Fighting deadly diseases - with a phone

A tool developed by Stanford researchers lets people around the world help build a mosquito map

Felix Hol, graduate student Haripriya Mukundarajan and Manu Prakash record mosquitoes using cellphones.

The next time you hear the buzz of a mosquito, rather than running inside or slathering on repellent, pull out your cellphone. With a tool developed by a Stanford lab, you can contribute to global knowledge about mosquitoes — and help reduce the prevalence of the diseases they spread.

Manu Prakash, PhD, assistant professor of bioengineering, and his lab are looking for citizen scientists to use their mosquito-monitoring platform, Abuzz. With enough users around the world recording mosquitoes, Abuzz will be able to produce a detailed global map of different species — helping public health officials in targeting mosquito populations.

More than mere pests, mosquitoes can carry deadly diseases, including malaria, yellow fever, dengue, West Nile virus, chikungunya and Zika. Diseases spread by mosquitoes result in millions of deaths each year, largely in areas with limited resources.

"We could enable the world's largest network of mosquito surveillance — just purely using tools that almost everyone around the world now is carrying in their pocket," said Prakash. "There are very limited resources available for vector surveillance and control, and it's extremely important to understand how you would deploy these limited resources where the mosquitoes are."

With enough users recording and submitting mosquitoes' high-pitched whine, Abuzz can create a map that tells us exactly when and where the most dangerous species of mosquitoes are most likely to be present. That knowledge could lead to highly targeted and efficient control efforts.

"If you see a mosquito and you swat it, you've saved yourself an itch for one day. But if you see a mosquito and you record it and you send the data to the Abuzz project, then you've contributed to an effort that can reduce the burden of mosquito-borne disease for many generations in the future, hopefully," said Haripriya Mukun-darajan, a graduate student in the Prakash lab.

Matching the buzz to the species

Abuzz is a low-cost, fast, easy way to gain an incredible amount of new data about mosquitoes. To help the researchers, hold your phone's microphone to the sound of that mosquito buzzing overhead and capture a recording. Then download the recording on the Abuzz website.

Because each mosquito species uses a different wing-beat frequency, producing a characteristic whine, the researchers will use the recording to pinpoint the species. They do so with an algorithm powered by a mosquito sound library — Prakash and his team recorded about 1,000 hours of mosquito buzzing from 20 different species to create the library.

Once they receive a recording, the researchers clean it up to reduce background noise and run it through the algorithm, finding the species that is most likely to have produced it. When they find a match, the researchers send information about the mosquito to the person who submitted the recording. They also mark the recording on a map on the website, showing exactly where and when that mosquito species was sighted.

Because the people who could benefit most from Abuzz may not have access to the latest smartphones, the researchers designed the platform so that it can work off recordings from almost any model of cellphone. Most of their mosquito data was recorded on a $20 clamshell-style cellphone from 2006.

The Abuzz algorithm has worked with as little as one-fifth of a second of a recording — although recordings that are one second or longer are the most desirable. That means recording a mosquito while it takes off from a surface is enough to create an Abuzz-worthy recording.

Enlisting citizen scientists

To ensure that Abuzz works the way they've intended, the researchers ran a field test with 10 local volunteers in a village in Ranomafana, Madagascar, in 2016. It took about 10 minutes to train the citizen scientists. The next day, they returned with 60 recordings that spanned three hours.

"It was very easy to tell people what to do, and people were very eager to participate," recalled Felix Hol, PhD, a postdoctoral scholar who helped conduct the field study. "Just 10 minutes of training and they could actually produce a lot of very usable data. That was a very beautiful experience for me."

To draw more citizen scientists, the group intends to release an app in the near future and has already produced detailed training videos.

"What I would love to see is people engaging in the problem," Prakash said. "Try to join the platform. Record mosquitoes. Learn about the biology. And in that process, you will be supporting the kind of research and scientific data that we and medical entomologists around the world so desperately need, and at the same time you will be making your own community safer."

The project is an example of Stanford Medicine's goal of developing knowledge about health and biomedical science and using that knowledge to benefit patients throughout the world.