Genotype-Specific Vector Competence of Aedes albopictus for Japanese Encephalitis Virus Genotypes I, III, and V

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, poses a significant public health threat in Asia. Although <i>Culex</i> species are primary vectors, the role of <i>Aedes albopictus</i> in JEV transmission has gained attention under changing ecological conditions. This study evaluated the vector competence of <i>Ae. albopictus</i> for three JEV genotypes: I (GI), III (GIII), and V (GV). Laboratory-reared <i>Ae. albopictus</i> were orally challenged with each genotype, and infection rate (IR), dissemination rate (DR), head-thorax positivity rate (HTR, proxy for potential transmission), and transmission rate (defined as saliva positivity) were assessed at 7 and 14 days post-infection (dpi). <i>Ae. albopictus</i> showed marked genotype-specific differences. By 14 dpi, GV had the highest DR (100.0%) and HTR (71.7%), with viral RNA detected in 36.7% of TR. GIII showed moderate competence (76.9% DR, 39.3% HTR), but low TR (6.6%). In contrast, GI-infected mosquitoes exhibited minimal infection and negligible transmission, with viral RNA rarely detected beyond the midgut. These findings indicate that <i>Ae. albopictus</i> is highly competent for transmitting JEV genotype V and moderately for genotype III, but not genotype I, under laboratory conditions. This highlights its potential role in the transmission dynamics of emerging JEV genotypes and underscores the need for continued surveillance.