Distribution and genetic diversity of Bombyx mori nucleopolyhedrovirus in mass-reared silkworms in Thailand

Silk is an economically and culturally important product of Thailand that is threatened by the outbreaks of the Bombyx mori nucleopolyhedrovirus (BmNPV) in silkworm rearings. BmNPV infects the larval stages of the silkworm Bombyx mori, causing fatal viral infection and preventing the larvae from reaching the pupal stage. Numerous BmNPV isolates have been described from silk-producing countries from all over the world. In this study, the geographic distribution of BmNPV in Thailand was analyzed by collecting 18 samples from different regions. The BmNPV samples were analyzed by PCR and whole genome sequencing was performed for eight specimens. Their genome size ranged from 125,888 bp to 126,783 bp, comprising 138 open reading frames. Although the sequenced BmNPV genomes could be phylogenetically differentiated, no correlation between geographic and genetic distance was observed, indicating a close relationship between the BmNPV from Thailand.