Examples of lineages A to D betacoronaviruses include human coronavirus (HCoV) HKU1 (lineage A), 2019-nCoV (HKU-SZ-005b) and SARS-CoV (lineage B), MERS-CoV and Tylonycteris bat CoV HKU4 (lineage C), and Rousettus bat CoV HKU9 (lineage D).