This week it was reported that traces of the SARS-CoV-2 virus already existed in the wastewaters of Milan and Turin (Italy) in December 2019. The study is not yet published (not even as a preprint, as far as I know), but reported by the Istituto Superiore di Sanità in Italy.
“Since 2007 my group has carried out research in environmental virology and collected and analysed samples of wastewater taken at the entrance of sewage treatment plants” explains Giuseppina La Rosa of the Department of Environment and Health of the Istituto Superiore di Sanità. This work was conducted by La Rosa’s group in collaboration with Elisabetta Suffredini of the Department of Food Safety, Nutrition and Veterinary Public Health.
“The study – continues La Rosa – examined 40 samples of waste water collected from October 2019 to February 2020, and 24 control samples for which the sampling date (September 2018 – June 2019) allowed to safely exclude the presence of the virus”.
The results, confirmed in the two different laboratories with two different methods, showed the presence of SARS-Cov-2 RNA in the samples taken in Milan and Turin on 18 December 2019 and in Bologna on 29 January 2020. In the same cities, positive samples were also found in the following months of January and February 2020, while the samples of October and November 2019, as well as all the control samples, gave negative results “.
“This research can help understand the beginning of the virus circulation in Italy and provides information consistent with other results obtained from the retrospective analysis on samples of hospitalised patients in France, which identified a SARS-CoV-2 positive in a respiratory sample dating back to the end of December 2019″.
“It should be noted that the discovery of the virus does not automatically imply that the main transmission chains that led to the development of the epidemic in our country originated from these first cases, but, in perspective, a surveillance network in the area may prove to be valuable to control the epidemic”.
This study proves, once again, the old adage that you should never throw anything out since you never really know when it might come in handy. That’s what I’m taking from it anyway!