What is the future of mosquito control? It might just be genetic modification.
In recent weeks, there has been media hype around a new study on genetically modified (GM) mosquitoes, with the most extreme headlines warning of “strengthened wild bugs.” But these kinds of messages are misleading and undercut a potentially valuable new tool to combat mosquitoes and the diseases they carry. This new technology could radically change pest control around the world, and right here in Louisiana. It’s time to start taking these new developments seriously as the future of pest control, while learning important lessons from our past mistakes.
Two important disease-carrying mosquitoes are in Louisiana: the yellow fever mosquito, or Aedes aegypti, and the Asian tiger mosquito, or Aedes albopictus. Both mosquitoes are not native to the United States, but they now plague our communities and are spreading. They can carry the viruses that cause yellow fever, dengue, chikungunya and some types of encephalitis, like eastern equine encephalitis. The yellow fever mosquito is particularly good at transmitting the Zika virus.
Pest control keeps these mosquito populations in check and has been successful in preventing the spread of these diseases. Right now, in Massachusetts, Michigan and other states, there is an outbreak of the rare, but potentially deadly, eastern equine encephalitis (where 30% of infected people die). Without effective mosquito management, an outbreak of EEE could happen again right here in Louisiana.
Many of these diseases don’t have a cure, so the best way to protect people’s lives is to manage mosquitoes themselves. The problem is that mosquito management is a challenging business. In Louisiana, mosquito control programs mostly rely on a suite of pesticides. But there are known risks and problems with the use of pesticides. Mosquitoes and other pests can, and do, become resistant to pesticides, which can lead to disease outbreaks. Another approach to managing mosquitoes is to reduce the number of places where mosquitoes develop. This means having good drainage and reducing standing water. Even with all these efforts, there is a lot of swamp in Louisiana and we can’t spray everywhere.
The results with the Oxitec genetically modified mosquitoes are very promising. Oxitec, a private company, has been releasing GM mosquitoes in monitored trials in Brazil and the Cayman Islands since 2009. That’s helped reduce populations of the yellow fever mosquito there by 80 to 95%. These GM mosquitoes have not yet been released in the United States, but they soon could be. In 2016, the U.S. government approved releases of Oxitec’s mosquitoes in the Florida Keys, but Oxitec withdrew its application and delayed releases.
The current controversy about GM mosquitoes happened because of a paper that challenged the notion that the Oxitec GM mosquito was living up to the claims of its creators and called into question the safety of the approach. But Oxitec has disputed the claims in the paper, and even some of the co-authors have reportedly asked for the paper to be retracted because it made several speculative claims and generated unnecessary concern.
Of course, every pest management tool we use comes with some risk; there are no silver bullets in pest management. When we rely on one approach to pest management, it inevitably fails. Pesticides have taught us this. For example, mosquitoes were one of the first pests to become resistant to DDT, a pesticide that accumulated in food chains and damaged wildlife. The mosquitoes that transmit malaria are now resistant to four commonly used classes of insecticides.
But at this point, there is no cause for concern about GM mosquitoes. In fact, quite the contrary. This approach provides the opportunity for more targeted control without the side effects of pesticides, like killing other insects that live in the same habitat as mosquitoes. We may even be slow the spread of these invasive species without impacting native species of mosquitoes that cause no harm.
However, we also need to move with caution, keep monitoring, and make decisions backed by sound scientific evidence. As with any new technology, we must remain vigilant. Just as we monitor for pesticide resistance and environmental contamination, government regulators need to maintain careful oversight over GM mosquitoes. And scientists and the media have a responsibility to maintain a healthy dialogue and foster trust to avoid the kinds of dramatic coverage that can erode public trust in these new technologies. In the end, Louisiana, with our swamps and large mosquito populations, stands to gain enormously from this new technology. It’s time we start to take this seriously as the future of pest control.
Helen Spafford, is a former department chair and associate professor of applied entomology at the University of Hawaii Manoa. She has conducted research on mosquito biology and management in Hawaii and Australia. She now lives in New Orleans.