A review of studies on animal reservoirs of the SARS coronavirus

Abstract

In this review, we summarize the researches on animal reservoirs of the SARS coronavirus (SARS-CoV). Masked palm civets were suspected as the origin of the SARS outbreak in 2003 and was confirmed as the direct origin of SARS cases with mild symptom in 2004. Sequence analysis of the SARS-CoV-like virus in masked palm civets indicated that they were highly homologous to human SARS-CoV with nt identity over 99.6%, indicating the virus has not been circulating in the population of masked palm civets for a very long time. Alignment of 10 complete viral genome sequences from masked palm civets with those of human SARS-CoVs revealed 26 conserved single-nucleotide variations (SNVs) in the viruses from masked palm civets. These conserved SNVs were gradually lost from the genomes of viruses isolated from the early phase to late phase human patients of the 2003 SARS epidemic. In 2005, horseshoe bats were identified as the natural reservoir of a group of coronaviruses that are distantly related to SARS-CoV. The genome sequences of bat SARS-like coronavirus had about 88-92% nt identity with that of the SARS-CoV. The prevalence of antibodies and viral RNA in different bat species and the characteristics of the bat SARS-like coronavirus were elucidated. Apart from masked palm civets and bats, 29 other animal species had been tested for the SARS-CoV, and the results are summarized in this paper.

2-D graphical representation of protein sequences and its application to coronavirus phylogeny

“…In addition, the subtree of SARS-CoVs shows that the viruses from masked palm civets collected in 2003 are different from those of 2004 indicating the viral transmission from animal to human occurred independently in these two instances. This result is similar to that reported by other authors (41)(42)(43).…”

Specific serology for emerging human coronaviruses by protein microarray

“…Equally, although the first cases were all connected with the MiddleEast, it is noticeable that they came from widely separated places. Since similar animal coronaviruses can be found in bats in all regions of the world, it is possible that these infections are to be found sporadically in many countries [7][8][9][10][11][12]. This makes a strong case for further studies of animal coronaviruses and prospective and retrospective searches for cases in other regions.…”

Synthetic recombinant bat SARS-like coronavirus is infectious in cultured cells and in mice

“…SARS-CoV, which exemplifies the challenges inherent in studying emerging pathogens, was the first 21st century emerging virus to exhibit efficient human-to-human transmission and rapid global spread (4)(5)(6). Although zoonotic SARS-CoV strains were isolated from civets and raccoon dogs (7)(8)(9), the epidemic likely originated from strains circulating in bats (Bat-SCoVs) (10)(11)(12). Bat CoVs cluster in both major mammalian CoV taxonomic groups, raising the possibility that Bat CoVs may be progenitors to all 4 known pathogenic human CoVs (11,13).…”

“…Although zoonotic SARS-CoV strains were isolated from civets and raccoon dogs (7)(8)(9), the epidemic likely originated from strains circulating in bats (Bat-SCoVs) (10)(11)(12). Bat CoVs cluster in both major mammalian CoV taxonomic groups, raising the possibility that Bat CoVs may be progenitors to all 4 known pathogenic human CoVs (11,13). Bats are also predicted to function as reservoirs for other important emerging human and animal viruses (14,15).…”

“…Bats are also predicted to function as reservoirs for other important emerging human and animal viruses (14,15). Although several complete Bat CoV genome sequences are available, no Bat CoV has been successfully cultivated in cell culture or in animals (11,13), severely limiting the identification of determinants of zoonotic CoV transspecies movement.…”