Italy’s sewage water shows SARS-CoV-2 present prior to reported outbreak in Wuhan

By Dr. Ananya Mandal, MDJun 20 2020

Italian researchers have found traces of the novel coronavirus SARS-CoV-2 in sewage wastewater that indicates that the virus may have been in circulation since December 2019. This controversial discovery shows that even before the first case was reported in Wuhan, China, in late December 2019, the virus had already arrived in northern Italy.

Novel Coronavirus SARS-CoV-2 Creative rendition of SARS-COV-2 virus particles. Note: not to scale. Credit: NIAID

The COVID-19 pandemic and Italy

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a worldwide pandemic of massive proportions and, in recent times, has been one of the most significant public health challenges. Almost all countries have been affected by the pandemic, which has now affected at least 8.8 million individuals and killed 462,000 persons around the world as of today.

The virus typically results in coronavirus disease (COVID-19) which requires hospitalization and often ventilation and critical care. Italy to date has recorded 238,275 cases, and the infection has resulted in 34,610 deaths in the country to date. The countries’ healthcare system has been completely overwhelmed by the sheer number of cases with a severe shortage of ICU units and ventilators for COVID-19 as well as other patients.

The first local case reported in Italy (an infected case with no travel history to a country where there is an outbreak) was recorded in the town of Codogno in the Lombardy region. Lombardy was marked as a “red zone” or containment zone on the 21^st of February. Nine other towns in Lombardy and neighboring Veneto reported cases, after which the country had to be locked down early in March.

Codogno, Milano, Italy - 03/09/2020 - Volunteers working in the red zone. Image Credit RomboStudio / Shutterstock

What was this study about?

Italian researchers from the Italian National Institute of Health or the Istituto Superiore di Sanità (ISS) collected forty samples of sewage water from wastewater treatment plants located in northern Italy between October 2019 and February 2020.

What was found?

A report was released this week on the findings of this analysis of sewage water from various water treatment plants. From the samples obtained in Milan and Turin on the 18^th of December 2019, the team found the presence of the SARS CoV-2.

The team said that samples of the virus were found in sewage water samples from Bologna, Milan, and Turin in January and February 2020. The sewage samples were taken in October and November 2019, however, had tested negative for the virus.

Giuseppina La Rosa, co-leader of the study and expert in environmental wastewater at the Italian National Institute of Health said in a statement, “This research may help us understand the beginning of virus circulation in Italy.” She is the spokeswoman for the institute and said that the results of the study would be published in a journal next week.

Implications and future directions

This study is the first that shows the presence of the virus even before it appeared in the news, and even before the first case was identified in China. This could mean that the spread of the virus had started earlier than thought until now. Researchers called these results of “strategic importance.”

Scientists from the Netherlands, France, Australia have also conducted similar studies and detected traces of the virus. This could help trace the original spread of the virus, feel researchers. Researchers on this team also feel that detecting the virus before it was declared a pandemic in March 2020 could help trace the spread of the virus.

For example, a study published in May 2020 by French researchers showed that there was a case of COVID-19 in France on the 27^th of December 2019, nearly a month before the nation had reported the first case. The first confirmed case of COVID-19 was reported from Spain in late February, early March. A recent study revealed traces of the virus in sewage water in the country in mid-January in Barcelona.

Noel McCarthy, from Warwick Medical School, Britain, said that this study and its results are “reliable evidence of cases of COVID-19 being present there at that time”. He added that this shows the presence of the virus even before it began to spread rapidly. Professor of epidemiology and data processing Rowland Kao, Edinburgh University, Scotland, said that this shows that the disease may be in circulation earlier than thought. He added, “(This finding) does not on its own, however, tell us if that early detection was the source of the vast epidemic in Italy, or if that was due to a later introduction into the country.”

Study author La Rosa added that these results do 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.” The team of researchers now plan on a pilot study starting July to see the presence of the virus in wastewater in the tourist resorts. Lucia Bonadonna, director of the department of environment and health, said that the ISS has proposed to the Italian health ministry a countrywide study to monitor the presence of the virus in wastewater.

This finding comes off the back of other shocking research out of Ecuador that found the SARS-CoV-2 virus in river water, creating a significant transmission risk in developing countries with inadequate sanitation facilities.