After malaria, dengue fever is the most serious mosquito-borne disease in the world. In an effort to curb its spread, researchers from New Orleans’ Tulane University School of Public Health and Tropical Medicine have developed mosquito traps that attract and kill egg-bearing females. Using a US$4.6 million grant from The Bill & Melinda Gates Foundation, the scientists plan to distribute 10,000 of the traps in Peru’s Iquitos region, an area known for dengue fever.
The traps are filled with a gallon of water, that is laced with both an attractant that mimics ideal egg-laying conditions, and a pesticide that kills the eggs once they’re laid. An insecticidal fabric lining kills the adult mosquitoes that enter the trap.
The approach is unique, as most traps are designed to attract mosquitoes looking for a source of blood. This trap draws in female mosquitoes that have already fed, and that therefore could already have picked up the dengue fever virus from a human host. “If we can lure that mosquito in and kill her before she has that next blood meal, then we can stop that transmission,” said Tulane’s Dr. Dawn Wesson. “If you do that enough times, you can actually stop the transmission of dengue or any other mosquito-borne pathogen. It’s a novel approach to not only mosquito control, but also disease control.”
A different approach has been developed at Israel’s University of Haifa. It uses a naturally-occurring chemical compound to discourage female mosquitoes from laying their eggs in the places they ordinarily would, in hopes that they won’t survive long enough to find an alternate location.
The Tulane research team plans to place their traps in and around homes in Iquitos, at the rate of two or three traps per house. Homeowners will refill the traps weekly, and replace the components bi-monthly. After one year, the team will look at the correlation between mosquito capture numbers and local cases of dengue fever, and compare that with numbers in a control area where no traps are in use.
If the traps are effective, they will next be tested in the Caribbean and Thailand.
“Right now there has really been nothing that can be safely used on a wide, multinational scale to reduce dengue transmission,” said Wesson. “If this trap works, we think it can change a lot of people’s lives.”