Immune response of gilts to single and double infection with porcine epidemic diarrhea virus.

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.

Retrospective investigation and evolutionary analysis of a novel porcine deltacoronavirus strain detected in Thailand from 2008 to 2015.

Porcine deltacoronavirus (PDCoV) in Thailand was first detected in 2015. We performed a retrospective investigation of the presence of PDCoV in intestinal samples collected from piglets with diarrhea in Thailand from 2008 to 2015 using RT-PCR. PDCoV was found to be present as early as February 2013. Phylogenetic analysis demonstrated that all PDCoV variants from Thailand differ from those from other countries and belong to a novel group of PDCoV that is separate from the US and Chinese PDCoV variants. Evolutionary analysis suggested that the Thai PDCoV isolates probably diverged from a different ancestor from that of the Chinese and US PDCoV isolates and that this separation occurred after 1994.