No abstract

Since outbreaks of porcine epidemic diarrhea virus (PEDV) in the United States in 2013, explosive outbreaks of PED in South Korea have infected all age groups of pigs in 2014-2015year. This study analyzed a large collection of the Spike protein coding gene to infer the spatial-temporal diffusion history of PEDV. The studying results suggested that PEDVs in Korea belonged to different genogroups. While classical G1 was continuingly circulating between provinces of Korea, the pandemic G2a were recently introduced from China and USA. By the application of Bayesian phylogeographical analysis, this study demonstrated the spatial-temporal transmission of PEDVs within Korea. Of the recent emerged G2a viruses, J3142 strains showed potential recombination breakpoint (376-2,143nt) of S1 gene between KNU1303_Korea strain_G2a (KJ451046) and 45RWVCF0712_Thailand strain_G2b (KF724935). The pandemic G2a virus was partial neutralized by the antibodies invoked by the G1- based PED vaccine virus.

This study was conducted to determine if humoral antibody response of foot-and-mouth disease (FMD) vaccine improved in 8-week-old growing pigs born to well-vaccinated sows pre-treated with 60 mg of poly-γ-glutamic acid (γ-PGA) three days before vaccination. Antibody against FMD virus serotype O was measured 0, 2, 4 and 6 weeks post-vaccination, using a PrioCHECK FMDV type O ELISA kit. The results showed that positive antibody reactions against FMDV serotype O antigen among a component of the vaccine significantly increased in response to pre-injection with γ-PGA.

SummaryTo effectively suppress porcine endogenous retroviruses (PERV)s, RNAi technique was utilized. RNAi is the up-to-date skill for gene knockdown which simultaneously multitargets both gag and pol genes critical for replication of PERVs. Previously, two of the most effective siRNAs (gag2, pol2) were found to reduce the expression of PERVs. Concurrent treatment of these two siRNAs (gag2+pol2) showed knockdown efficiency of up to 88% compared to negative control. However, despite the high initial knockdown efficiency 48 h after transfection caused by siRNA, it may only be a transient effect of suppressing PERVs. The multitargeting vector was designed, containing both gag and pol genes and making use of POL II miR Expression Vector, which allowed for persistent and multiple targeting. This is the latest shRNA system technique expressing and targeting like miRNA. Through antibiotics resistance characteristics utilizing this vector, miRNA-transfected PK15 cells (gag2-pol2) were selected during 10 days. An 88.1% reduction in the level of mRNA expression was found. In addition, we performed RT-activity analysis and fluorescence in situ hybridization assay, and it demonstrated the highest knockdown efficiency in multitargeting (gag2+pol2) miRNA group. Therefore, according to the results above, gene knockdown system (siRNA and shRNA) through multitargeting strategy could effectively inhibit PERVs.

Two porcine deltacoronavirus (PDCoV) strains, named DH1/2016 and DH2/2016, were isolated from feces of piglets which had severe watery diarrhea symptoms. A comparison of the complete genome sequences suggested that the DH1/2016 and DH2/2016 strains are highly homologous to each other and to PDCoVs isolated in early 2014 from the United States.