Researchers created a strain of Aedes aegypti mosquitoes in the lab that has been infected with two types of Wolbachia - a bacterium that can reduce the risk of dengue spreading to humans. The new strain is more effective at blocking dengue than the singly-infected insect, researchers from University of Melbourne said.
This strain could also be useful in preventing the dengue virus from developing resistance to Wolbachia, reported.
"It would be a higher hurdle for the virus to get over the top of," said Cameron Simmons from University of Melbourne.
Wolbachia biocontrol could be useful for other viruses carried by Aedes aegypti, including Zika, chikungunya and yellow fever virus, Simmons said.
Wolbachia is transmitted through the females to the next generation, which means the bacterial infection can spread rapidly through mosquito populations.
Previously, scientists have found they can limit the replication of these viruses in mosquitoes by injecting mosquitoes with a strain of Wolbachia called wMel. Studies have shown that when a mosquito bites an infected person, the ability of the virus to spread throughout the Wolbachia-infected insect's tissues is limited.
If no dengue virus makes it to the salivary glands of the mosquito, the insect cannot pass the virus on to humans. "It is a dead end essentially for the virus. The Wolbachia stops the mosquito being able to onward transmit the virus to a human host," said Simmons. The findings were published in the journal PLOS Pathogens.