ASHKELON, Israel Sewer surveillance in Israel’s coastal city of Ashkelon has pinpointed unknown outbreaks of COVID-19 by identifying traces of the virus in the sewage system.

The project, similar to those undertaken in other countries, was carried out by wastewater management technology firm Kando and researchers from Israeli educational institutions including Ben Gurion University and the Technion in Haifa.

The research pointed to wastewater as a means of detecting outbreaks of the disease early as well as the ability to narrow hotspots down to specific streets, Kando said.

Early studies by scientists in The Netherlands, France, Australia and elsewhere suggest sewage sampling for signs of the SARS-CoV-2 coronavirus could help assess the number of infections in a geographic area, without having to test every person.

Samples of wastewater from the Paris sewage system have been showing traces of COVID-19 again since the end of June, having vanished when France imposed a lockdown.

For the Israeli pilot study, the coastal city of Ashkelon, with 150,000 residents, was chosen as it was thought to have a low number of cases. But researchers discovered significant remnants of the coronavirus in municipal wastewater, Kando said.

The results suggest that tracking coronavirus remnants in the sewer network can be a more efficient gauge of the extent of outbreaks than testing individuals, especially given the asymptomatic nature of many suffering from COVID-19, it said.

Surveillance scheme hunts for COVID traces in Israel's sewers