Genetic characteristics associated with the virulence of porcine epidemic diarrhea virus (PEDV) with a naturally occurring truncated ORF3 gene

Table 3 Pathogenicity evaluation of the 17GXCZ-1ORF3d and 17GXCZ-1ORF3c variants

Groups	Inoculum dose (PFU/mL)	Mortality	Fecal shedding, log₁₀ copies/mL, by PID, mean							Onset of clinical signs as judged by PIH^a	Quantification of Viral load, log₁₀ copies/mL, mean			PEDV antigen detection in frozen tissues^b
Groups	Inoculum dose (PFU/mL)	Mortality	1	3	5	7	9	11	14	Onset of clinical signs as judged by PIH^a	D	J	I	D	J	I
17GXCZ-1ORF3d-P15 (Group A)	1.0 × 10⁶ (2 mL)	100%, 4/4	7.12	8.37	/	/	/	/	/	14–36	5.79	7.62	7.54	+	+ + +	+ + +
17GXCZ-1ORF3d-P90 (Group B)	1.0 × 10⁶ (2 mL)	25%, 1/4	-	0.99	3.42	–	–	–	–	120–144	1.13	2.08	1.15	–	–	–
17GXCZ-1ORF3d-P120 (Group C)	1.0 × 10⁶ (2 mL)	0%, 0/4	-	0.99	1.36	1.16	1.15	1.43	-	–	–	–	1.11	–	–	–
17GXCZ-1ORF3c-P15 (Group D)	1.0 × 10⁶ (2 mL)	100%, 4/4	3.31	6.98	/	/	/	/	/	18–36	5.62	3.82	6.27	–	+ +	+ + +
17GXCZ-1ORF3c-P90 (Group E)	1.0 × 10⁶ (2 mL)	100%, 4/4	5.20	5.38	6.15	/	/	/	/	30–54	3.38	3.12	5.42	–	+ +	+
17GXCZ-1ORF3c-P120 (Group F)	1.0 × 10⁶ (2 mL)	50%, 2/4	5.19	6.15	6.86	4.23	6.28	5.46	4.04	24–120	1.17	2.04	2.68	–	–	+ + +
Mock (Group G)	GM (2 mL)	0%, 0/4	–	–	–	–	–	–	–	–	–	–	–	–	–	–

^aPIH: post-inoculation hour; D: duodenum; J: jejunum; I: ileum; PFU: plaque formation unit; –: no result.
^bPEDV antigen detection in frozen tissues. + , + + , and + + + denote less than 30%, 30–60% and more than 60% of villous enterocytes, respectively, showing a PEDV antigen-positive signal. The viral loads in fecal waste and in the tissues of the small intestine were detected via RT-qPCR.

ISSN: 1297-9716