Rehan Hasan / EyeEm / Getty Images / EyeEm
Norovirus spreads the news when an outbreak on cruise ships occurs. But the virus infects many more people than vacationers.
According to the Centers for Disease Control and Prevention Centers, around 20 million people in this country suffer from acute bowel disease with Norovirus each year. It is responsible for more than half of all food-borne illnesses in the US.
It can also get into the municipal water supply, if mixed with the Norovirus contaminated wastewater through old pipes or storm overflow with drinking water.
"There is a high likelihood that the norovirus has caused this infection in a massive outbreak related to drinking water quality," says environmental biologist Kelly Reynolds of the University of Arizona, Mel, and Enid Zuckerman College of Public Health, Tucson ,
] Water companies regularly check for contamination, but according to Reynolds, existing tests for norovirus are time-consuming and require sophisticated laboratory equipment.
When Tucson's water company approached them for help in improving the status quo, Reynolds believed he knew how to find a cheaper and faster approach.
She asked her colleague Jeong-Yeol Yoon of the University of Arizona if he could build one A cheap norovirus detector and he has agreed.
Yoon's lab specializes in building small hand-held devices for testing water quality and food safety. Many of these devices use a cell phone camera connected to a microscope.
"You can easily connect the microscope attachment to a smartphone," says Yoon. "In the past, the magnification was about 60x and 100x, and nowadays it has 200x, 400x, and 600x magnifications, and still costs less than $ 100."
The norovirus test he developed also uses paper-based microfluidic chips. These are low-cost wafers to which water samples are drawn, so no external pumps are required.
Even with the available magnification, the viruses are too small to be seen. Yoon mixes a water sample with tiny fluorescent polystyrene beads coated with antibodies against the norovirus. If the virus is in the water sample on the paper chip, the pearls lump around the virus so that the camera of the mobile phone can recognize them.
Yoon says the device works fast.
"From rehearsal to answer … five minutes," he says.
Yoon presented details of his invention on August 27 at the American Chemical Society's National Meeting in San Diego. An article describing preliminary results with the device is published in ACS Omega .
Even though most norovirus infections are caused by eating contaminated food, a sufficiently sensitive test would be "useful" for reliably detecting the virus in water samples, says Rachel Noble, Mary and Watts Hill Jr. Distinguished Professor in the Department of Environmental Sciences at the University of North Carolina.
After hurricanes and other storms, flooding can overflow sewage systems and possibly mix with drinking water. Managers of municipal water systems would breathe easier if they were sure they would not have to worry about norovirus contamination at all.
She and other researchers worked on similar projects to develop a quick test for norovirus. Yoo's device is promising, but "many of these ideas work in the lab," says Noble. Unfortunately, they do not work so well once they have been tested in practice. Particularly undesirable are false negative results, i. H. To declare a water virus free if this is not the case.
"Few virus particles can be in a water system," says Noble. But these few particles can still cause disease and be missed in a test sample.
Yoon's device is still undergoing rigorous testing to ensure that it accurately identifies contaminated samples. At the moment, most of the tests are trying to be sure that people can perform the test reliably.
"Volunteers from my lab, some students, and other laboratory staff just test the smartphone tool to see how easy it is," says Reynolds of Arizona. These are people with "very little knowledge of infectious diseases or viruses or even water samples," she adds.
Reynolds says the first results are encouraging.
"We will transfer the field trials to Tucson Water employees in the fall," she says. This should help to determine the reliability of the new device.