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Should my bacteria worry about genetically modified mosquitoes?

I hate to admit it, but I kind of like the idea of genetically altering mosquitoes — or the bacteria they carry around — to fight disease.

I’m enough of a geek to think this is cool stuff and, frankly, I am not that fond of mosquitoes. But then I start to worry about how this could impact my own bacteria … Tom Paulson the microbiome.

I’ll explain that shortly, but first it needs to be said that this once-novel idea of producing GM skeeters is no longer so novel.

Turns out, lots of labs are now working on some variation of genetic modification in mosquitoes aimed at undermining the bug’s ability to spread disease whether it be malaria, dengue or some other ‘vector-borne’ illness. I seem to read a story about genetically modified mosquitoes every other week. The Gates Foundation funds a number of these projects.

So the media may still think this approach is new, wacky and weird. But it isn’t really. I can’t seem to find a comprehensive list of all the US-based projects for genetically modifying insects, but here’s an old but good overview by the Pew Charitable Trust and a more recent European Union report listing thousands of such projects or proposed projects.

Perhaps the best story of late on GM skeeters is by Michael Specter, in the New Yorker — about Oxitec‘s GM mosquito factory in Brazil. (Non-subscribers have to pay to read it, but it’s well worth the price).

Another such project was reported recently by scientists at Johns Hopkins University (my alma mater), in which a common bacterium found in the guts of these bugs was altered to secrete proteins toxic to the malaria parasite. They report that these toxins harm neither humans or mosquitoes.

I haven’t read their paper so I can’t tell how they tested the human toxicity. Chances are, it was a fairly quick test that looked at immediate harm to human cells or something like that. The problem here is that, when it comes to testing human harm, these quick toxicity tests may be almost meaningless.

Here’s why:

Drug-resistant Staph bacteria

As this fascinating news report on the human microbiome by Liz Szabo explains, the human body is an amazingly complex community of microbes. In fact, beneficial and necessary bacterial cells outnumber human cells in our body by about 10-to-1. We are each of us, in effect, more a bacterial metropolis than we are an isolated creature fighting off the microbial world:

Scientists say we’re closer to a coral reef, with an estimated 10,000 species of bacteria, fungi, yeasts and assorted others making up our ecosystem.And while a few of these microbes can make us sick if they get out of control, 99% are benign or even protect us from harm. Bacteria have evolved with humans for millennia, helping us digest our food, synthesize vitamins, regulate our immune system and more.

And, as Szabo reports, we are doing things that increasingly threaten to disrupt this complicated and delicate, symbiotic dance between our bodies and the bacteria which — by virtue of the numbers — keep us alive and, arguably, actually run the planet.

Most of us have awakened, or maybe have yet to awaken (HEY, WAKE UP!) to the rising problem of drug-resistant disease worldwide. This has been produced largely by an overuse of antibiotics, which also cause other problems in our food supply — and in us.

So now we are altering the genetics of mosquitoes, or maybe the bacteria they carry, in order to attack a disease-causing microbe. As I said, I’m okay with exploring this. It could be a better approach than spraying everything with chemicals and there’s not been much evidence of harm, so far.

We can’t help but mess with Mother Nature because she started it, messing with us first.

Still, a massive dose of humility and a more cautionary approach is in order given how little we know about the microbial ecosystem that basically helps run everything, inside us and outside.

We really aren’t smart enough yet to accurately test for how GM skeeter experiments could alter the microbiome, out there or within our inner ecosystem. We should tread carefully and keep in mind that bacteria are us.


About Author

Tom Paulson

Tom Paulson is founder and lead journalist at Humanosphere. Prior to operating this online news site, he reported on science,  medicine, health policy, aid and development for the Seattle Post-Intelligencer. Contact him at tom[at] or follow him on Twitter @tompaulson.