Mosquito Traps for the Future
The New York Times reports on a new, simple approach to mosquito control that—if accurate—could be a game changer in the world’s efforts to eradicate mosquito-borne diseases. In a nutshell: Fill an old soda bottle with brown sugar, rotting fruit juice and a biological poison and put it near the breeding ground. Mosquitoes drink the sugar water and die. According to the report, in early tests the traps reduced mosquito population by 90 percent, and, more importantly, all but eliminated the most dangerous ones, older females. The research was done by scientists at Hebrew University in Jerusalem.
For the poison, the scientists used Spinosad, a bacterial insecticide that the Times claims is harmless to humans and to most beneficial insects. A cheaper and more widely accessible approach is to simply use boric acid – already widely used as cockroach control.
Mosquito borne diseases—which include malaria, yellow fever and dengue fever, West Nile virus and several kinds of encephalitis—kill millions of people each year. Aid organizations such as UNICEF estimate that malaria alone kills a child every 30 seconds, making it one of the biggest causes of childhood mortality. Malaria takes a particularly heavy toll on sub-Saharan Africa. Mosquitoes require a source of water to breed; uncovered water tanks can therefore be a major problem.
Mosquito control has long been both a humanitarian rallying cry and a political football. In 1939, scientists discovered that DDT had strong insecticidal properties; the synthetic chemical was then used extensively during the Second World War to control malaria and typhus (a disease spread by lice). After the war, DDT was widely adopted as an agricultural pesticide.
In 1962, Rachel Carson’s Silent Spring sharply attacked the indiscriminate use of DDT, which was a carcinogen and ecologically dangerous, especially to predator birds that are high on the food chain. Carson’s book is widely considered to have inaugurated the modern environmental movement.
More recently, industry groups and conservative pundits have attacked Carson and her legacy, accusing her of “genocide” and claiming that the DDT bans that resulted from the publication of Silent Spring have led to millions of deaths in the developing world.
Never mind that DDT has never been banned for use in combating malaria, or that the real issue is that indiscriminate exposure was breeding insect resistance—something that was clear as early as the 1950s and which Carson herself addressed:
“No responsible person contends that insect-borne disease should be ignored. The question that has now urgently presented itself is whether it is either wise or responsible to attack the problem by methods that are rapidly making it worse. The world has heard much of the triumphant war against disease through the control of insect vectors of infection, but it has heard little of the other side of the story – the defeats, the short-lived triumphs that now strongly support the alarming view that the insect enemy has been made actually stronger by our efforts.”
Less controversially, the global bed net campaign, supported by the Millennium Villages project and other groups, has aimed to reduce the incidence of malaria in developing nations by purchasing and distributing insecticide-treated bed nets to at-risk populations. According to the CDC foundation, bed nets have been shown to greatly reduce malaria deaths, especially for children under 2.
Amidst the sea of controversy and human tragedy around mosquito-borne illnesses, what effect will the new approach have? It may be too early to tell. Maybe a better question is, why didn’t we figure this out before?