Screwworms in Big Pine… The Next Oxitec GMO Product?

With the USDA announcing they are releasing sterile screwworms in Big Pine to combat an outbreak of animal infections there, many concerned citizens have written Never Again asking if these insects might be GMO or in some way connected to Oxitec. From the evidence we have today, the best answer is, “Not yet.”

The New World screwworm, Cochliomyia hominivorax, first appeared in the United States in the very same area in the Florida Keys that’s having an outbreak now. Despite its name, the screwworm is actually a fly that feeds on living animal flesh. The fly infects the exposed wounds of livestock, wild animals, and domestic pets. By the 1930’s screwworm infections were present throughout the Southeastern United States, causing great financial losses to livestock producers.

In the 1950’s, a novel technique was developed to combat the fly. Called SIT, Sterile Insect Technique, it involves irradiating insects with gamma rays from a radioactive cobalt source. The radiation leaves the insects sterile. By releasing sterile insects and letting them mate with wild ones, the overall population can be reduced or eliminated, and in fact this technique was used successfully to eliminate screwworms in the United States and Panama.

The USDA considers fighting screwworms an ongoing battle. The government agency maintains a sterilization laboratory in Panama under a program called COPEG, which releases large quantities of sterile flies along the border between Panama and Columbia in an attempt to prevent the pest from migrating into the United States.

Oxitec Plans GMO Screwworm Product

The USDA press conference did not provide any details about the sterile screwworms or where they might be coming from. With Oxitec’s entire business model built around GMO insects for sale to public agencies, citizens were naturally concerned that the company might have an interest. And they were right. Oxitec’s Luke Alphey, lead developer of the Oxitec GMO mosquito, is in fact working on GMO screwworm. Although the company does not appear to have a product ready at this time, a paper released in June of this year shows that the intention is to market one as an “improved” version of the classic, radiation SIT technique.

A GMO screwworm would involve many of the same concerns as GMO mosquitoes, most importantly the “leaky DNA” problem that affects all genetically modified animals. When GMO animals mate with wild ones, their DNA is released in unpredictable combinations. The Oxitec GMO mosquito has already been shown to cause another species to rise up and dominate. The company hopes to sell another add-on product, a second GMO mosquito to fix it. Undoubtedly, they would love to sell us GMO screwworms, too.

The USDA Responds

We asked Joelle Hayden of the USDA’s Animal and Plant Health Inspection Service if Oxitec or any GMO product were involved in the Big Pine release. Here is what she had to say:

We plan to eradicate the pest with the Sterile Insect Technique (SIT). Sterile male flies are released in the area and mate with the wild female flies. They do not produce any viable offspring and breed themselves out of existence.  It can simply be described as a form of insect birth control carried out in a particular area.  This method has been used to control screwworm flies and other insects since the 1950’s. We have used it successfully to eradicate the flies in this country, Mexico and South America.

The flies are sterilized with low doses of radiation. They are not genetically modified in any way. The SIT is one of the most environmentally friendly insect pest control methods ever developed. It is considered safe for people, pets and the environment. The flies are flown in from a USDA facility in Panama where they are grown, housed and made sterile.

We released sterile flies on Big Pine Key and No Name Key today.  We had ten release sites available on Big Pine Key and four release sites on No Name Key. We plan to release roughly 900,000 flies today and Friday.  We will continue releasing sterile flies until we can confirm that we’ve eliminated the population of wild New World screwworm.  We don’t know exactly how long this process will take, but we are committed to keeping the public well informed on our efforts.

— Joelle Hayden, USDA APHIS [emphasis ours]

So for the moment, it appears that the USDA is using the classic, radiation-based SIT technique which does not carry the same risks as GMO’s. While no radiation source is safe, the irradiated animals themselves cannot transmit their damaged DNA further down the line. The actual irradiating takes place in Panama.

But do not let your guard down, in his paper describing the GMO screwworm, Luke Alphey says that an open field trial of GMO screwworms would help prove their case for selling those insects, too. Residents of the Florida Keys do not want to be the test location for GMO screwworms, either.

Never Again thanks all of the citizens who contacted us about this issue.


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