Genetic code and radiological changes: What does the new Coronavirus reveal to us?
INTRODUCTION: SARS-CoV-2 proves to be a challenge to the world scientific community, due to its high transmissibility and diverse clinical manifestations. Thus, the continuous virulence character of this virus is discussed, a fact that arouses sources related to the genetic composition and the effects of COVID-19. OBJECTIVES: Correlate the characteristics of the SARS-CoV-2 genome with the clinical reflexes of the infection triggered by the virus, with radiological evidence of these changes. MATERIAL AND METHODS: Literature review, of a descriptive character, in which 12 articles were selected, between the 2019 and 2020, in PubMEd database, with the following descriptors: “SARS-CoV-2”, “genetics” and “radiography”. RESULTS: SARS-CoV-2, belonging to the Coronaviridae Family, Betacoronavirus genus, is a single-stranded RNA virus and positive polarity, not segmented. This RNA virus consists of eleven open reading frame sequences (ORF), of which sequences 1ab and 2 stand out. ORF1ab is responsible for the expression 16 non-structural proteins that assist the virion production process. On the other hand, ORF-2 is responsible for the formation of virus spikes and the adsorption of the virus to the cell, by type 2 angiotensin-converting enzymes (ACE-2), in view of close insertion to the coding zone of the S1 protein cleavage site, which becomes more exposed, due to the four new amino acid residues added. Thus, the tropism of virus increases to respiratory tissues, rich in ACE-2. Thereby, anatomical abnormalities are found, such as consolidations and morphological changes of the first and second order bronchi. This fact occurs due to the cytokine “storm”, related to the virus's ability to infect lymphocytes and to changes in the ORF8 base sequence, responsible for the decrease in immune signaling. Furthermore, the presence of ACE-2 in other tissues promotes their involvement in SARS-CoV-2 infection, such as brain, myocardium, vessels and eyes. Moreover, there are secondary changes, like kidney and liver manifestations, resulting from exacerbated inflammatory reactions. Even so, the main radiological changes are present in lungs, with emphasis on computed tomography, in which, initially, subpleural opacities can be observed. With the aggravation of the disease, the pattern of mosaic paving and partial consolidation with possible progression to extensive bilateral consolidation of lungs is also observed. CONCLUSION: The high SARS-CoV-2 virulence, therefore, and its tropism to various tissues allows anatomopathological changes, which can be scaled by imaging tests. In addition to this, continuous studies on viral load and the mutagenic potential of this virus are necessary.
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