CORONAVIRUS Coronaviruses are pleomorphic, single-stranded RNA viruses. Human coronaviruses were known to cause disease: 229E (HCoV-229E) and OC43 (HCoV-OC43).The virus is now known as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease it causes is called coronavirus disease 2019 (COVID-19). COVID-19  symptoms are usually mild and begin gradually. Some people become infected but