ABSTRACT

Coronaviruses are divided into three serological groups based on their natural hosts, nucleotide sequences, and serological relationship [1,5]. Group I and II viruses mainly infect mammals, while group III viruses are found in birds [3,5]. Of the 28 known coronaviruses, ve are identied as human coronaviruses (HCoVs; i.e., 229E, OC43, NL63, SARS, and HKU1)

belonging to group I and group II. The rst two human coronaviruses HCoV-229E (group I) and HCoV-OC43 (group II) identied in the mid-1960s caused common cold symptoms [5,8,9]. Following the outbreak of 2002, SARS-CoV (group IIb) and two other strains HCoV-NL63 (group I) and HCoVHKU1 (group II) have since been identied [1,3,4,8-19].