Search

The first confirmed case of African swine fever (ASF) in Vietnam was officially reported in February 2019. To date, the ASF virus (ASFV) has been detected in all 63 cities/provinces in Vietnam. In order to get a better understanding of the potential role of the EP402R gene in a grouping of ASFV serotypes, thirty ASFV sequences of EP402R genes (accession numbers: MN711757-86) from North Central Coast of Vietnam and 68 well-known references of serotype groups from previous studies were further analyzed. Interestingly, we found that a short fragment of 90 nucleotides was very typical for 8 serological groups of ASFVs. A primer set was designed to amplicon the short fragment of 90 nucleotides using the Primer3 program to establish a simplified method for the serotyping of ASFV. Our results indicated that phylogenetic analysis of the short fragment (90 nucleotides) of the EP402R gene is a very specific and useful method for ASFV serotyping when compared to the previous method using a long fragment (816 nucleotides) of this gene and well-known serotype references based on haemadsorption inhibition (HAI) assay.

Background: African swine fever (ASF) is a highly contagious and deadly viral disease affecting domestic and wild pigs of all ages. African swine fever virus (ASFV) has spread rapidly through Eastern and Southeastern Asia first appearing in Vietnam in 2019. Objectives: Molecular typing of African swine fever virus (ASFV) in Vietnam has identified two principal variants circulating based on the sequencing of the intergenic region (IRG) between the I73R and I329L genes. Identification of additional genetic markers would enable higher resolution tracing of outbreaks within the country. Methods: Sequence analysis suggested the IRG between the A179L and A137R genes may also exhibit variability, PCR primers were designed and samples from Vietnam were subject to Sanger sequencing. Results: We developed a novel method for sub‐grouping of ASFV based on the IRG between the A179L and A137R genes of ASFV. Our results demonstrated that the finding of the insertion or deletion of an 11‐ nucleotide sequence (GATACAATTGT) between the A179L‐A137R genes. Conclusions: The sub‐grouping method may provide useful insights into the evolution of genotype II ASFV as well as providing evidence of a relationship between geographically separated outbreaks. [ABSTRACT FROM AUTHOR]