Potential vectors of malaria in Kamamaung, Myanmar and their bionomics
Potential vectors for malaria and their bionomics were studied at the Katine Htit and Kine Taw villages from Kamamaung Township, Phapun District, Kayin State, Myanmar from May 2014 to April 2015. Anopheles mosquitoes were collected from fixed mosquito catching stations with Kanda net (Knet) for animal bait. Indoor, outdoor biting catches and light trap collection methods with WHO sucking tubes and larval survey were done seasonally. Head and thorax of mosquitoes were dissected to find out Plasmodium sporozoites in salivary gland by ELISA test for conforming potential vectors. Results revealed that the major vector Anopheles minimus and secondary vectors An. culicifacies, An. maculatus, An. vagus and An annularis were occurring in all seasons, although An. minimus was observed in maximum numbers during cool season. The adults of main vector An. dirus were observed occurring in both rainy and cool seasons in both areas.
Surveys on larvae resulted in identifying An. dirus in 6.4% and 5.6% of wells in Katine Htit and, 5.66% and 5.66% of wells in Kine Taw villages in the rainy and cool seasons. An. minimus An. culicifacies, An. vagus, An. annularis and An. maculatus larvae were abundantly found occurring in water and sand pools of Yunsalin creek. Anopheles culicifacies B, An. minimus A, and An. dirus D were occurring in both the villages as observed with polytene chromosome technique. Vector incrimination study found that 1.07% of An. minimus was Pf sporozoite positive at Katine Htit village and 3.7% of An. dirus being Pv210 sporozoite positive at Kaine Taw village. Anopheles minimus was occurring in early midnight and An. dirus was observed at high density at 21: 00–22: 00 hr. All collected Anopheles mosquitoes from both villages were susceptible to DDT 4%, deltamethrin 0.05%, permethrin 0.75% and cyfluthrin 0.15%. The highest malaria parasite positive rate was found to be in July. The parasite positive status was observed throughout the year except April in both villages. This study suggests that there is active malaria transmission in the study area and malaria control and preventive measures are necessary.
Malaria, Anopheles spp, vector, bionomics, seasonal occurrence, polytene chromosome, sporozoite, parasite positive status.