JERUSALEM — As the novel coronavirus began to circulate within the population of Israel in March, a group of scientists immediately started sampling sewage nationwide, wondering what it would say about the spread of the contagious virus.
In April, as the number of people testing positive for COVID-19 spiked in one Israeli city, researchers also found that traces of the coronavirus increased in its sewage system. In cities with lower numbers of known cases, they found fewer traces of the virus in the sewage.
Now the scientists say this a reliable and non-invasive way to monitor geographic outbreaks of the disease, especially as many places, including Israel, have eased stay-at-home orders with the expectation that cases may increase.
“This could really help us track the emergence of a second wave,” said Ariel Kushmaro, one of the researchers and professor of biotechnology at Ben Gurion University of the Negev, explaining that evidence of the virus shows up in feces days before it can be detected by the standard nose and throat swab tests. The group is currently awaiting government funding and approval to implement the program on an official level.
Israel is not the only country where scientists are looking at sewage to understand the extent of infections caused by the virus. Researchers around the world, from the Netherlands to the United States, say it could be a powerful epidemiological tool, and much more efficient than mass testing individuals for the disease.
Testing shortages, logistics and the fact that many people can have COVID-19 without experiencing symptoms have been among the biggest challenges for identifying the number of cases, the actual death rate and its geographic spread.
“Yet sewage data is able to capture the whole population,” said Mariana Matus, CEO of the Boston-based sewage data company Biobot Analytics. “Such samples enable our public health interventions to match and better understand the actual infected population.” Biobot, along with researchers at MIT, Harvard and Brigham and Women’s Hospital recently launched a free program to test sewage samples from any interested wastewater facilities in the United States, aiming to create a map of where the virus has spread.
The Israeli team has also made its research open to the public, saying that the country’s relatively high rate of testing individuals for COVID-19, and the cross-referencing of sewage data with medical testing data, establishes reliable correlation ratios that others can rely on when using sewer data to calculate the number of infected people.
Monitoring wastewater is a public health tool in general, with Biobot and others increasingly using it to track the amount of addictive opioids consumed in certain geographic areas. In Israel, polio virus found in the sewage in 2013 caused the country to increase its vaccination efforts.
The discovery of traces of coronavirus in sewage has also raised some health concerns. Kushmaro and others say COVID-19 is unlikely to spread through wastewater, where mainly traces of the virus’s genetic material rather than the live virus itself have been found. But Dror Avisar, head of Tel Aviv University’s Water Research Center, is among those raising concerns about the possible survival of the virus in raw sewage, and the potential for contaminated water or recycled treated wastewater as a source of infection. With Israel treating and reusing 87% of its wastewater, he and others say more research is needed.
“It’s really important to find the answer to this, to make sure treatment kills the virus,” said Gidon Bromberg, co-director of the Israeli-Jordanian-Palestinian non-governmental organization EcoPeace Middle East, which has released a paper on the topic. “This should also be a wakeup call about water management because there is also a lot of untreated sewage in the region, especially in Gaza and the West Bank, and this can cross borders.”
More from U.S. News