# Comparison of Selected Characteristics of SARS-CoV-2, SARS-CoV, and HCoV-NL63
### Animal Origin of SARS-CoV
#### 1.4.3 HCoV-NL63 and Its Natural Hosts  
The human coronavirus HCoV-NL63 was identified in the Netherlands in late 2004 in a seven-month-old child with bronchiolitis and fever. HCoV-NL63 is a member of the group of alphacoronaviruses and is most closely related to HCoV-229E. The differences between HCoV-NL63 and HCoV-229E are prominent. First, they share, on average, only 65% sequence identity. Before the discovery of HCoV-NL63, it was generally thought that all group I coronaviruses uncl3 (aminophenidase N) as the receptor, as was described for HCoV-229E. NL63 is not able to use CD13 as a receptor for cell entry, but unusually uses the ACE2 receptor. The virus is capable of replication in monkey kidney cells, whereas HCoV-229E is not. SARS-CoV, being a betacoronavirus, is also able to replicate in monkey kidney cells. This virus was subsequently identified in various countries, indicating a worldwide distribution. The coronavirus was isolated from a patient sample in the supernatant of the renal cell line tMK with a cytopathic effect on the LLC-MK2 cell line (monkey kidney cell line) using the Virus Discovery--complementary DNA--amplified fragment length polymorphism (cDNA-AFLP) (VIDISCA) method [59]. To determine the etiology of HCoV-NL63, prevalence was tested in a group of 139 subjects and positivity was detected in four patients, which is approximately 3% [60]. Viral infection has been confirmed worldwide. It is associated with many common symptoms and diseases. Manifestations of the disease include mild-to-moderate upper respiratory tract infections, severe lower respiratory tract infections, and bronchitis. The virus occurs mainly in young children, the elderly, and immunocompromised patients. It also has a seasonal occurrence in Europe. A study in Amsterdam estimated the presence of HCoV-NL63 as approximately 4.7% of common respiratory diseases [61]. It is currently assumed that the virus was modified and transmitted primarily from infected bats and subsequently from palm civets to humans. The virus could have been transmitted from bats to civets that were in contact in animal markets in China [9]. The first evidence of transmission of HCoV-NL63 virus was found in the fecal samples of European and African bats belonging to the Vespertilionidae family [62]. Isolated CoVs are genetically related to HCoV-NL63. Viruses with some degree of similarity to HCoV-NL63 have been found in the tricolored bat _Perimyoti subl flavus_, namely bat CoV ARCoV.2 [63]. This study provided sufficient evidence that HCoV-NL63 replicates on a lung cell line from a tricolored bat, as confirmed by RNA detection and nucleocapsid protein production. Results were published by [PERSON] et al. [64], who described a high genetic similarity of coronaviruses of Kenyan bat species in the family Hipposideridea, with up to 90% similarity of the genomic sequences between BtKYNL-63-9a and HCoV-NL63. They also described a possible recombination between BtKYNL-63-9a and HCoV-229E. Both of these HCoVs are alphacoronaviruses. Comparison of the properties of human CoVs shows common characteristics (Table 1).  
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