zc45 and zxc21 zc45 and zxc21 zc45 and zxc21, sometimes known as the zhoushan virus, are two bat-derived strains of severe acute respiratory syndrome–related coronavirus. they were collected from least horseshoe bats (rhinolophus pusillus) by personnel from military laboratories in the third military medical university (chongqing, china) and the research institute for medicine of nanjing command (nanjing, china) between july 2015 and february 2017 from sites in zhoushan, zhejiang, china, and published in 2018. these two virus strains belong to the clade of sars-cov-2, the virus strain that causes covid-19, sharing 88% nucleotide identity at the scale of the complete virus genome. zc45 and zxc21 virus classification (unranked): virus realm: riboviria kingdom: orthornavirae phylum: pisuviricota class: pisoniviricetes order: nidovirales family: coronaviridae genus: betacoronavirus subgenus: sarbecovirus species: severe acute respiratory syndrome–related coronavirus strain: zc45 and zxc21 a phylogenetic tree based on whole-genome sequences of sars-cov-2 and related coronaviruses is: sars‑cov‑2 related coronavirus (bat) rc-o319, 81% to sars-cov-2, rhinolophus cornutus, iwate, japan bat sl-zxc21, 88% to sars-cov-2, rhinolophus pusillus, zhoushan, zhejiang bat sl-zc45, 88% to sars-cov-2, rhinolophus pusillus, zhoushan, zhejiang pangolin sarsr-cov-gx, 85.3% to sars-cov-2, manis javanica, smuggled from southeast asia pangolin sarsr-cov-gd, 90.1% to sars-cov-2, manis javanica, smuggled from southeast asia bat rshstt182, 92.6% to sars-cov-2, rhinolophus shameli, steung treng, cambodia bat rshstt200, 92.6% to sars-cov-2, rhinolophus shameli, steung treng, cambodia (bat) raccs203, 91.5% to sars-cov-2, rhinolophus acuminatus, chachoengsao, thailand (bat) rmyn02, 93.3% to sars-cov-2, rhinolophus malayanus, mengla, yunnan (bat) rpyn06, 94.4% to sars-cov-2, rhinolophus pusillus, xishuangbanna, yunnan (bat) ratg13, 96.1% to sars-cov-2, rhinolophus affinis, mojiang, yunnan (bat) banal-52, 96.8% to sars-cov-2, rhinolophus malayanus, vientiane, laos sars-cov-2 sars-cov-1, 79% to sars-cov-2