Full text loading...
Chapter 26 : Emerging Nidovirus Infections
Category: Viruses and Viral Pathogenesis
Ebook: Choose a downloadable PDF or ePub file. Chapter is a downloadable PDF file. File must be downloaded within 48 hours of purchase
This chapter discusses emerging nidovirus infection, such as severe acute respiratory syndrome (SARS). It is well known that some animal coronaviruses (e.g., feline infectious peritonitis virus and transmissible gastroenteritis virus) cause fatal infections in their hosts. However, relatively little attention had been focused on human coronaviruses (e.g., human coronavirus 229E [HCoV-229E] and HCoVOC43) before the SARS era. This is partly explained by the fact that these human coronaviruses (and even recently identified human coronaviruses, with the exception of SARS coronavirus [SARS-CoV]) were associated primarily with mild enteric and respiratory diseases in healthy individuals. The genome of SARS-CoV is that of a typical coronavirus. The genome of coronavirus is a single, positive-stranded RNA, approximately 29.7 kb in length. The SARS outbreak highlighted the importance of multidisciplinary research and of cooperation between multiple laboratories in tackling emerging diseases. Much basic and clinical research on coronaviruses has been triggered by this outbreak. The SARS pandemic also led to the search for novel coronaviruses in humans and animals, resulting in the identification of at least two new human and several new animal coronaviruses within the last 4 years. As more and more coronaviruses that are phylogenetically distinct from classical group 1 to 3 viruses are discovered, an alternative classification system of coronaviruses will need to be considered.
Phylogenetic tree of bat coronaviruses identified in China. The names and putative hosts of all recently found bat coronaviruses ( 3 , 28 , 31 , 41 , 67 ) are indicated. The tree was constructed by the neighbor-joining method based on partial RNA-dependent RNA polymerase sequences (402 nt) of bat coronaviruses, animal SARS-CoV isolated in 2003 (SZ3) and 2004 (PC4-13), and human SARS-CoV. The bootstrap values were determined by 1,000 replicates. The scale bar shows the estimated genetic distance of these viruses. The GenBank accession numbers of these sequences are shown in the tree. The accession numbers representing SARS-CoV and animal SARS-CoV are shaded.