Mosquitoes are an annoyance to nearly everyone who encounters them, and the little buzzers are responsible for spreading diseases like malaria, yellow fever and, of more recent note, Zika virus. Now scientists in Brazil are fighting back by releasing millions of genetically modified mosquitoes that, ideally, will mate with their wild counterparts and produce offspring with very short lifespans, thus causing disease-carrying family lines to die out within a few generations. Since mosquitoes only live a short time, this could greatly reduce the population of mosquitoes spreading infectious diseases in just a few weeks.
British biotech firm Oxitec is the company leading the charge on the development of genetically modified male mosquitoes belonging to the Aedes aegypti species, which are responsible for the spread of a slew of diseases. The company launched the Friendly Aedes aegypti project in April 2015 in the town of Piracicaba, where some 60,000 people live under daily threat of diseases like dengue fever and Zika virus. Oxitec has been releasing its “self-limiting” mosquitoes across the city, and reporting huge reductions in cases of diseases those mosquitoes spread. After being released into the wild, the male mosquitoes breed with disease-carrying females and produce offspring that die quickly. The company reports that this technique can bring mosquito populations down by 90 percent, according to the results of five field tests conducted between 2011 and 2014.
Despite that good news, there were early concerns that releasing genetically modified mosquitoes may somehow contribute to the spread of viruses like Zika, rather than combat it. Many people blamed Oxitec for the recent Zika epidemic in Brazil, claiming that the aforementioned field tests actually caused the problem. However, experts at the World Health Organization have dismissed that notion in part because the field tests were not conducted in the same region as the Zika hotspot and, while the strategy is controversial, many epidemiologists believe this is the fastest and most effective way to reduce the spread of mosquito-born diseases.
Oxitec is still waiting for approval from the Brazilian government to release their next batch of genetically modified mosquitoes, which would number in the millions. The company contracted with the town of Piracicaba in a $1.1 million deal, and erected what it claims is the “first and biggest factory” for genetically modified mosquitoes there, producing 60 million GM mosquitoes per week. (That’s three times the output of China’s largest mosquito factory, which is working on a similar project.) While Piracicaba is Oxitec’s only customer in Brazil, the company has worked in other parts of the world, doing exactly the same thing in an effort to stamp out mosquito-born diseases that are difficult to treat and, sometimes, deadly. Earlier this year, millions of the company’s little buzzers were released in the Cayman Islands and in Florida as well, two other places where Zika has spread.