ABSTRACT
Japanese encephalitis virus (JEV) infection in mosquitoes was monitored in Vietnam from 2006 to 2008. A total of 15,225 mosquitoes, identified as 26 species in five genera were collected and 12,621 were grouped into 447 pools for examination of JEV infection by assays for cytopathic effects in C6/36 cells and by RT-PCR to detect flavivirus RNA. Three JEV strains were isolated from Culex tritaeniorhynchus Giles collected in northern and southern Vietnam and two JEV strains were isolated from Culex vishnui Theobald collected in the highlands of Vietnam. Genetic and phylogenetic analyses, based on complete E gene nucleotide sequences, revealed that the five JEV strains were classified into the genotype I group and six amino acid differences were found in these five strains. These results indicated that multiple JEV genotype I populations are circulating countrywide in Vietnam, transmitted by bites of their Cx. tritaeniorhynchus and Cx. vishnui.
Subject(s)
Culex/virology , Encephalitis Virus, Japanese/classification , Insect Vectors/virology , Amino Acid Sequence , Animals , Base Sequence , Cell Line , Encephalitis Virus, Japanese/isolation & purification , Encephalitis Virus, Japanese/pathogenicity , Encephalitis, Japanese/virology , Genes, Viral , Genetic Variation , Genotype , Membrane Glycoproteins/analysis , Membrane Glycoproteins/genetics , Phylogeny , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction , Vietnam , Viral Envelope Proteins/analysis , Viral Envelope Proteins/geneticsABSTRACT
A rapid and comprehensive protocol, which combines simple purification and liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI/MS/MS), was developed for identification of arboviruses in infected culture fluid. Using this protocol, various arboviruses were detected including uncommon viruses that were described previously as Banna virus and Yunnan orbivirus. This approach is useful for the rapid screening of viral samples that cannot be identified by conventional gene amplification or immunological methods.
