And I thought human-scented traps were a diabolical method of killing mosquitos.
Turns out there are people who hate the dreaded insects even more than me — and are willing to go to extreme lengths to prove it.
If the sentence, “Mutant sterilized mosquitos self-inflict genocide,” doesn’t warm your heart, I don’t know what to say.
Here’s how we got to this point. I received several interesting responses following my column about researchers in Kenya finding success controlling mosquitos using a blend of chemicals that mimic the smell of people. One person emailed me a link to his blog, which used similarly hyperbolic language as mine about the mosquito scourge; it was delightful.
Another slipped me a printout at church of an article entitled, “Sterile Insect Technique.” It wasn’t quite as dramatic as Deep Throat leaking Watergate information to Bob Woodward and Carl Bernstein, but it still carried a certain air of excitement.
Here’s how you do it: Sterilize male insects in a lab by radiating their reproductive cells. Release the resulting mutants into the wild. Let nature take its course. Rinse and repeat.
The mutants — my word to describe them, not one I’ve seen used in any of the staid scientific literature on the topic — will still mate with a female, who typically only has one partner, but the coupling will not produce offspring. Therefore the female dies without reproducing, reducing the population.
Imagine for illustrative purposes that you had 10 female insects and 10 male insects in a wild population. And say scientists released 10 mutant, sterile males into the fray. That would give the 10 females a 50/50 chance of — unbeknownst to them — mating with a sterile partner. That would mean only five of the females survived to reproduce rather than 10.
That obviously has a deleterious effect on the population — and its ramifications would be increased as you increased the ratio of mutants to regular males.
This really works.
We used it to wipe out screwworms — maggots that feed on living flesh and caused millions in economic damages to the cattle industry — in the 1950s and 1960s.
And it happened surprisingly quickly: The USDA began using the method in Florida in 1957 and had eradicated the flies from the entire Southeast by 1959, according to a USDA fact sheet. By 1966 the screwworm had been eliminated from the country. They still exist in South America, but the USDA maintains a barrier at the Darien Gap — a 100-mile undeveloped area in Panama where there is no road connecting North America to South America (oh, the fascinating facts you run across when researching mosquitos).
Sterile insect technique has a lot of benefits. It’s proven and does not come with the environmental and resistance-buildup concerns that pesticides bring.
Using the method for mosquito control carries another advantage: It’s the female mosquito that feeds on human blood, so there’s no chance that the mutant males produced in the laboratory would somehow bite humans and cause unanticipated problems.
The Food and Drug Administration is pondering allowing a British company named Oxitec to do a trial run on the mosquito that causes Zika in Florida that is similar, although not identical, to sterile insect technique. That species, Aedesaegypti, is particularly troublesome, as it also carries yellow fever and dengue fever, which remain major problems in the developing world.
Rather than using radiation to make mosquitos sterile, Oxitec manipulated the Aedesaegypti’s DNA to create a “self-limiting” gene. They can reproduce, but the gene causes the offspring to die before adulthood. The company has already done it with success in Brazil.
The limitation is that different mosquito species — there are a bunch of them — don’t interbreed. So either technique can only be used on one species at a time. Don’t expect that we’ll be able to eliminate mosquito-kind completely, but we can at least wipe certain species that carry the nastiest diseases from our shores.
Talk about making America great again.
