Molecular Advances in Severe Acute Respiratory Syndrome-associated Coronavirus (SARS-CoV)

Chow, Ken Yan Ching; Hon, Chung Chau; Hui, Raymond Kin Hi; Wong, Raymond Tsz Yeung; Yip, Chi Wai; Zeng, Fanya; Leung, Frederick Chi Ching

It has been demonstrated that the SARS-CoV possesses the ability to infect macaques, which display symptoms similar to the clinical signs of SARS patients (78 ) , and to replicate in cats and ferrets (79 ) . Together with the evidence implied by the phylogenetic studies, it is tempting to identify the possible animal reservoir of the coronavirus. Recent studies of domestic and wild animals in Guangdong, where the SARS epidemic was first reported, identified the existence of the SARS-CoV from several animals found in the livestock market, including Himalayan palm civets (Paguma larvata) and raccoon dogs (Nyctereutes procyonoides; ref. 80 ), in spite of the failure of another group to identify any SARS-CoV after the screening of more than 60 animal species (81 ) . The genome sequences of the coronaviruses isolated from these animals are almost identical (99.8%) to that of the SARS-CoV, revealing the extremely close phylogenetic relationship between them. Another major finding from the sequence analysis highlighted a 29-bp deletion upstream the N gene, which was noted only in one Guangdong isolate available from the Gen-Bank (GD01, accession number 278489). Such deletion leads to the fusion of the two ORFs identified in mRNA 8 into one ORF. Yet its biological significance remains to be elucidated (8 ) . Comparison of the S gene nucleotide sequence of the animal and human SARS-CoV indicated 11 consistent nucleotide signature mutations that appeared to distinguish them.