Researchers around the world are looking at blood samples taken in late 2019 to see if there are any early signs of the coronavirus. The latest example is of researchers looking at old blood samples taken from children in Milan. One boy’s blood sample tested positive for SARS-CoV-2, the coronavirus that causes COVID-19, and researchers say that it is similar to the strain that was found in Wuhan, according to the study published in Emerging Infectious Diseases.
The authors report that the sample was taken in early Dec. 2019, about three months earlier than the first official reported coronavirus case in Italy. The segment of viral genetic material was identified as matching the Wuhan and other strains of the coronavirus, although they could not identify it further as to which exact strain it was.
The child was not asymptomatic, which is why they took blood samples from him on the suspicion that he had measles. Children sampled in this group were experiencing fever, cough and skin rashes. This child had cough and inflammation in the mucous membrane in his nose and was admitted to the hospital with respiratory symptoms and vomiting, according to the study. All the children in this group tested negative for measles, but only this one child tested positive for SARS-CoV-2.
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“This finding is of epidemiologic importance because it expands our knowledge on timing and mapping of the SARS-CoV-2 transmission pathways,” write the authors. “Long-term, unrecognized spread of SARS-CoV-2 in northern Italy would help explain, at least in part, the devastating impact and rapid course of the first wave of COVID-19 in Lombardy.”
Other researchers are also investigating blood samples taken in late 2019 by testing for the coronavirus and its antibodies. Some are also looking at sewage samples for surveillance and retrospectively as an investigation. Together with this new study, the findings suggest that the virus may have been circulating in Italy long before the first case was detected.
However, there needs to be more studies to confirm if that was the case. Virus found in sewage is typically damaged. Antibodies are indirect evidence that the coronavirus was present. There could be cross contamination of samples if not handled carefully, and all tests have the potential to produce false positives.
Benjamin Neuman, who is professor and chair of biological sciences at the University of Texas-Texarkana, says to the South China Morning Post, “I will continue to watch and wait for more compelling evidence.”
For up-to-date information about COVID-19, check the websites of the Centers for Disease Control and Prevention and the World Health Organization. For updated global case counts, check this page maintained by Johns Hopkins University or the COVID Tracking Project.
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