The University of Arizona may have stopped a potential coronavirus outbreak earlier this year by testing dormitory wastewater for COVID, according to an article on the Water World website.

Sewage testing showed the presence of the virus’ RNA in raw wastewater samples from a particular dorm. The university then tested dorm residents and found two people who were asymptomatic but tested positive.

Wastewater tests also recently found possible presence of the virus at the University of Colorado residence halls and at the University of California-San Diego. 

Some U.S. cities have employed the practice of wastewater epidemiology, also called “sewage surveillance,” to understand infection rates because wastewater can signal infections up to one week before an individual might test positive with clinical testing.

Researchers looked at wastewater to measure how prevalent SARS-CoV-2 is in a given community, according to an article on the STAT website.

Researchers collected samples in late March from a wastewater treatment plant serving a large metropolitan area in Massachusetts and found that the amount of SARS-CoV-2 particles in the sewage samples indicated a far higher number of people likely infected with Covid-19 than the reported cases in that area.

Read the full Water World article.