Host feeding patterns and preference of Anopheles minimus (Diptera: Culicidae) in a malaria endemic area of western Thailand: baseline site description.

Rungarun Tisgratog,Michael J Bangs,Theeraphap Chareonviriyaphap,Siripun Tuntakom,Waraporn Juntarajumnong,Vincent Corbel,Chatchai Tananchai

doi:10.1186/1756-3305-5-114

Abstract

BackgroundHost feeding patterns of Anopheles minimus in relation to ambient environmental conditions were observed during a 2-year period at Tum Sua Village, located in Mae Sot District, Tak Province, in western Thailand, where An. minimus is found in abundance and regarded as the most predominant malaria vector species. Detailed information on mosquito behavior is important for understanding the epidemiology of disease transmission and developing more effective and efficient vector control methods.MethodsAdult mosquitoes were collected every 2 months for two consecutive nights from 1800 to 0600 hrs. Three collection methods were used; indoor human-landing collections (HLC), outdoor HLC, and outdoor cattle-bait collections (CBC).ResultsA total of 7,663 female Anopheles mosquitoes were collected of which 5,392 were identified as members of 3 different species complexes, the most prevalent being Anopheles minimus complex (50.36%), followed by Anopheles maculatus complex (19.68%) and Anopheles dirus complex (0.33%). An. minimus s.s. comprised virtually all (> 99.8 percent) of Minimus Complex species captured. Blood feeding behavior of An. minimus was more pronounced during the second half of the evening, showing a slight preference to blood feed outdoors (~60%) versus inside structures. Significantly (P < 0.0001) more An. minimus were collected from human-baited methods compared with a tethered cow, indicating a more anthropophilic feeding behavior. Although a significant difference in total number of mosquitoes from the HLC was recorded between the first and second year, the mean biting frequency over the course of the evening hours remained similar.ConclusionsThe Human landing activity of An. minimus in Tum Sua Village showed a stronger preference/attraction for humans compared to a cow-baited collection method. This study supports the incrimination of An. minimus as the primary malaria vector in the area. A better understanding of mosquito behavior related to host preference, and the temporal and spatial blood feeding activity will help facilitate the design of vector control strategies and effectiveness of vector control management programs in Thailand.

Highlights

Host feeding patterns of Anopheles minimus in relation to ambient environmental conditions were observed during a 2-year period at Tum Sua Village, located in Mae Sot District, Tak Province, in western Thailand, where An. minimus is found in abundance and regarded as the most predominant malaria vector species
Several important vectors of malaria are prevalent in the area, including members of the Anopheles minimus complex [4], one of the most important malaria vectors in rural forested and scrub areas of western Thailand [1,5,6]
A total of 3,859 Minimus Complex species were collected from indoor human-landing collections (HLC) (1,197:31.02%), outdoor HLC (1,786: 46.28%) and cow baited collections (876: 22.7%)

Summary

Introduction

Host feeding patterns of Anopheles minimus in relation to ambient environmental conditions were observed during a 2-year period at Tum Sua Village, located in Mae Sot District, Tak Province, in western Thailand, where An. minimus is found in abundance and regarded as the most predominant malaria vector species. At least two genetically distinct sibling species, An. minimus and Anopheles harrisoni, belong to the Minimus Complex [7]. In Thailand, An. minimus is regarded as the most predominant malaria vector species and is found throughout the country [10,11], whereas An. harrisoni is restricted along the western Thailand-Myanmar border, in Kanchanaburi Province [7,11,12,13]

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