resulted in significant inhibition of the SE replication in intestines of SPF chickens (P<0.05). In addition, environmental contamination by SE fecal shedding was decreased in bacteriophage-treated birds. Therefore, bacteriophage $CJ{\phi}07$ examined in this study may be a plausible alternative to antibiotics for the reduction of salmonella infection both in poultry.

• Korean Journal of Veterinary Service
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• v.28 no.1
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• pp.1-21
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• 2005

Pullorum disease and Fowl typhoid are kind of poultry specific disease for poultry. The peculiar character of these poultry specific diseases is that it can be infected by transmitting vertically and horizontally, also it is hard to be discovered by clinical sign, and pathology or immunology. So, to develop the PCR method which distinguishes these two genetically similar diseases of separated the specific DNA fragment from each strain and use it for differential diagnosis by subtraction PCR method. Standard strain of S gallinarum and S pullorum, and field isolation strain were verified by biochemistry, It confirmed existence of plasmid by using the PFGE. Then, Isolated DNA from it and used it as materials for the experiment. After cutting genomic DNA of two strains by using Sau 3Al, It ligated primer to tester DNA for PCR amplification and separated specific DNA fragment bacteria with method of subtraction PCR. And, It confirmed that it is a piece of unique DNA in every bacteria using base sequence of separated DNA fragment. 1. The six specific DNA fragment were separated from the DNA of S gallinarum and S pullorum by the subtraction PCR method. 2. In the result of comparison after setting base sequence of each fragment, each separated base sequence of DNA fragment they did not correspond to each other 3. As the result of each DNA fragment is derived from the each strain of DNA, and there was no homology of genomic DNA level in mutual. 4. The fragment originated in plasmid and includes S pullorum did not separate. 5. In the result of searching base sequence in Genebank, it partially shows homology in Salmonella enterica, S typhimurium, S dublin, Escherichia coli, Shigella flexneri, Yersinia pestis, Klebsiella pneumoniae. 6. Primer design by S gallinarum DNA 2, 3 fragment used PCR, They are positive reaction in only S gallinarum at 276, 367 bp position.

• Korean Journal of Poultry Science
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• v.32 no.2
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• pp.113-123
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• 2005

Avian influenza (AI) virus (AIV) is distributed worldwide and it has been isolated from various species of wild and domestic birds. AI transfers with high speed and shows diverse pathogenicity syndroms. In Korea, several low Pathogenic AIV, H9N2, have been isolated from the commercial farms with severe decrease of egg production and mortality resulted in severe economic loss since 1996. Therefore, it has been requested to develop AI vaccines to prevent clinical signs and economic losses from the field infection of AIV. To develop a killed vaccine that efficiently prevents low pathogenic AIV (H9N2), evaluation on the pathogenicity and selection of an inactivator for H9N2 is taking place and is being tested safety and immunogenicity of vaccine produced. Based on the pathogenicity test and viral reisolation test, the ADL0401 isolate is the characteristic low pathogenic AIVs and has fairly similar biologic functions compared with MS96 which is the official low pathogenic AIV (H9N2) and one of the predominant AIV isolated from poultry farms in Korea. In antigenicity tests, the ADL0401 and MS96 virus have no significant antigenic difference. In inactivation tests, the ADL0401 isolates can be easily inactivated with $0.1\%$ Formalin at $37^{\circ}C$ within 1 hour with a little decrease of HA titer. The vaccine developed in the present report has no harmful effect on bird and forms good immune capability. Therefore, the isolates, ADL0401 can be used for a killed vaccine which can reduce the clinical signs and viral shedding in the birds infected with H9N2 low pathogenic AIVs.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.313-325
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• 2019

In most cases of HPAI (highly pathogenic avian influenza) outbreaks, stamping-out operations are initiated by officially designating the affected premise, which is subsequently followed by depopulation of infected flocks. The primary objective of this study was to develop an evaluation method that correlates the level of biosecurity and the risk of having an HPAI outbreak in domestic poultry farms. A total of eight farms were selected nationwide, including layer farms, broiler farms, and an animal welfare type farm. The biosecurity level of the chosen poultry farms was assessed based on a total scoring index of 183 divided into three categories, general management (51), quarantine management (106), and sanitation management (26). Conclusively, the five layer farms (JS, GE, CS, HS, OE), scored higher overall scores compared to the animal welfare farm (CH) and broiler farms (JG, LB). In terms of scoring, which adds up to a total of 183 points, most layer farms scored between 130 and 157, while the two broiler farms and the welfare farm scored 45, 75 and 70, respectively. Next, an independent HPAI risk assessment of the farms was carried out. Regarding the correlation between biosecurity levels and HPAI risks, in the farms that presented a higher overall score in terms of biosecurity and outweighed the risks of HPAI, they tended to earn more points in the quarantine management category. The results of this study suggest that a viable system for evaluating biosecurity levels can establish strong correlations with the risk of having HPAI.