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Common Bacteria Might Help Control Disease-Carrying Insects

  • Jessica Berman

An Aedes aegypti mosquito known to carry the Zika virus, is photographed through a microscope at the Fiocruz institute in Recife, Brazi, Jan. 16, 2016.

An Aedes aegypti mosquito known to carry the Zika virus, is photographed through a microscope at the Fiocruz institute in Recife, Brazi, Jan. 16, 2016.

By using a common bacteria, scientists have figured out a way to potentially sterilize disease-carrying mosquitoes. That could make it possible to control the mosquito that spreads Zika and Dengue.

Wolbachia is a common bacteria that has the ability to infect up to 70 percent of the world's insect species.

It has evolved in different ways — some insects even rely on it for their existence, but in others, it plays a parasitic role and can interfere with the viability of eggs.

Two genes may hold the key

Unfortunately, say experts, it doesn't infect many disease-carrying mosquitoes.

But researchers may have found a way to use Wolbachia's sterilizing power on mosquitos that carry Dengue, and Zika.

"It's kind of been the issue with the Wolbachia field is that all of the insects that are really, really medically relevant don't have their own Wolbachia infection,” said John Bechmann, an entomologist at Yale University in Connecticut.

“So that's one reason why this is such an important discovery ... one thing that limited the field is people have always tried to make these fake or non-natural infections that can infect these mosquitoes," said Bechmann. "Now we don't have to do that. We can just put the genes in."

Researchers at Yale and Vanderbilt University in Tennessee have discovered two genes in Wolbachia that might make Aedes aegypti, the mosquito that carries Zika and Dengue, sterile.

Experiments so far have been successfully performed in fruit flies, and researchers are optimistic that it will work in mosquitoes.

Two strategies outlined

The scientists reported success in two strategies to stop the spread of Zika and Dengue.

One method was to flood the environment with male mosquitos carrying Wolbachia. When infected males and uninfected females mate, Wolbachia kills any eggs the female is carrying.

The other approach that worked was introduce male and female mosquitos, both infected with Wolbachia, into a mosquito population. Over time, the Wolbachia-infected mosquitos replaced the Zika- and Dengue-infected mosquitos by making them sterile.

Two companion articles on the Wolbachia gene discovery were published in the journals Nature and Nature Microbiology.

Bechmann says controlling these diseases may one day be as simple as breeding Wolbachia-carrying mosquitos in captivity then releasing into the wild.

Funding needed

"The problem has always been figuring out systems that work well in mosquitoes and this is one that's going to be great for that,” said Bechmann, who added that the technology also has the potential to work with Anopheles gambiae, the mosquito that carries malaria.

Bechmann and colleagues are in the process of trying to get funding to conduct the research in mosquitoes.

Because the mosquitoes are genetically modified, Bechmann says his biggest concern is overcoming regulatory hurdles to permit the release of altered, sterilized mosquitoes.