Dengue-Destroying Bacteria Can’t Take The Heat

A strain of Wolbachia bacteria being used for dengue control efforts around the world has turned out to be sensitive to high temperatures.

AsianScientist (Jan. 12, 2017) – A promising strain of bacteria that stops dengue transmission in mosquitoes struggles to survive hot conditions, according to a study published in PLOS Pathogens. But there is a silver lining, because researchers now know which particular strains will survive the steamy tropics, where disease-bearing mosquitoes thrive.

Scientists have recently discovered that a strain of bacteria, Wolbachia, can greatly reduce the ability of mosquitoes to transmit dengue. And it’s also effective against Zika and chikungunya. Wolbachia spreads through mosquito populations quickly, making it an excellent alternative to pesticides. However, Wolbachia mosquitoes fail to establish or the infection invades very slowly.

Mr. Perran Ross, a PhD student at the University of Melbourne, subjected Aedes aegypti mosquitoes to temperatures from 26 degrees to 37 degrees under controlled laboratory conditions to see how well the bacterium survives.

He found that the wMel Wolbachia strain, currently being used in many field trials around the world, survived in significantly lower numbers as the temperature rose. But other strains of Wolbachia were tested and some proved resistant to these higher temperatures.

“Although it was alarming to see that Wolbachia is vulnerable to high temperature, it is promising that other strains are more robust. These strains are also effective at blocking viruses,” Ross said.

“There is a great diversity of Wolbachia strains out there that we should be taking advantage of. We urgently need to consider alternative strains because wMel may not be as effective in hotter climates as we’d hoped.”

Since 2011, researchers from the University of Melbourne have been collaborating with groups from Monash University, Glasgow University, Singapore and elsewhere to develop successful Wolbachia release strategies in Cairns, Singapore and Kuala Lumpur.

Ross’s findings may lead to the deployment of temperature-resistant strains of Wolbachia in Aedes aegypti and other mosquito species in the field.

The article can be found at: Ross et al. (2017) Wolbachia Infections in Aedes aegypti Differ Markedly in Their Response to Cyclical Heat Stress.


Source: University of Melbourne; Photo: Shutterstock.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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