Current malaria control operations rely heavily on insecticide treated nets (ITNs) and indoor residual spraying (IRS), both of which are insecticide-based and target only mosquitoes that feed or rest inside houses. Although these methods are extremely powerful and have saved many lives, the protection that they confer is insufficient to eliminate malaria in the most endemic regions of Africa.
It has long been postulated that complementary methods to build upon these gains could include, among other options, novel technologies derived from synthetic human odors.
By reformulating an existing malaria transmission model to more accurately describe the feeding behavior of wild mosquitoes, we have now estimated the likely efficacy of odor-baited traps for malaria control in Africa and described a plausible target product-profile for developers to aim for.
Basically, to be effective, the traps should be very cheap to deploy, the baits should be at least as attractive as humans, and the geographic location of these traps should be optimized to capture the greatest possible proportions of mosquito populations, for example by placing them in just a small section of the village area, where approximately 80% of infective mosquitoes are likely to be found.
Because such traps attract mosquitoes from long distances, it is also important that they are positioned far from houses so as to minimize risk of excessive mosquito bites and increased exposure to mosquito-borne pathogens. Unlike ITNs which can be marketed as household consumer products, traps provide only communal benefits and would require a customized delivery mechanism to maximize its usefulness.
We expect that even if the target product profiles that we have outlined here were manageable cost-wise, vertical and presumably community-based delivery mechanisms would be necessary to supply and deploy the traps. We propose that where local governance and administrative systems are already strengthened, or where they can be supported by centralized national malaria control programmes, sustainable implementation of a traps-based strategy may possibly be achieved through participatory approaches similar to those applied for scaling up community-based sanitation technologies like Ventilated Improved Pit (VIP) latrines or water source protection among rural communities in developing countries.
Traps and delivery systems satisfying these criteria could dramatically reduce malaria transmission in endemic Africa, achieving protection as good as ITNs. Perhaps even greater impact, and possibly elimination of transmission, may be achieved if the traps are used to complement rather than replace ITNs.
For more information see:
Okumu FO, Govella NJ, Moore SJ, Chitnis N, Killeen GF (2010) Potential Benefits, Limitations and Target Product-Profiles of Odor-Baited Mosquito Traps for Malaria Control in Africa. PLoS ONE 5(7): e11573. doi:10.1371/journal.pone.0011573.
Okumu FO, Killeen GF, Ogoma S, Biswaro L, Smallegange RC, et al. (2010) Development and Field Evaluation of a Synthetic Mosquito Lure That Is More Attractive than Humans. PLoS ONE 5(1): e8951. doi:10.1371/journal.pone.0008951.