Last Updated: 10/06/2022
Wolbachia-based interventions for malaria vector control
Objectives
To define the factors that enable infection with Wolbachia to reduce the Anopheles mosquitoes’ vectorial capacity for malaria.
- Determine the impact of Wolbachia on vector competence of An. stephensi for malaria parasites.
- Characterize changes in the internal physiological environment of An. stephensi due to Wolbachia infection.
- Evaluate the mosquito fitness costs associated with Wolbachia infections.
- Introduce Wolbachia into two additional Anopheles malaria vectors, An. gambiae and An. arabiensis
Wolbachia are maternally-transmitted, Gram-negative, endosymbiotic bacteria that are estimated to infect more than 65% of all the insect species and approximately 28% of surveyed mosquito species, but surprisingly neither Anopheles malaria mosquitoes nor the major dengue mosquito vector, Aedes aegypti. A unique feature of Wolbachia biology in many arthropods is their ability to spread through host populations by means of a reproduction-interfering mechanism referred to as sperm-egg cytoplasmic incompatibility (CI). Lack of naturally occurring Wolbachia in those important disease vectors provides both a challenge, and a tantalizing opportunity to spread these bacteria into wild populations without the need for a complex driver system. As the first that introduced stable Wolbachia infection into Ae. aegypti, we recently achieved another milestone by successfully transferring Wolbachia from Ae. albopictus into the important Asian malaria vector, Anopheles stephensi, by embryonic microinjection. Wolbachia maintains a stable infection in An. stephensi and induces almost complete embryos death when infected males mate with uninfected females. Our long-term goal is to develop a Wolbachia-based control strategy as an eco-friendly, cost-effective and sustainable intervention to either suppress mosquito populations or block malaria transmission through population replacement. Our central hypotheses are that a stable association formed between Wolbachia and Anopheles will alter the mosquitoes’ physiological environment and result in a persistently tolerated Wolbachia infection as well as immune-mediated resistance to malaria parasites. In addition to addressing fundamental interactions among Wolbachia, malaria parasite, and mosquito host, this work will lead to development of Wolbachia-based control strategies for malaria control. This novel intervention is promising because it can target vectors that do not rest or feed indoors (and are therefore not susceptible to current control methods) and also permanently reduce the high vectorial capacity of the dominant malaria vectors.
Dec 2014 — Nov 2019
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