• 한국동물위생학회지
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• 제42권1호
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• pp.1-7
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• 2019

Porcine reproductive and respiratory syndrome (PRRS) is economically the most important and challenging disease in swine industries worldwide and caused by PRRS virus (PRRSV). Previous studies reported that pigs with heterozygous genotypes in the guanylate-binding proteins (GBP1 and GBP5) exhibited increased resistance against PRRSV infection. The present study was conducted to produce higher numbers of the heterozygous pigs based on the PRRS resistant polymorphisms found in GBP1 (GBP1E2 and WUR) and GBP5, and evaluate the resistance of heterozygous pigs against challenge with a type 2 PRRSV (JA142) in comparison with homozygous pigs. In the challenge study, 12, 4 week-old PRRSV-negative piglets were selected based on the genotypes of the 3 polymorphisms (GBP1E2, WUR and GBP5). Among them, 8 piglets [homozygous (n=4) and heterozygous (n=4)] were challenged with JA142 and kept in the same room, and the remaining 4 piglets were kept separately as a negative control. In results, the sperms collected from the boars of GBP1E2-GG genotype produced approximately 28~41% higher numbers of heterozygous piglets as compared with those from the boars of GBP1E2-AG genotype. In the challenge study, we found that heterozygous piglets showed the significantly lower levels of viremia than homozygous piglets at 14, 21 and 28 dpc. Consistently, these heterozygous piglets also exhibited significantly higher ADWG than homozygous piglets. Therefore, in the current study, selection of boars based on SNP markers could increase the production of PRRS resistant piglets and the PRRS resistant pigs were found to be more resistant to PRRSV infection.

• Asian-Australasian Journal of Animal Sciences
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• 제31권4호
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• pp.489-498
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• 2018

Objective: Foot and mouth disease (FMD) and porcine reproductive and respiratory syndrome (PRRS) are major diseases that interrupt porcine production. Because they are viral diseases, vaccinations are of only limited effectiveness in preventing outbreaks. To establish an alternative multi-resistant strategy against FMD virus (FMDV) and PRRS virus (PRRSV), the present study introduced two genetic modification techniques to porcine cells. Methods: First, cluster of differentiation 163 (CD163), the PRRSV viral receptor, was edited with the clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 technique. The CD163 gene sequences of edited cells and control cells differed. Second, short hairpin RNA (shRNAs) were integrated into the cells. The shRNAs, targeting the 3D gene of FMDV and the open reading frame 7 (ORF7) gene of PRRSV, were transferred into fibroblasts. We also developed an in vitro shRNA verification method with a target gene expression vector. Results: shRNA activity was confirmed in vitro with vectors that expressed the 3D and ORF7 genes in the cells. Cells containing shRNAs showed lower transcript levels than cells with only the expression vectors. The shRNAs were integrated into CD163-edited cells to combine the two techniques, and the viral genes were suppressed in these cells. Conclusion: We established a multi-resistant strategy against viral diseases and an in vitro shRNA verification method.

• 한국동물위생학회지
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• 제43권3호
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• pp.155-159
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• 2020

This study was conducted to investigate the infection of livestock diseases using 500 blood samples from wild boars captured in six cities and one county in northern Gyeonggi province, South Korea. We examined 239 cases of classical swine fever virus (CSFV), and each of 500 cases of foot and mouth disease virus (FMDV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), Mycoplasma hyopneumoniae (MH), Actinobacillus pleuropneumoniae (APP), Pasteurella multocida type A (PMA), Hemophilus parasuis (HP), Salmonella (Sal.) spp. infections. Antibodies were detected against CSFV (23.4%), PRRSV (4.0%), PCV2 (60.4%), MH (3.0%), APP (69.2%), PMA (52.8%), HP (11.8%), and Sal. spp. infections (37.2%). No antibodies were detected against FMDV. As a result of antigenic analysis of 68 positive cases (13.6%) out of 500 PRRS antigen tests, 61 North American cases, 6 European cases, 1 North American-European complex case. PCV2 has 158 positive cases (31.6%) out of 500 antigen tests, and the results indicate that a considerable number of individuals are infected. To our knowledge, this is the first seroprevalence report of MH, APP, PMA, HP, and Sal. spp. infections in wild boars in South Korea.

• 한국동물위생학회지
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• 제28권1호
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• pp.49-69
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• 2005

More than 30 years have elapsed since the first report of the International Committee on Taxonomy of Viruses (ICTV) was published in 1971. Since that publication, the ICTV recognizes about 1,550 virus species, but some 30,000 virus strains and isolates are being tracked by virologists in different fields of biology. The ICTV is the 'international court' of experts that rules on names and relationships of all virus, but only to the level of species. Virus taxonomy is changing rapidly, with changes ranging from the trivial(use of italics for species names) to profound reorganization driven by the explosion of sequence information. The universal system of viral taxonomy now accepts Linnean-like classification at the levels of order, family, subfamily, genus, and species. The suffix '-virales' identifies an order, Families are identified by the suffix '-viridae' subfamilies are identified by the suffix '-virinae', and genera are identified by the suffix '-virus'. The importance of distinguishing subspecies, strains, and isolates in vaccine development, diagnostics, etc. is recognized, but these lower levels are not formally classified by ICTV. This paper mainly introduces taxonomy and classification of animal viruses on the basis of the seventh report of the ICTV edited by Van Regenmortal et al. in 2000.

• 한국동물위생학회지
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• 제30권2호
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• pp.197-203
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• 2007

A total of 501 serum samples were selected from blood samples that were submitted to Department of Veterinary Pathology, Kangwon National University from all provinces in Korea from September 2001 to August 2002. Their sera were examined for antibodies to swine influenza virus subtype H1N1 (SlV H1N1) and porcine repro-ductive and respiratory syndrome virus (PRRSV) according to the age of pig, season, and herd size using enzyme-linked immunosorbent assay. The seroprevalence of SIV H1N1, PRRSV, and dual infection were 39.12%, 61.48%, and 25.95%, respectively. The seroprevalence of SIV H1N1 according to herd size was not significant differences (p>0.05). The results showed that the PRRSV infection spread widely in swine herds throughout the country.

• 한국동물위생학회지
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• 제38권1호
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• pp.1-7
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• 2015

This study was investigated to diagnose pathogenic organisms of atrophic piglets in northern area of the Gyeongnam province, Korea. Samples such as feces, blood and necropsy specimens of 42 atrophic piglets (${\leq}10$ weeks old) were taken from May to December 2013 for this survey. Samples were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) assay and bacteria isolation for detection of pathogenic agents. 93 pathogens were isolated from 42 samples can be classified into ll groups. We identified bacterial agents in 56 cases (60.2%) and viral agents in 31 cases (33.3%). However, 6 cases (6.5%) were undetected. Among these pathogens, the most prevalent disease were porcine reproductive and respiratory syndrome (PRRS) in 22 cases (23.7%). The major diseases were Colibacillosis in 15 cases (16.1%), Glasser's disease in 12 cases (12.9%), and porcine epidemic disease (PED) in 9 cases (9.7%). Mixed infections were accounted for 77.8% of atrophic piglets. In particular, the rate of mixed infections with PRRS virus showed the highest frequency (71.4%). In addition, there is a seasonal variation. Viral pathogens were dominantly detected in winter, but in the rest of the season bacterial agents were mainly detected. Gastrointestinal diseases occurred mainly in the pre-weaning piglets, the respiratory diseases and wasting diseases occurred mainly in the post-weaning piglets.

• 대한수의학회지
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• 제37권4호
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• pp.755-763
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• 1997

Recently new technologies for the establishment of high health herds are becoming efficient tools in the control of PRRS virus and secondary infections. Medicated early weaning(MEW) and nursery depopulation(ND) have shown to be one of the most successful procedures in the eradication and control of pathogens. Indirect evidence of the role of PRRSV in precipitating secondary infection comes from successful improvement in growth and in decreasing mortality on farms that have eliminated PRRSV through ND. Hence the present experiments were conducted in an effort to compare ND with MEW procedures as a means of eliminating PRRSV controlling secondary pathogens and improving performance of pigs in endemically infected swine herds. Following MEW and ND procedures practiced in the farms, some benefits obtained were as follows: 1. A decrease in PRRSV circulation in the nursery, but no entire elimination. 2. Decrease in the frequency of secondary bacteria and in the use of antibiotics. 3. Mycoplasma hyopneumoniae infection was prevented during the nursery stage. 4. ND protocol had a lower cost and management changes than MEW techniques. 5. Nursery performance was improved after the depopulation, cleaning and disinfection procedures, even though PRRSV still being cycled in the old nursery rooms. These studies revealed that the MEW and ND protocols are not always successful for PRRS virus elimination but it's great effect on control of secondary pathogens and improvement of performance make MEW and ND an efficient tools for the establishment of healthier and more efficient herds.

• 대한수의학회지
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• 제58권2호
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• pp.73-79
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• 2018

Outbreaks of porcine reproductive and respiratory syndrome virus (PRRSV) in vaccinated sow herds from occurrence to stabilization were monitored and analyzed in terms of serology and reproductive performance. Three different conventional pig farms experienced severe reproductive failures with the introduction of a type 1 PRRSV. These farms had adopted mass vaccination of sows using a type 2 PRRSV modified live vaccine (MLV). Therefore, to control the type 1 PRRSV, an alternative vaccination program utilizing both type 1 and type 2 MLV was undertaken. Following whole herd vaccinations with both types of MLV, successful stabilization of PRRS outbreaks was identified based on serological data (no viremia and downward trends in ELISA antibody titers in both sows and suckling piglets) and recovery of reproductive performance. Additionally, through comparison of the reproductive parameters between outbreak and non-outbreak periods, it was identified that PRRSV significantly affected the farrowing rate and the number of suckling piglets per litter at all three pig farms. Comparison of reproductive parameters between periods when the different vaccination strategies were applied revealed that the number of piglets born in total and born dead per litter were significantly increased after the introduction of the type 1 PRRS MLV.

• 농업과학연구
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• 제48권2호
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• pp.251-264
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• 2021

Bovine respiratory syncytial virus (BRSV) and bovine viral diarrhea virus (BVDV) are the main viral contributors to bovine respiratory disease (BRD) with high mortality and morbidity. BRD control measures include vaccination that modulates immunological profiles reflected in blood cells, serum, and body secretions, such as milk. This study evaluated the immune responses to an inactivated BRD vaccine in lactating cows reared in a natural environment on a dairy farm. The cows were intramuscularly inoculated with the vaccine, and serum, blood, and milk were collected pre-and post-vaccination. Our study revealed a prominent increase in BRSV-specific antibodies both in serum and milk, while the change in BVDV-specific antibodies was insignificant. Serum interleukin (IL)-1β and IL-6 levels significantly decreased, but this change was not reflected in milk. Evaluation of pattern recognition receptors (PRRs) via RT-qPCR revealed downregulation of nucleotide-binding oligomerization domain 2 (NOD2). The concentrations of BRSV antibodies, BVDV antibodies, IL-2, and IL-17A in serum and milk were strongly correlated, implying a concurrent influence on both body fluids. Thus, immunological factors modulated as a result of vaccination generally measured in serum were reflected in milk, demonstrating the suitability of milk evaluation as an alternative approach for immunological observations. Furthermore, the correlation between BRSV antibodies and NOD2 and that between BVDV antibodies and toll-like receptor (TLR) 2, TLR3, TLR4, and TLR5 imply the possible role of PRRs for the assessment of the immune response developed in immunized cows reared on the farm.

• 한국동물위생학회지
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• 제43권4호
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• pp.227-236
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• 2020

In this study, we have developed 3D8 scFv transgenic pig (TG) by microinjection of fertilized one-cell pig zygotes (2.17%). The effect of 3D8 scFv TG on porcine reproductive and respiratory syndrome virus (PRRSV) resistance were evaluated through PRRSV VR2332 (1×103 TCID50/mL) challenge and transmission experiments. As a result, the average daily weight gain (ADWG) of TG increased compared to the wild type pigs (WT) in PRRSV challenge groups and the serum viremia levels of the TG was significantly lower than of WT on the 7 day and 21 day after infection, meaning that the viral shedding was suppressed by 3D8 scFv expression. These results suggest that the expression of 3D8 scFv in pig could suppress spreading of infected virus to pigs sharing a room.