Immune response of gilts following single and double infection with porcine epidemic diarrhea virus (PEDV) at gilt acclimatization and prepartum were investigated. One hundred PEDV-naïve gilts were divided into two groups: negative (Neg) and feedback (FB) groups. Antibody responses in serum, colostrum, and milk samples were measured by IgG/IgA ELISA and virus neutralization assay (VN). Fecal shedding was investigated using RT-PCR. In summary, a single infection at gilt acclimatization resulted in slightly increased serum antibody titers as determined by VN assay and IgG ELISA, but not by IgA ELISA. Viral RNA was detected in fecal samples up to 6 days post-exposure. A double infection at prepartum resulted in significantly increased IgA and VN titers in milk samples compared to the single-infection group. No fecal shedding was detected following the double infection.
Keywords: Lactogenic immunity; Oral exposure; Porcine epidemic diarrhea virus; Thailand.