How soap, chairs and clothing could stop mosquito bites — and diseases
Known to health experts as the most deadly animal on the planet, the minuscule mosquito, with its dreaded whine, is responsible for millions of deaths from multiple diseases each year.
In 2015, more than 210 million people had malaria, with an estimated 429,000 dying from the disease. That same year, more than 1.4 million people were thought to have chikungunya — a debilitating disease causing fever and joint pain — and each year, 390 million people are estimated to become infected with dengue, according to the World Health Organization. Yellow fever continues to cause outbreaks in Africa and South America, and 2015 saw an explosion of the Zika virus in 70 countries that had never experienced it before.
These diverse, deadly diseases are all united by the way they are transmitted: the mosquito bite.
"We need to kill mosquitoes," businessman and philanthropist Bill Gates told CNN during an exclusive interview. "So people have come along and given us ideas to (do) that."
These people have come to him through the Bill and Melinda Gates Foundation, with ideas for everyday products that could be tweaked to cut down on the number of people bitten and infected each year.
"Science today should give us tools to solve a lot of the big killers," Gates said.
To date, mosquito control methods such as insecticide-treated bed nets and indoor spraying of insecticides in homes have been the driving force behind falling infection rates, specifically in efforts to control malaria.
These nets are credited with nearly 70% of malaria cases prevented since 2000.
But despite this progress, the disease continues to kill, and experts believe creative ideas are needed to help those who remain unprotected -- especially when they're away from home.
It's all around you
"What's going to happen is that you have round-the-clock protection," said Fredros Okumu, director of science at the Ifakara Health Institute in Tanzania, where more than 4 million cases of malaria were reported in 2015. "Repellent can be fitted on your wall ... on a floor mat ... their chair ... sandals."
Okumu's team is making this wide range of goods mosquito-free by fitting them with a bespoke fabric coated with mosquito repellent and targeting objects people can't live without, making their use inherent.
The repellents are volatile in nature, meaning they easily evaporate and can be detected from greater distances than ones that typically sit on your skin.
Prototypes of the fabric on a chair have shown protection for up to six months, according to Okumu.
But the strategy gets more complex.
Rather than simply divert the mosquitoes onto someone else's skin, Okumu wants to capture them using a mosquito landing box, which mimics human odor to lure the bugs.
"We're able to capture them," he said. "And this way, we are providing protection to whoever is using this facility ... (and) communal protection to everyone else."
So far, most attention has been given to the chair, on which Velcro is used to attach repellent fabric to the underside, providing protection while avoiding direct contact with a user's skin -- an important point given the strength of the insecticides.
But Okumu believes that other furnishings and everyday items, such as footwear, can incorporate this material and enable people to be protected wherever they go -- and easily.
"People might be very poor ... but one thing that is almost universal is that they always wear some form of footwear," he said, adding that this can ensure maximum compliance. "This is part of our evolution."
When it comes to disease control, however, human behavior is a major barrier.
"The issue is whether people will use it or buy it," said Flaminia Catteruccia, assistant professor of immunology and infectious disease at the Harvard T.H. Chan School of Public Health. "Something for long-term use has to also be thoroughly tested" for side effects.
Would you use the chair or wear the sandals? Okumu believes you would.
"The fight against malaria is so difficult, we'll need all tools," Catteruccia added. "It's important to explore methods ... at the community or village level, these may be effective."
Among those exploring multiple approaches to mosquito control are students in the graduate program and researchers at the Johns Hopkins Center for Bioengineering Innovation and Design.
During a "Zika hackathon" competition last year, they were challenged to come up with creative ways to fight the Zika epidemic, with a focus on the mosquitoes spreading the virus.
"For a large part of the planet, mosquito disease remains a huge problem," said Dr. Soumyadipta Acharya, director of the Johns Hopkins graduate program. "New thinking is needed from various angles."
A key area given attention was catching people during their daily activities -- such as washing.
It's in your soap
In contrast to long-lasting, volatile insecticides that could harm your skin, an opposite group of compounds is shorter-lived and residual, meaning they can comfortably reside on your skin.
Acharya's team is trying one of these, permethrin, in soap.
"There are different insecticides for different uses," he said. "(This one) stays behind on the skin, as all soaps do as well."
The teams at Johns Hopkins are not the first to develop anti-mosquito soaps. Last year, another repellent-based product -- known as Faso soap -- began development in Burkina Faso after the researchers behind it won the Global Social Venture Competition at the University of California, Berkeley and received funding to develop it further.
But both versions are still in early development and face multiple challenges before being allowed onto the market.
"There are many tests needed to evaluate the safety and efficacy," Acharya said, adding that teams also need to figure out how long a soap's effects last: It should be at least 24 hours, before a person would wash again.
Catteruccia added that soap will provide very personal protection and not have "benefits at the community level," she said. "Mosquitoes are also highly resilient, so they will always be able to get round this."
Insecticide resistance has been a challenge for health teams around the world. According to the World Health Organization, 60 of 96 countries where malaria is endemic have reported resistance since 2010.
But Acharya is hopeful that a soap, if proven effective, could be used along with other approaches to help protect people wherever they go. His teams are also working on banners to be hung near homes that emit repellents, as well as traps with real-time sensors to monitor mosquito numbers in a community and alert residents to protect themselves when spikes occur. The traps were piloted in Brazil earlier this year.
"It's going to be a multipronged approach," Acharya said, highlighting that soaps, sprays, banners, traps and more can work together to keep mosquitoes at arm's length. "Together, your odds of getting bitten are reduced."
It's in your clothes and accessories
"Wearable technology can protect against mosquito bites during the day," said James Logan, senior lecturer in medical entomology at the London School of Hygiene and Tropical Medicine.
Logan is also working on technologies to protect people through the clothes they wear and the accessories and furniture they own. His approach with clothing is two-pronged: impregnating the clothes themselves and also the detergents they're washed with. By also incorporating insecticides into plastics, he hopes to extend protection to hats, handbags and household items.
"It's about what people will accept," said Logan, whose teams regularly speak to people in affected communities to learn which products they're most likely to use.
One prototype recently trialed in Thailand was a school uniform laced with the insecticide permethrin to prevent infections from dengue. More than 1,800 students were enrolled from 10 schools, with five schools using the new product and the other five monitored as a control group.
The number of mosquitoes caught inside classrooms of students wearing the treated uniforms was significantly reduced in the month after their introduction. The challenge, however, was making the effect last. The uniforms' ability to knock down mosquitoes fell dramatically after four washes.
"That study was encouraging," said Logan, who is preparing prototypes of a wider range of products: general clothing, footwear, jewelry and detergents. "It's important you target your demographic," he added. "And we need to understand the diversity of everyday lives."
By creating diverse good for people to choose from, Logan hopes these protective products will be "relevant anywhere in the world," to overcome the barrier of human compliance.
"It's always going to be a combination of different interventions taken to communities," he said. "Wearable technologies won't eliminate malaria on their own, but they will help."