The Aedes aegypti mosquito is one of the most notorious insects because of it can transmit tropical diseases such as dengue, yellow fever, malaria, and Zika virus. Climate change threatens to amplify their damage as increasing global temperatures enable the mosquitoes to survive in new geographical areas that were traditionally too cold.
But, there is a glimmer of hope to this tale. It turns out, mosquitos have a natural emeny: Wolbachia. Wolbachia is a bacteria that infects over half of arthropod species, including A. aegypti. These bacteria can stop the viruses that mosquitos carry from being contagious, blocking transmission to humans. Little is known about how the Wolbachia can do this, and has become the subject of global research.
In a paper published in Frontiers in Microbiology, Suzanne Ford and colleagues unravel some of the mystery behind Wolbachia "virus blocking.". Wolbachia introduced to A. aegypti mosquitoes was found to be stably-inherited by offspring, meaning that the bacteria was passed from mosquito parents to offspring, and that this blocked transmission of dengue, Zika, and chikungunya viruses.
This study also aimed to inspect the genetic inheritance of the bacterium and how blocking could be enhanced in a lab to make viral transmission from mosquitoes more ineffective. The researchers found a specific signaling pathway that resulted in resistance to dengue virus in mosquitoes. Mosquitoes that are resistant to the virus have faster cell replication in their midgut region than those who are susceptible. This study found Wolbachia bacteria enhanced this effect. These mosquitoes in turn do not acquire the dengue virus as easily, and as a result, they don't pass it to other animals, such as humans.
This is an important step forward, because so little is known about how Wolbachia bacteria reduce transmission of tropical viral diseases. Imagine if Wolbachia-infected mosquitoes populated the globe, eliminating mosquito-borne viruses altogether!