New York, April 18 (IANS): In a significant discovery, researchers have identified a target for dengue fever that can help develop vaccines for the deadly disease that has infected over 100 million people worldwide so far.

In two recent papers, they explained how flaviviruses produce a unique RNA molecule that leads to disease.

Flaviviruses are considered dangerous emerging pathogens.

“The research shows that the virus causing dengue fever and other closely related viruses like West Nile and Japanese encephalitis use instructions encoded on a single strand of RNA to take over an infected cell and reproduce,” explained Jeffrey S. Kieft, an associate professor of biochemistry and molecular genetics at University of Colorado's school of medicine.

The viruses also exploit an enzyme that cells use to destroy RNA to instead produce short stretches of RNA that, among other things, may help the virus avoid the immune system of its host.

“Ironically, these viruses use a structured RNA molecule to resist an enzyme that normally 'chews up' RNA,” Kieft added.

More than 40 percent of people around the world are at risk of being bitten by mosquitoes infected with the virus that causes dengue fever.

Many develop headaches, pain and fever, but some develop a life-threatening condition where tiny blood vessels in the body begin to leak.

Other flaviviruses, such as West Nile virus, are rapidly spreading around the globe.

Another paper reveals the discovery that the resistant RNA folds up into an unprecedented "knot-like" structure.

The enzyme, normally adept at breaking up RNA structure, encounters this particular structured RNA and cannot "untangle" it; thus the enzyme is thwarted.

“This is the first time this sort of RNA structure has been observed and it has characteristics that may be amenable to targeting by new drugs,” researchers noted.

The papers were published in the journals eLife and Science.