• Korean Journal of Veterinary Service
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• v.26 no.1
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• pp.1-9
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• 2003

The aim of this survey was to investigate the characteristics of outbreak farm determined as the classical swine fever(CSF) at Gangwha-gun and Seo-gu, Incheon metropolitan area from October 7 to November 25 in 2002. Sixty pigs in six different farms were confirmed to the CSF and a total of 9,106 pigs containing 3,194 related epidemiologically was slaughtered to stop spreading of the disease. Clinical signs of pigs diagnosed with the CSF were high fever, anorexia, depression, paralysis of hindlimbs, cyanosis, etc and gross lesions were typically represented with hemorrhage of submandibular and superficial lymph node, infarction of spleen, and petechial (ecchymotic) hemorrhage of kidney and skin. But some outbreak farms had not shown remarkable symptoms, so they were confused with other bacterial diseases. White blood cell (WBC) counts, the classical swine fever virus(CSFV) antigen and antibody enzyme linked immunosorbent assay(ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR) results about six farms indicated that total 60 pigs were infected with the CSFV. Although the origin and infection route of the CSFV were not clear, but the transmissions between farms were mainly through indirect contact such as the movement of farm personal and vehicles from outbreak farm.

• Korean Journal of Veterinary Service
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• v.27 no.3
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• pp.239-247
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• 2004

Classical swine fever (CSF) was confirmed in 19 herds in Jeunbuk provence (Iksan, Gimje, Wanju, Buan, and Jangsu) in Korea between March and May, 2003 and 10,263 pigs were slaughtered. Pigs contacted with CSF virus in primary outbreak farm show fever, reduced appetite, arched back and chill in company with sever respirative sign and then most infected farms also were observed to fever, reduced appetite, sudden death, and leukopenia (101 pigs). In order to detecting infectious pig with CSF virus, A total of 555 pigs were inspected in 65 herds and blood samples were collected and serological test (ELISA), antigen ELISA, and reverse transcription-polymerase chain reaction (RT-PCR) had been done. Positive rate were $74\%$ (410 pigs) in antibody ELISA, $2\%$ (11 pigs) in antigen ELISA and $33\%$ (182 pigs) in RT-PCR, respectively. As shown that the RT-PCR was useful than the ELISA for determining CSF virus in blood, meat, and other organs.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.259-262
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• 2012

Classical swine fever (CSF) is a highly contagious disease among swine that has an important economic impact on worldwide. One clinical symptom of CSF is leukopenia, in particular lymphopenia, which is a characteristic event that occurs early in the course of CSF. Though lymphopenia associated with apoptosis, the pathogenic mechanism underlying the lymphopenia has not been well studied. To understand these mechanisms, we investigated the response of porcine B cell lines to infection with SW03, virulent strain isolated from swine tissue in Korea. This study demonstrated that SW03-infected L35 cell were induced apoptosis through the detection of activated caspase-3. In addition, SW03 infection leaded to alterations in pro-apoptotic, Bax, and anti-apoptotic, Bcl-xL proteins of Bcl-2 family. Our results would suggest that SW03-infected L35 cells induced apoptosis via intrinsic mitochondrial pathway.

• Korean Journal of Veterinary Research
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• v.46 no.3
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• pp.197-206
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• 2006

In March 2003, classical swine fever (CSF) infection was reported in a piggery located at Iksan city, Jeollabuk-do in Korea. Subsequently, a total of 72 infected farms were confirmed between March and December, 2003. Based on epidemiological investigation of the earlier confirmed infected farms, the source of infection was shown to be from a breeding farm. Targeted surveillance of 82 piggeries that had acquired pigs from this breeding farm showed 44 piggeries were infected with CSF virus. CSF virus was introduced into this breeding farm by movement of selected breeder pigs from its 12 contracted farms which were located in areas that had been affected by CSF epidemic in late 2002. CSF had then spread through out the country mainly by direct transmission through the sale and movement of pigs from this breeding farm. Consequently, 47 (62%) among 72 CSF affected farms were associated, directly and indirectly, with this breeding farm. This study showed that inadequate control for breeding farms and transport restriction in CSF outbreak areas resulted in the nationwide spread of CSF and the failure of the eradication campaign that has been underway for several years by the Korean animal hygiene authority as well as the fanners. Improvements of control policy through further research of the 2003 CSF epidemic will be needed to reestablish the Korean CSF eradication program in the future.

• Korean Journal of Veterinary Research
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• v.46 no.2
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• pp.107-117
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• 2006

This paper described the epidemiological characteristics of 2002 outbreak of classical swine fever (CSF) in Korea. A total of thirteen CSF-infected farms could be classified into two clusters according to the location and time of outbreak. Two farms located in the same county of Gangwon province and 11 farms located in several different districts of Incheon metropolitan/Gyeonggi province were identified as CSF-infected from April 16 to 30 and from October 7 to December 21 in 2002, respectively. As the result of epidemiological analysis, the two clusters of outbreaks were turned out to be independent epidemics which had different sources of virus introduction. Three farms were found to have been infected primarily; one located in Cheolwon county of Gangwon province and two located in Kangwha county of Incheon metropolitan area. The most likely factors of virus introduction into these primary infected farms were considered to be direct or indirect contact by foreign workers and/or owners of the infected farms who had come back from traveling in China before outbreaks. This was supported by the genetic typing of CSF viruses isolated from the pigs of infected farms. All the virus isolates of 2002 outbreak were found to be genetic type 2, whereas the viruses isolated before 2000 were type 3 and the reference strains, such as attenuated live vaccine virus (LOM strain) and high virulent challenge virus (ALD strain), were type 1. Accordingly, we concluded that the 2002 CSF outbreak must have been caused by a newly introduced virus from overseas and the type 3 virus must have been eradicated after the last outbreak of 1999 by the national CSF eradication campaign which were implemented since 1996. Based on the combined analysis of epidemiological data and genetic typing, the transmission routes of classical swine fever virus were found to be the movement of vehicles (60%) and persons (10%), neighbourhood spread (20%) and unknown (10%). It is expected that the analyzed data and findings of classical swine fever outbreak epidemic could be very useful to establish the disease control and eradication program for the country in the future.

• Korean Journal of Veterinary Research
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• v.43 no.2
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• pp.263-270
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• 2003

The objective of the present study was to investigate the use of fluid released from muscle samples as an alternative to serum for ELISA to detect classical swine fever(CSF) virus antibodies in slaughter pigs. The optimal correspondence between serum 1:20 OD values and muscle fluid OD values was achieved at a muscle fluid dilution of 1:2. Significant correlation was found between serum and neck muscle ELISA ($r_s=0.880$, p<0.0001, ${\kappa}=0.82$; specificity of 97.0% and sensitivity 90.6%). The semimembranous muscle showed similar correlation in CSF ELISA($r_s=0.877$, p<0.0001, ${\kappa}=0.75$; specificity of 94.1% and sensitivity 89.1%). High correlation was obtained between serum and mesenteric lymph node in the CSF ELISA ($r_s=0.937$, p<0.0001, ${\kappa}=0.87$; specificity of 97.1% and sensitivity 93.0%). Measmement agreement between serum ELISA and muscle fluid ELISA was calculated and expressed as limits of agreement. The correspondence of ELISA of serum and muscle fluid indicated limits of agreement. Above 95% of all muscle fluid values were distributed within this limits of agreement. Among the samples used for ELISA for detecting CSFV antibodies, mesenteric lymph node had the most correlation and agreement with serum ELISA. F-test for comparison of variances showed no significant difference between the serum and muscle fluid. In conclusion, muscle fluid is a useful postmortem alternative to serum to detect CSFV antibodies.

• Korean Journal of Veterinary Research
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• v.47 no.1
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• pp.51-57
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• 2007

To establish a statistically reliable sampling strategy for serological surveillance of classical swinefever (CSF) in Korea, antibody test data from CSF surveillance conducted during year 2005 were analyzed.The most appropriate sampling method was determined to be stratified multi-stage random sampling strategy,in which the primary sampling unit is a pig farm and the secondary are the pigs by the strata of breedersand finishers in the selected farm. The optimum sample size was 5 to 19 including 1 to 2 breeders accordingto the number of pigs in the farm. The optimum sampling strategy demonstrated in this study was veryFindings of our study provide practical guidelines for surveillance of herd immunity level to CSF in Korea.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.12-12
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• 2003

Several cases of classical swine fever (CSF) were reoccurred in Cheolwon province and Incheon city in 2002. Two isolates (Cheolwon and Incheon) of classical swine fever viruses (CSFV) were successfully isolated and classified into genotype-2 with a phylogenetic analysis [l, 2]. (omitted)

• Korean Journal of Veterinary Research
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• v.47 no.4
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• pp.429-435
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• 2007

The risk of an outbreak of classical swine fever (CSF) was evaluated in relation to the vaccination and seroprevalence of antibodies. Blood samples were collected from 60 piggeries throughout Korea and information regarding CSF vaccination habits was also obtained via in-person interviews with pig farmers. The results of the survey indicated that 51 out of 60 farms were regularly performing CSF vaccinations in reproductive herds. Farmers preferred to vaccinate their reproductive pigs before weaning (41 farms) than on (9 farms) or after weaning (1 farm). In growing herds, however, double vaccinations as recommended were implemented for only 40 farms (66.7%) and vaccine schedules were identified as being frequently ignored. Moreover, many farms (18/40) were found to vaccinate earlier or later than the recommended time. According to antibody seroprevalence levels, only 36 farms (60%) were considered to be safe regarding potential risk for a CSF outbreak. Among the remaining pig farms, 6 were at low-risk (10%), 12 were at medium-risk (20%), and another 6 were at high-risk (10%). Antibody levels were found to be consistent with vaccination status obtained from personal interview surveys. Our findings demonstrate the importance of vaccinations regarding the prevention of a CSF outbreak, suggesting that vaccinations must be promoted toward pig raisers and practitioners.

• Korean Journal of Veterinary Service
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• v.26 no.2
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• pp.163-184
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• 2003

This study was conducted to survey the farm which suffered from disease similar to classical swine fever(CSF) in Gyeongbuk province. Clinical signs appeared first in a few number of growing pigs which showed specific signs of diarrhea, depression, sleepiness, and reluctance to get up or to eat. Younger piglets may have appeared chilled, shiver and huddle together. As the disease progresses the affected pig's skin went red and purple. In histopathological signs, there were many haemorrhages throughout the body and larger haemorrhages in some organs such as lymph nodes. And there is a precipitous fall in the number of circulating leukocytes in the blood. In spite of insisting of farmer which did not vaccinate to classical swine fever, significant antibody production was detected in these affected pigs at enzyme-linked immuonsorbent assay. According to the above results at first glance, these affected pig suspected with CSF in clinical signs and histopathological lesions only. Because the symptoms and post-mortem picture were very similar to CSF, these false positive results would have been dangerous to diagnostician. But by reverse transcriptase polymerase chain reaction(RT-PCR) and comparative nucleotide sequence analysis, the disease was correctly diagnosed with post-weaning multisystemic wasting syndrome(PMWS) and porcine reproductive and respiratory syndrome(PRRS) compoundly. And the antigen which were detected the lesion similar to CSF virus, was confirmed with LOM vaccine strain of CSF. In most national CSF eradication program and in countries which are free of the CSF virus, vaccination against CSF is not practiced and generally is not allowed. But now in Korea, routine vaccination is practiced because of outbreaking the CSF repeatedly. When CSF is diagnosed the whole herd and other in contact animal are slaughtered continuously.