ZC45 and ZXC21

ZC45 and ZXC21, sometimes known as the Zhoushan virus,^[1] 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.^[2][3]

ZC45 and ZXC21
Virus classification
(unranked):	Virus
Realm:	Riboviria
Kingdom:	Orthornavirae
Phylum:	Pisuviricota
Class:	Pisoniviricetes
Order:	Nidovirales
Family:	Coronaviridae
Genus:	Betacoronavirus
Subgenus:	Sarbecovirus
Species:	Betacoronavirus pandemicum
Strain:	ZC45 and ZXC21

A phylogenetic tree based on whole-genome sequences of SARS-CoV-2 and related coronaviruses is:^[4][5]

SARS‑CoV‑2 related coronavirus	(Bat) Rc-o319, 81% to SARS-CoV-2, Rhinolophus cornutus, Iwate, Japan[6] Bat SL-ZXC21, 88% to SARS-CoV-2, Rhinolophus pusillus, Zhoushan, Zhejiang[7] Bat SL-ZC45, 88% to SARS-CoV-2, Rhinolophus pusillus, Zhoushan, Zhejiang[7] Pangolin SARSr-CoV-GX, 85.3% to SARS-CoV-2, Manis javanica, smuggled from Southeast Asia[8] Pangolin SARSr-CoV-GD, 90.1% to SARS-CoV-2, Manis javanica, smuggled from Southeast Asia[9] Bat RshSTT182, 92.6% to SARS-CoV-2, Rhinolophus shameli, Steung Treng, Cambodia[10] Bat RshSTT200, 92.6% to SARS-CoV-2, Rhinolophus shameli, Steung Treng, Cambodia[10] (Bat) RacCS203, 91.5% to SARS-CoV-2, Rhinolophus acuminatus, Chachoengsao, Thailand[5] (Bat) RmYN02, 93.3% to SARS-CoV-2, Rhinolophus malayanus, Mengla, Yunnan[11] (Bat) RpYN06, 94.4% to SARS-CoV-2, Rhinolophus pusillus, Xishuangbanna, Yunnan[4] (Bat) RaTG13, 96.1% to SARS-CoV-2, Rhinolophus affinis, Mojiang, Yunnan[12] (Bat) BANAL-52, 96.8% to SARS-CoV-2, Rhinolophus malayanus, Vientiane, Laos[13] SARS-CoV-2
	SARS-CoV-1, 79% to SARS-CoV-2