Metagenome Analysis of Arboviruses in Anopheles Mosquitoes from Cox's Bazar District, Bangladesh

From November 2018 to April 2019, 1,702 Anopheles mosquitoes were collected in three unions in the Cox's Bazar District, Bangladesh using CDC-light traps and pyrethrum spray catches and kept in individual vials containing silica gel desiccant for storage at room temperature. The mosquito specimens were combined into 230 pools based on date of collection, household ID (HHID), feeding status and sex and extracted to purify total nucleic acids with treatment to reduce mosquito contents. Random reverse transcription, PCR amplification and next-generation sequencing (NGS) were conducted for a metagenome analysis of arboviruses. The sequence-based taxonomic classification identified eukaryotic, bacterial, viral and unclassified genetic material in the Anopheles mosquito pools. Viruses were found in 61 out of the 95 mosquito pools (64.2%). These viruses shared various degrees of nucleotide sequence similarity with viral sequences in GenBank, which included sequences of Rhabdovirus, Iridovirus, Flavivirus, Bunyavirus, Negevirus, Anopheles totivirus, levi-like virus, sobemo-like virus, etc. and many unclassified viruses. In addition, there are 28 de novo assembled contigs with length of 2 kb or greater that did not match any nucleotide sequences in GenBank. More analysis is needed to determine whether these sequences belong to novel arboviruses in Anopheles. Further genetic, phylogenetic and taxonomic characterization of these arboviruses, and investigation of their relatedness with arboviruses in avian, animal and clinical specimens will enhance knowledge-based disease surveillance and control of arboviral infections.