In parts of the world where window screens are uncommon or unaffordable, insecticide-treated mosquito nets (made from cotton, polyethylene, polyester, polypropylene or nylon) are increasingly used to protect against mosquitos that carry malaria, dengue, Zika and other viruses.
The nets are cheap, at about $2.50 a piece, and last three to four years. Their cost-effectiveness makes them well-suited for widespread distribution in developing countries where mosquito-borne diseases are a significant threat. In regions with high rates of malaria, nets can reduce transmissions of the disease from mosquitoes to humans by as much as 90 percent.
Not everyone who needs one has one, though. Global health organizations are still working to distribute mosquito nets to all who may benefit.