The swine hepatitis E virus (HEV) is considered to be a new zoonotic agent due to its close genomic resemblance to the human HEV and its ability to infect nonhuman primates. Hepatitis caused by HEV infection has been a serious public health problem in developing countries. However, recent seroprevalence studies indicate that the HEV also circulates in industrialized countries. In this study, a nested reverse transcription (RT)-PCR was developed to detect a part of the swine HEV open reading frame 2. Three Korean isolates of swine HEV were identified in 128 swine sera (2.3% prevalence) by the nested RT-PCR method. They were isolated from 2-to 3-month old pigs showing an age-specific prevalence of the HEV viremia. A phylogenetic tree analysis with a number of swine and human HEV isolates indicated that all Korean isolates of the swine HEV belong to genotype III. They were closely related to the swine and human HEV isolates that were identified in the United States and Japan. In addition, they formed a distinct branch in genotype III, showing a 92.7 to 99.8% identity at their nucleotide sequences. The overall prevalence of anti-swine HEV antibodies in swine was 15%. Antibodies to the swine HEV were not detected in 1-month-old pigs. However, the anti-swine HEV antibodies appeared in pigs older than 1 month and also showed an age-specific prevalence. The antibody prevalence rates to the swine HEV were 6.0, 10.0, 36.0, and 25.0%, in 2-, 3-, 4-, and 5-to-7-month-old pigs, respectively. In addition, the seroprevalence in sows to the swine HEV was 8.8%. On the other hand, 18% of blood donors in Korea were found to be positive for anti-HEV antibodies. Overall, this study indicates that subclinical HEV infections may prevail in swine and human populations in Korea.The hepatitis E virus (HEV) was originally identified as the causative agent of enterically transmitted non-A, non-B hepatitis (33). HEV-mediated hepatitis is a serious public health problem in developing countries of Asia, Middle East, and Africa and also in Mexico (1). The highest incidence of HEV infections occurs in young adults, and the mortality rate of HEV-infected pregnant women is approximately 20% (1,4,12,17,20). HEV is mainly transmitted through a fecal-oral route by consuming contaminated water (3, 13). It is a nonenveloped small virus with an approximately 7.5-kb single-stranded, positive-sense RNA genome (9, 40). HEV was previously classified into the family Caliciviridae. However, it is now reclassified into the Hepatitis E-like viruses as an unassigned genus (8,32). The HEV genome is composed of three open reading frames (ORF). These are ORF 1, 2, and 3, which encode the nonstructural proteins, the capsid protein, and a cytoskeletonassociated phosphoprotein, respectively (9,40,51).HEV isolates are generally classified into four genotypes based on the phylogenetic analysis of the full-length genome (37). Genotypes 1, 2, 3, and 4 are represented by the Burmese isolates, the Mexican isolate, the U.S. isolates, and the new Chinese isolates, respective...

A recombinant La Sota strain (KBNP-C4152R2L) in which fusion (F) and hemagglutinin-neuraminidase (HN) genes were replaced with those of a contemporary genotype VIId virus, KBNP-4152, has been developed. To attenuate the virulence of the recombinant strain, the F cleavage motif was mutated from 112 RRQKR 116 to 112 GRQAR 116 , and to reduce pathogenic instability, a codon which does not allow changes to basic amino acids by single point mutation was inserted at codon 115. In addition a six-nucleotide sequence was inserted into the intergenic region between matrix protein and F genes for attenuation without breaking the "rule-of-six." The HN protein length was increased from 571 to 577 as a marker. Serological tests revealed that the antigenicity of KBNP-C4152R2L was similar to that of KBNP-4152 but distinct from that of the La Sota strain. KBNP-C4152R2L was avirulent (intracerebral pathogenicity index, 0.0; mean death time, >168 h) and stable in pathogenicity through in vivo passages. The killed oil emulsion of and live KBNP-C4152R2L were completely protective against mortality and egg drop caused by virulent strains, and KBNP-C4152R2L was applicable to in ovo vaccination. Therefore, KBNP-C4152R2L is a promising vaccine strain and viral vector in terms of antigenicity, productivity, safety, and pathogenic stability.

In general, three-dimensional ground reaction forces (GRFs) and ground reaction moments (GRMs) that occur during human gait are measured using a force plate, which are expensive and have spatial limitations. Therefore, we proposed a prediction model for GRFs and GRMs, which only uses plantar pressure information measured from insole pressure sensors with a wavelet neural network (WNN) and principal component analysis-mutual information (PCA-MI). For this, the prediction model estimated GRFs and GRMs with three different gait speeds (slow, normal, and fast groups) and healthy/pathological gait patterns (healthy and adolescent idiopathic scoliosis (AIS) groups). Model performance was validated using correlation coefficients (r) and the normalized root mean square error (NRMSE%) and was compared to the prediction accuracy of the previous methods using the same dataset. As a result, the performance of the GRF and GRM prediction model proposed in this study (slow group: r = 0.840-0.989 and NRMSE% = 10.693-15.894%; normal group: r = 0.847-0.988 and NRMSE% = 10.920-19.216%; fast group: r = 0.823-0.953 and NRMSE% = 12.009-20.182%; healthy group: r = 0.836-0.976 and NRMSE% = 12.920-18.088%; and AIS group: r = 0.917-0.993 and NRMSE% = 7.914-15.671%) was better than that of the prediction models suggested in previous studies for every group and component (p < 0.05 or 0.01). The results indicated that the proposed model has improved performance compared to previous prediction models.

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