Re‐emergent snakehead rhabdovirus in Thailand after two decades: Isolation and genomic characterization

Abstract Snakehead rhabdovirus (SHRV) is a novirhabdovirus associated with disease outbreaks in warm‐water fish in Southeast Asia, including striped snakehead ( Channa striata ), but recent information on SHRV in Thai snakehead aquaculture remains limited. In May 2024, high mortality was reported in cultured snakehead from multiple farms in Suphan Buri, Thailand. Necropsy and histopathology results revealed severe, multifocal necrosis in the kidney, spleen, heart, and skin, consistent with a systemic viral disease. Virus isolated from pooled liver–spleen homogenate was propagated in E‐11 cells, and reverse‐transcription PCR identified the agent as SHRV. Transmission electron microscopy showed bacilliform virions approximately 180–200 × 60–70 nm. Following ultracentrifugation and sucrose purification, SDS‐PAGE resolved four dominant viral proteins consistent with glycoprotein (G), nucleoprotein (N), phosphoprotein (P), and matrix protein (M), which were further confirmed by LC–MS/MS. Partial genome sequencing and analysis identified six coding regions (N, P, M, G, NV, L), and sequence comparison revealed amino acid differences relative to a previously reported regional SHRV strain (GenBank Accession NC_000903.1). SHRV‐containing supernatants produced marked cytopathic effects in E‐11 cells at a 10 −10 dilution within 24 h, and the purified virus was successfully titrated by plaque assay. Collectively, these findings document the re‐emergence of SHRV in Thailand after more than two decades and provide a contemporary isolate with pathological, molecular, ultrastructural, and proteomic characterization to support improved surveillance, diagnostics, and farm biosecurity in snakehead aquaculture.