A Newer, Faster Way To Detect Norovirus In Water Supplies

Norovirus sickens tens of millions of people each year. They get the disease from contaminated food or water. Engineers have developed a rapid, inexpensive test to detect the virus in water supplies.

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An estimated 20 million people in the United States suffer acute intestinal illness from norovirus every year. Some of these infections come from contaminated water. NPR's Joe Palca has this report about a new, cheap, fast way of detecting the virus in water.

JOE PALCA, BYLINE: According to the Centers for Disease Control and Prevention, norovirus can show up in private wells, in agricultural runoff, and Kelly Reynolds says it can even get into municipal water supplies.

KELLY REYNOLDS: So when we have a massive outbreak related to drinking water quality, there's a high probability that norovirus caused that infection.

PALCA: Reynolds is a water quality expert at The University of Arizona in Tucson. She says drinking water supplies can become contaminated when old pipes or storm overflow causes wastewater to mix with drinking water. Water utilities regularly check for contamination, but Reynolds says existing tests take time and require sophisticated equipment.

REYNOLDS: Tucson Water approached me and said, how can we improve on the status quo?

PALCA: Reynolds had an answer. Her colleague Jeong-Yeol Yoon is a biomedical engineer at Arizona. Reynolds asked Yoon if he could build an inexpensive norovirus detector, and he said yes. Yoon's approach starts with a cellphone camera and a microscope.

JEONG-YEOL YOON: You can buy the microscope attachment to a smartphone very easily. In the past, the magnification is about 60x, 100x, and nowadays, you can get 200 and 400 and 600, and they are still under $100.

PALCA: But even with that magnification, Yoon wasn't able to do what he really wanted to do.

YOON: I want to count the norovirus particles one by one, but we know that it is not possible because they are so small.

PALCA: So he uses tiny, fluorescent, plastic beads coated with a substance that attaches to norovirus particles. If a virus is in a sample, the beads will make a clump around it - a clump the cellphone camera, with the microscope attachment, can see. Testing a water sample is pretty fast.

YOON: Our method is just, from sample to answer, I would say five minutes.

PALCA: Yoon is presenting details about his invention today at the American Chemical Society National Meeting in San Diego. Right now Yoon's colleague Kelly Reynolds says some of her junior colleagues are working with the new device.

REYNOLDS: These are volunteers from my laboratory. Some students and other staff around the lab are just testing the smartphone tool just to see how user-friendly is this with very little knowledge about infectious disease or about viruses or even water sampling.

PALCA: Reynolds says initial results are encouraging.

REYNOLDS: We'll be transitioning the field trials to Tucson Water employees in the fall.

PALCA: Reynolds says if the experience with Tucson Water is positive, the device could be adopted by water utilities around the country.

Joe Palca, NPR News.

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