Severe acute respiratory coronavirus 2, the seventh human coronavirus, was discovered in Wuhan, Hubei province, china, during the recent epidemic of pneumonia in January 2020. After then, the virus spread all over the world, and as of May 2020, it has infected 4806299 people and caused 318599 death. SAARS-Cov and middle east respiratory syndrome coronavirus cause severe pneumonia with a fatality rate of 2.95% and 9.6%. The other four human coronaviruses, OC43, NL63, HKU1, and 229E, generally cause self -limited symptoms.In this review, we summarize the state of the art of the coronavirus disease 19 pandemic ( covid-19, as defined by the world health organization in Feb 2020), including the origin of SARS-COV-2, its ability to infect human cells, epidemiology, clinical pathological and laboratory finding, molecular and serological diagnosis, and safety issues. we also provide information on available therapies, vaccine development, and the potential role of artificial intelligence in the governance of healthcare systems and its usefulness in fighting the covid-19 outbreak. since the discovery of the novel coronavirus, SARS-COV-2, scientists have debated its origin. It has been speculated that SARS-COV-2 is the product of laboratory manipulations. however, genetic data do not support this hypothesis and show that SAARS -cov-2 did not derive from a previously known virus backbone.
genomes analysis and comparison with previously known coronavirus genomes indicate that saars-cov-19 presents unique features that distinguish it from other coronaviruses: optimal affinity for angitioenisin converting enzyme 2 receptor and polybasic cleavage site at the s1\s2 spike junction that determines infectivity and host range.
SARS-COV -2 is highly similar to bat sars-like coronaviruses and bats might be the reservoir host. RaGT13 is 96% identical to sars-cov-2 with some difference in the spike receptor binding domain that could explain the difference in ACE2 affinity between sars-cov-2 and sars-like coronaviruses. The polybasis cleavage site of sars-cov-2 is not present in pangolin bata-coronavirus, which shares similarities with sars-cov-2. Also,the sequence of rbd of the spike protein suggests that it arose from a natural evolutionary process.
estimates of the most recent common ancestor of sars-cov-2 date the epidemic to between late November 2019 and the beginning of December 2019, which is compatible with the first reported cases. Thus, there was unnoticed human transmission after the zoonotic event and before the acquisition of the polybasic furin cleavage site. Patients with sars-cov-2 infection may present symptoms ranging from mild to severe with a large portion of the population being asymptomatic carriers. The most common reported symptoms to include fever 83% , cough 82%, and shortness of breath 31%.In patients with pneumonia, chest x -rays usually show multiple and ground glass opacity.
Gastrointestinal symptoms such as vomiting, diarrhea, and abdominal pain are described in 2-10% of the patients with covid-19, and in 10% of patients, diarrhea and nausea precede the development of fever and respiratory symptoms.
COvid-19 patients usually show decreased lymphocyte eosinophils counts, lower median hemoglobin values as well as an increase in WBC, neutrophil counts, and levels of CRP, LDH, AST, and ALT. More,initial CRP serum levels have been reported to be an independent predictor for the development of severe COVID-19 infection.
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