Genetically Modified Mosquitoes: Epidemic-ending Super Heroes or Environmentally Unethical Villains

by Pamela Barclay on January 18, 2012

Touted by some to be a top medical breakthrough and others as an unnecessary risk, genetically engineered mosquito species have become a reality in efforts to control the spread of disease to humans.

Insects have transmitted diseases to humans throughout history. Mosquitoes typically spread disease more frequently in equatorial regions, but with global climate changes and increasing virulence of disease strain, geographic areas impacted are increasing. Several diseases, including Malaria and dengue fever, are commonly spread via mosquitoes.

There is no vaccine or approved medical treatment for dengue fever; therefore controlling the populations of mosquitoes is essential. Current population control measures are decidedly low-tech and include draining areas of standing water, the application of insecticides, and the use of insecticide-treated bed nets. These interventions have inherent challenges in access to and distribution of bed nets and insecticides, human exposures to hazardous chemicals, environmental degradation, and creating insecticide-resistant mosquitoes.

Taking the “bite” out of the bug

A field test of genetically modified male mosquitoes was conducted on Grand Cayman Island at the end of 2009 and the report was recently published by Nature Biotechnology. The modified mosquitoes were developed by Oxitec, a British biotechnology company, to reduce the spread of the dengue virus. They used a variation of the Sterile Insect Technique (SIT) that has been used successfully to control several agricultural pest insects. Rather than sterilize the mosquitoes using radiation which damages the viability of the mosquito, Oxitec modified the genetic make-up of the laboratory mosquitoes to include a dominant lethal gene in which offspring would not survive to adulthood. Based on this field test it was concluded that genetically modified mosquitoes are able to compete with wild male mosquitoes for mates outside of a laboratory controlled environment.  This suggests that it is possible to reduce the number of mosquitoes that may carry the  dengue virus through the regular release of genetically engineered male mosquitoes.

So, what does this mean?

  • Mosquito species are not being removed from the environment and would continue to be a part of local food webs and ecological niches.
  • The genetically modified mosquitoes are not self-sustaining due to the lethal gene that has been integrated. To sustain results of reduced mosquito populations, regular releases would need to occur.
  • The mosquitoes being genetically altered belong to a specific species of mosquito, Aedes aegypti, which is responsible for the spread of the dengue virus.

While uncertainties exist over the potential for unforeseen consequences and public backlash, like what has been seen in the use of genetically modified crops and agriculture, what is certain is that this is likely only the first in many field tests to come. In fact, if you live in the Florida Keys, where the first cases of dengue fever were reported in 2009, genetically modified mosquitoes may be coming to a neighborhood near you as early as this spring.

[ image deleted 2/3/2012]

SOURCES:

Harris, A.F, Nimmo, D., McKemey, A. R., Kelly, N., Scaife, S., Donnelly, C. A., Beech, C., Petrie, W.D., & Alphey, L. (November 2011). Field performance of engineered male mosquitoes. Nature Biotechnology (29, 11). P. 1034-1037. online

Ostera, G. R. & Gostin, L. O. (March 2011). Biosafety concerns involving genetically modified mosquitoes to combat malaria and dengue in developing countries. Journal of the American Medical Association (305,9). P 930-931. online

Shelly, T. & McInnis, D. (November 2011). Road test for genetically modified mosquitoes. Nature Biotechnology (29, 11). P. 984-985. online

Charles January 18, 2012 at 3:39 pm

Nice post. Dengue turns up in more and more places. It seems to turn up in the south of France on a yearly basis. I liked the bullet point summation. Gets straight to the point and tells me everything I wanted to know.

I think you could go a little bit further in what you’ve written… to add more context to the debate. There has been one notable example of where this has worked. The successful eradication of a Glossina austeni (species of tsetse fly that causes trypanosomiasis) population from Unguja Island. I think there they used the SIT as well.

Pamela Barclay January 18, 2012 at 3:45 pm

Charles, thanks for the feedback! I think what I struggled most with was striking a balance with giving enough information, but not too much…your comments are helpful!

azmanam January 18, 2012 at 4:01 pm

Nice work. You don’t really go into the ‘unnecessary risks’ that you mention in the lede, except to say there are unforeseen consequences and potential public backlash (which there are for every policy proposal. Ever.). More here on specific criticisms would have been nice.

Love the use of section titles to help the reader out. One nit-picky comment (and you may have a whole class on accessibility later in the semester, I don’t know): If you use section titles like that, you should format them as Heading 2 rather than Bold (yes, I went into the page source to check it out. Don’t judge me!). This won’t make a lick of different for most of your readers, but blind readers using a screen reader will really benefit from this minute change in formatting: http://www.raymondselda.com/importance-of-html-headings-for-accessibility/. The title of your post is Heading 1 by default, so you don’t want to compete with that – Heading 2 is probably the way to go :)

Pamela Barclay January 18, 2012 at 6:27 pm

I appreciate the feedback, and I am sure my classmates will appreciate any preferences and insight into formatting!

PF Anderson January 18, 2012 at 11:07 pm

Awfully glad to see accessibility and sections headers mentioned. One potential drawback is that Wordpress doesn’t make it easy or straightforward to add headers WITHIN a blogpost, and they usually have default headers to structure the CSS for the site.

If you do add headers within the blogpost, usually be going in to edit the HTML for the specific post, there is the extra hassle of testing to ensure that the headers don’t conflict or duplicate header levels being used for the titles of the actual blog itself. If you use the same headers used elsewhere on the site, it could potentially create confusion, rather than making things better.

I did a little digging in the code myself, and it looks like Headers 1 through 3 are reserved for the blog structure, so you would need to begin with H4 and down. I lack confidence in how those might actually look formatting wise. I would not be surprised it it required some custom formatting of the stylesheet for the entire blog to handle this.

I’ve tried a number of strategies myself. I’m not happy with any of them, but I have tended to make “headings” all caps and bold, and am not using header tags within the body of the blogposts. I’ll ask some of my blind friends what they prefer. Excellent issue!

Pamela Barclay January 19, 2012 at 12:16 pm

If you get any feedback from your friends, please be sure to share!

Andrew Maynard January 18, 2012 at 7:05 pm

Thanks for the call-out on headings – will definitely cover that in class along with SEO techniques in general! Andrew

rosette715 January 18, 2012 at 4:19 pm

I think the story reads very well. I am, however, left to wonder whether this is a good thing or not. Eradication of any disease from society always seems like it should be a plus, but Mother Nature prevails in the end, leaving mankind to come up with another genetically modified answer to the issue.

Pamela Barclay January 18, 2012 at 6:35 pm

Thanks for the comments…as far as I can tell one of the main criticisms of this effort is that there has not been sufficient review to determine any harmful effects of releases like this or opportunities for public consulatation.

Dan Kahan January 18, 2012 at 4:50 pm

Interesting!
Like others, was left wondering what the debate is — who sees villains here & why. Is it just anticiapted “public backlash”?

Pamela Barclay January 18, 2012 at 6:39 pm

From what I have seen in the media, concern has been expressed over lack of review of potential harms and public involvement in the process. Since people are not intended to eat the mosquitoes, some of the concerns of other GMO’s are not necessarily relevant. Overall, I actually thought the article researchers did a good job in addressing concerns in relation to not eliminating an ecological niche by exterminating a species of mosquito and ensuring that the genetically engineered mosquitoes are not self-sustaining out of the lab.

Angela January 18, 2012 at 4:53 pm

Hi! Interesting and very relevant topic – thanks for writing about it and so clearly. As far as I remember from a colleague who is researching GM mosquitoes, there have been several different trials, e.g. one where the mosquito is modified in a way that won’t allow the parasite that causes malaria to exisit within its body? Wondered if you could include some more context like this: other modification strategies, that there is a parasite/symbiosis involved, who funds this research (e.g. Bill Gates Foundation).

Pamela Barclay January 18, 2012 at 6:43 pm

There have been a couple of other attemps to modify mosquitoes, the one that you mention in your comment is one, another that I have read about is to actually load the mosquito with bacteria that can outcompete the parasite.

I am not sure as to funding sources, but I will do some searching and reply with what I find!

Pamela Barclay January 19, 2012 at 9:48 pm

I looked up some funding information and it appears that funding for different GM mosquito projects has come from a variety of sources:
* Bill and Melinda Gates Foundation
* Venture capitalists
* Universities (University of Toronto, Oxford University, University of Queensland)
* Australia’s National Health and Medical Research Council
* The Queensland Government

Carol Rose January 18, 2012 at 5:39 pm

Having suffered through malaria in East Africa and dengue in Honduras, a large part of me wants to say, “Wonderful!” However, another part of me worries that there will be an unforeseen side effect that we will regret. It seems to work that way so often when we actually mess with the natural world. I will be following these developments.

Pamela Barclay January 18, 2012 at 6:45 pm

Hi Carol, Thanks for reading and commenting! It is this potential for unforseen and unknown consequences that has most people worried!

Bob M. January 18, 2012 at 6:50 pm

Good post. Easy to follow. I like the overall formatting: use of section titles, bullet points, sources.

Pamela Barclay January 19, 2012 at 12:16 pm

Thanks for the feedback!

Lawrence January 18, 2012 at 7:59 pm

Good job Pam. I am also left wondering if this is a realistic option in controlling malaria as the process would probably have a substantially higher cost than most malaria interventions. Would genetically modifying mosquitoes not make that big of a difference anyways because of their short lifespans and thus right rate of evolution? Or maybe I just have a Hollywood induced fear that genetically modifying a species could lead to a deadly mutant variety which turns us all into zombies?

Pamela Barclay January 19, 2012 at 12:27 pm

The report I concentrated on focused genetically modifying mosquitoes to control the spread of the dengue virus as a single species of mosquito is responsible. From what I have read, using this same process for malaria may be more complex. This may be a case, as with many problems, where a “one-size fits all” solution is unlikely.

Kerri January 18, 2012 at 9:25 pm

I really liked reading your post! Very easy to read and interesting. I’m with Lawrence on this one, hopefully it is just hollywood fear and we don’t need to worry about it leading to a negative endeavor!

Pamela Barclay January 19, 2012 at 12:30 pm

Thanks for the feedback! While the genetic modification is a lethal gene that is designed to reduce the lifespan of the modified mosquito and any offspring, a certain percentage of the offspring still may survive to adulthood…

Michelle M January 18, 2012 at 9:49 pm

Looking through the previous comments, all of the points that I was going to raise have already been addressed. I think you have pitched at a great level for the public. Re unforeseen risks of the whole project, it seems to have an in-built safety valve in terms of the mosquitoes dying and needing to be continuously re-released. Surely if there was a problem it would disappear quite quickly and they would simple cancel any more releases. I am sure there are other factors, but this seems like a good thing – just in case.

Pamela Barclay January 19, 2012 at 12:32 pm

I agree, I think that the researchers were smart to ensure the carriers of the modified genetics were not self-sustaining.

Patricia January 18, 2012 at 10:11 pm

Good job!! This is a good example of how science can be transmitted to non-scientific people. The information is well presented, the titles and sections help a lot.

I would’d have liked a little bit on the cons of genetically modified mosquitoes, juts to give the public a taste of both sides of the story, but that’s just me and does not demerit at all your post.

Just one observation, and this is from my biological background. All scientific names are written the first word with capital letter, so when you wrote aedes aegypti it should be Aedes aegypti.

Patricia

Pamela Barclay January 19, 2012 at 12:34 pm

Thanks for the feedback! I will go back and fix the name to be more accurate!

Most of the arguments that I have seen against the genetically modified mosquitoes have been about unforseen or undefined potential impacts…more of a fear of the unknown

PF Anderson January 18, 2012 at 11:09 pm

Hi! Just curious — what’s the source for the image?

Pamela Barclay January 19, 2012 at 12:35 pm

http://www.oxitec.com/our-targets/aedes-mosquitoes/the-dengue-mosquito-aedes-aegypti/

I am still trying to figure out how formatting works in Word Press and tried to make a caption with the source, but was clearly unsuccessful!

PF Anderson February 3, 2012 at 3:06 pm

I’m guessing that by now you’ve probably figured out there are several problems with using that image, and finding the rights to use the image.
1) It is uncited and from a commercial source. The assumption is that they have copyright even if they don’t say so on the page.
2) They did not list a source for the image, nor did they include a copyright statement, which means you have no idea who actually created and owns the image.
3) I dug around in the code and found they link to the image on someone else’s server (a suspicious way to do business, and one that clearly shows they do NOT have rights to the image). The source they used was this: http://www.behealthyandwell.com/wp-content/uploads/2010/10/aedes-aegypti__7856981-300×219.jpg
4) I searched for that URL in the image search engine TinEye (temporary URL for search results: http://www.tineye.com/search/0eca0920d5c6df8617880e506ef0e2e591e46da0/ ) and found 27 other uses of the image on the FIRST page of 25 pages of results. Oh dear. There is absolutely no way to track down the original photographer short of visiting every single link, and even that might work.
5) That means that if someone came back and complained, you would probably need to assume they are telling the truth, unless you want to fight them for it. It is risky to place an employer in the position of risking being responsible for use of an image.
6) I tried searching for the image in Google, hoping that I would find the original source listed on top (but it didn’t work out that way): https://www.google.com/search?tbs=sbi:AMhZZit0U87A_1qqpjvSWuP3cC4X6aSVLpVDxpaPe1TN7yB8em3-sz2hvaKO7CM1-Wssa_1KJMQGOkgh2nHnwme9iP2FdbcT0yvT5txkthNTlVD8a1xEjuF-Sunydd3T5xJpAces6LSOY4DSsov72ttnlkTYSsMaueyz9VIEBB42C6a_1CxkSYJe9KJV3zqeSBxIC4aUO3uqOhLUsRtEg7le_1KYpm1KygED4Us4Q-Rpe1UFEh7i2-deM8iKz0e20rtoGHV3gwAliSdzTqr1ug9ko19maEq5siFVLUbkNvfPveCR5CkCUd548Lt0tSqh9oiaXJrgGjhLI85FB5VYfJAtRM_1w86DQIi20nKRz_1pQuakQ58KlcAwnMOPZw24DjIzd4TQcBsXz6C8KjYWTJnMaaTHJA42F76Ea-GLw-xHA3QZ1vfhvqGN4cLsO5tNEcBaQqmcTybgrJWhNi_1Rb6UM2JHRrA1HGILIx3Mq2giOHkRZUj7s_1w7PHlkUUzV6AGda4uXMbRf4jkDYOMY4sawBgIQA1KECdMTgV5r3W6LJ7B89ACNCI65S0b26a-38oMUpYRqSflf8hoYUx43Ek7DR9YMIEDLAhPC5fcB-6W_1lio9oUSGJDVmLHOtyXTLFXR0GXVh2hMrokbah197x_1iNayPXhix0OdYrhHgFOH08Z0UBCle9fHdjbtv4n3-7rCSbMUDh2GmQoFoDvi3jtNSA2TK_1c3NivqA11KX6tYVPUQCoXJ_1XKViPDuLSzKnUfKOEcg1AF8ArFXYs_1fHbQQNLWgui2VbEDOWkfOGFhYYzt0ZG807PYKZDpsL3ai8_1ryqQYDxO0jvsaWAos2FLKtz34re7coV5shA0Qw6Joyd_1FGzZXwnKyHri4PDL3Db-GRw80nSUVmJPdJs281_1DoKpp-w8ojWwiyAIQBD1VLixC2nakM51hVLREeIrdd69dV9w4786SsGV-nT9Zn-nLby34Ior4MprRxddhwGuEDWJe4mAAcaQFUjAG9CWZi0wQ3ULc65g1OkJz2FdYVzhXvjkfVF-s3ZMkhTCLJ921qmm1qxjy_1uGpprAblkDfnXDUGCmajydMtpWcsDXAIUQxBQHPCshvxsHL68BVDtE1KEbKNtXfnRWPHIpNAar6Mg8pfTQ2mybAe2W42S5JZK0j1J3JvVBK-ekhuDGq8JnFGTV1e2Rq0d9S7JwyGpP97htD_1C7_1ES_1PkI5LiFNJ0HjUCdjO-cQKy0h1T0zf9XSghhkInQpqR1h6SWGZyiDTizp_1uRcWLo6RdmMttjEySHqasBbtHiMBWh9pYjehnXLYUz7dJPZCBLfb7SwuCDsnR2dkShwBmxXa095X6ddj8uKqKbpNEl3mHtj2gS0J6_1vk2pZXulR9MjxX_1ZeiS7tIdg&hl=en&ei=rjosT_SMEKbi2AW3oOCQDw
7) I tried searching for matching images in Google. That was also interesting and unsuccessful in finding the original source. https://www.google.com/search?hl=en&tbs=simg:CAESWhpYCxCwjKcIGjwKOggBEhTdBMIEjgXHBNwE3gTZBNoE2wTKBBogxYsTaDXAdTXHDgx2peGW4qOYeq-um3SX-Fx036ZUaYEMCxCOrv4IGgoKCAgBEgThS0i5DA&q=dengue+aedes+aegypti&tbm=isch&sa=X&ei=DjssT9iHDIjY2AWxrsXgDg&ved=0CD8Qsw4&biw=904&bih=902
8) I found one possibility that might be an owner, and some alternatives.
Possible owner: http://grupos.emagister.com/imagen/aedes_aegypti_vector_del_dengue/1021-358855
The problem is they give the date they posted the image, and it is the same day that BeHealthy posted it. Who got it first?
An alternative image that can be licensed for use: http://www.sciencephoto.com/media/370148/enlarge
An image that is probably not quite similar enough but is Creative Commons http://en.wikipedia.org/wiki/File:Aedes_aegypti.jpg
Possible images from the CDC: http://www.cdc.gov/dengue/entomologyEcology/index.html
And my favorite, images from the Wikimedia Commons:
http://commons.wikimedia.org/wiki/File:Aedes_aegypti_CDC-Gathany.jpg
http://commons.wikimedia.org/wiki/File:Mattiparkkonen_Aedesaegypti.JPG
http://commons.wikimedia.org/wiki/File:Aedes_aegypti_during_blood_meal.jpg
http://commons.wikimedia.org/wiki/File:Aedes_aegypti_biting_human.jpg
Any of the Wikimedia Commons images include full licensing and citation information (as well as provenance of the image) at the bottom of the page.

Pamela Barclay February 5, 2012 at 12:07 pm

The photo has been removed. Since our first week we talked about the use of photos in our posts in class and have focused on the use of sites like wikimedia commons.

Thanks for identifying some of your favorites!

Debbie Morrison January 18, 2012 at 11:48 pm

Hi Pamela, I enjoyed reading your post – well written, from the perspective of a non-science person. I particularly like your section ‘So what does this mean?’. This is an effective way to summarize the article. With regards to your concluding paragraph, as below – as the reader I am left wondering, what uncertainties still exist? Perhaps identifying the ‘uncertainties’ for the reader would close your piece effectively.

“While uncertainties exist over the potential for unforeseen consequences and public backlash, like what has been seen in the use of genetically modified crops and agriculture, what is certain is that this is likely only the first in many field tests to come. In fact, if you live in the Florida Keys, where the first cases of dengue fever were reported in 2009, genetically modified mosquitoes may be coming to a neighborhood near you as early as this spring.”

Regarding your links – you link to the same article in two links – I am not sure if it is necessary to link to the same article twice [first paragraph and fourth paragraph] ? Not sure – this is a minor detail, I am sure your prof would guide you in the right directions. Overall very good! :) Thank you!

Pamela Barclay January 19, 2012 at 12:38 pm

Thank you for your comments! I was not sure how to make it clear that I was using the same report from beginning to end, so creating the link seemed a simple way to do so…I very much appreciate the feedback!

Debbie Morrison January 18, 2012 at 11:49 pm

Hi Pamela, I enjoyed reading your post – well written, from the perspective of a non-science person. I particularly like your section ‘So what does this mean?’. This is an effective way to summarize the article. With regards to your concluding paragraph – as the reader I am left wondering, what ‘uncertainties’ still exist? Perhaps identifying the ‘uncertainties’ for the reader would close your piece effectively.

Regarding your links – you link to the same article in two links – I am not sure if it is necessary to link to the same article twice [first paragraph and fourth paragraph] ? Not sure – this is a minor detail, I am sure your prof would guide you in the right directions. Overall very good! :) Thank you!

azmanam January 19, 2012 at 8:04 am

I was thinking about this more last night. So, does this mean that eventually there will be no ‘natural’ populations of mosquitoes and the only mosquitoes in existence will be the artificially introduced GM mosquitoes?

I dunno… artificially supporting a industryspecies that can’t sustain itself anymore sounds like a recipe for collapse and disaster if not thought through really well.

Am I drawing an illogical conclusion?

Pamela Barclay January 19, 2012 at 12:41 pm

The mosquitoes in this report are designed to die off and would require the re-release of additional modified mosquitoes to continually control the population. The modified mosquitoes can compete with the wild male mosquitoes, but are not quite as effective…I imagine the level of population control would be highly determined by the number of genetically modified males released into the area.

MB Lewis January 19, 2012 at 9:49 pm

Hi Pam: I remember you from our talk about robotics mentoring! And I remember back then you said you had an interest in innovative uses of technology applied to global health problems (esp in regards to water, right?) I see you’re still tracking the topic… This is a great story to bring to public attention, and I think you’ve told it well. The clarity in your first sentence, summing up what’s the essence of the matter at hand, is perhaps the best I’ve seen all week. Genetically modified insects initially sound so sci-fi, but you’ve broken it down into little bite-size pieces for us to nibble at, even bringing it closer to home in the last paragraph. Keep it coming….
MB

Maryse January 20, 2012 at 9:11 pm

Hi Pamela! Like so many others who commented, I very much enjoyed the article. It was clear and succinct, although it did take me a couple of reads to understand how this GM mosquito thing would work in the wild. Depending on who your audience is for this material, you might want to consider a metaphor for describing how this process works. E.g., “In a sense these GM mosquitoes are culling the population. As they fail to sexually reproduce because they’ve been neutered, the next generation of mosquitoes is reduced.” I’m sure you can come up with something better but I thought it best to illustrate what I meant. I find when I’m reading unfamiliar material, some kind of metaphor helps. You may not want to use it in this instance, as I’ve kind of said earlier, it depends on how you’ve conceptualized your audience. Cheers, Maryse PS The SEO and using secondary heads for blind readers is a great hint. Thank you, PF Anderson.

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