ABSTRACT
In this study, 650 tissue samples which were collected from 16 pig farms in Hubei Province, were used to detect porcine circovirus (PCV) and Porcine epidemic diarrhea virus (PEDV). The results showed that the positive rates of PCV1, PCV2, PCV3 and PEDV single infection were 1.08%, 4.15%, 2.46% and 6.46%, respectively. In the double infections, PEDV+PCV2 had the highest positive rate of 3.54%, followed by PCV2+PCV3, with a positive rate of 1.54%. In multiple infections, PEDV+PCV2+PCV3 had the highest positive rate of 2.00%. The results indicated that the positive rates of PEDV and PCV were decreased compared with the previous studies, but the prevalence of PEDV and PCV was still wide in Hubei Province, and most of which were co-infection.
ABSTRACT
Swine enteric viruses are a major cause of piglet diarrhea, causing a devastating impact on the pork industry. To further understand the molecular epidemiology and evolutionary diversity of swine enteric viruses, we carried out a molecular epidemiological investigation of swine enteric viruses (PEDV, PDCoV, PoRVA, and TGEV) on 7107 samples collected from pig farms in south-central China. The results demonstrated that PEDV is the predominant pathogen causing piglet diarrhea, and its infection occurs mainly in relatively cold winter and spring in Hunan and Hubei provinces. The positive rate of PEDV showed an abnormal increase from 2020 to 2021, and that of PoRVA and PDCoV exhibited gradual increases from 2018 to 2021. PEDV-PoRVA and PEDV-PDCoV were the dominant co-infection modes. A genetic evolution analysis based on the PEDV S1 gene and ORF3 gene revealed that the PEDV GII-a is currently epidemic genotype, and the ORF3 gene of DY2020 belongs to a different clade relative to other GII-a strains isolated in this study. Overall, our results indicated that the variant PEDV GII-a is the main pathogen of piglet diarrhea with a trend of outbreak. G9 is the dominant PoRVA genotype and has the possibility of outbreak as well. It is therefore critical to strengthen the surveillance of PEDV and PoRVA, and to provide technical reserves for the prevention and control of piglet diarrhea.