Virus neutralizing antibody titers in PEDV infected sows. (A) Plasma, (B) Oral fluid and (C) fecal samples were analyzed for the VN titers against PEDV by immunofluorescence assay. The VN titer was determined as the reciprocal dilution of the test sample that induced greater than 90% inhibition of viral infection. Each bar represents mean VN titers ± SEM from six sows. Lower case alphabet indicates a statistically significant difference (“a” P < 0.05 and “b” P < 0.01) between mock-uninfected and PEDV-infected corresponding primiparous and multiparous sow groups.