Gates Foundation funds UQ dengue research

University of Queensland parasitologist Prof Scott O'Neill has won a prestigious grant from the Bill and Melinda Gates Foundation in the US to work on a remarkable symbiotic bacteria that induces sterility in insects.

O'Neill was one of only 43 international recipients of this year's Gates Foundation grants, totalling AUD$566 million.

He is investigating the possibility of using a genetically modified form of the bacterium Wohlbachia to control the potentially lethal viral disease dengue fever, transmitted by the mosquito Aedes aegypti.

O'Neill's team is investigating the biology of Wohlbachia, which, in its many different forms, infects up to 75 per cent of the world's insect species, and many other invertebrates, including worms.

Wohlbachia is sexually transmitted, and inherited -- females pass the infection to their progeny via their eggs.

In some insect species it persists as a harmless tenant, without affecting the host, but in others, it can drastically skew sex ratios by overriding chromosomal sex-determination mechanisms; virtually no males survive, the infected females reproduce by parthenogenesis.

The unique reproductive strategy of Wohlbachia, its ability to manipulate sex ratios, and the manner in which it is transmitted between generations, makes it a potentially ideal vector for genes coding for protein toxins, peptide hormones or even antibody molecules, specifically targeted to disrupt the life cycles or behaviour of pest insects like mosquitoes that transmit malaria and dengue fever.

O'Neill's laboratory is sequencing the genomes of two Wohlbachia strains, one that infects Drosophila melanogaster, and the other that infects the nematode Brugia malayi.

Some Wohlbachia strains are known to drastically shorten the lifespan of insects -- O'Neill hopes to employ genetically modified versions of these strains to shift the population age structure of pest insect like A. aegyptoides, so that most mosquitoes will die before they mature and acquire the capacity to transmit the dengue virus.

He is using whole-genome microarrays to investigate gene expression in the bacteria, to determine the mechanisms involved in the Wohlbachia-host interaction.

Microsoft founder Bill Gates, in a press release announcing the grants, said, "It's shocking how little research is directed toward the diseases of the world's poorest countries.

"By harnessing the world's capacity for scientific innovation, I believe we can transform health in the developing world and save millions of lives."

Gates called for proposals for the grants in 2003, hoping to attract ideas that could not secure funding from more traditional sources like government agencies and pharma companies.

Former National Institute of Health director and Nobel laureate Dr Harold Varmus, who chaired the scientific board that guided the grants project, told reports the foundation had received more than 1000 proposals from scientists in 33 countries.

The board whittled the proposals down to 43 that they thought had the best chance of succeeding and making a major difference to health in poor countries.

Dengue fever infects up to $100 million people a year, causing sometimes fatal fever and haemorrhaging. There have been sporadic outbreaks of dengue fever in Cairns in recent years.