It's a dry winter day in southeast Brazil, but a steamy tropical summer reigns inside the labs at Oxitec, where workers are making an unusual product: genetically modified mosquitoes to fight dengue fever.
The British biotech firm has altered the DNA of the Aedes aegypti mosquito to prevent it from spreading the potentially deadly virus, which has hit Brazil harder than any other country this year.
Oxitec's new factory in the Brazilian city of Campinas, outside Sao Paulo, is the first in the world to launch production of genetically modified (GM) mosquitoes to target dengue.
In one room, females mate with a handful of males in cages.
In another, larvae grow on dozens of trays. In a third, bottles full of GM males await release into the wild.
The mosquitoes, which Oxitec has dubbed OX513A, have been bred to carry a sort of genetic self-destruct mechanism that causes their offspring to die before they reach sexual maturity, preventing them from reproducing.
The company says if sufficient numbers of GM males are released into the wild, they will mate with females on a large enough scale to significantly reduce or even wipe out the dengue-carrying population.
Once they're released, the mosquitoes look for wild females to copulate and reproduce. But thanks to this genetic modification, which is transmitted, all their offspring die before reaching adulthood, so they can neither bite nor transmit the dengue virus.
Brazilian authorities have not yet given the go-ahead to sell the mosquitoes.
And genetic engineering skeptics have raised questions about the impact they could have on the ecosystem
Curbing dengue would be a public-health blessing for the South American country, which has registered 659,051 cases this year and 249 deaths -- by far the worst outbreak in the world.
There is no cure for the virus, and patients can only treat their symptoms -- a fever similar to a bad case of the flu with headaches, muscle and joint pain, vomiting and a rash.
In severe cases, patients can suffer bleeding, shock or death.
PHOTO: Larvae of transgenic Aedes aegypti mosquitos pictured through a microscope at an Oxitec laboratory in Campinas, Brazil, August 21, 2014 (AFP Photo/Nelson Almeida)