Single blinded semi-field evaluation of MAÏA® topical repellent ointment compared to unformulated 20% DEET against Anopheles gambiae, Anopheles arabiensis and Aedes aegypti in Tanzania

Abstract

Background N,N-Diethyl-3-methylbenzamide (DEET) topical mosquito repellents are effective personal protection tools. However, DEET-based repellents tend to have low consumer acceptability because they are cosmetically unappealing. More attractive formulations are needed to encourage regular user compliance. This study evaluated the protective efficacy and protection duration of a new topical repellent ointment containing 15% DEET, MAÏA® compared to 20% DEET in ethanol using malaria and dengue mosquito vectors in Bagamoyo Tanzania. Methods Fully balanced 3 × 3 Latin square design studies were conducted in large semi-field chambers using laboratory strains of Anopheles gambiae sensu stricto, Anopheles arabiensis and Aedes aegypti. Human volunteers applied either MAÏA® ointment, 20% DEET or ethanol to their lower limbs 6 h before the start of tests. Approximately 100 mosquitoes per strain per replicate were released inside each chamber, with 25 mosquitoes released at regular intervals during the collection period to maintain adequate biting pressure throughout the test. Volunteers recaptured mosquitoes landing on their lower limbs for 6 h over a period of 6 to 12-h post-application of repellents. Data analysis was conducted using mixed-effects logistic regression. Results The protective efficacy of MAÏA® and 20% DEET was not statistically different for each of the mosquito strains: 95.9% vs. 97.4% against An. gambiae (OR = 1.53 [95% CI 0.93–2.51] p = 0.091); 96.8% vs 97.2% against An. arabiensis (OR = 1.08 [95% CI 0.66–1.77] p = 0.757); 93.1% vs 94.6% against Ae. aegypti (OR = 0.76 [95% CI 0.20–2.80] p = 0.675). Average complete protection time (CPT) in minutes of MAÏA® and that of DEET was similar for each of the mosquito strains: 571.6 min (95% CI 558.3–584.8) vs 575.0 min (95% CI 562.1–587.9) against An. gambiae; 585.6 min (95% CI 571.4–599.8) vs 580.9 min (95% CI 571.1–590.7) against An. arabiensis; 444.1 min (95% CI 401.8–486.5) vs 436.9 min (95% CI 405.2–468.5) against Ae. aegypti. Conclusions MAÏA® repellent ointment provides complete protection for 9 h against both An. gambiae and An. arabiensis, and 7 h against Ae. aegypti similar to 20% DEET (in ethanol). MAÏA® repellent ointment can be recommended as a tool for prevention against outdoor biting mosquitoes in tropical locations where the majority of the people spend an ample time outdoor before going to bed.

Prolonged Repellent Activity of Plant Essential Oils against Dengue Vector, Aedes aegypti

“…N , N -diethyl-meta-toluamide (DEET) is considered a gold-standard mosquito repellent for the protection of people against mosquito bites [ 3 , 4 ]. However, several studies have reported its adverse effects such as skin reactions, encephalopathies etc.…”

Repellent activity of trans‐anethole and tea tree oil against Aedes aegypti and their interaction with OBP1, a protein involved in olfaction

“…However, the efficacy of DEET is not only due to its binding to OBPs, it also blocks electrophysiological responses of olfactory sensory neurons and host odor recognition by inhibiting sensory neurons and eliciting host avoidance behavior by activating neural circuits that cause aversion (Ditzen et al, 2008; Syed & Leal, 2008; Pellegrino et al, 2011). DEET has been frequently used as a topical mosquito repellent; however, due to its numerous side effects DEET‐based formulations are not favored (Mbuba et al, 2021).…”

Comparison of the Trapping Efficacy of Locally Modified Gravid Aedes Trap and Autocidal Gravid Ovitrap for the Monitoring and Surveillance of Aedes aegypti Mosquitoes in Tanzania

“…The geolocation latitude (tropical area) provides a conducive environment for Aedes mosquitoes to thrive. Bagamoyo experiences annual rainfall ranging between 800-1000 mm, a temperature between 22-33 • C, and a relative humidity of 73% [37]. Trap optimization was carried out in the semi-field system (SFS) [37] of the Ifakara Health Institute (IHI) in Ifakara Ambient Chamber Test (IACT) [38].…”

“…Bagamoyo experiences annual rainfall ranging between 800-1000 mm, a temperature between 22-33 • C, and a relative humidity of 73% [37]. Trap optimization was carried out in the semi-field system (SFS) [37] of the Ifakara Health Institute (IHI) in Ifakara Ambient Chamber Test (IACT) [38]. The IACT chamber is 3.5 m long, 2.3 m wide, and 2 m tall [38].…”