Recent bulletins carry news of dengue fever on the rise in Panama, Pakistan and the Bahamas. Add these destinations to those mapped by the Centers for Disease Control, including Brazil, Paraguay, Bolivia, Vietnam, Australia, Thailand, the Caribbean and the Philippines, and it’s clear dengue is spreading at an alarming pace throughout the tropics and subtropics. How are we fighting back?
Controlling dengue is largely an exercise in combating the mosquito species Aedes aegypti, which transmits the viral disease to over 50 million people per year and is becoming resistant to pesticides. Now New Scientist magazine is reporting that Oxford, England-based Oxitec, Ltd. is applying its genetic engineering expertise in field trials in the Caribbean, Malaysia and Brazil to reduce mosquito populations. Oxitec has created a disruptive strain of A. aegypti by modifying the genome to include genes that kick in after reproduction to kill the mosquito in the pupa stage. Genetically modified insects have been released into wild, and trials have been encouraging. Now the company has also engineered flightless females among the modified population, which are released to maximize the odds that the “killer males” will mate only with unmodified females and thereby cut an even wider swath.
Critics point out that genetic modification can lead to both intended and unintended consequences. It will pay to keep an eye on this experiment both as a weapon against a growing scourge and as an index of whether these tactics will prove to be safe over the long-term.
Photo by Curtis Palmer.
