Complete Genome Sequence of a Porcine Epidemic Diarrhea Virus Strain from Vietnam, HUA-14PED96, with a Large Genomic Deletion.

A highly virulent strain of Porcine epidemic diarrhea virus (PEDV) causing severe diarrhea has recently emerged in Vietnam. Genomic sequences from a novel strain, HUA-14PED96, isolated from a Vietnamese piglet with serious diarrhea show relatively high identity with U.S.-like PEDV strains, and have a 72-nt deletion in the open reading frame 1a (ORF1a) gene.

A novel strain of porcine epidemic diarrhea virus in Vietnamese pigs.

Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea and dehydration in suckling pigs and has caused high rates of death among piglets and substantial economic loss in Vietnam since 2009. To investigate the genotypes of prevailing PEDVs, intestinal and fecal samples from piglets from central and northern Vietnam were collected and analyzed. Phylogenetic analysis of the nucleotide sequences of complete spike genes of PEDVs from Vietnam resulted in the identification of two divergent groups. PEDVs (HUA-PED45 and HUA-PED47) belonged to the G2b group, along with Chinese, US, and Korean strains occurring at the end of 2010, in May 2013 and in November 2013, respectively. Six strains from the Quang Tri region were assigned to the G1b group, along with Chinese and US strains. The Vietnamese PEDVs detected in infected piglets had a nationwide distribution and belonged to the G2b and G1b genotypes.

A rapid molecular strategy for early detection and characterization of Vietnamese foot-and-mouth disease virus serotypes O, A, and Asia 1.

A one-step RT-PCR method using newly designed primers VN-VP1F/VN-VP1R targeting the full VP1 capsid protein-coding gene, combined with direct sequencing of its PCR product, has been developed successfully for universal detection and characterization of Vietnamese FMDV serotypes O, A, and Asia 1 directly from clinical samples. The one-step RT-PCR amplified 821-bp dsDNA products covering the entire VP1 gene of FMDV serotypes O, A, and Asia 1. The obtained dsDNA products were suitable for direct sequencing, cloning, and other molecular epidemiology studies of Vietnamese FMDV strains, which eliminated the need for cell culture and virus purification. This one-step RT-PCR system was applied to detect and characterize 55 field FMDV strains, including 34 serotype O, 17 serotype A, and 4 serotype Asia 1 isolates collected from endemic outbreaks in Vietnam from 2005 to 2010. Interestingly, the PCR products obtained from the present PCR method could be used as DNA templates for the second PCR typing method using serotypes O, A, and Asia 1-specific primers (Le et al., 2011). The use of the second PCR amplification increased markedly the sensitivity of the test for FMDV detection. The present RT-PCR method promises to be an effective tool for molecular epidemiological studies of FMD in Vietnam.