Norovirus – There’s an App for That

What’s in your drinking water? Hopefully, there are no norovirus particles, but how do you know? Norovirus is a common cause of nausea, vomiting, abdominal pain, and diarrheal infections. In some cases, the illness can even lead to death. How can you keep yourself safe?

There may be help on the way. A team of researchers based out of the University of Arizona are trying to find a way to check water supplies for norovirus using a smartphone. A smartphone test has the potential to be a relatively easy and inexpensive way to test for the virus.

Norovirus Smartphone App
An in-house developed smartphone-based fluorescence microscope and an image-processing algorithm isolated the particles aggregated by antibody−antigen binding, leading to an extremely low limit of norovirus detection (Photograph: Soo Chung and Sean Perea ©2019)

The scientific journal, ACS Omega, reports initial results by Walter Q. Betancourt, Lane E. Breshears, Soo Chung, Christina M. Morrison, Sean Perea, Kelly A. Reynolds, and Jeong-Yeol Yoon sound promising. The team described the development of a simple test using a piece of paper, a water sample, antibodies, florescent material, a camera, and a smartphone.

Smartphone-based Fluorescence Microscope
A smartphone with a microscope attachment and a bandpass filter (525 ± 20 nm; green emission) captures the fluorescent images of a μPAD (Photograph: Soo Chung and Sean Perea ©2019)

A sample of water from the possibly contaminated sourced is used to soak a specially treated type of paper to begin the test. Next, antibodies against norovirus are added to the paper. Fluorescent material is attached to the antibodies so that they can be seen more easily since antibodies are quite small. The antibodies then attach themselves to any norovirus particles that may be present in the paper. The smartphone’s camera is used to take a picture of the paper. The image is uploaded to an app that uses algorithms to analyze the fluoresce patterns seen in the image.

Using test samples of water known to have norovirus in them, the research team began testing the process. They concluded their test was able to detect norovirus even when the concentrations of norovirus were quite low.

Having the ability to identify very low concentrations of norovirus is significant because the virus is extremely contagious, and it can be challenging to inactivate or kill. As few as ten virus particles may cause illness, according to the European Centre for Disease Prevention and Control (ECDC). That’s the reason norovirus spreads so quickly in places like cruise ships. Noroviruses have also impacted schools, hospitals, and communities.

It’s essential to know if your drinking water is contaminated with norovirus, even at a very low level. Norovirus has been reported in a wide range of water sources, including surface water, groundwater, drinking water, and mineral water. Malfunctions or overflows from sewage systems as well as stormwater runoff can contaminate water sources. Wells are particularly susceptible to norovirus contamination.

A simple, low-cost test for norovirus could be helpful for several reasons. Norovirus leads to around 700 million cases of gastroenteritis and over 200,00 deaths each year. The norovirus particles are microscopic and get through most available water filters. The only way to kill the virus is to boil contaminated water for at least one minute (three minutes if you at an elevation of greater than 6,500 feet above sea level). Taking the time to boil all water used for drinking or cooking can be time-consuming and impractical.

More research will be needed before the test is ready for the market. Real-world conditions are ever-changing and variable, and water is not the same everywhere. Water can include different minerals, compounds, and other contaminants as well as be at different temperatures, creating the possibility of false negatives as well as false positives.

The team will also need to determine if the general public can safely use the test or if it will be restricted to water monitoring professionals. Either way, a simple, portable test for norovirus would be a welcome addition to the battle again illness.

[source: ACS Omega]

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