Crisis in South Korean cricket farms: Occurrence of Gryllus bimaculatus densovirus and its spread

Abstract

The emergence and spread of densovirus infections pose significant challenges to the cricket industries in South Korea, where two-spotted crickets (Gryllus bimaculatus) serve as crucial feed for fish and reptiles. Diseased two-spotted crickets were collected from the reported farms and examined to identify pathogens. Through metatranscriptome analysis and virome sequencing, we elucidated the complete genome sequence of Gryllus bimaculatus densovirus (GbDV) and characterized its structural and nonstructural protein coding regions, including inverted terminal repeats (ITRs) and conserved motifs; as of yet, there is no reported densovirus infection in G. bimaculatus. Electron microscopy confirmed the presence of densovirus particles in infected crickets. Viral load assays were conducted in a timely and regional manner across 20 cricket farms to monitor the spread of the virus and its adverse impact on cricket availability in the market throughout South Korea. The rapid decline in the number of cricket farms highlights the urgent need for proactive disease surveillance and control methods to mitigate the economic and ecological consequences of densovirus infections.