ABSTRACT
Phylogenetic analysis has demonstrated that the etiologic agent of the 2020 pandemic outbreak is a betacoronavirus named SARS-CoV-2. For public health interventions, a diagnostic test with high sensitivity and specificity is required. The gold standard protocol for diagnosis by the Word Health Organization (WHO) is RT-PCR. To detect low viral loads and perform large-scale screening, a low-cost diagnostic test is necessary. Here, we developed a cost-effective test capable of detecting SARS-CoV-2. We validated an auxiliary protocol for molecular diagnosis with the SYBR Green RT-PCR methodology to successfully screen negative cases of SARS-CoV-2. Our results revealed a set of primers with high specificity and no homology with other viruses from the Coronovideae family or human respiratory tract pathogenic viruses, presenting with complementarity only for rhinoviruses/enteroviruses and Legionella spp. Optimization of the annealing temperature and polymerization time led to a high specificity in the PCR products. We have developed a more affordable and swift methodology for negative SARS-CoV-2 screening. This methodology can be applied on a large scale to soften panic and economic burden through guidance for isolation strategies.
Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Organic Chemicals , Real-Time Polymerase Chain Reaction/methods , SARS-CoV-2 , Benzothiazoles , DNA, Single-Stranded , Diamines , Enterovirus , Genome, Viral , Humans , Phylogeny , Polymerase Chain Reaction , Quinolines , Rhinovirus , Sensitivity and Specificity , Temperature , Viral LoadABSTRACT
Background: Pregnant women are susceptible to the novel coronavirus (SARS-CoV-2) and the consequences on the fetus are still uncertain. Here, we present a case of a pregnant woman with subclinical hypothyroidism and PAI-1 4G/5G mutation who was infected with SARS-CoV-2 at the end of the third trimester of pregnancy. Methods: nested PCR were performed to detect the virus, followed by ssDNA sequencing. Results: transplacental transmission of SARS-CoV-2 can cause placental inflammation, ischemia and neonatal viremia, with complications such as preterm labor and damage to the placental barrier in patients with PAI-1 4G/5G mutation. Conclusion: we show the possibility of transplacental transmission of SARS-CoV-2 infection during the last weeks of pregnancy.