Distributions and breeding habitats of the Japanese encephalitis virus mosquito vector, Culex vishnui, and other Culex Vishnui Subgroup species in the Ryukyu Archipelago, Japan

Abstract

The immature distributions and breeding habitats of the vector mosquito, Culex vishnui Theobald, of Japanese encephalitis virus, and other species of the Culex Vishnui Subgroup, in paddy fields, fallows and other sites were examined from 2004 to 2008 in five islands of the Ryukyu Archipelago, Japan. Culex vishnui was found in three islands, Okinawajima, Ishigakijima and Iriomtejima, but it was not collected from the two northern islands, Amamioshima and Iheyajima. The greatest percentage of positive breeding pools with Cx. vishnui was significantly higher in Ishigakijima (68.8%) and Iriomotejima (43.7%), compared with Okinawajima (19.0%). Culex vishnui was the dominant species collected from Iriomotejima, while Cx. tritaeniorhynchus Giles was the most abundant species collected from the other four islands. Culex vishnui shared same paddy fields and fallows with Cx. tritaeniorhynchus and Cx. pseudovishnui Colless in Ishigakijima and Iriomotejima. In Amamioshima, Cx. pseudovishnui was commonly associated with Cx. tritaeniorhynchus in paddy fields.