Mosquito diversity and orthoflavivirus detection in Khao Yai National Park, Thailand.

Khao Yai National Park, a UNESCO World Heritage Site in Thailand, hosts diverse ecosystems that sustain a wide variety of mosquito species. This study was designed to characterize mosquito diversity across an altitudinal gradient in Khao Yai National Park and detect orthoflaviviruses in mosquitoes. Mosquitoes were collected monthly over two years (2023-2024) from eight locations ranging from 479 to 1290 m above sea level. A total of 1041 mosquitoes, representing 36 species from five genera, were identified through morphological and molecular analyses. Culex was among the most diverse mosquito genera in the national park, accounting for 16 out of 36 identified species. Orthoflavivirus detection using polymerase chain reaction and sequencing analysis revealed the presence of Japanese encephalitis virus and Tembusu virus in Culex tritaeniorhynchus and dengue virus in Aedes aegypti. Species richness, Shannon diversity index, and abundance patterns suggested reduced mosquito assemblage complexity at higher elevations, although this relationship was descriptive and not strictly monotonic. This pattern is consistent with previous observations suggesting that altitude may influence mosquito distribution. In addition, variations in temperature, humidity, and rainfall were observed alongside changes in mosquito abundance, suggesting that these environmental factors may contribute to shaping mosquito population dynamics. This study provides baseline data that may support ongoing surveillance and future risk assessment of mosquito-borne diseases in Khao Yai National Park and similar ecosystems.