For decades, nets and sprays have been the only effective methods for controlling the mosquitoes that cause malaria. However, Spanish chemist Pilar Mateo thinks she can do better with her invention of embedding pesticides in microcapsules stirred into house paints at her Valencia company. The insecticides are released from the paint slowly, remaining effective for two to four years, while sprays need to be reapplied at least every six months. “The paint acts like a vaccine for houses,” she says. The amounts of pesticides released from the paint are harmless to people but are devastating to insects, according to the tests made by scientists. The paint has already been approved for use in fifteen countries, including China and England. Mateo is seeking approval in the US and a recommendation from the World Health Organization. She says she has received offers to buy her patent but refuses to sell out. Instead, her new venture, another company in Africa, will produce it commercially at a factory in Ghana and employ a great number of workers. “By taking production outside Spain, we can reduce the cost and make it more accessible,” she says. Her idea is to sell the paint as an affordable alternative to sprays. After years of donating paint to poor people in Latin America, Mateo wants to fund her broader humanitarian efforts. “It’s not just the insects that are the problem”, she says, “It’s the poverty.”