A Thursday news release from the ISS detailed that a recent analysis of 40 wastewater samples collected from October 2019 to February 2020, alongside 24 control samples, had identified the earliest traces of SARS-CoV-2 RNA from water obtained on December 18, 2019, in the Italian cities of Milan and Turin. The first reported cases emerged from Wuhan, China, on December 31.
Polymerase chain reaction testing allows scientists to identify fragments of RNA from SARS-CoV-2 remaining in the water.
The results, which were confirmed by two separate labs that utilized two different methods, also showed that samples collected in January and February of this year in the Italian cities of Milan, Turin and Bologna returned positive traces of the virus.
“This research may help us understand the beginning of virus circulation in Italy,” Giuseppina La Rosa, an expert in environmental wastewater with the ISS who co-led the study, told Reuters.
La Rosa cautioned those who may presume this is what kickstarted the outbreak, as the samples did not “automatically imply that the main transmission chains that led to the development of the epidemic in our country originated from these very first cases.”
She noted in the ISS news release that samples of the country’s wastewater have been collected by herself, Marcello Iaconelli, Giusy Bonanno Ferraro, Pamela Mancini and Carolina Veneri since 2007.
La Rosa and her co-authors’ research comes in the wake of similar analyses by scientists in the Netherlands and France.
Dutch researchers concluded that the first traces of the virus were confirmed in sewage water samples taken on March 5 from a wastewater plant in the Utrecht, Netherlands, city of Amersfoort.
Likewise, French scientists detected “high concentrations” of SARS-CoV-2 RNA in samples of sewage water from greater Paris that were obtained several days before March 10, the day Paris first recorded multiple COVID-19 deaths, according to Science.
A higher concentration of SARS-CoV-2 RNA in wastewater correlates with a higher amount of infected individuals nearby.
Sputnik reported in May that a hospital in Paris confirmed it had treated Amirouche Hammar, the country’s first COVID-19 patient, on December 27, 2019 - one month before the French Ministry of Health’s first announcement of infections in the country and four days before the World Health Organization’s China bureau was informed of multiple cases of “pneumonia of unknown etiology” on December 31.
The ISS told Reuters that it intends to launch a new study in July to monitor the wastewater of tourist resorts.