Via the South China Morning Post: Hunt for Italy’s coronavirus patient zero finds a case in November 2019. Excerpt:
A young woman who visited a Milan hospital with a rash on her arms in November 2019 could be the earliest confirmed case of Covid-19 in Italy, according to a re-examination of sample materials collected at the time.
Raffaele Gianotti, a dermatopathologist with the University of Milan, said Sars-CoV-2 – the virus which causes Covid-19 – had been found in the 25-year-old woman’s preserved skin tissue. She was misdiagnosed with a rare autoimmune disorder, but could now be Italy’s “patient zero”.
The disease was unknown until early January 2020, when Chinese researchers isolated the virus to an outbreak at a seafood market in the central city of Wuhan. Since then, it has been reported across the globe, infecting and killing millions.
“Our patient could represent the oldest case in literature of detection of the virus on tissue samples,” Gianotti and his collaborators from Spain and Britain said in a peer-reviewed paper published in the British Journal of Dermatology last Thursday.
“Could this case be Italy’s patient zero?”
According to the researchers, the woman had a sore throat but no other symptoms and a thorough examination gave no clue as to the cause of the skin irritation. Her doctors drilled into the rash and obtained a core sample of skin tissue. Finding nothing, they refrigerated the sample.
It was not until July last year, as the first wave of the pandemic swept across Europe, that they recalled the mysterious rash, which looked similar to what they were seeing in some of their Covid-19 patients. Numerous studies by researchers in Italy and elsewhere have shown the virus can cause a rash.
Initially, the woman was thought to have lupus erythematosus tumidus, a serious disease which causes the immune system to attack healthy tissue. Usually, recovery from the condition takes two or three years, but by April 2020, her rash had disappeared, adding to the mystery of her condition.
The woman tested positive for Covid-19 antibodies in June and, a month later, the doctors retrieved the stored skin sample. Testing was a challenge, as the concentration of any coronavirus present would be too low for a conventional polymerase chain reaction (PCR) kit to detect.
The Italian team used another method, known as RNA FISH, which releases fluorescent molecules that hook specifically to the coronavirus gene and is sensitive enough to detect the presence of a single copy of the virus.
Under the microscope, the researchers saw a “clear, strong” sign of the virus. To double-check their results, they treated the skin tissue with a chemical stain that changes colour on contact with a unique protein that forms the core of the novel coronavirus. The result was again positive.
The matched results from two different techniques left little room for doubt, but Gianotti wanted to be sure, so the team repeated the experiments on control samples – using tissues stored from 2018 for the negative group and samples from Covid-19 patients in intensive care units for the positive.
The second round of tests confirmed the results.
