The prevalence and molecular characterization of Porcine teschoviruses in Guangdong Province, China

Porcine teschoviruses (PTVs) are globally endemic and widely circulate within pig populations. This study aimed to investigate the prevalence and genetic characteristics of PTVs in Guangdong Province, China. A total of 341 fecal and 99 tissue mixture samples were collected from pigs in seven cities across the province. These samples were screened for PTVs using reverse transcription-polymerase chain reaction (RT-PCR). The overall PTV positivity rate was determined to be 19.32%. In this study, the PTV3 PTV/CN/GD/316 strain was successfully isolated from a tissue mixture sample obtained from a pig exhibiting diarrhea. The isolation was performed using swine testicular (ST) cells. The complete viral genome of this isolate measured 6,999 nucleotides (nt) and encoded a polyprotein of 2,205 amino acids. Phylogenetic analysis of the complete VP1 gene identified seven distinct PTV genotypes (PTV2, PTV3, PTV4, PTV9, PTV14, PTV17, and PTV19) among the 21 PTV isolates obtained, with PTV3 being the dominant genotype (38.10%), followed by PTV9 (19.05%). Furthermore, our findings revealed a significant co-infection of PTVs with other common swine pathogens, including PCV2, PEDV, PCV3, PRRSV, CSFV, and PDCoV. The co-infection rate with these viruses was remarkably high, reaching 97.65%. Collectively, these data demonstrate the widespread circulation of PTVs in pig farms in Guangdong Province and highlight the prevalence of co-infection scenarios with other viral agents. The genetic analyses of all available PTV VP1 sequences also underscore the considerable diversity of PTV genotypes circulating within the Guangdong region.IMPORTANCECurrently, PTVs are widespread globally, with their infection rates showing a rising trend. The prevalence and molecular characterization of PTVs help prevent and control the spread of diseases. The findings of this study indicate a high prevalence and considerable genetic diversity of PTVs in certain areas of Guangdong Province, China. The occurrence of co-infection with other pathogens is also relatively common. Based on these data, we can better safeguard swine health and mitigate the economic impact of these infections on the agricultural industry.