Fig. 1.

Characteristics of epidemics of PEDV from 2011 to 2021 in China. (A) A schematic representation of 149,869 fecal and intestinal tissue samples of pigs collected from the year 2011 to 2021. The upset plot arranged five common swine diarrhea-causing viruses: PEDV, TPEV, RV, PDCoV, SADS-CoV. The color shades and the size of circles represent the yearly sample size. (B) Phylogeographic distributions of 65 whole genomes sequenced PEDV strains from the year 2011 to 2021 in the study. The topological tree was built with the maximum likelihood method and 1,000 bootstrap replicates. The branch of the strain GDS09, belonging to the G1 genotype, is depicted in black in the phylogenetic tree. The size of circles in the provinces represents the sample size of sequenced PEDV full genomes. (C) Cytopathic effects of Vero-E6 cells infected with three representative PEDV strains (GDS29, JSS04, and GDS09) at 6, 12, 24, or 36 h postinfection (hpi), scale bar indicates 100 μm. (D) Immunofluorescence staining of the PEDV S protein in infected Vero-E6 cells. Cells were fixed at 6, 12, 24, or 36 hpi, and S protein was detected by indirect IFA. Nuclei were shown by 40,6-diamidino-2-phenylindole staining. The images of cells were acquired by a fluorescence microscope (Nikon Eclipse 80i), scale bar indicates 100 μm. (E) Viral titers in the culture supernatants were determined by TCID₅₀ assay. Data are shown as mean ± SEM and are representative of three independent experiments.