Days could be numbered for Dengue spreading mozzies!

Jan 5 2009

Australian researchers say the days of the Dengue spreading mozzie could be numbered and the news could not have come at a better time.

The researchers from the University of Queensland, Brisbane, using funds provided by the American billionaire Bill Gates and his wife Melinda, have made a breakthrough which could put a stop to the spread of the deadly Dengue fever once and for all.

Back in 2005 Bill and Melinda Gates donated 10 million dollars to an international research team led by the University of Queensland to find a way to beat Dengue fever.

While health authorities in Cairns in the tropical north of Australia continue to battle to control the spread of an outbreak there the Queensland researchers say they have successfully infected the Aedes aegypti mosquito species that carry the Dengue virus, with a Wolbachia bacterium which halves its 30-day lifespan, significantly reducing its ability to transmit Dengue to humans.

Dengue fever affects millions of people each year and the scientists believe their research work will help stop the disease spreading as the virus takes about two weeks to mature and become infectious inside a mosquito's body.

Professor Scott O'Neill says that only very old mosquitos are able to transmit the disease and when the naturally occurring Wolbachia bacteria is put into the mosquito it actually halves their adult lifespan and they don't live long enough to be able to transmit the virus.

The discovery is the result of injecting 10,000 mosquito embryos with a bacterium that occurs naturally in fruit flies but has never been detected in Dengue-carrying mosquitoes.

Professor O'Neill says the test was designed to see whether the bacterium reduced the lifespan of the insects without killing them or preventing them from breeding and was able to be passed on to offspring.

The laboratory tests apparently involved researchers allowing the bacteria-infected mosquitoes to bite their arms because the species needs human blood to breed and were successful, but it could be several years before the technique can be tested in the wild.

The researchers say it is a strategy for preventing dengue fever outbreaks worked out in the laboratory and the next stage is to move the research into a more realistic setting.

Dengue fever also known as "breakbone fever," is transmitted by mosquitos and is a painful and debilitating disease for which there is currently no cure or vaccine - the symptoms include high temperatures and muscle aches - in its hemorrhagic form Dengue fever can be fatal and kills 22,000 people each year.

Professor O'Neill says Dengue fever is becoming an increasing problem around the world including Australia - as many as 65 cases have been confirmed in northern Queensland since November.

The Queensland research team now plan to infect a caged population of mosquitoes in the tropical Queensland state to see if the Wolbachia spreads naturally among mosquitoes as they do among fruit flies - if this proves to be successful they hope to deploy the new dengue control measure in other parts of Australia, Thailand and Vietnam.

Professor O'Neill says they hope this strategy will be applied to other diseases transmission systems such as malaria, which they are also working on.

The research is published in the current issue of the journal Science.