While conducting clinical field evaluations of his lab's various ultra-low-cost disease diagnostics inventions, Stanford bioengineering professor Manu Prakash snapped a picture of Ugandan children sitting on the graves of their siblings, a tragic reminder of the impact of childhood diseases in rural Africa.

Prakash's latest project is an electromagnetic patch that noninvasively detects live parasitic worms in infected patients.

To help test this novel idea, Prakash, who is affiliated with the Stanford Woods Institute for the Environment, and co-investigator Judy Sakanari, a research pathologist at the UC San Francisco School of Medicine, received a $100,000 Grand Challenges Explorations award from the Gates Foundation.

The first prototypes will be used to detect the worm that causes onchocerciasis, or "river blindness," which afflicts approximately 37 million people in Africa, Central and South America, and Yemen. Transmitted through repeated bites of blackflies, it is a major cause of preventable blindness.

Current diagnostic methods require the use of expensive ultrasound equipment to determine whether parasitic worms are alive under the skin or inside lymph nodes. Prakash's more frugal design consists of a Band-Aid-size patch embedded with a sensor that detects minute electrical changes when worms wiggle under the skin or form calcified cysts. He expects that the final device will cost less than $10 and will be easier to use in rural settings.

Prakash and Jim Cybulski, a Stanford mechanical engineering PhD student, were also working at several sites to clinically evaluate "Foldscope," an inexpensive microscope made of folded paper that is being mass produced and used for diagnosing diseases such as malaria, schistosomiasis, African sleeping sickness, tuberculosis and various filarial diseases in field conditions. Cybulski recently won a Global Health Equity Scholars Fellowship (funded by the National Institutes of Health) for field testing this device.

The magnitude of the malaria problem in Uganda, which has one of the highest rates of infected mosquitoes in the world, became crystal clear during their trip in November.

"There was one hut where we trapped 400 mosquitoes in one night," Prakash said. "And some public health centers that we visited had almost 100 malaria cases per day, with mothers of large families bringing in at least one child a week for testing."

He added, "Being in the field gives meaning to working in global health. It teaches you empathy, a driving force so strong that transforms ideas into actions."

Prakash's lab is also exploring how to develop "human capital" in these resource-constrained settings, a strategy that would generate more jobs and build the infrastructure to provide these services locally. "We are looking at various ways to bring appropriate tools and training to these young college graduates who don't have much to do," he said.