Virus slowly reveals its deadly path

Evidence placing COVID-19 in Europe, Brazil and US in late 2019 fuels research

A report from Brazil last week pointed to the spread of the coronavirus in that country as early as December 2019. For many researchers, the revelation is another piece of the jigsaw puzzle that they are trying to put together on COVID-19 when it was flying under the radar around the world.

The presence of antibodies specific for SARS-CoV-2－the virus that caused a pandemic that has killed more than 2 million people worldwide－was found in serum samples dating to the last month of 2019, the health department in the southeast Brazilian state of Espirito Santo reported last Tuesday. Studies in Europe had earlier reported on what appeared to be evidence pointing to the spread of the virus in the subsequently hard-hit region in late 2019. And in the United States, there are suspicions the virus was circulating there as early as November 2019.

In Espirito Santo, the antibodies to SARS-CoV-2 were detected in 210 people. Sixteen of the samples suggested the presence of the virus in the state before Brazil announced the first confirmed case on Feb 26,2020. One of the cases was collected on Dec 18, 2019.

The health department said that 7,370 serum samples had been collected between December 2019 and June 2020 from patients suspected of infection with dengue and chikungunya－both mosquito-born diseases.

Espirito Santo's health department said it takes about 20 days for a patient to reach detectable levels of SARS-CoV-2 antibodies after an infection, so the infections could have occurred between late November and early December 2019.

The Brazilian health ministry has instructed the state to conduct in-depth epidemiological investigations for further confirmation.

The findings in Brazil are the latest among studies worldwide that have added to growing evidence that COVID-19 silently circulated outside China earlier than previously thought.

Researchers from the University of Milan have recently found that a woman in the northern Italian city was infected with COVID-19 in November 2019, according to media reports.

Through two different techniques on skin tissue, the researchers identified in a biopsy of a 25-year-old woman the presence of RNA gene sequences of SARS-CoV-2 dating back to November 2019, according to Italian regional daily newspaper L'Unione Sarda.

"There are, in this pandemic, cases in which the only sign of COVID-19 infection is that of a skin pathology," said Raffaele Gianotti, who coordinated the research.

"I wondered if we could find evidence of SARS-CoV-2 in the skin of patients with only skin diseases before the officially recognized epidemic phase began," said Gianotti, adding "we found' the fingerprints' of COVID-19 in the skin tissue."

Based on global data, this is "the oldest evidence of the presence of the SARS-CoV-2 virus in a human being," said the report.

In late April 2020, Michael Melham, the mayor of Belleville in the US state of New Jersey, said that he had tested positive for COVID-19 antibodies and believed he had contracted the virus in November 2019.

In France, scientists found a man was infected with COVID-19 in December 2019, roughly a month before the first cases were officially recorded in Europe.

Citing a doctor at Avicenne and Jean-Verdier hospitals near Paris, the BBC reported in May 2020 that the patient "must have been infected between 14 and 22 December in 2019, as coronavirus symptoms take between five and 14 days to appear".

Waste water samples

In Spain, researchers at the University of Barcelona detected the presence of the virus genome in waste water samples collected on March 12,2019, the university said in a statement in June last year.

On Nov 30 last year, a study by the US Centers for Disease Control and Prevention, or CDC, found that COVID-19 was likely in the United States as early as mid-December 2019.

According to the study published online in the journal Clinical Infectious Diseases, CDC researchers tested blood samples from 7,389 routine blood donations collected by the American Red Cross from Dec 13,2019 to Jan 17, 2020, for antibodies specific to the novel coronavirus.

COVID-19 infections "may have been present in the US in December 2019", about a month earlier than the country's first official case on Jan 19,2020, the CDC scientists wrote.

These findings are yet another illustration of how complicated it is to solve the scientific puzzle of virus source tracing.

Regarding these studies, the World Health Organization said it will "take every detection in France, in Spain, in Italy very seriously, and we will examine each and every one of them".

"We will not stop from knowing the truth on the origin of the virus, but based on science, without politicizing it or trying to create tension in the process," WHO Director-General Tedros Adhanom Ghebreyesus said in late November last year.

Xinhua