Observations on Anopheles Balabacensis (Diptera: Culicidae) in Thailand

Abstract

The relationship of Anopheles balabacensis Baisas to the transmission of human malaria was studied in village and forest settings in Thailand. Data were accumulated on seasonal abundance, biting habits and infection rates of mosquitoes. In the dry season, An. balabacensis could only be found in the forest. While indoor transmission probably occurred in the villages during the rainy season, the risk of acquiring malaria was highest in the forest. Emphasis was also placed on locating and describing oviposition sites throughout the year. Oviposition occurred all year in wet areas of the forest, but larvae could be collected near villages only during the rainy season. Eggs of An. balabacensis, when deposited on moist soil at margins of ground pools, remained viable long enough to survive intervals between rains in the monsoon season, but there was no evidence that they could survive the dry season.