• Korean Journal of Veterinary Service
• /
• v.32 no.3
• /
• pp.177-187
• /
• 2009

The purpose of this study was to evaluate the effect of a subsequent infection of PCV2 on piglets with PEDV. The results obtained were as follows: Antibodies against PCV2 and PEDV were detected at 24, 36, 48, 60 and 72h postinfection. And the antibody titers of alone infections with PEDV were gradually reduced and increased from 60 hpi to 72 hpi. Whereas, the antibody titers of dual infections with PCV2 and PEDV were gradually reduced all the time. PEDV antigens were detected at 24, 36, 48, 60 and 72 hpi, being seen almost exclusively in feces and small intestines from PEDV-infected piglets and PCV2-coinfected piglets. The detection rate of PEDV in feces and jejunum tissues by RT-PCR were 94.9% and 91.1% in dual infections and 87.1% and 83.6% in alone infections with PEDV, respectively. In dual infected piglets, significantly more PEDV antigens were detected in the feces and small intestines tissues at 24 hpi (P<0.05) than in the same feces and tissues of the alone infected piglets. Thereafter, at 72 hpi significantly more PEDV antigens (P<0.05) was detected in the jejunal tissues of the dual infected piglets with than of alone PEDV-infected piglets. The detection rate of PEDV antigen in the duodenum, jejunum and ileum by IFA were 91.3%, 91.3% and 83.3% in dual infected piglets and 75.0%, 83% and 75% in alone infected piglets, respectively. Intense and specific fluorescence signals were more often seen within jejunal villous enterocytes in dual infected piglets than alone infected piglets.

• Korean Journal of Veterinary Service
• /
• v.34 no.2
• /
• pp.117-123
• /
• 2011

This experiment was conducted to investigate the presence of recognized abortifacient viruses from aborted fetuses and stillborn piglets in cases of reproductive failure in sows by PCR. A total of 219 samples of aborted fetuses or stillborn piglets, submitted to the School of Veterinary Medicine of Kangwon National University between 2006 and 2009 May, were collected from 5 provinces in Korea. Abortifacient virus infections were detected in 82 (37.4%) out of 219 aborted fetuses or stillborn piglets as well as on 39 (40.2%) out of 97 pig farms. The major viral infections were porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV) and Aujesky's disease virus (ADV) for which 46 (21%), 19 (8.6%) and 16 (7.3%) were positive, respectively, with 9 fetuses had complicated infection of PCV2+PRRSV or ADV or both. And 8 (3.6%) for SIV, 3 (1.3%) for PPV and 1 (0.4%) for JEV were positive as minor viral infection. The results suggest that PCV2, PRRSV, ADV is apparently the most important viral infectious agents associated with fetal infection leading to abortion or stillbirth in Korea. SIV, PPV and JEV might have a minor impact on reproductive disease.

• Korean Journal of Veterinary Service
• /
• v.32 no.3
• /
• pp.189-200
• /
• 2009

The purpose of this study was to evaluate the effect of a subsequent infection of PCV2 on piglets with PEDV. In clinical signs, the signs observed in dual-infected with PEDV and PCV2 piglets and alone infected with PEDV piglets ranged from diarrhoea to vomiting and dehydration. Dual-infected piglets developed signs of anorexia, vomiting and watery diarrhoea within 12 hpi. Nevertheless alone -infected piglets caused pasty diarrhea at first. In mortality, dual infections showed 25%, but alone -infections showed 8.3%, respectively. In gross findings, piglets dual-infected with PEDV and PCV2 appeared the severe findings of congestion, distension of lumen, milder curdes of undigested milk in stomach than those of single-infected piglets. In histopathological findings, piglets of dual-infection group appeared the more severe findings of villous atrophy and fusion, congesion, exfoliation, vacuolation, squamation, loss of cilia and proliferation of crypt. Significant (P<0.05) decrease in VH:CD ratio in dually infected piglets compared to piglets from alone-PEDV infections. In immunohistochemical findings, strong hybridization signals in dual-infected piglets observed moderate to severe villous atrophy or vacuolation with positive cells arranged continuously over the villi. In the lumen, exfoliated enterocytes were strongly positive in dual-infected piglets. A number of PEDV-positive cells in dual-infected pigs were significantly higher than that in alone PEDV-infected piglets.

• Korean Journal of Veterinary Service
• /
• v.41 no.3
• /
• pp.203-210
• /
• 2018

Pasteurella multocida is an opportunistic organism that plays a significant role in porcine respiratory disease complex (PRDC). In the current study, we provide nationwide information of P. multocida isolates from pneumonic lungs of slaughter pigs by determining their prevalence, subspecies, biovars, capsular types, virulence-associated genes, and minimum inhibitory concentrations. P. multocida was the second most frequently confirmed (19.2%) bacterial pathogen and most of the isolates (88.9%) showed simultaneous infection with other respiratory pathogens, especially Mycoplasma hyopneumoniae (63.3%, P<0.001) and porcine circovirus type 2 (53.3%, P=0.0205). Of 42 isolates investigated, 41 (97.6%) were identified as P. multocida subspecies multocida, and only one isolate was identified as subspecies septica (biovar 5). All the isolates were capsular type A and the most prevalent biovar was biovar 3 (40.5%), followed by biovar 2 (31.0%). Comparing virulence-associated genes and biovars, all biovar 2 isolates exhibited $hgbB^-pfhA^+$ (P<0.001); all biovar 3 (P=0.0002) and biovar 13 (P=0.0063) isolates presented $hgbB^+pfhA^-$. Additionally, all biovar 2 (P=0.0037) isolates and most of biovar 3 (P=0.0265) isolates harbored tadD. P. multocida showed the highest resistance levels to oxytetracycline (73.8%), followed by florfenicol (11.9%). Continuous monitoring is required for surveillance of the antimicrobial resistance and new emerging strains of P. multocida in slaughter lines.

• Korean Journal of Veterinary Service
• /
• v.39 no.4
• /
• pp.231-237
• /
• 2016

The present study was conducted to investigate the lesion of red internal organs in slaughtered pigs and provided assistant data for pig farms. During March to December 2015, a total of 1,160 lung samples out of 58 herds were collected randomly from pigs slaughtered in Jeonbuk province. In addition, 290 hilar lymph nodes from pig with pneumonic lung lesion (5 samples per herd) were screened for selected viral and bacterial pathogens. Gross lesions of lungs such as swine enzootic pneumonia (SEP), pleuritis, pleuropneumonia, pericarditis and liver white spots were examined. The overall prevalence of SEP was 64.3% (746/1,160). In the analysis of seasonal prevalence, there was an increase of occurrence during the spring months (287/400, 71.8%) and decrease during the fall months (93/200, 46.5%) among the whole herds. The mean number of SEP score per pig was $1.20{\pm}1.28$. The prevalence of pleuropneumonia, pleuritis, pericarditis, and milk spot was 25.5% (296/1,160), 44.1% (512/1,160), 3.8% (44/1,160) and 17.6% (204/1,160), respectively. The most frequent region with lung lesion was diaphragmatic lobes (left 17.1%, right 17.3%). In the detection of viral pathogens by PCR, porcine circovirus type2 (PCV2) was positive in 86.9% (252/290), while porcine reproductive and respiratory syndrome virus (PRRSV) was not detected, In the case of bacterial pathogens, 50 microorganisms were isolated by PCR and/or microbiological test. The most frequently isolated bacteria was Streptococcus suis (20, 34.4%), followed by Pasteurella multocida (17, 29.3%), Streptococcus spp. (11, 3.4%), Actinobacillus pleuropneumoniae (2, 8.9%).

• Korean Journal of Veterinary Research
• /
• v.51 no.1
• /
• pp.7-14
• /
• 2011

This study was focused on the genotyping and quantification of Porcine circovirus type 2 (PCV2) in thirty PCV2-positive pigs with different clinical symptoms (PCV2-infected without wasting, PCV2-infected with wasting, PCV2-infected with wasting and lymphoid depletion). The quantity of PCV2 DNA in diverse tissues was significantly differed among these groups. (One-way ANOVA test, p<0.001) Interestingly, PCV2-DNA load in tissues of PCV2-infected pigs without wasting and PCV2-infected pigs with wasting and lymphoid depletion were not significantly differed (p = 0.38), while they were all significantly higher when compared with PCV2-infected pigs with wasting-only. PCV2 DNA quantity in tissues was significantly higher in PCV2a and 2b co-infected pigs compared to the PCV2b only-infected pigs (Wilcoxon test, p = 0.039). The PCV2a and 2b co-infected pigs had increased wasting and lymphoid depletion rate but it was not statistically significant. Therefore, this cross-sectional study suggested that PCV2 DNA load in tissues was diverse by clinical and histological findings. Furthermore, co-infection of PCV2a and 2b affected to the PCV2 DNA load in tissues with increased rate of wasting and lymphoid depletion.

• Korean Journal of Veterinary Research
• /
• v.50 no.4
• /
• pp.265-271
• /
• 2010

Post-weaning multisystemic wasting syndrome (PMWS) is a new emerging disease affecting nursery and growing pigs in worldwide. Porcine circovirus type 2 (PCV-2) is a most important pathogen associated with PMWS. This study was carried out to investigate the pathological changes in the pancreas of pigs diagnosed as PMWS. To detect the PCV-2 antigen and nucleic acid in the tissue, immunohistochemistry and polymerase chain reaction (PCR) was conducted, respectively. 24 pigs of 4-10 weeks old showed clinical signs of PMWS such as chronic wasting, respiratory distress and diarrhea were examined. Histopathologically, interstitial and periductular mononuclear cells infiltration were observed in pancreas. Multifocal to diffuse necrosis of acinar tissues or necrotizing to granulomatous pancreastitis with numerous syncytial cells infiltration were examined in severe cases. PCV-2 nucleic acid was detected from all tested pancreas using PCR. The PCV-2 antigen in 12 pancreas sections was detected by immunohistochemical staining. PCV-2 has a tropism for vascular endothelial cells and infiltrated macrophages. Although gross lesions are uncommon in the pancreas of pigs with PMWS, histopathological changes and the presence of PCV-2 in this tissue may be related to clinical signs associated with digestive disorders.

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