Comparison of Modified Ovillanta, Modified Gravid Aedes Trap, Biogents Gravid Aedes Trap and Biogents Sentinel for Capturing Aedes aegypti in Tanzania

Aedes aegypti surveillance is essential for guiding arbovirus control strategies. The BG-Sentinel (BGS) trap is a widely used reference trap for monitoring adult Ae. aegypti, but its cost and need for electricity limit its use in resource-constrained settings. This study evaluated locally made, low-cost oviposition-based traps relative to the BGS trap. The Ovillanta trap was modified with internal adhesive surfaces to capture adult mosquitoes. Six trap types were evaluated at six outdoor locations, including (1) Ovillanta with yeast (2) Ovillanta with only water, (3) BG-Gravid Aedes Trap (BG-GAT) with yeast, (4) one modified GAT (1MoGAT) with yeast, (5) four modified GATs (4MoGAT) with yeast, and (6) a standard BGS trap with BG-Lure. Traps were deployed for three consecutive 24 h sampling periods before rotation. This process was repeated four times resulting in a total of 72 experimental days. The primary outcome was total number of captured female Ae. aegypti. The yeast-baited modified Ovillanta captured more Ae. aegypti than the other oviposition-based traps (n = 468), with catches comparable to the BGS trap (n = 497; IRR = 1.03, 95% CI: 0.76–1.41; p = 0.859). Removing yeast from the Ovillanta reduced captures by 31% (n = 321; IRR = 0.69, 95% CI: 0.51–0.95; p = 0.023). The BG-GAT (n = 95), 4MoGAT (n = 35), and 1MoGAT (n = 31) captured significantly fewer Ae. aegypti than the yeast-baited modified Ovillanta (all p < 0.0001). Around 95% of captured mosquitoes were unfed across all trap types. These findings suggest that the yeast-baited modified Ovillanta may provide a low-cost alternative for adult female Ae. aegypti surveillance, but further evaluation across diverse ecological and operational settings is needed.