Article repurposed from http://www.forbes.com/sites/kavinsenapathy/2016/04/11/the-worlds-deadliest-animal/
Lions and tigers and bears, oh my! From rabid dogs and bats killing around 59,000 people a year to snake bites killing 100,000 and disabling many more, toothy vertebrates haunt humanity’s dreams for good reason.
But death tolls from fanged beasts pale in comparison to the havoc mosquitoes wreak. Between malaria, dengue and yellow fever, the World Health Organization chalks up millions of annual deaths to the insect. One specific type of mosquito out of around 3,500 species, the Aedes aegypti spreads these diseases and has made headlines in the wake of increased microcephaly cases almost certainly caused by mosquito-borne Zika virus in Brazil, Argentina and other nations in Central and South America.
With the Centers for Disease Control estimating Ae. aegypti’s range extending as far north as central California on the west coast and Rhode Island on the east (the numbers and risk in these areas are unknown) and experts predicting that the risk and range of these mosquitoes will increase with time, the threat from these mosquitoes is real.
“Although it’s true that Aedes aegypti is found mainly in the southern US, predictions of the future of global climate change increase the range of Aedes aegypti substantially,” says entomologist Erfan Vafaie, Extension Program Specialist with Texas A&M AgriLife Extension.
“[E]ven if it’s not a problem in your backyard now, it very well can be,” he tells me, explaining that with the effects of predicted global climate change, the majority of the world’s population will be at risk of dengue transmission by the year 2085.
Oxitec, a biotechnology company that prides itself on “innovative insect control” offers a solution in the form of high-tech mosquitoes. The tiny winged-wonder has polarized public opinion during the FDA’s open commenting period on the company’s finding of no significant impact in support of an investigational release of genetically engineered (GE) mosquitoes in the Florida Keys. The FDA tentatively agrees that the mosquito trial in Florida will result in no significant impacts on the environment. The commenting period ends right before midnight on Wednesday, April 13th, and anyone can leave a comment.
Oxitec created the OX513A engineered version of Ae. aegypti through an ingenious feat of biotechnology. The lethal gene makes a protein that kills baby skeeters before they can reach maturity and spread disease. But the protein, which interferes with the mosquito’s cell functions, doesn’t kill it in the presence of tetracycline (a common antibiotic) which the male GE mosquitoes consume as a supplement in the lab to allow them to reach maturity. The mature male mosquitoes, which don’t bite, seek out and fertilize females, which tend to only mate once in a lifecycle. Responsible for spreading disease, only females suck blood as a protein source for eggs. When Oxitec mosquitoes mate with wild females, both male and female offspring carry the lethal gene and, in the absence of tetracycline feed, kick the bucket before they can bite, drastically reducing the Ae. aegypti population.
“This is crazy and unnecessary. Leave nature alone,” reads a comment submitted to the FDA on April 7th, echoing others who believe Oxitec’s mosquito is an unnatural abomination. What they don’t realize is that Ae. aegypti is an invasive species. “It’s important to note the Aedes aegypti isn’t native to the vast majority of its range. It’s native to Africa, but globe hopped all over the world and it’s been [in the US] for over 300 years,” says Joe Ballenger, entomologist, molecular biologist and science communicator who writes at Ask An Entomologist and helps run the Entomology public Facebook group. “Here in North and South America, basically anywhere outside of Africa, there is no reason to believe that [Ae. aegypti is] important to the environment.”
“Humans have a bad habit of smugly or misguidedly removing a piece of the ecological puzzle without exploring how doing so will affect the whole. Better by far to focus on how humans can protect themselves,” writes another commenter. A reasonable concern, the idea that Ae. aegypti is a vital part of the ecological puzzle can be assuaged with the simplest fact-checking. Eliminating Ae. aegypti “would be no different than eliminating kudzu,” says Ballenger of hypothetically eliminating the species from North and South America altogether, though the Oxitec mosquito will only drastically reduce and not eradicate the species.
There are other tools for mosquito control, but they don’t work very well and come with their own host of problems. “Mosquito control has not changed in like fifty years,” Ballenger explains. Many of the pesticides used to control mosquitoes are losing efficacy as the insects evolve resistance. Ballenger also points out that mosquitoes only need about three drops of water to grow. “Insecticide fogging is still an important part of mosquito control because it’s hard to find the habitats,” he says, asking me to consider how hard it would be to eliminate spots that hold even a quarter cup of water. I imagine the numerous crevices and pockets in my own neighborhood with a new, wary sense of wonder.
“I would like to see the public support this,” says Ballenger. He stresses that while the Florida Keys pilot is only one step in testing the efficacy of Oxitec’s mosquito for broader release, “if it works really well it may keep mosquito control companies from using pesticides.” When available, vaccines are a good tool to control mosquito-borne diseases, but there aren’t vaccines for all of them, including Zika, dengue and chikungunya. “[T]he mosquito is a choke point basically,” he says. “All these diseases depend on this one thing.”
“There are two risks to really consider, the risk of using the Oxitec mosquitoes and the risks of not using the Oxitec mosquitoes,” says Vafaie. “[I]f for by some overlooked method the gene ‘jumped’ to another closely related mosquito, it would simply result in the death of that individual mosquito in the larval stage,” he explains of the practically impossible worry some commenters express that the lethal gene may somehow escape.
Vafaie isn’t concerned about performing the pilot release in the Keys. “There is very little evidence to support worrisome risks associated with worst-case-scenario of the genetic modification technique in the Oxitec mosquito.”
The risk of not using the mosquitoes seems far more dire. Says Vafaie: “According to the CDC, approximately 2.5 billion people live in areas with risk of dengue transmission, with 500,000 cases of dengue hemorrhagic fever and 22,000 deaths annually, mostly amongst children. With the current increasing risks of chikungunya and Zika virus in North America, the risks are becoming even more real for everyday Americans. Stopping the Oxitec mosquito could result in a great delay in our ability to reduce the two species of mosquitoes responsible for the transmission of most of these viruses and result in several hundreds of thousands, or millions, of people continuing to suffer and die.”
There have been over a thousand comments received during the FDA’s open commenting period, some of which are well-supported arguments in favor of the program, some that reek of paranoia, and many in between. Certain parents are worried about whether the mosquitoes will hurt their families. Others express that the benefits outweigh the risks of using the high-tech mosquitoes. Yet another makes a Jurassic Park analogy. “Life will find a way,” writes the commenter, implying that like in the movies, man will lose control of its 6-legged creation.
While the FDA does consider comments from the public, those “based on sound grounds” are what make a difference.
“Public comments will most likely be most effective if they are concise, well-informed, and raise issues and concerns that have some data or research to support them,” Vafaie says. “Comments that suggest that genetically modifying mosquitoes may result in a superior race of insects that will outperform humans and eventually become our overlords will likely not be taken seriously.”
Anyone can submit a comment to the FDA until the evening of April 13th.
Kavin Senapathy is a science communicator and mom of two living in Madison, Wisconsin. Follow her on Facebook and Twitter.