![]() ![]() Molecular evolutionary analyses suggest that SARS-CoV-2 emerged as a capable human pathogen, likely from a bat reservoir, although the mechanism of the original spillover(s) is a subject of ongoing debate. ![]() The betacoronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) was first isolated in China in late December 2019 in samples collected from hospitalized patients with atypical pneumonia ( Huang et al., 2020 Zhu et al., 2020 WHO, 2020 Gorbalenya et al., 2020 Singh et al., 2021). We highlight the importance of retrospective surveillance studies in understanding the early dynamics of COVID-19 spread and we encourage other groups to perform retrospective investigations to seek confirmatory proofs of early SARS-CoV-2 circulation. Our findings should be complemented by high-throughput sequencing to obtain additional sequence information. We conclude that a SARS-CoV-2 progenitor capable of producing a measles-like syndrome may have emerged in late June-late July 2019 and that viruses with mutations characterizing B.1 strain may have been spreading globally before the first Wuhan outbreak. ![]() One of these mutations (C14408T) was also identified among sequences downloaded from public databases that were obtained by others from samples collected in Brazil in November 2019. Mutations typical of B.1 strains previously reported to have emerged in January 2020 (C3037T, C14408T, and A23403G), were identified in samples collected as early as October 2019 in Lombardy. The earliest sample with evidence of SARS-CoV-2 RNA was from September 12, 2019, and the positive patient was also positive for anti-SARS-CoV-2 antibodies (IgG and IgM). ![]() No strong evidence of infection was found in samples collected between August 2018 and July 2019 from 100 patients. Five of the RNA-positive individuals also had detectable anti-SARS-CoV-2 antibodies. Sera (N = 146) were tested for anti-SARS-CoV-2 IgG, IgM, and IgA antibodies. Two of the positive patients were from the pandemic period (2/12, 16.7%, March 2020–March 2021) and 11 were from the pre-pandemic period (11/44, 25%, August 2019–February 2020). RNA from oropharyngeal swabs (N = 148) and urine (N = 141) was screened with four hemi-nested PCRs and molecular evidence for SARS-CoV-2 infection was found in 13 subjects. Overall, 435 samples from 156 cases were investigated. As a reference laboratory for measles and rubella surveillance in Lombardy, we evaluated the association between SARS-CoV-2 infection and measles-like syndromes, providing preliminary evidence for undetected early circulation of SARS-CoV-2. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
March 2023
Categories |