Comparison of carbon dioxide-baited trapping systems for sampling outdoor mosquito populations in Tanzania

For collecting mosquitoes (Diptera: Culicidae) the outdoor catching efficie ncy of four types of trapping devices baited with carbon dioxide (CO2, 300 ml/min) was evaluated and compared in two areas of Tanzania. The types of t raps employed were: the CDC miniature trap with the incandescent light bulb switched on or off; electric nets (ENT) and a Counterflow Geometry (CFG) t rap. In Njage, south-east Tanzania, Anopheles gambiae Giles sensu stricto w as the most abundant of the seven mosquito species obtained, comprising of 74.3% of the total number caught (n = 2171). In Muheza, north-east Tanzania , Culex quinquefasciatus Say was the predominant species (90.9%) among 1080 caught. At both localities the CFG trap was superior to the CDC trap with light-on or light-off for sampling both An. gambiae and Cx. quinquefasciatu s. Efficiency of the CFG trap and ENT were similar for sampling these speci es of mosquitoes (P > 0.05). However, ENT was superior to the CDC trap with light-off for collecting both species. Significantly more (P < 0.05) Cx. q uinquefasciatus were obtained by the CDC trap with light-off than with ligh t-on, especially outdoors. It is concluded that both ENT and the CFG are ef fective tools for sampling populations of An. gambiae and Cx. quinquefascia tus outdoors.