A safe and convenient chikungunya-pseudotyped lentiviral vector for epidemiological studies on chikungunya virus in Thailand

Abstract

Background: Recently, the pertussis incidences in Korea has een increasing. The average annual incidence of 2000-2008 was 8 cases/year. However, it was rapily increased to 66 cases/year at 009. Moreover, the pertussis incidence was most high in 2011, 89 ases/year. for last 10 years. Therefore, we analyzed the genotype ariations of 7 house keeping genes and 10 antigenic determinant enes to evaluate the the level of genotype changes in currently istributing strains. Methods: Total 83B. pertussis strains isolated from2000 to 2011 ere analyzed in this study. The target genes were 7 house keepng genes and 10 antigenic determinant genes. After sequencing of arget genes, the sequence data were querried to Bordetella MLST equence type database for determining of genotype and bacterial equence type. The genotype profiles and the relatedness among ach genotypes were analyzed by MLST program packages. Results: As compared to house keeping genes set, more variant atternwasobserved inantigenicdeterminantgenes set. Especially txS1 gene was the most variant gene. In the bacterial sequence ype, the number of observed sequence types during last 10 years as 7 types and the most frequent type was type 1 (79.6%). The ime-dependent transition pattern was also observed in these 7 equence type. In the old isolates group (1968/1975), the major ype was type 6 and then it was changed as type 1 in 1999-2008. owever, itwas changedagain to type2 in2009. This transitionwas ainly attributed togenotypechangeofptxS1andfim3gene.Based n BURST alaysis, there were 2 clonal complexs (ACCI and ACCII) n the Korean isolates. Moreover, the recently increased sequence ype was revealed as ST2 derived from ST3 in ACCI. Conclusion: Genotype changes in Korean distributing strains re still progressing and there was a specific driving force in ntigenic determinant genes. Especially, the major sequence type hanges were accompnied by increasing of incidences. Therefore, ontinusus surveillance of genotype change of the distributing trains should be performed.