• Korean Journal of Veterinary Service
• /
• v.45 no.2
• /
• pp.87-99
• /
• 2022

A novel porcine circovirus 4 (PCV4) was recently emerged in Chinese and Korean pig herds, which provided epidemiological situation where three pathogenic PCVs, PCV2, PCV3, and newly emerged PCV4, could co-infect pig herds in these countries. In this study, a new triplex quantitative real-time polymerase chain reaction (tqPCR) method was developed for the rapid and differential detection of these viruses. The assay specifically amplified each viral capsid gene, whereas no other porcine pathogenic genes were detected. The detection limit of the assay was below 10 copies/µL and the assay showed high repeatability and reproducibility. In the clinical evaluation using 1476 clinical samples from 198 Korean pig farms, the detection rates of PCV2, PCV3 and PCV4 by the tqPCR assay were 13.8%, 25.4%, and 3.8%, respectively, which were 100% agreement with those of previously reported monoplex qPCR assays for PCV2, PCV3, and PCV4, with a κ value (95% CI) of 1 (1.00~1.00). The prevalence of PCV2, PCV3, and PCV4 at the farm levels were 46.5%, 63.6%, and 19.7%, respectively. The co-infection analysis for tested pig farms showed that single infection rates for PCV2, PCV3, and PCV4 were 28.8%, 44.4%, and 9.6%, respectively, the dual infection rates of PCV2 and PCV3, PCV2 and PCV4, and PCV3 and PCV4 were 12.6%, 3.5%, and 5.1%, respectively, and the triple infection rate for PCV2, PCV3, and PCV4 was 1.5%. These results demonstrate that three pathogenic PCVs are widely spread, and their co-infections are common in Korean pig herds, and the newly developed tqPCR assay will be useful for etiological and epidemiological studies of these pathogenic PCVs.

• Korean Journal of Veterinary Service
• /
• v.24 no.2
• /
• pp.127-132
• /
• 2001

Porcine circoviruses(PCV) are the smallest nonenveloped DNA viruses containing a unique single-stranded circular genome. No recognized link was found between PCV infection of pig and disease. But the PCV consistently identified from postweaning multisystemic wasting syndrome(PMWS) and researches indicate that there are strong relationships between PCV and PMWS. Clinical signs were emaciation, dyspnea, high fever with normal appetite. Necropsy findings showed respiratory disease complex lesion and lymph node anomalities. An indirect-immunofluorescent antibody procedure was used to assay swine sera for the presence of PCV atibodies. Antibodies against PCV were found in an average of 20% of the samples tested. The PCV DNA was amplified from lymph nodes collected from pigs. PCV specific primers were successfully amplified PCV DNAs. Further studies are needed to determine the possible role this virus might have in disease.

• Korean Journal of Veterinary Research
• /
• v.41 no.4
• /
• pp.505-510
• /
• 2001

A total of 701 swine sera from 55 swine farms (Mar, 1998 through Feb, 2001) were nation-widely collected for the presence of antibody to porcine parvovirus (PPV) in sows and 30-, 60-, 90-day-old pigs. Sero-prevalence by haemagglutination inhibition assay with guinea pig red blood cells was investigated on the basis of year, region and season, respectively. In general, there was no significant difference with gradual decrease of passive immunity for the sero-prevalence to PPV in sows and 30-, 60-, 90-day-old pigs for the period of 1999 and 2000. However, regional variation was observed in the provinces of Kyonggi, Choongnam and Kyungnam, Natural infection of the virus in 90-day-old pigs was increased during the fall and the winter. Thus, it seems that the natural infection of PPV in growing pigs may be attributed to the increased outbreak of postweaning multisystemic wasting syndorme in co-infection with porcine circoviruses.

• Korean Journal of Veterinary Service
• /
• v.46 no.4
• /
• pp.315-324
• /
• 2023

This study was carried out to investigate the genotypic diversity of PCV2 and co-infection of PCV3 in the hilar lymph nodes of 700 randomly-selected slaughter pigs. Fourteen samples per each farm were obtained from 50 farms between February and August in 2022. Of the 50 farms, 44 farms that had been positive for PCV2 by RT-PCR were genotyped. As a result of PCV2 genotyping, positive rate of PCV2 DNA was 62.3% (436/700). Among the PCV2 DNA-positive samples, positive rate of a single PCV2 genotype was 79.1% (345/436), while multiple PCV2 genotypes were only detected in 20.9% (91/436). Of the 436 single infection cases, PCV2d genotype was most prevalent. Positive rates of PCV2 and PCV3 were 53.6% and 26.0% at the sample level, 5.1% and 8.0% at the farm level, respectively. And the co-positive rate of two viruses was 8.7% (61/700) at the sample level, 62.0% (31/50) at the farm level. These results demonstrate that PCV2 prevalence in slaughter pigs is very high and co-infection between different PCV2 genotypes and between PCV2 and PCV3 is relatively common. Therefore, genetic diversity and co-infection between other porcine circoviruses should be consistently monitored in the future.

• Korean Journal of Veterinary Research
• /
• v.39 no.2
• /
• pp.353-358
• /
• 1999

New emerging post weaning multisystemic wasting syndrome (PMWS) threatening swine industry worldwide and investigation of the etiological agent is underway. The porcine circovirus (PCV) consistently identified from PMWS pigs and research result indicate that there is strong relationship between PCV and PMWS. Fauns with PMWS submitted pigs suffered from various PMWS typical signs and necropsy finding showed lymph node anomalies. The PCV DNA was amplified from inguinal lymph node collected from pigs with PMWS. PCV specific primers were successfully amplified PCV DNAs and were able to differentiate PCV type I and II. We have identified noble PCV virus with genetic variation. The virus showed insertion of the nucleic acid at the 5' of the genome but did not have PCR product with primer set corresponding to PCV type II virus.