June 30, 2005 | By: Haven Miller

A $10 million grant to researchers in five countries will further international efforts to combat a disease that strikes 50 million people a year worldwide.

The grant, awarded by the Bill and Melinda Gates Foundation and administered by the Foundation for the National Institutes of Health, will enable scientists in Australia, Asia and the United States to improve methods for controlling mosquitoes that carry dengue (pronounced DEN-geh) viruses.

One of the scientists is Stephen Dobson, associate professor of entomology at the University of Kentucky’s College of Agriculture.

“Although dengue is not a concern for most people in the United States, it is a globally important disease. Estimates are that over 50,000 dengue-related deaths occur each year, and that one fifth of the global population is at risk.” Dobson said.

Dengue symptoms range from a severe, flu-like sickness to the form known as Dengue Hemorrhagic Fever (DHF) that can result in death. It is spread by mosquitoes that bite infected people and then carry the disease to non-infected people.

The team of 11 researchers from Australia, Thailand, Vietnam, Japan and the United States will use genetic technologies to develop a strategy to disable or reduce populations of mosquitoes carrying the disease.

“The dengue virus has evolved an elegant and efficient strategy that employs hungry mosquitoes to ensure its transmission to new people. We are targeting a critical weakness in this transmission cycle: ‘Time.’ It takes almost two weeks for a mosquito to pick up the virus in 
her first blood meal and then transmit the virus to an uninfected person in her subsequent feedings. Our strategy is to block dengue transmission by reducing the lifetime of the mosquito, so that she does not live long enough to transmit the dengue virus,” Dobson said. 

The five-year project is part of the Gates Foundation’s Grand Challenges in Global Health initiative which supports efforts to improve the lives of people in the developing world. The project will be lead by Scott O’Neill of the University of Queensland, Australia.

“This project, if successful, has the potential to dramatically improve the lives of people living in dengue affected regions of Australia and the rest of the world,” O’Neill said. “At the moment there is no vaccine available and no effective drug to treat dengue cases. The primary method of control is insecticide-based programs that target mosquito populations and are expensive to maintain. This project will provide a large area-wide control strategy that is cost-effective, self-perpetuating and will not require the use of insecticides.” 

Team members will collaborate with local communities and various government agencies in each of the countries to examine the use of a bacterium (Wolbachia) that has been shown to shorten the lifespan of insects. 

“Wolbachia occurs in over 20 percent of insect species, from beetles to butterflies.” Dobson said. “However, the mosquito that transmits dengue doesn’t have this bacterium. Not yet. Our goal is to infect the dengue-transmitting mosquitoes with this bacterium that naturally-occurs in other insects. The hope is that the artificially infected mosquitoes will die before they have the opportunity to transmit dengue.”



Contact: Stephen Dobson 859-257-4902