• Korean Journal of Veterinary Service
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• v.42 no.2
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• pp.117-120
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• 2019

Bovine viral diarrhea Virus (BVDV) infections cause respiratory, gastrointestinal, and reproductive problems, such as infertility, abortion, stillbirth, and sickly offspring. Many countries have reduced the economic damage through the application of different control programmes, and some have successfully eradicated BVD. Detection and elimination of cattle persistently infected (PI) with BVDV is important for BVD eradication because PI cattle are a main source of BVD transmission. In this study, the prevalence of Korean native cattle persistently infected (PI) with BVDV was investigated and determined in 49 farms with 3,050 cattle. The all samples were collected by ear notch sampling. Korean native cattle with initial positives on antigen-ELISA (Ag-ELISA) were sampled again after 3~4 weeks and cattle with second positives in both Ag-ELISA and immunohistochemistry (IHC) were identified as PI cattle. Among the 49 farms, 14 (28.6%) farms had at least more than one PI cow and 21 (0.69%) of 3,050 cattle were determined as PI cattle. As a result of this work, it is suggested that national BVD eradication program is required to reduce economic losses by BVDV infection in Korean cattle industries.

• Korean Journal of Veterinary Service
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• v.36 no.2
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• pp.105-110
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• 2013

Bovine viral diarrhea virus (BVDV) is very important disease in domestic and wild ruminants and has a world wide distribution. Cattle persistently infected with BVDV (BVDV-PI) are the primary reservoir for BVDV infection in Korean native cattle herds. The prevalence of cattle persistently infected with BVDV (BVD-PI) was determined using 4,260 heads from 29 Korean native cattle farms at 8 districts from 2011 to 2012. The sera and ear nothches were collected for each sample. We surveyed BVD-PI cattle using antibody ELISA and antigen capture ELISA for detection of antibody and antigen respectively. Three thousand seventy-six cattle (72.2%) were positive for BVDV antibody and a total of 27 BVD-PI cattle were found in 12 farms. 11 cattle (40.7%) out of the total 27 BVDV-PI cattle were six months old or under. The positive rate of BVDV antibody (83.2%) from 12 farms with BVD-PI cattle was higher than the positive rate of BVDV antibody (63.6%) from 17 farms without BVD-PI cattle.

• Korean Journal of Veterinary Research
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• v.47 no.2
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• pp.163-167
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• 2007

Bovine viral diarrhea (BVD) is very important disease in cattle industry with a worldwide distribution. Detection and elimination of persistently infected calves with bovine viral diarrhea virus (BVDV) was valuable strategy for BVD eradication because those calves were main source for transmission. We surveyed persistent infection with BVDV by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) using whole blood and skin. Five hundred thirty nine Korean native calves were tested. Four calves (0.7%) were positive for BVDV antigen for both tests. Those calves remained positive for follow-up by RT-PCR and IHC. Therefore they were identified as persistently infected with BVDV. We confirmed that immunohistochemistry using skin biopsy samples was very useful tool to detect persistently infected calves with BVDV. As far as we know, this would be first report on persistent infection with BVDV in Korea.

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.05a
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• pp.23-36
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• 2000

Japanese encephalitis virus (JEV) is the causative agent of a mosquito-borne encephalitis and is transmitted to human via persistently infected mosquito vectors. Although the virus is known to cause only acute infection, there were reports that showed neurological sequelae, latent infection in peripheral mononuclear cells, and recurrence of the disease after acute encephalitis. Innate resistance of certain cell lines, abnormal SN1 expression of the virus, and anti-apoptotic effect of cullular bcl-2 have been suggested as probable causes of JEV persistence even in the absence of defective interfering (DI) particles. Although possible involvement of DI particles in JEV persistence was suggested, neither has a direct evidence for DI presence nor its molecular characterization been made. Two questions asked in this study are whether the DI virus plays any role in JEV persistent infection if it is associated with and what type of change(s) can be made in persistently infected cells to avoid apoptosis even with the continuous virus replication, DI-free standard stock of JEV was infected in BHK-21, Vero, and SW13 cells and serial high multiplicity passages were performed in order to generate DI particles. There different-sized DI RNA species which were defective in both structural and nonstructural protein coding genes. Rescued ORFs of the DI genome maintained in-frame and the presence of replicative intermediate or replicative form RNA of the DI particles confirmed their replication competence. On the other hand, several clones with JEV persistent infection were established from the cells survived acute infections during the passages. Timing of the DI virus generation during the passages seemed coincide to the appearance of persistently infected cells. The DI RNAs were identified in most of persistently infected cells and were observed throughout the cell maintenance. One of the cloned cell line maintained the viral persistence without DI RNA coreplication. The cells with viral persistence released the reduced but continuous infectious JEV particle for up to 9 months and were refractory to homologous virus superinfection but not to heterologous challenges. Unlike the cells with acute infection these cells were devoid of characteristic DNA fragmentation and JEV-induced apoptosis with or without homologous superinfection. Therefore, the DI RNA generated during JEV undiluted serial passage on mammalian cells was shown to be biologically active and it seemed to be responsible, at least in part, for the establishment and maintenance of the JEV persistence in mammalian cells. Viral persistence without DI RNA coreplication, as in one of the cell clones, supports that JEV persistent infection could be maintained with or without the presence of DI particles. In addition, the fact that the cells with JEV persistence were resistant against homologous virus superinfection, but not against heterologous one, suggests that different viruses have their own and independent pathway for cytopathogenesis even if viral cytopathic effect could be converged to an apoptosis after all.

• Korean Journal of Veterinary Service
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• v.36 no.1
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• pp.7-13
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• 2013

Bovine viral diarrhea virus (BVDV) is one of the most important disease viruses in cattle that can cause severe economical losses due to decreased fertility, abortion, diarrhea, and respiratory symptoms. Therefore, this study was aimed to investigate prevalence of BVDV infection (Transiently infection, Persistently infection) in dairy cattle in Gyeongnam southern area, Korea and use this data as the basis for establishing an eradication program and policy. A total of 44 bulk-tank milk samples (farms) collected in milk collecting center were tested for BVDV antibody using an ELISA. As the result, out of a total of 44 bulk-tank milk samples (farms), 38 (86.4%) samples were BVDV antibody positive. Blood samples (17 farms, n=543) were collected from BVDV antibody positive farms in bulk-tank milk, tested for BVDV antigen with ELISA and PCR. BVDV infected farms were 47% (8/17) and BVDV infected head were 2.2% (12/543). Persistently infected cattle (PI) were detected at 6 (35.3%) farms out of 17 farms and a total of 6 (1.1%) out of 543 head of cattle were identified as PI. The seropositive of BVDV antibody at farms and head were 100% (17/17) and 49.45% (91/184), respectively. The seroprevalence of BVDV antibody in PI infected farms (67.35%) much higher than that of BVDV antibody in transiently infected cattle (TI) infected farms (45%) and uninfected farms (34.48%). For eradication of BVDV infection in cattle populations, First of all, we should remove PI and need vaccination.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.582-585
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• 2009

Bovine viral diarrhea virus (BVDV) is an economically important worldwide disease in livestock industry. In this study, the occurrence of BVDV in Korean indigenous cattle was performed by RT-PCR using nasal swab. Twelve of 21 cattle were identified as BVDV positive and classified as persistently infected (PI). These animals showed the occurrence of diseases such as diarrhea and pneumonia. BVDV PI outbreaks were found mostly in PI calves. Sequencing and phylogenetic analysis based on the 5'-untranslated region (UTR) showed that our case belonged to BVDV-2a. These results suggested that the nasal swab sampling was available method for the detection of PI animals, underscoring the need for BVDV control strategies in Korean indigenous cattle.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.743-750
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• 1999

Bovine viral diarrhea viruses (BVDVs) were isolated from cattle with respiratory and diarrhea signs as well as persistently infected cattle. These isolates were analysed serologically to characterize serogroups and to compare serological relationship with reference viruses of type I and II. Most isolates from calf diarrheal cases and persistently infected individuals showed a significant difference in cross-neutralization test with the viruses isolated from nasal discharges showing severe respiratory signs. Serologically most of the commercial vaccine strains could be classified into classical BVDV (type I) such as NADL strain. This serological difference among BVDV isolates suggested the need for new vaccines to protect cattle from both respiratory and enteric BVDV infections in field. The immunogenicity of BVDVs which showed a good propagation capability in MDBK cells and high rates of neutralizing activity (isolate : KD26-1, PHG, B5 and 95002) against all viruses used in this study, was confirmed in guinea pig when treated as single or combined groups.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.150-153
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• 2007

The aim of this study was to investigate the prevalence of bovine viral diarrhea virus (BVDV) infection in Chonbuk province. Blood samples were taken from 92 korean calves to determined their serological status against BVDV, Capture enzyme-linked immunosorbent assay (ELISA) was used to test for antigen. The number of seropositive calves ranged from 3.3% to 12.9%. Antigens against BVDV were detected in 3.3% of healthy calves, 6.4% of digestive symptom calves, 12.9% of respiratory symptom calves, respectively. Sex and age of calves had no significant differences on the prevalence of BVDV. The results indicate that transmission of BVDV may have become exposed as a result of contact with acute infected or persistently infected cattle.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.5
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• pp.471-477
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• 2001

Failure to use effective methods of reduction, fixation, and immobilization may lead to nonunion with osteomyelitis, owing to the compound nature of most fractures of the mandible. Nonunion results in fibrous pseudoarthrosis at the fracture site with instability that, once formed, does not improve spontaneously. Once the nonunion with osteomyelitis secondary to fractures has become established, intermaxillary fixation and drainage of infected tissue should be instituted as early as possible, because the fixation & drainage enhances the patient comfort and hinders ingress of microorganisms & debris by movement of bone fragments. The authors treated three cases of nonunion with osteomyelitis by intermaxillary fixation, incision & persistent drainage on the previous fistula site and endodontic drainage of infected teeth in the fracture site of mandible. The localization & sequestration of the infected bone around the fracture was better performed persistently by natural homeostatic mechanism in $8{\sim}10$ weeks and the bony union was then attained without bone grafting.

• Parasites, Hosts and Diseases
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• v.39 no.4
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• pp.285-292
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• 2001

The present study aimed to evaluate control efficacy of clonorchiasis by two schemes of repeated treatment with praziquantel at two endemic villages in China. Residents of one village at Guangxi Autonomous Region were treated and examined 6-monthly and of another at Liaoning Province 12-monthly, In residents that took 25 mg/kg x3 (total 75 mg/kg) of Praziquantel every 6 months for one Year the e99 Positive rate showed a significant drop from 69.0% to 17.1%. In contrast, a group of same praziquantel medication once showed a slight marginal decrease in the egg rate from 18.9% to 12.2% after one year Of 39 subjects examined 3 times, 56.4% were cured, 7.7% persistently positive, one (2.6%) reinfected after cure or newly infected, but 25.6% were persistently negative. The present finding suggests that 6-monthly medication with 75 mg/kg of praziquantel should effectively lower the prevalence but incomplete for control of clonorchiasis in heavy endemic areas.