Bat origin of human coronaviruses

Abstract

Bats have been recognized as the natural reservoirs of a large variety of viruses. Special attention has been paid to bat coronaviruses as the two emerging coronaviruses which have caused unexpected human disease outbreaks in the 21st century, Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle East Respiratory Syndrome Coronavirus (MERS-CoV), are suggested to be originated from bats. Various species of horseshoe bats in China have been found to harbor genetically diverse SARS-like coronaviruses. Some strains are highly similar to SARS-CoV even in the spike protein and are able to use the same receptor as SARS-CoV for cell entry. On the other hand, diverse coronaviruses phylogenetically related to MERS-CoV have been discovered worldwide in a wide range of bat species, some of which can be classified to the same coronavirus species as MERS-CoV. Coronaviruses genetically related to human coronavirus 229E and NL63 have been detected in bats as well. Moreover, intermediate hosts are believed to play an important role in the transmission and emergence of these coronaviruses from bats to humans. Understanding the bat origin of human coronaviruses is helpful for the prediction and prevention of another pandemic emergence in the future.

Recent advances in the detection of respiratory virus infection in humans

“…It has been classified as a lineage C β‐coronavirus, and its structure comprises a ~30 kb positive‐sense, single‐stranded RNA genome, which is closely related to the lineage C β‐coronaviruses of Tylonycteris bat CoV HKU4 and Pipistrellus bat CoV HKU5 54 . By genomic analysis of lineage C β‐coronaviruses, human MERS‐CoV has shown high similarities to MERS‐CoV derived from camels with >99.5% nucleotide identities, suggesting that the human and camel isolates belong to the same coronavirus species 4 . As of September 30, 2019, 2468 laboratory‐confirmed cases of MERS‐CoV infections, including 851 deaths in 27 countries, have been reported to WHO (https://www.who.int/emergencies/mers-cov/en/).…”

“…Most recently, a novel coronavirus 2019‐nCoV (https://www.who.int) has caused the pneumonia in 41 confirmed cases of patients, including 7 in serious condition, 1 dead, and 2 recovered (https://www.shine.cn/news/nation/2001119576/). The full genomic sequence of this coronavirus was released on January 10, 2020 (http://virological.org/t/initial-genome-release-of-novel-coronavirus/319?from=groupmessage&isappinstalled=0), which is more than 82% identical to those of SARS‐CoV and bat SARS‐like coronavirus (SL‐CoV) 4 …”

Evidence for genetic variation in Natterer’s bats (Myotis nattereri) across three regions in Germany but no evidence for co-variation with their associated astroviruses

“…[1, 2]). Indeed, bats are increasingly recognized as reservoirs for a wide range of viruses, some of which carry a zoonotic potential, for example rabies and other viruses of the genus Lyssavirus, SARS-like, MERS-like and other coronaviruses [2–5]. Consequently, several studies have investigated the genetic co-variation between different bat species and their associated viruses [6, 7].…”

Full genome characterization of two novel Alpha-coronavirus species from Italian bats

“…Six CoV strains are recognized to infect humans. Two Alphacoronaviruses (HuCov-229E, -NL63) and two Betacoronaviruses (HuCoV−OC43, -HKU1) are responsible for the common cold and severe respiratory pathologies in infants, elderly people and immunocompromised patients and are characterized by human-to-human transmission (Hu et al, 2015). The other two Betacoronaviruses species, the Severe Acute Respiratory Syndrome virus (SARS-CoV in 2002-2003 and the Middle East Respiratory Syndrome virus (MERS-CoV in 2012) caused severe respiratory pathologies with case fatality rates of 9% and 35%, respectively (WHO, www.who.int).…”