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DNA barcoding on track to revolutionise malaria control

16 September 2007

Scientists wishing to tackle the deadly disease malaria are using DNA barcoding to help.

Malaria, along with several other devastating diseases, is transmitted by mosquitoes. Each year, up to 500 million people across the world are infected with malaria, and more than a million people die as a result of contracting the disease.

There are 3490 species of mosquito currently recognised and until now, a major obstacle in eradicating malaria has been correctly identifying them. DNA barcoding, however, is proving to be the most accurate way to identify mosquito species and therefore which particular strain of disease it carries.

'Managing malaria doesn't mean getting rid of all mosquitoes, it means controlling the key species that transmit the disease,' says Yvonne-Marie Linton, biomedical researcher at the Natural History Museum and leader of the Mosquito Barcoding Initiative (MBI) .

Anopheles gambiae Photo credit:Judith A. Stoffer, Walter Reed Biosystematics Unit

Anopheles gambiae Photo credit: Judith A. Stoffer, Walter Reed Biosystematics Unit

'But different mosquito species can look so similar that it's hard to identify them, which undermines any attempts at control. DNA barcoding offers a cheap and accurate way of telling the difference between species, based on snippets of DNA code.'

First global effort

The MBI, which includes 11 institutions worldwide, is led by the Natural History Museum in the UK and the Smithsonian in Washington DC. This is the first time mosquito researchers from around the world have collaborated in a global effort to tackle mosquito-borne diseases.

Worldwide access

The DNA information is held in a database that can be accessed by researchers globally. This means scientists out in the field or in developing countries will immediately know what species they are working with, without having to depend on high-tech laboratories or outdated visual guides.

More efficient and effective control

By accurately identifying the carrier species, it is possible to target the larval habitats or adult resting sites of the mosquito in question, minimising cost and making disease control more efficient and more effective.

As Yvonne-Marie Linton explains this week at the second International Barcode of Life Conference in Taipei, 'The MBI has already made more than 3000 DNA records for more than 250 species available since we started six months ago, but there is still lots of work to be done.'

Progress so far
A male Anopheles oswaldoi B mosquito, which is naturally infected with the human malarial par

Male Anopheles oswaldoi B mosquito from Putumayo in southern Colombia. Scientists have discovered it is naturally infected with the human malarial parasite Plasmodium vivax.

'The good news is we are already starting to see significant progress in some malarial-stricken areas.

For example, one species in Latin America, Anopheles oswaldoi, was not thought to be a carrier of malaria in southern Brazil and yet they were carriers in north Brazil, Venezuela and Colombia. DNA barcoding revealed An. oswaldoi to be a group of four species, rather than one .

By separating out the group it is now possible to accurately track where it is a malaria carrier and where it is not - information that can be used by authorities in those countries to devise effective control measures.'

Aims of the initiative

The MBI aims to sequence the DNA of 80 per cent of all known mosquitoes within two years, and will also include information on species that transmit other mosquito-borne diseases, for example West Nile virus and dengue fever.

From October 2007, the MBI will be teaming up with the Scholar Ship , a floating research institute headed by Dr Ravinder Bhatia, and will be sailing around the world, offering high-tech DNA barcoding facilities onboard, which will allow other mosquito workers to participate in this exciting venture.

The Mosquito Barcoding Initiative is a Demonstrator Project of the Consortium for the Barcode of Life (CBOL) which represents a group of major natural history museums, universities, zoos, herbaria and others interested in biodiversity. Working together, they will enable the rapid identification of the Earth's fauna and flora, an estimated 10 million species by 2010.