Mitochondrial genome analysis and molecular identification of two Culex tritaeniorhynchus (Diptera: Culicidae) clades from the Republic of Korea

Culex tritaeniorhynchus is the primary vector of Japanese encephalitis virus (JEV) and is thought to exist as 2 forms: the continental type (Ct-C) and the Japanese type (Ct-J), distinguished by variations in the cytochrome oxidase subunit 1 (COI) region of mitochondrial DNA (mtDNA). However, the extent of genetic variation within and between the 2 types remains largely unexamined. To address this gap in the literature, we performed mitochondrial genome sequencing and additionally developed a rapid and cost-effective identification method that may facilitate efficient vector management and research. The method for type identification is based on a restriction fragment length polymorphism (RFLP) assay, targeting type-specific sequence variations in the COI region. Phylogenetic analysis using mtDNA confirmed that Ct-C and Ct-J represent genetically distinct taxa within the genus Culex. The proposed molecular identification method has been validated to effectively differentiate between the 2 types in the ROK. Early detection of cryptic invasions is critical for effective vector management. The results of this study confirm that the 2 types of Cx. tritaeniorhynchus, the primary vector of JEV, represent genetically distinct lineages. These findings may serve as a foundational reference for developing vector control strategies aimed at suppressing JEV in East Asia.