Severe acute respiratory syndrome coronavirus-like virus in Chinese horseshoe bats

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Publication Date

9-27-2005

Abstract

Although the finding of severe acute respiratory syndrome coronavirus (SARS-CoV) in caged palm civets from live animal markets in China has provided evidence for interspecies transmission in the genesis of the SARS epidemic, subsequent studies suggested that the civet may have served only as an amplification host for SARS-CoV. In a surveillance study for CoV in noncaged animals from the wild areas of the Hong Kong Special Administration Region, we identified a CoV closely related to SARS-CoV (bat-SARS-CoV) from 23 (39%) of 59 anal swabs of wild Chinese horseshoe bats (Rhinolophus sinicus) by using RT-PCR. Sequencing and analysis of three bat-SARS-CoV genomes from samples collected at different dates showed that bat-SARS-CoV is closely related to SARS-CoV from humans and civets. Phylogenetic analysis showed that bat-SARS-CoV formed a distinct cluster with SARS-CoV as group 2b CoV, distantly related to known group 2 CoV. Most differences between the bat-SARS-CoV and SARS-CoV genomes were observed in the spike genes, ORF 3 and ORF 8, which are the regions where most variations also were observed between human and civet SARS-CoV genomes. In addition, the presence of a 29-bp insertion in ORF 8 of bat-SARS-CoV genome, not in most human SARS-CoV genomes, suggests that it has a common ancestor with civet SARS-CoV. Antibody against recombinant bat-SARS-CoV nucleocapsid protein was detected in 84% of Chinese horseshoe bats by using an enzyme immunoassay. Neutralizing antibody to human SARS-CoV also was detected in bats with lower viral loads. Precautions should be exercised in the handling of these animals. Coronaviruses (CoV) are found in a wide variety of animals in which they can cause respiratory, enteric, hepatic, and neurological diseases of varying severity. As a result of the unique mechanism of viral replication, CoV have a high frequency of recombination (1). Their tendency for recombination and high mutation rates may allow them to adapt to new hosts and ecological niches. Among CoV that infect humans, including human CoV 229E (HCoV-229E), human CoV OC43 (HCoV-OC43), severe acute respiratory syndrome CoV (SARS-CoV), human CoV NL63 (HCoV-NL63), and CoV HKU1 (CoV-HKU1), SARS-CoV causes the most severe disease, with >700 fatalities reported since the SARS epidemic in 2003 (2-8). The isolation of SARS-CoV from caged animals, including Himalayan palm civets and a raccoon dog, from wild live markets in mainland China suggested that these animals are the reservoir for the origin of the SARS epidemic (9). However, subsequent studies suggested that the civet may have served only as an amplification host for SARS-CoV and provided the environment for major genetic variations permitting efficient animal-to-human and human-to-human transmissions (10-13). Because civets are often mixed with different species in overcrowded conditions at markets, we conducted a surveillance study for CoV in noncaged animals from the wild areas of the Hong Kong Special Administrative Region (HKSAR). In this report, we describe the identification and molecular characterization of a SARS-CoV-related virus from Chinese horseshoe bats in Hong Kong and propose that this virus be named bat SARS CoV (bat-SARS-CoV).

Keywords

Horseshoe bats, Coronaviruses, SARS (Disease), Asia, China

Geographic Subject

Asia; China

Document Type

Article

Notes

Volume 102, Issue 39

Identifier

K26-05405

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