Viruses, spread through mosquito bites, cause human illnesses such as dengue fever, Zika and yellow fever. A new control technique harnesses a naturally occurring bacterium called Wolbachia that blocks replication of viruses and breaks the cycle of mosquito-borne disease, according to an international team of researchers.

Image/CDC

“Wolbachia is present in around 50 percent of all insects,” said Beth McGraw, professor and Huck Scholar in Entomology at Penn State, who did this research while at Monash University. “Interestingly it is not present in some of the major mosquito vectors (insects that transmit pathogens). After researchers put Wolbachia into mosquitoes, they found that, quite excitingly, Wolbachia effectively vaccinates mosquitoes, preventing viruses from replicating.”

Spread by Aedes aegypti mosquitoes, dengue virus affects millions of people each year. Symptoms include fever, body aches and nausea, although a more severe version, known as dengue hemorrhagic fever, can be fatal.

In the tropics and subtropics where Ae. aegypti resides, several large releases of Wolbachia are underway to test whether Wolbachia can reduce the incidence of human disease.

In a paper published recently in Virus Evolution, McGraw and her team report that dengue virus failed to evolve resistance to Wolbachia in controlled lab-based experiments. These findings show promise for the long-term efficacy of Wolbachia following field release.

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