Genetic Modification for Disease Control

Genetic engineering isn’t only limited to livestock these days. What about disease control?

A company called OxiTec, founded by Dr. Luke Alphey of the UK, has patents on genetically engineered mosquitoes whose offspring are unable to reproduce. They sell these mosquitoes (and other insects) to customers who want to reduce local insect pest populations for agricultural or health reasons.

OxiTec sells two types of these insects: “Bisex RIDL” and “Female-specific RIDL”. The first means that you release both sexes into the wild, but any progeny the altered mosquitoes have will die at a predetermined stage of the life cycle. The second means that the males carry the fatal gene and pass it down to their offspring. The female offspring die, but the male offspring are able to mate and once again pass on the deadly gene.

Reducing the number mosquitoes, the spreaders of dengue, chikungunya, malaria, etc. will save thousands of human lives each year. Even the website’s tagline reads, “RIDL employs modern technology to provide effective, clean control of insect pests.” Meaning that the toxic, chemical pesticides that the public knows do not need to be used. This seems safe for the environment, right?

Right.

Here’s a 2009 video of Dr. Alphey speaking about his company’s research and products. In my opinion, he does a very good job of explaining the scientific processes in an easy to understand manner. He gives multiple examples about how RIDL helps contain insect pests, and it seems very effective.

With continued releases, this technology keeps insect numbers low and reduces incidence of disease. The New World Screw Worm was highly prevalent throughout North and Central America, but by releasing thousands of sterile male Screw Worms a week, countries save an estimated “$1.3 billion in economic damage each year at a cost of $10 million.” That’s a ridiculous amount. And an incredible way to cut down on the use of insecticides in the environment.

On an unrelated note, and I’m playing Devil’s Advocate here, it is interesting that in the company’s description of current Aedes (the genus of mosquito that spreads dengue, yellow fever, and chikungunya) control methods, it neglects to mention the recent trial completed in Australia in which bacteria-infected mosquitoes were discovered to stop dengue transmission and were successfully released in Australian neighborhoods. Whether the website has not been updated since August 2011 or they intentionally left it out I can’t tell.

I do know that the Australian study, in which researchers released thousands of mosquitoes infected with Wolbachia, a bacteria that stops the spread of dengue, made headlines in many different media due to its success. Hopefully there’s no animosity between the two groups. But it’s never bad to have multiple successful, competing ideas, as long as they both accomplish what they set out to do. Indeed, in the video Dr. Alphey says, “None of this [eradicating diseases] will be done solo; it will all be done with other partners, and in many cases using a combination of approaches, not just the one [RIDL] I suggested.”

This is a very exciting, cutting-edge area of research and I’ll definitely follow the company’s progress.

Photo Credits: www.oxitec.com, www.fohn.net