Bacteria might seem unlikely allies when fighting disease, yet they could hold the key to controlling malaria. This deadly tropical illness is caused by Plasmodium parasites, transmitted to humans via mosquito bites. However, mosquitoes can be made somewhat resistant to the parasite, by infecting them with Wolbachia bacteria, which block the parasite’s development. Infected individuals thus carry, and transmit, far fewer parasites. Researchers have recently succeeded in infecting Anopheles stephensi, a species largely responsible for malarial transmission in the Middle East and Asia; the picture reveals the presence of Wolbachia (stained green) in a mosquito’s ovaries. Infected females pass Wolbachia on to their offspring, and infected males only breed successfully with infected females, so parasite resistance quickly spreads within the population. A similar technique, applied to mosquitoes transmitting the virus responsible for dengue fever, has yielded promising results, raising hopes that this approach might provide solutions for malaria too.
Written by Emmanuelle Briolat
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