Difference of the pathogenicity and humoral immune status in Chinese virulent genotype GIIa and GIIb porcine epidemic diarrhea virus strain infected conventional one-and two-month-old weaned pigs.

Abstract Although the pathogenicity of GII-genotype PEDV strains infected pigs have been extensively studied, little is known about the differences in pathogenicity and humoral immune status between the GIIa and GIIb subgenotypes. Hence, in the present study, we compared the differences of pathogenicity and humoral immunity status in one-and two-month-old weaned pigs elicited by Chinese virulent genotype GIIa (CH/HBXT/2018) and GIIb (CH/HNPJ/2017) PEDV strains. The results showed that all pigs in one-and two-month-old infected with GIIa strain developed severe diarrhea (100%), while the morbidity of GIIb strain in one-and two-month-old pigs were 80% (4/5) and 20% (2/5), respectively. GIIa strain produced higher levels of PEDV specific IgG, IgA and VN antibodies compared GIIb strain in the study. Taken together, the data presented indicate that GIIa strain was more pathogenic and produced higher levels of PEDV specific antibodies.