Corona viruses are enveloped RNA viruses that are distributed broadly among humans, other mammals, and birds and that cause respiratory, enteric, hepatic and neurologic diseases. Seven corona virus species are known to cause human disease. Four viruses-229E. OC43. NL63 and HKu1- are prevalent and typically cause common cold symptoms in immunocompetent individuals.
The three other strains-severe acute respiratory syndrome coronavirus (SARS-Cov), Middle East respiratory syndrome coronavirus (MERS-Cov) and 2019 Novel Coronavirus (COVID-19)- are zoonotic in origin and have been linked to sometimes fatal illness. IgG and lgM antibodies to 2019 Novel Coronavirus can be detected with 2-3 weeks after exposure. lgG remains positive, but the antibody level drops overtime.