Coronavirus Infections/virology; Cross Infection/transmission; Middle East Respiratory Syndrome Coronavirus/genetics; Pneumonia/virology; Adult; Aged; Aged, 80 and over; Animals; COVID-19/diagnosis; COVID-19/epidemiology; COVID-19/virology; Camelus/virology; Chiroptera/virology; Coronavirus Infections/epidemiology; Coronavirus Infections/mortality; Coronavirus Infections/transmission; Cross Infection/prevention & control; Cross Infection/virology; Diagnostic Imaging/methods; Diagnostic Imaging/statistics & numerical data; Humans; Male; Middle Aged; Middle East Respiratory Syndrome Coronavirus/immunology; Multiple Organ Failure/etiology; Multiple Organ Failure/mortality; Pneumonia/complications; Severe acute respiratory syndrome-related coronavirus/isolation & purification; Severe acute respiratory syndrome-related coronavirus/pathogenicity; SARS-CoV-2/isolation & purification; Saudi Arabia/epidemiology; Severe Acute Respiratory Syndrome/diagnosis; Severe Acute Respiratory Syndrome/epidemiology; Severe Acute Respiratory Syndrome/virology; Severity of Illness Index; Zoonoses/transmission; Zoonoses/virology