Far too many journalists with no education in the sciences are writing ignorant drivel about the sciences. Dengue virus is primarily transmitted by Aedes mosquitoes, particularly A. aegypti but can also be transmitted by A. albopictus, A. polynesiensis and A. scutellaris. Mosquitos, humans, and nonhuman primates are the only hosts for the disease. Elimination or reduction of hosts, primarily mosquitoes, does not have any mechanism to create a deadlier version of the virus; and in fact, should greatly decrease the chance of any such occurrence.
Funny thing about dengue. There are 4 varieties. Get one and recover, you're immune to that one for life, and immune to the others for a short time. Get infected with one of the others after the immune period, and you're much more likely to have a far worse, and deadlier, illness. There is no vaccine, so the only means of prevention is to not get bit, and especially not get bit twice. And you can only do that by: 1. not living where the mosquitoes live, 2. live in a plastic bubble, 3. eliminate all mosquitoes, 4. eliminate the disease in all the hosts.
To control dengue fever, one biotech has developed genetically modified mosquitoes whose offspring die before they can spread the disease.
These mosquitoes have already been released in Brazil, Malaysia, and the Cayman Islands. In Key West, Florida, the disease reappeared 3 years ago, after an absence of over 70 years.
And the US Food and Drug Administration is currently reviewing an application from the UK-based Oxitec. Florida residents are gathering names for a petition.
Nature News explains:
- Their mosquitoes (known as OX513A) are an engineered version of Aedes aegypti, the main transmitter of dengue fever, which infects at least 50 million people a year.
- The modified males carry a lethal gene kept in check only by a special diet.
- They survive to mate with wild females, but the offspring die.
- In field tests conducted in Juazeiro, Brazil, the engineered insects shrank the A. aegypti population in an 11-hectare area by 85% over a year.
The Florida Keys Mosquito Control District (FKMCD) in Stock Island is a taxpayer-funded operation that spends more than $1 million a year to control A. aegypti in Key West with insecticides.
In 2010, the FKMCD asked Oxitec if it would do a field trial with its mosquitoes in Key West. The next year, the company applied for FDA approval. A media report that very month suggested that officials were hoping for a mosquito release as early as January 2012, prompting concerns among residents.
The petition raises prospects of unintended consequences, such as the emergence of a deadlier dengue virus that gets around the absence of A. aegypti. And residents in Key West say they don’t want to be tested like “guinea pigs” and “I don’t want my family being used as laboratory rats for this.” Michael Specter writes in The New Yorker:
There is, of course, another theoretical catastrophe to consider: a dengue epidemic in Key West. So far the city has largely been spared, but the region, as Oxitec’s chief scientist Luke Alphey told me when I spoke with him for my article, is “living in a sea of dengue.”
When Oxitec opened up Moscamed, a mosquito-production facility, earlier this month in Juazerio, residents cheered. But the University of Sao Paula team engaged the community before seeking approval for their trial from Brazil’s agency for biotechnological safety, CTNBio.
[Via Nature, New Yorker]
Image: female Aedes aegypti / CDC
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