Public healthScent-based strategy blocks mosquito transmission of disease

Published 23 May 2019

Could it be that your scent is just a bit too attractive? It is known that mosquitoes are drawn to certain human chemical odors that lead the insects to sources of food. New technology would temporarily modify skin microbiome to reduce attraction of disease-causing mosquitos by altering human scents.

Could it be that your scent is just a bit too attractive? It is known that mosquitoes are drawn to certain human chemical odors that lead the insects to sources of food. ReVector, a new program from DARPA’s Biological Technologies Office, intends to diminish that attraction — or even actively repel mosquitoes — by engineering the skin microbiome to temporarily alter chemical production. By modulating the interaction of skin-associated microbes with metabolites from the body, ReVector technologies might lower the incidence of mosquito feeding and thus reduce the opportunity for the insects to transmit diseases such as malaria, dengue, and chikungunya that reduce military readiness.

ReVector addresses a persistent need among U.S. military forces to protect against insect vectors of disease. Troops already employ bed nets, special clothing, and insect repellants to avoid mosquitoes, and take anti-malarial therapeutics to block the effects of mosquito feeding, but these approaches entail logistical burdens that are not feasible during deployments, produce side effects that make them impractical, or require frequent application or dosing that can yield inconsistent protection. DARPA says that through ReVector, DARPA is aiming for an easily delivered treatment — for example, a topical solution — with an effect that is expressed within hours and sustained for at least two weeks before wearing off despite normal hygiene practices. By the end of the four-year program, researchers will have to demonstrate a safe, precise treatment that delivers a 100-fold reduction in mosquito feeding.

“Mosquitoes present one of the most stubborn threats out there to the health of deployed troops. Despite an array of existing countermeasures and prevention efforts, mosquito-transmitted diseases remain prevalent around much of the world,” said Christian Sund, the ReVector program manager. “DARPA wants to apply the tools of biological engineering to create a new protective approach that is optimized for troops in the field. Our end goal is a treatment that is simple to apply, low maintenance, and without undesirable side effects.”

Engineering the skin microbiome is no simple task. Apart from deciphering the inherently complex interactions among microbes and human physiology, researchers selected to support ReVector will have to account for variability between individual microbiomes. Any product developed must be versatile enough to function on multiple distinct microbiomes to accommodate natural variability over time and among individuals within the military population.

Program safety is paramount, and the research teams supporting ReVector will have to present plans for early and continued engagement with federal regulators to inform their proposed interventions, facilitate future clinical testing, and ultimately chart a course for deployment in the field. DARPA anticipates engagement with the U.S. Food and Drug Administration and the Environmental Protection Agency at a minimum. DARPA will also enlist the guidance of independent experts in ethical, legal, and social implications of new biotechnologies. By the end of the program, teams’ ReVector interventions must be ready for human clinical trials.

If the program is successful, one of its outputs will be platform technologies for learning about the skin microbiome and understanding how to temporarily modify it for beneficial ends. DARPA envisions future uses of ReVector technology in medical contexts such as treating infections and healing wounds.