Rapid Genomic Characterization of Imported Chikungunya Virus Informs Frontline Response, China, 2025

In May 2025, an imported chikungunya virus (CHIKV) case was detected in Shanghai, a megacity endemic for Aedes albopictus. Within 48 h of sample receipt, we used a culture-independent metatranscriptomic workflow to recover the complete viral genome directly from clinical serum. Phylogenetic analysis identified an Indonesian origin and critically, the absence of the E1-A226V mutation, suggesting a lower vector adaptation risk. The subsequent absence of secondary cases was consistent with this profile and prompt vector control.