摘要
The outbreak of the deadly virus(novel coronavirus or Severe Acute Respiratory Syndrome Coronavirus-2)that emerged in December 2019,remained a controversial subject of intense speculations regarding its origin,became a worldwide health problemresulting in serious coronavirus disease 2019(acronym COVID-19).The concern regarding this new viral strain“Severe Acute Respiratory Syndrome Coronavirus-2”(acronym SARS-CoV-2)and diseases it causes(COVID-19)is well deserved at all levels.The incidence of COVID-19 infection and infectious patients are increasing at a high rate.Coronaviruses(CoVs),enclosed positive-sense RNA viruses,are distinguished by club-like spikes extending from their surface,an exceptionally large genome of RNA,and a special mechanism for replication.Coronaviruses are associated with a broad variety of human and other animal diseases spanning fromenteritis in cattle and pigs and upper chicken respiratory disease to extremely lethal human respiratory infections.With World Health Organization(WHO)declaring COVID-19 as pandemic,we deemed it necessary to provide a detailed review of coronaviruses discussing their history,current situation,coronavirus classification,pathogenesis,structure,mode of action,diagnosis and treatment,the effect of environmental factors,risk reduction and guidelines to understand the virus and develop ways to control it.