Division of Infectious Diseases, Center for Global Health
Health Sciences Center
The University of New Mexico
Dr. Foo-Hurwitz has disclosed four inventions to STC and has three pending U. S. patent applications for her paratransgenic delivery-system technologies to control infectious diseases.
Control of Aedes aegypti, the mosquito vector of the dengue, Chikungunya, yellow fever and Zika viruses, has posed a tremendous challenge for public health officials worldwide. Insecticide campaigns that involve using toxic chemicals in crowded urban settings pose great threats for human and environmental health, are expensive and may select for mosquito resistance when implemented sub-optimally. Larval source management (LSM) with larvicides directed at urban and rural standing water offers potential solutions to regional patterns of mosquito-borne disease transmission. Larvicides are relatively easy to administer, and can quickly achieve high kill rates as larvae are relatively immobile and unlike adult mosquitos, cannot change their habitat to avoid controlled activities. However, a variety of health and environmental issues are associated with organophosphate-based larvicides.
Dr. Foo-Hurwitz and her group have developed an environmentally friendly larvicide delivery system, which is a next-generation approach to mosquito larval eradication through a novel, yeast-based delivery system for essential oils (EOs). EOs, the chemical components that give a distinctive flavor or scent to aromatic plants, are produced by plants for protection against insects and microorganisms. While most are non-toxic to humans, some are highly effective in killing mosquito larvae at very low concentrations. However, EOs are not used commercially as larvicides, as they are highly unstable when exposed to sunlight.
To overcome this hurdle, the EOs are loaded into Baker’s yeast through a simple process of heating and agitation. The yeast cells are killed when the oils enter the cells, but the integrity of the yeast cells remains, sequestering and protecting the loaded oil from the outside environment. In this respect the EO-laden yeast particle is an ideal field delivery vehicle: it preserves the activity of its payload (the EO) while losing the capacity to replicate, and thus to impact aquatic ecosystems. The efficacy of this approach is further facilitated by a welldocumented feature of larval biology: mosquito larvae will preferentially consume and digest yeast. The released EO in the larval gut interferes with multiple biochemical and developmental processes leading to death. The ability of EOs to exert multiple effects on the larvae further decreases the probability of resistance development.
In lab-based experiments, ingestion of our lemongrass oil-laden cells by Aedes and Culex (carrier of West Nile virus) mosquito larvae resulted in 100% mortality. This technology has the virtues of being inexpensive, portable, readily scalable, and ecologically appropriate, and when utilized as part of an integrated vector management plan, can have an enormous impact on global and public health.
PENDING U. S. PATENT APPLICATIONS (UNM-AFFILIATED)
Cultured Extremophilic Algae Species Native to New Mexico
Recombinant Expression Systems and Products
Novel Non-Toxic Larvicide