Monday, July 8, 2013

A look into the Institute for Responsible Technology - Second Act

Hello dear readers,

As promised, I continue examining the "Health Impact" section from the Institute for Responsible Technology's webpage. I'm picking up where I left off last time: on the section about Bt corn and allergens.

I can hear my husband right now telling me "BioChica, you've got to explain what Bt is". OK, voice in my head. I'll listen to you. Here's my feeble attempt: Bt or Bacillus thuringiensis, is a naturally occurring bacteria that produces a protein that acts as an insecticide. There are various strains of the bacteria, and the protein that is produced by each strain has variable insecticidal properties.  Scientists have taken this protein and inserted it into different commercial crops. If a pest who is sensitive to the Bt endotoxin starts chewing on the GM crop, then its gut gets blown up. Not literally, but it's a close figurative approximation. As an FYI, you can also buy Bt sprays to kill insects that chomp on your garden plans, so the Bt toxin doesn't necessarily have to be genetically engineered into a crop: it has been used for decades as a pesticide.

The voice in my head has now quieted down, allowing me to resume my review of the Institute for Responsible Technology's section on Bt corn and allergens. The first argument is "hundreds of people exposed to Bt spray had allergic-type symptoms". This is linked to an article published in 1990 in the American Journal of Public Health, looking at the health implications of the Bt pesticide. In 1984, there was an infestation of gypsy moths in western Oregon and helicopters sprayed Bt over a populated area. The study looked at cultures obtained from human specimens in 4 clinical labs in the area to determine if the Bt bacteria was present. I read the complete study, and the only sentence that I could find that could be related to hundreds of people having allergic-type symptoms was the following: "Many of the complaints from the public received by the Lane County Health Department were related to skin rashes, angioedema, eye irritation, and respiratory involvement. It could be argued that these symptoms are more consistent with diseases caused by the insect itself rather than B.t.-k. There have been reports of major outbreaks of dermatitis in the NE US involving thousands of persons exposed to gypsy moth larvae. Dermatitis in these outbreaks was attributed to irritation by ... hairlike projections of the gypsy moth caterpillar". Wha-a-a-a-at? In case you didn't catch that, the paper states that these allergic-type symptoms were most likely due to the pest itself, rather than the treatment. Despite what the Institute for Responsible Technology implies in their webpage, the authors are concluding that it's unlikely that the Bt spray has anything to do with the symptoms. The study concludes that Bt should be examined in lab cultures, and not ruled out as a contaminant. Additionally, it states that Bt has the potential for causing disease in immunocompromised individuals, and such patients should be given advice on how to use biopesticides and how to protect themselves. I think it makes perfect sense and is a reasonable recommendation.

Can someone remind me what any of this has to do with GMO?

The next section states: "...mice fed Bt had powerful immune responses and damaged intestines", linked to several papers published. Unfortunately, they're immunology-heavy papers and although I did pretty well in my intro to immunology courses, I don't remember much at all. In fact the only thing I remember is that my prof spoke like Antonio Banderas. I have a feeling that I'll spend a lot of time with Dr. Wikipedia this weekend...



No comments:

Post a Comment