COVID-19: Epidemiology, pathogenesis, diagnosis and clinical symptoms

Abstract

Coronaviruses have been known to the mankind for decades. In the past, they were thought to cause mild infections of the upper respiratory tract. The emergence at the beginning of the 21st century of two highly transmissible and pathogenic viruses β-coronaviruses, i.e. Severe Acute Respiratory Syndrome Coronavirus (SARS- CoV) and Middle East Respiratory Syndrome Coronavirus (MERS-CoV), causing respiratory failure leading to the death of a large number of patients, highlighted a significant threat to the entire world. The 21st century has brought events at a catastrophic scale - the COVID-19 pandemic. SARS-CoV-2 virus from the Coronaviridae family responsible for the disease, appeared at the end of 2019 in Wuhan, China, and in a short time has lead to the devastation of lives of millions of people around the world. A comparison of the SARS-CoV-2 genome sequence and other available β-coronavirus genomes indicates the closest association of SARS-CoV-2 with the BatCov RaTG13 bat coronavirus strain (96% similarity). Therefore, it is suggested that SARS-CoV-2 virus may have evolved naturally from the RaTG13 virus strain transmitted by bats. The consequences of the COVID-19 pandemic include, among others, a significant number of illnesses and fatalities, inefficiency of health care systems, mental disorders and unprecedented methods of fighting the pandemic requiring closure of large sectors of the economy and a drastic reduction of interpersonal contacts. This survey presents basic information about β-coronaviruses. It also describes the course of COVID-19, taking into account a wide range of clinical symptoms from the respiratory, cardiovascular, digestive, reproductive and nervous systems, kidneys and skin. In addition, problems of mental disorders related to the current situation, both in patients and medical personnel as well as in general population, are discussed. The most common symptoms of COVID-19 in children are presented. The article also describes methods used for a diagnosis of the SARS-CoV-2 infection, and disturbances in hematological, biochemical, hemostatic and inflammatory parameters found in COVID-19 patients, emphasizing their role as prognostic factors for the severity of the disease.

Keywords

• covid-19
• sars-cov-2
• diagnosis
• coagulopathy
• coronaviruses
• acute respiratory distress syndrome
• cardiovascular complications
• neurologic and psychiatric symptoms
• multiorgan failure