Since the banning of DDT, malaria has gained ground as a major cause of death and despair in poor tropical countries. The DDT outcry was triggered by Rachel Carson's epic environmental tome, Silent Spring. It was as politically powerful as it was wrong.
To be fair, we didn't know then, but her assertion that pesticides are killing us has had a long, long half-life. Even now, writers blithely toss off statements that our water is fouled with pesticides and pesticides cause all sorts of health problems - all without much evidence.
You'd think in this setting, GM solutions - which greatly reduce the need for pesticides - would be hailed as wonderful solutions.
You'd be wrong.
Nonetheless, the march of GM progress continues to offer potent weapons to attack many of humankind's oldest scourges. One of these is the malaria-carrying mosquito.
After mosquitoes bite a host with malaria, the parasite that causes the disease proliferates in the insect, readying itself to infect the next human victim. It's no fun being infected, and one might think that mosquitoes would have developed a resistance to the malaria parasite over time. But several studies have suggested that mosquitoes engineered to build defenses against malaria are less fit than insects that chose to live with the parasites.
Now there's reason to take heart. Several years ago, a group of medical entomologists at Johns Hopkins University created a strain of Anopheles stephensi (a mosquito that bites rodents) equipped with a gene called SM1 that makes the mosquitoes resistant to infection with Plasmodium berghei, a rodent malaria parasite. In the new study, published online this week in Proceedings of the National Academy of Sciences, the group carried out a series of experiments in which 250 of these insects were put in a cage together with 250 wild-type counterparts and allowed to feed on malaria-infected mice. The resistant insects lived longer and produced more eggs than did those not resistant to the parasite, and after nine generations, some 70% of the population was resistant. The researchers speculate that carrying SM1 is a less costly strategy than whatever defenses malaria-resistant mosquitoes develop in the wild. [More]
I didn't realize it was a parasite and not the mosquito who was the culprit. What I do know is conquering malaria would be close to a miracle for Sub-Saharan Africa.
GM mosquitoes that interfered with development of the malaria parasite would make it more difficult for the organism to become re-established after it had been eradicated from a target area, they said.
Malaria, spread by the single-celled parasite Plasmodium, is endemic in parts of Asia, Africa, and central and south America.
The organism is passed to humans through the bite of the Anopheles mosquito. Each year it makes 300 million people ill and causes a million deaths worldwide.
Some 90% of cases are in sub-Saharan Africa, where a child dies of malaria every 30 seconds. [More]
My point is not to excoriate early environmentalists like Carson, who certainly acted in good faith, and had significant beneficial impact on how we use the tools of technology. But technology does not stand still, and if we cannot revise our decisions in the light of new knowledge, we shall not advance the cause of bettering the human condition.
This it the way, I believe, genetic modification will slowly become a technology we feel comfortable using. Just like steam engines terrified pre-industrialists with their power, GM technology will have a acclimatization period. We should take the time. Launching polemics or trading attacks will not advance this cause.
Good science will.