GMO Mosquitoes: Will Zika Change the Equation?

As the Zika virus outbreak continues and mosquito season in this hemisphere approaches, there will be a ramp up in vector control activities. These activities are aimed at reducing mosquito populations and are practiced for several types of mosquitoes, most notably those that spread West Nile Fever. However, even prior to the Zika outbreak, because of the threat of dengue and chikungunya, aggressive campaigns against Aedes mosquitoes had taken place in certain areas such as Texas, Hawaii, and Florida.

Florida, which has had several instances of local transmission of both dengue and chikungunya, has been a national leader in mosquito control as exemplified by the Key West Mosquito Control District. Over the past years, faced with a continual threat of dengue, the use of Oxitec's sterile male genetically modified mosquitoes to reduce Aedes aegypti populations has been contemplated as a means to augment ordinary mosquito control operations. 

However, in today's context, "genetically modified" evokes an unjustified Frankenstein/Jurassic Park horror in many people and has stalled release of these mosquitoes in the US (they have been part of trial releases in the Cayman Islands, Panama, and Brazil).

Given this context, pre-Zika, my colleagues and I sought to understand how the public conceives of GMO mosquitoes and what their support or opposition is influenced on. To meet this aim we fielded surveys to residents of a Florida community in which the release of these mosquitoes is being contemplated. PLoS Currents Outbreaks just published the results of that work.

There were several findings that we found particularly striking:

  • Being a female was significantly associated with being opposed to the use of GMO mosquitoes
  • Having never known anyone with chikungunya or dengue was significantly associated with opposition to use of GMO mosquitoes

The 2nd finding is what I deem the most important, as it reflects the role of risk assessment on an individual level and will likely change as people's threat assessment changes. A headline-grabbing virus like Zika may be just the threat that will cause people to think differently about GMO mosquitoes -- something that is already happening.

We hope to follow this paper with a follow-up post-Zika study of the same area as well as explore the mechanics and public health communication strategies used in the Cayman Islands, Panama, and Brazil. Additionally, it will be important to put GMO mosquitoes firmly in the tradition of such endeavors as the eradication of the agricultural screwworm pest, irradiated sterile mosquitoes, and Wolbachia-infected mosquitoes.

It is the role of public health authorities and physicians to help calibrate the general public's analysis and our hope is that this paper can help move the discussion of GMO mosquitoes further forward.


How GMOs Could Have Prevented Nigerian Mystery Illness Cluster

Each time a cluster of illness occurs there is a process to determine its cause. One of the first thing that comes to mind with clusters, broadly speaking, is determining whether an infectious disease is present or something else. "Something else" will include a list of things, chief of which is a common exposure to some toxin. 

The recent cluster of illness (blurry vision, headache, alterations of conciousness) in Nigeria--which recently experienced several imported cases of Ebola--sparked concerns of Ebola, for obvious reasons. However, it appears that no infectious cause of illness is responsible for this event which has claimed the lives of 18.   

Currently there are two competing explanations: methanol contaminated gin and the WHO's preliminary hypothesis: pesticides. Both are good explanations because they fit the symptomatology of the cases and are biologically plausible. Final diagnosis should be able to confirmed with laboratory testing. 

The investigation of this event illustrates several aspects of public health investigations, the most important of which is the importance of surveillance. Without knowing what illnesses are occurring in an illness, it is impossible to detect unusual occurrences and place them in the context of what is the usual baseline mix of disease in an area. 

Another aspect of this case is the possible link with pesticides (which may not turn out be the case). Though I am a big fan of pesticides as I value human life and the conditions required for our flourishing--such as an abundant supply of food--pesticides can be dangerous if the quantity ingested exceeds a threshold. Because of these limitations, alternatives to pesticides are actively sought. One such alternative are GMO crops that are resistant to plant pathogens. One would think that such a pathbreaking advance in genetics and agriculture would be embraced, yet it is not.

Why are GMOs feared? It is not because of any evidence of their danger for there really isn't any as no one has died or been harmed from GMO-poisoning (an oxymoron). Yet for those who seek an alternative to pesticides, which cause up to 20,000 illnesses yearly in the US, GMOs are often considered off-limits because of the vocal anti-science, anti-reason, anti-GMO movement which often resorts to threats, violence, and property destruction in their nihilistic quest. 

Remember the corn we eat and the dogs we walk are all GMOs as artificial selection and breeding for specific traits are exactly the principles behind all genetic engineering. 

You would think that people that scream "safety" would actually care about safety and embrace GMOs, but it isn't safety that motivates them, it is hatred of the human minds that made GMOs possible.

GMO Mosquitoes: The 21st Century Bug Zapper

There are several mosquito-borne diseases that merit a lot of attention in the US. These include dengue, chikungunya, and West Nile Fever. The key to the control of these infections--none of which  are vaccine-preventable--is controlling the mosquito which serves as the vector for human infection. 


Vector-control is a challenging task. Prior to the sermons of fellow Pittsburgher Rachel Carson, which led to bans on DDT use and the collapse of the malaria eradication efforts in the 1960s, mosquito control was achieved using this highly efficacious insecticide. Current vector-control activities employ other compounds targeting mosquito larvae as well as adults. Often, simple efforts such as removing standing water from tires and other household items are highly effective measures. 

A new 21st century approach to vector control that I find very promising is the use of genetically modified mosquitoes. In this approach, pioneered by Oxitec, male mosquitoes are genetically engineered to produce offspring that cannot live outside the laboratory because they require the presence of the antibiotic tetracycline to live. In the wild, when a female mosquito mates with one of these engineered male mosquitoes, the offspring produced will die. Such an activity can substantially reduce vector populations and, therefore, render infection with mosquito-borne viruses less likely. Thus far this approach has been used against Aedes mosquitoes (the vector for chikungunya, dengue, and yellow fever).

Already, this approach has been employed in Malaysia, Brazil, and Panama with great success. Even Florida, recently plagued with dengue, has used this approach.

What I can't seem to fathom is why this measure, which could literally change the landscape in the realm of vector control, is met with derision and fear over tampering with the "fragile ecosystem." Such a reaction completely drops the context. All types of vector control, from bug zappers to DDT to a fly swatter, represent attempts to "tamper" with the ecosystem and are laudable attempts to tame mosquito-borne diseases. Mosquito lives aren't as important as human lives, unless one holds a wickedly egalitarian and nihilistic standard. 

I wonder if these individuals would have counseled against smallpox eradication because of the ecological niche once played by the virus. 

A favorite quote of mine, from Francis Bacon, is applicable here: "Nature, to be commanded, must be obeyed." Viewing nature as a realm able to be shaped and reconfigured by man's mind, while respecting the rules of reality, is what is sorely missing in the minds of those who reflexively oppose the use of these mosquitoes. It is reminiscent of Mary Shelley's panic over the progress of science, which inspired her Frankenstein.