To Control Dengue Researchers Shorten Mosquitoes Lifespan

Australian researchers reported they had found a way of infecting mosquitoes with bacteria to reduce their lifespan and thereby reduce there chances of infecting more people.

The study published this week in the journal Science, reported that the researchers genetically engineered bacteria known as Wolbachia, to infect the Aedes aegypti mosquito species that carry the dengue virus. The bacteria significantly shortened mosquitoes' lifespan, from around two months to around a month.

Wolbachia is a type of bacteria that naturally infects many insects and tends to allow mother mosquitoes to live long enough to pass the bug along to their offspring but not to mature to the stage when it is capable of transmitting dengue, as the virus takes about two weeks to mature and become infectious inside a mosquito's body. The researchers found that infected mosquitoes lived half as long as uninfected mosquitoes.

The researchers said this could be useful in an area where dengue is prevalent and mosquito-control efforts have failed that by introducing a bunch of Wolbachia-infected mosquitoes which shorten the lifespan of the local mosquito population and lower the burden of disease.

Scott O'Neill, head of University of Queensland's School of Biological Science said, "Dengue virus and the disease it causes is only transmitted to humans by the older female Aedes aegypti mosquito. If we can introduced this into populations it should move the management of dengue fever from an outbreak management paradigm to a prevention paradigm," Dengue fever, which is a painful and debilitating disease also known as breakbone fever, in it's hemorrhagic form kills 22,000 people a year and has no vaccine or cure.

O'Neil and his team hope to infect a caged population of mosquitoes in Australia's tropical Queensland state which has had more than
50 confirmed dengue cases since November. "Dengue around the world is getting worse now. We are seeing more and more activity around the world including Australia. If that proves successful we hope to deploy this new dengue control measure in other parts of Australia, as well as Thailand and Vietnam," O'Neill said.

"Ultimately we would like to see if it could be applied to other diseases transmission systems like malaria, which we are currently working on as well," he added.

There are fears though that Wolbachia-infected mosquitoes might lead to the evolution of new strains of dengue, but with the disease spreading any idea is worth a shot.

Andrew Read and Matthew Thomas of Pennsylvania State University said in a commentary that the researchers need to show that Wolbachia will spread naturally among mosquitoes the way they do among fruit flies which would open the possibility that dengue viruses would evolve the ability to multiply more quickly inside a mosquito's body.