Attenuation of a Highly Pathogenic Porcine Deltacoronavirus Strain CZ2020 by a Serial Passage In Vitro

Figure 4

Clinical signs, diarrhea scoring, and fecal viral shedding analyses of the piglets inoculated with PDCoV CZ2020 and its high passages. (a) Representative images of three-day-old pigs challenged or mock-challenged with indicated PDCoVs. (b) Three-day-old piglets were orally inoculated with 2 × 10⁵ TCID₅₀ of indicated PDCoVs per pig or mock inoculated with DMEM. Fecal consistency was scored as the following criteria: 0 = solid feces, 1 = pasty feces, 2 = semiliquid feces, 3 = liquid feces, respectively. The plot was drawn based on the fecal consistency scores. (c) Rectal swabs were collected daily from each inoculated piglet, and the viral RNA was quantified by TaqMan-based RT-qPCR with primers targeting the N gene.

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