Comparison of sampling anopheline mosquitoes by light‐trap and human‐bait collections indoors at Bagamoyo, Tanzania

Abstract

The mosquito sampling efficiency of CDC miniature light-traps, relative to night-biting collections, was evaluated indoors at two sites in coastal Tanzania. We found that the total number of anophelines captured overnight by light-traps (hung beside a bednet in use) was 1.23 times the number of anophelines captured by human-bait collections. This relationship was not affected significantly by changes in the mosquito density, order of trapping method, date of sampling, or number of household occupants. Malaria sporozoite rates were twice as high among mosquitoes captured by light-trap as compared to those captured by night-biting collection. This was attributed to the tendency of light-traps to capture a larger proportion of gravid mosquitoes, which also had high sporozoite rates. The differences in sporozoites rates according to abdominal stage indicates that unfed mosquitoes captured by light-traps may define more precisely the human-biting activity and sporozoite rates as seen by night-biting collections. Our study shows that light-traps, when used in combination with night-biting collections, can be an effective and sensitive means for measuring human-biting activity and the sporozoite rate.

Light traps fail to estimate reliable malaria mosquito biting rates on Bioko Island, Equatorial Guinea

“…collected by indoor LTs versus indoor HLC varied between 1.06-1.91. However these numbers are based on varying ratios of light traps and human collectors (LTC:HLC); such as 3:2 [9,12], 1:2 [10], or 1:1 [11,13], and cannot,therefore, be compared directly. After adjusting for the varying number of light traps and human collectors, the one-to-one LTC:HLC ratio for An.…”

“…gambiae s.l. ranged from 0.59 in Bagamoyo, Tanzania [10], 1.08 in Burkina Faso [11], 1.59 in Sierra Leone [12], 1.6 in Muheza, Tanzania [9], to 1.91 in Zambia [13]. The two Tanzanian ratios differed by 2.7-fold even though the collections were carried out close in time (five to seven years) and space (140 km).…”

An island within an island: genetic differentiation of Anopheles gambiae in São Tomé, West Africa, and its relevance to malaria vector control

“…Samples of 60 females each were also collected in May 1997 and May 1999 from Riboque using CDC light traps. Both methods are considered comparable and equally representative for A. gambiae sampling (Davies et al, 1995). Female A. gambiae were individually stored in silica-gel-filled tubes and kept at À201C until further processing.…”

Comparative Evaluation of Methods Used for Sampling Malaria Vectors in the Kilombero Valley, South Eastern Tanzania

“…Various field evaluations have affirmed the effectiveness of the CDC-LT and statistically established correction indices have been proposed to adjust the numbers of mosquitoes sampled [13,20,21]. The use of CDC-LT alongside occupied bed nets [22], is being widely adopted as a more sensitive and convenient method for entomological monitoring.…”

“…Alternatives to human landing catches therefore generally rely on traps baited with humans or with whole human odor. These include Centers for Disease Control light traps (CDC-LT) placed beside occupied untreated bednets [11][12][13], odor baited entry traps [14] and Mbita trap [15,16]. In this category also are the odor baited counter flow geometry traps such as the Mosquito Magnet models of the American biophysics corporation [17][18][19].…”