Scientists from the government-backed Oswaldo Cruz foundation infected the mosquitoes with a bacteria that blocks Dengue fever virus from infecting them. The bacteria that’s being introduced – Wolbachia – is harmless to humans. The hope is that these mosquitoes will multiply, breed and become the predominant mosquito, gradually wiping out the insects’ ability to spread the virus to humans.
Dengue is a viral infection transmitted by a type of mosquito called Aedes aegypti. It can range from a mild, flu-like illness to a potentially deadly one, which develops in around 5 percent of patients. To date, there are no vaccines or effective treatments.
Brazil’s Ministry of Health reports that the first quarter of 2017 saw a significant drop in dengue cases (down 90%) compared with the same period in 2016.