한국에서의 돼지 파보바이러스 8형의 최초 검출 및 유병률 조사 = First detection and prevalence of Porcine parvovirus 8 in South Korea

다국어 초록 (Multilingual Abstract)

Porcine parvoviruses (PPV) are small, non-enveloped, ssDNA (single-stranded DNA) viruses that belong to the Parvoviridae family. In 2022, a novel porcine parvovirus 8 (PPV8) was first identified in China, and subsequently in Europe and Colombia, implying the global prevalence. The objective of this study was to investigate the prevalence of novel PPV8 in Korean swine herds as they pose a new threat to the swine industry. From October to December 2023, a total of 3,175 samples comprising 1,487 serum samples, 1,487 nasal swabs, and 201 oral fluids were collected from 40 pig farms. The samples were subsequently screened for PPV8 by polymerase chain reaction (PCR) using gene-specific primers. As a result, 35 (87.5%) out of 40 farms were positive for PPV 8, and 178 pooled samples (24.6%) out of 723 total pooled samples were positive. By sample type, 18.7% of pooled serum samples, 25.4% of pooled nasal swabs, and 44.0% of pooled oral fluid were positive for PPV8. By production stage, growing pigs showed the highest positivity rate (37.9%) among all age groups, followed by weaning (31.7%), and finishing (22.5%). Co-detection analysis further indicated that PPV8 frequently occurred alongside PRRSV and PCV2, particularly in weaning and growing pigs. Through whole genome sequencing, Korean PPV8 strains are clustered into two distinct clades (Clade I and Clade II), showing amino acid differences between the two clades in the predicted T-cell and B-cell epitopes based on the VP1/VP2 gene. These findings provide the first evidence of PPV8 detection in Korean swine herds and demonstrate that this emerging virus is already circulating in domestic pig populations. As the pathogenic significance of PPV8 remains unclear, further population-based surveillance and experimental studies are warranted to clarify its epidemiological and clinical roles.

목차 (Table of Contents)

• INTRODUCTION 1
• MATERIAL AND METHODS 4
• 1. Samples 4
• 1.1 Collected samples 4
• 1.2 Sample processing and nucleic acid extraction 5
• 2. PCR assay for Porcine parvovirus 8 (PPV8) 6
• 2.1 PCR for detection of PPV8 6
• 2.2 PCR for Whole-genome sequencing (WGS) 7
• 2.3 Cloning and sequencing of PPV8 genomes 7
• 3. Phylogenetic analysis 8
• 4. Epitope prediction analysis 9
• RESULT 10
• 1. Prevalence by sample type 10
• 2. Prevalence by age group 10
• 3. Prevalence by province 11
• 4. Prevalence by farm level 12
• 5. Co-infection of PPV8 with SIV, PRRSV, and PCV2 13
• 6. Phylogenetic analysis of PPV8 13
• 7. Predicted T-cell and B-cell epitopes 15
• DISCUSSION 17
• CONCLUSION 22
• REFERENCES 23
• 국문 초록 29
• TABLES 31
• FIGURES 39