Next week biotech company Oxitec of Abingdon, UK, will open a factory in Campinas, Brazil, to raise millions of modified mosquitoes. Once released, they will mate with wild females, whose offspring then die before adulthood. That should cut the number of dengue-carrying Aedes aegypti mosquitoes. In April, Brazil’s National Technical Commission for Biosecurity (CTNBio) approved their commercial use.
The mosquitoes could be an important step forward in controlling dengue, which affects more than 50 million people every year, with a 30-fold increase in the last 50 years. There is no vaccine or preventive drug, so all anyone can do is to spray insecticide on a large scale in a bid to kill dengue-carrying mosquitoes.
No one is sure if the insects will succeed. Margareth Capurro at the University of São Paulo has studied the effects of a trial release in Jacobina last year. She plans to submit her report this month.
Capurro says her data show the number of mosquito eggs falling by an impressive 92 per cent in Jacobina. But so far this has not led to a drop in the incidence of dengue.
That may be because the study was too small, says Capurro. Only after a full epidemiological study next year will we know for sure if the GM mosquitoes are working.