1. Comparative epidemiology of porcine circovirus type 3 in pigs with different clinical presentations.
- Author
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Zhai SL, Zhou X, Zhang H, Hause BM, Lin T, Liu R, Chen QL, Wei WK, Lv DH, Wen XH, Li F, and Wang D
- Subjects
- Animals, Case-Control Studies, China epidemiology, Circoviridae Infections complications, Circoviridae Infections epidemiology, Circoviridae Infections virology, Diarrhea epidemiology, Diarrhea etiology, Diarrhea virology, Genetic Variation, Molecular Epidemiology, Phylogeny, Real-Time Polymerase Chain Reaction, Respiratory Tract Diseases epidemiology, Respiratory Tract Diseases etiology, Respiratory Tract Diseases virology, Swine Diseases pathology, Circoviridae Infections veterinary, Circovirus classification, Circovirus genetics, Diarrhea veterinary, Respiratory Tract Diseases veterinary, Swine, Swine Diseases epidemiology, Swine Diseases virology
- Abstract
Background: Porcine circovirus type 3 (PCV3), as an emerging circovirus species, was reported to be widely circulating in the United States, China, South Korea and Poland. Previous studies revealed that PCV3 was mainly concentrated in sick animals with respiratory disease, skin disease, reproductive disorders and so on. However, the circulating status of PCV3 in pigs with other clinical presentations (especilly asymptomatic or diarrhea) was not well established., Findings: In this study, to conduct a comparative epidemiological survey of PCV3, 80 weaned pig serum samples with severe respiratory disease (SRD), 175 weaned pig serum samples with mild respiratory disease (MRD), 216 asymptomatic weaned pig serum samples, 35 diarrheal weaned pig samples and 35 non-diarrheal weaned pig samples were collected from eight provinces of China. Via qPCR testing, PCV3 was circulating in all sampling provinces, with total positive rates varying from 1.04% to 100%. Interestingly, the PCV3-positive rate was significantly higher in weaned pigs with SRD (63.75%, 51/80) than in those weaned pigs with MRD (13.14%, 23/175) and asymptomatic pigs (1.85%, 4/216) (P < 0.01). Similarly, the PCV3-positive rate was significantly higher in diarrheal weaned pigs (17.14%, 6/35) than in non-diarrheal weaned pigs (2.86%, 1/35) (P < 0.05). Moreover, the lower Ct values of qPCR were frequently found in those weaned pigs or fattening pigs with respiratory disease and diarrhea rather than that in asymptomatic pigs. Sequence analysis showed that low genetic diversity existed among those PCV3 sequences collected from pigs with different clinical presentations., Conclusions: The present study further extends evidence that newly described PCV3 widely circulates in six additional provinces of Southern and Northern China and has high similarity to previously reported isolates. As an emerging virus of swine, although the present case-control study reveals that PCV3 has a potential association with swine respiratory disease and diarrhea, further investigations into the pathogenesis are needed to ascertain the role of PCV3 in swine health.
- Published
- 2017
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