Killing Bugs by Painting Your House

A Spanish company fights malaria with pesticides in house paint | “The primary problem for half the planet is that their homes are sick”

Nick Leiber

For decades, nets and sprays have been the only effective methods for controlling the mosquitoes that cause malaria and dengue. Pilar Mateo thinks she can do better. The Spanish chemist has invented a way to embed pesticides in microcapsules stirred into house paints at her Valencia company, Inesfly. The insecticides are released from the paint slowly, remaining effective for two to four years, while sprays typically need to be reapplied at least every six months. “The paint acts like a vaccine for houses and buildings,” she says.

Mateo says she’s received offers to buy her patent but refuses to sell out. Instead, her new venture, Inesfly Africa, will produce it commercially at a €10 million ($13 million) factory in Ghana. After years of donating paint to poor people in Latin America and Africa, Mateo wants the venture to fund her broader humanitarian efforts. “It’s not just the insects that are the problem,” she says. “It’s the poverty.”

The minute amounts of pesticides released from the paint aren’t harmful to people but are devastating to insects, according to independent tests by scientists. The paint is already approved for use in 15 countries, including China, Germany, and Spain. Mateo is seeking approval in the U.S. and a recommendation from the World Health Organization. Her idea is to sell it as an affordable alternative to sprays. “It makes sense,” says Adriana Costero-Saint Denis, a program officer at the National Institutes of Health. “You want something that has slow release, which is effective for a long period.”

Mateo didn’t plan to spend her life killing bugs. While earning a Ph.D. in chemistry from the Universitat de València, she settled into a comfortable routine, tinkering with formulas at her father’s paint factory, Industrias Químicas Inesba. In 1988, inspired by a newspaper article about a local hospital overrun by cockroaches, she shifted to pest control and developed her microencapsulation technology, patenting it in 1996. A Bolivian doctor visiting Valencia contacted Mateo and asked her if it might work to combat vinchucas, bloodsucking insects found across Latin America that transmit a nasty parasitic disease called Chagas.

Mateo had never heard of Chagas, which can cause heart failure and other cardiac or intestinal complications. In 1998, Mateo traveled to Bolivia to test her technology, a visit that morphed into an ongoing love affair with the country. She divides her time living with indigenous peoples in Bolivia’s forests, building and painting houses, and conducting research in her lab in Valencia. “We spend all this time talking about medicines and diseases when the primary problem for half the planet is that their homes are sick,” she says.

Using roughly $6 million of her family’s money and $12 million in grants from nonprofits, Mateo has done research, created educational programs about hygiene, and helped paint more than 8,000 homes in Latin America and Africa. After the former Bolivian health minister tried to rescind the country’s approval of the paint, locals protested. President Evo Morales in November invited Mateo to his office, and the Andean nation again allowed the paint.

Health authorities are increasingly receptive to technologies that can overcome resistance bugs build up to insecticides, says S. Patrick Kachur, chief of the malaria branch of the Centers for Disease Control and Prevention in Atlanta. Mateo’s formula helps slow the development of resistance because the paint is packed with multiple pesticides, which she buys from big companies such as BASF, Bayer, and Dow AgroSciences.

Traditional sprays typically hold just one formula because mixing them could render them ineffective; the microcapsules keep ingredients from interacting. Most important, the microcapsules reduce the quantities of insecticides needed.

Tom McLean, chief operating officer of the Innovative Vector Control Consortium in Liverpool, a group funded by the Bill & Melinda Gates Foundation to control parasitic diseases, says it has been a challenge to get insecticide makers to invest in fighting public health problems caused by insects because the returns are relatively meager. The market for pesticides to combat malaria and dengue “is much smaller, for example, than the market for golf greens,” says McLean. “Insecticide companies have struggled to make the finances and R&D in [pest] control really work.”

Mateo is planning to launch a U.S. partnership to make and distribute the paint. A tinkerer whose husband says she often dreams up projects in the middle of the night, Mateo is also unveiling an insecticide-free lice-killing shampoo in Europe. Her new partnership in Accra plans to employ 500 workers in Ghana and sell the paint around the world. “By taking production outside Spain ... we can reduce the cost and make it more accessible,” says Alejandro Pons, chief executive officer of the Ghanaian venture. “It will cost the same as normal paint but will mean you don’t get malaria.”

The bottom line A Spanish company is opening a €10 million factory in Ghana to make paint that slowly releases pesticides to help control malaria.


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