Even before people show signs of being sick, virus shows up in the wastewater. During the COVID-19 pandemic, universities and cities have deployed tools to test their water systems to detect coronavirus particles, often predicting new waves of the outbreak. Ari Goldfarb, CEO of Kando, said his company is helping governments around the world analyze their water to guide public health policy, including an early warning system on airplane toilets that’s now being tested in Israel. He said his tech is also detecting upticks of the polio virus in Israel, which is helping the government direct resources to unvaccinated neighborhoods. In the U.S., Los Angeles and El Paso, Texas, are drawing on Kando’s tech and historical data to monitor wastewater and get early notice on pollutants that could damage treatment plants.