Air Date: Week of March 17, 2006

Researchers at the University of California have successfully created a genetically altered line of mosquitoes that are resistant to the most common type of dengue fever. There are an estimated 50 million people infected with the dengue virus each year. Emily Taylor reports.

Transcript

TAYLOR: Bad bugs bugging you? Now there’s a reason to fear the little pests a little less. Researchers, headed by University of California-Irvine vector biologist, Anthony James, have successfully created a mosquito that is highly resistant to the Type 2 dengue fever virus. They did it by identifying a vulnerability in the virus. It happens when the virus replicates and leaves its RNA susceptible to being chopped up by a naturally-occurring protein, dicer-2. If dicer-2 goes to work, the damaged RNA prevents the virus from replicating.

This process happens naturally only after the virus has replicated enough times to be transmitted. But by cloning a section of the mosquito’s RNA and injecting two inverse copies of it into mosquito embryos, James and his team were able to let the dicer-2 protein do the chopping before initial replication and transmission occurred. As a result, the virus never replicated at all.

This genetically altered and, now, benign virus was used to “inoculate” and create a new line of mosquitoes highly resistant to the dengue fever and able to pass this resistance down to future generations. Dengue fever is endemic in more than 100 nations, it infects an estimated 50 million people each year and kills 20,000 of them. James says he and his team will now look into population replacement strategies to eliminate carriers of dengue fever and infection rates. That’s this week’s Note on Emerging Science, I’m Emily Taylor.