A Novel Synthetic Odorant Blend for Trapping of Malaria and Other African Mosquito Species

Abstract

Estimating the biting fraction of mosquitoes is of critical importance for risk assessment of malaria transmission. Here, we present a novel odor-based tool that has been rigorously assessed in semi-field assays and traditional African villages for estimating the number of mosquitoes that enter houses in search of a blood meal. A standard synthetic blend (SB) consisting of ammonia, (S)-lactic acid, tetradecanoic acid, and carbon dioxide was complemented with isovaleric acid, 4,5 dimethylthiazole, 2-methyl-1-butanol, and 3-methyl-1-butanol in various combinations and concentrations, and tested for attractiveness to the malaria mosquito Anopheles gambiae. Compounds were released through low density polyethylene (LDPE) material or from nylon strips (nylon). Studies were done in a semi-field facility and two traditional villages in western Kenya. The alcohol 3-methyl-1-butanol significantly increased the attraction of SB. The other compounds proved less effective or inhibitory. Tested in a village, 3-methyl-1-butanol, released from LDPE, increased the attraction of SB. Further studies showed a significantly enhanced attraction of adding 3-methyl-1-butanol to SB compared to previously-published attractive blends both under semi-field and village conditions. Other mosquito species with relevance for public health were collected with this blend in significantly higher numbers as well. These results demonstrate the advent of a novel, reliable odor-based sampling tool for the collection of malaria and other mosquitoes. The advantage of this odor-based tool over existing mosquito sampling tools is its reproducibility, objectiveness, and relatively low cost compared to current standards of CDC light traps or the human landing catch.

Nectar Meals of a Mosquito-Specialist Spider

“…• 10 E). For the rearing and maintenance of spiders in the laboratory, we followed procedures that are standard for our salticid research (see: [25]) and summarize only essential details here.…”

Polyamidoamine Nanoparticles as Nanocarriers for the Drug Delivery to Malaria Parasite Stages in the Mosquito Vector

“…[94,95]. Several approaches are currently available for oral delivery to mosquitoes by droplet or liquid feeding, through dry diets [96], or via nylon strips continuously dispensing synthetic mosquito attractants for several weeks [97,98]. Some of these methods have been already used to deliver to dipterans lipid-based [99] and chitosan nanoparticles [100].…”

Impact of odour-baited mosquito traps for malaria control : design and evaluation of a trial using solar-powered mosquito trapping systems in western Kenya

“…Studies to characterise the components of human odour which are attractive to hostseeking Anopheles gambiae s.s. have led to the identification of a large number of compounds (Mukabana et al, 2012b;Okumu et al, 2010b;Verhulst et al, 2011b) which, at appropriate concentrations, can be combined to create synthetic mosquito lures that mimic a human host (Menger et al, 2014b;Okumu et al, 2010b). These lures can remain attractive to mosquitoes even after a year of use .…”

“…The number of mosquitoes relative to humans and the mosquito survival rate depend on several aspects; in the first case the relative attractiveness of the OBT compared to a human (Okumu et al, 2010a;Okumu et al, 2010c). The blend [MB5] of attractants used in this intervention (Mukabana et al, 2012b;Verhulst et al, 2009) was reported to be more attractive than a human odour (Okumu et al, 2010b), however, the same level of efficacy is yet to be confirmed in field settings. Besides, there is some uncertainty about whether mosquitoes tend to directly prefer the trap over a human.…”

“…However additional vector-control interventions are needed because Anopheles mosquitoes biting at times and in places without LLINs, sustain residual transmission (Durnez & Coosemans, 2013). Existing tools are also threatened by insecticide and drug resistance (Das, 2015;Ranson et al, 2011;WHO, 2015b) Blends of synthetic chemical attractants can attract more vectors than a human (Mukabana et al, 2012b;Okumu et al, 2010b), motivating development of mass mosquito-trapping systems for malaria control . This paper reports the first trial of odour-baited traps [OBTs] as a malaria control intervention.…”