Field evaluation of two commercial mosquito traps baited with different attractants and colored lights for malaria vector surveillance in Thailand

BACKGROUND: Sampling for adult mosquito populations is a means of evaluating the efficacy of vector control operations. The goal of this study was to evaluate and identify the most efficacious mosquito traps and combinations of attractants for malaria vector surveillance along the Thai-Myanmar border. METHODS: In the first part of the study, the BG-Sentinel™ Trap (BGS Trap) and Centers for Disease Control and Prevention miniature light trap (CDC LT) baited with different attractants (BG-lure® and CO(2)) were evaluated using a Latin square experimental design. The six configurations were BGS Trap with BG-lure, BGS Trap with BG-lure plus CO(2), BGS Trap with CO(2), CDC LT with BG-lure, CDC LT with BG lure plus CO(2), and CDC LT with CO(2). The second half of the study evaluated the impact of light color on malaria vector collections. Colors included the incandescent bulb, ultraviolet (UV) light-emitting diode (LED), green light stick, red light stick, green LED, and red LED. RESULTS: A total of 8638 mosquitoes consisting of 42 species were captured over 708 trap-nights. The trap types, attractants, and colored lights affected numbers of female anopheline and Anopheles minimus collected (GLM, P < 0.01). Results revealed that BGS Trap captured many anophelines but was significantly less than the CDC LT. The CDC LT, when baited with BG-lure plus CO(2) captured the greatest number of anopheline females with a catch rate significantly higher than the CDC LT baited with BG-lure or CO(2) alone (P < 0.05). The number of anopheline females collected from the CDC LT baited with CO(2) was greater than the CDC LT baited with BG-lure (646 vs 409 females). None of the alternative lights evaluated exceeded the performance of the incandescent light bulb in terms of the numbers of anopheline and An. minimus collected. CONCLUSION: We conclude that the CDC LT augmented with an incandescent light shows high potential for malaria vector surveillance when baited with CO(2) and the BG-lure in combination and can be effectively used as the new gold standard technique for collecting malaria vectors in Thailand.