Species composition, seasonal prevalence and flavivirus occurrence of mosquitoes in Daegu and Gunwi, South Korea during the period of 2015–2016

As the vector-borne diseases rapidly increased due to climate change, we investigated the incidence of flavivirus occurrence among female mosquito species in urban and rural study sites in Daegu and Gunwi, South Korea using Realtime PCR. We collected more individuals and more species of mosquito in 2016 than in 2015. In 2015, we recorded a total of 22,033 mosquitoes (Trap Index, 224.8) representing 10 species from 5 genera, whereas in 2016, a total of 27,137 mosquitoes (Trap Index, 278.7) representing 13 species from 6 genera were collected. The number of mosquitoes in 2016 was higher in all study sites, except in the migratory bird habitats where the number decreased. Of the 14 species collected over the two years, Aedes vexans nipponii and Anopheles spp. were dominant in the cowsheds in rural farmland; Culex pipiens complex, in urban residential areas; and, Anopheles spp. and Cu. pipiens complex in migratory bird habitats caught in a black light trap. Cu. pipiens complex and Ae. albopictus in urban parks and Ae. albopictus and Armigeres subalbatus in migratory bird habitats were the dominant species caught in BG-sentinel traps. We found that the number of mosquitoes was highest during July–September. We analyzed 1,725 pools to detect flavivirus, where Chaoyang virus was detected among Ae. vexans niponii collected from cowsheds in rural farmland in 2016. The increased number of mosquitoes recorded in 2016 was mainly due to increased temperatures in the study areas, and reflected the change in study sites.