There is a page in the history books waiting to be written for the eradication of malaria. In recent years, malaria has killed more people globally than war—it’s killed predominately children, and predominately in sub-Saharan Africa. Despite being curable, and eliminated from most developed countries, malaria is the fifth deadliest infectious disease in the world.
A team of scientists in Italy is looking to write that history.
And they’re doing it in an ingenious way—they’ve used CRISPR-Cas9 to edit mosquito genes involved in their sexual development such that mosquitoes with the modified gene can’t bite people and can’t lay eggs. That’s all well and good, but you can’t CRISPR the mosquitoes out there in the world. So the team is coupling these sterilizing genes with something called a gene drive, a technique that guarantees that the gene will be inherited during sexual reproduction (up from its normal probability of 50%) and thereby ensures the gene’s spread through the population, notwithstanding its being extremely maladaptive.
In short, if it works, this technique would spread to an entire species of disease-causing mosquitoes (which, for the record, are only a handful of the 3,500 mosquito species extant). Malaria would be gone from the earth in our lifetimes. We don’t know yet if it will work, and they’ve only just started testing the technique in lab settings.
But, at the risk of stating the obvious, if it does work, it would be a good thing. It would save literally millions of lives over the years. It would contribute mightily to Africa’s development.
Not so, to read the media’s reporting, which invariably invokes the word “controversial” to describe these experiments. A handful of environmental activists, we are told, are worried. (Several of the anti-GMO and environmental activists I interviewed in Switzerland last year said that use of genetic modification to eliminate disease causing mosquitos and malaria could be something they could get behind; this worry might be a fringe even of that group and the controversy somewhat manufactured).
Why they’re worried is less clear.
You get, of course, the usual misanthropic lamentations of the lost sanctity of nature. It’s also been claimed, insanely, that “the insects’ population crash could . . . lead to other mosquitoes coming with other diseases.” Right. Do you want to be the one to tell the children with malaria that their suffering is simply a worthy sacrifice in a totally hypothetical battle against as-yet-imaginary diseases? Beyond that, the concerns appear to just be calls for caution: “This is an experimental technology [true, so were vaccines, for a while] which could have devastating impacts [true, about this and everything else].”
There’s nothing wrong with caution. That’s why we have lab tests. That’s why we have risk and cost-benefit analyses. Of course we should make sure these gene drives work and are broadly safe before we use them in the field. But we can’t let caution become a byword for cowardice or a smokescreen for fringe metaphysical ideologies about our place in nature. This same notion of caution, endlessly and baselessly urged in the completely artificial “debate” over genetically modified foods, is starving Africa.
Instead of unbridled speculation, the way to assess these concerns about caution and environmental risk are to put them in context, and look at the comparative ways we’ve fought malaria in the past. There is no endemic malaria in the United States today. But even in 1880s it could be found in the Mississippi Valley up to Minnesota and the East Coast up to New York. Before that, it had nearly killed off the settlers of Jamestown, Virginia. How did we get here?
It wasn’t easy. The most concerted effort was a CDC operation called the National Malaria Eradication Program that ran from 1947, when malaria was still endemic in 13 southeastern states, to 1951, when it was declared eliminated. This was, without a doubt, one of the greatest public health triumphs of all time. Incidentally, this campaign is why the CDC is headquartered in Atlanta instead of Washington, D.C.
The military connotations of the word operation are exactly right. The NMEP involved spraying DDT—yes, that DDT—from military airplanes. Around five million American homes were individually sprayed with the stuff. Swamps were drained, and 30,000 miles of drainage ditches were dug. The disease-carrying mosquito species were more or less eliminated. And everything was fine. Ecosystems did not collapse.
Better than fine: a deadly disease that once plagued this continent is no longer a concern in Miami, New Orleans or Houston. Indeed, the WHO tried to use these same strategies around the world after the American success, but the effort failed for, amongst other reasons, lack of funding, coordination, pesticide resistance and growing environmentalist opposition.
This, the extensive use of history’s most notorious, if over-vilified, pesticide, and naked environmental engineering, is the comparison case for assessing the risks of malaria eradication with gene-drive modified mosquitoes. Indeed, in comparison, the surgical elimination of the offending species with clever genetic engineering looks environmentally anodyne. If we don’t regret the NMEP, and I certainly don’t, we are in no position to deny a less risky remedy to Africa.
So let’s give it a try.
Or, at the very least, let’s stop clouding the heroic efforts of the scientists trying to do that in imagined controversy. The West hardly could have handled the advent of genetically modified foods less maturely. Let’s do better this time.
James Toomey is a 2018-2019 Petrie-Flom Center Student Fellow.
