Interspecies Jumping of Bat Coronaviruses

Abstract

In the last two decades, several coronavirus (CoV) interspecies jumping events have occurred between bats and other animals/humans, leading to major epidemics/pandemics and high fatalities. The SARS epidemic in 2002/2003 had a ~10% fatality. The discovery of SARS-related CoVs in horseshoe bats and civets and genomic studies have confirmed bat-to-civet-to-human transmission. The MERS epidemic that emerged in 2012 had a ~35% mortality, with dromedaries as the reservoir. Although CoVs with the same genome organization (e.g., Tylonycteris BatCoV HKU4 and Pipistrellus BatCoV HKU5) were also detected in bats, there is still a phylogenetic gap between these bat CoVs and MERS-CoV. In 2016, 10 years after the discovery of Rhinolophus BatCoV HKU2 in Chinese horseshoe bats, fatal swine disease outbreaks caused by this virus were reported in southern China. In late 2019, an outbreak of pneumonia emerged in Wuhan, China, and rapidly spread globally, leading to >4,000,000 fatalities so far. Although the genome of SARS-CoV-2 is highly similar to that of SARS-CoV, patient zero and the original source of the pandemic are still unknown. To protect humans from future public health threats, measures should be taken to monitor and reduce the chance of interspecies jumping events, either occurring naturally or through recombineering experiments.

Full Genome Nobecovirus Sequences From Malagasy Fruit Bats Define a Unique Evolutionary History for This Coronavirus Clade

“…Bootscan analyses identified signatures of recombination in the S1 subunit of both P. rufus and R. madagascariensis Nobecovirus spike proteins, suggesting that this region of the genome, which modulates host range through cell surface receptor binding, may be under selective pressure. In addition to facilitating direct bat-to-human spillover, recombination can also play an important role in facilitating cross-species emergence via intermediary bridge hosts: both SARS-CoV-1 and MERS-CoV demonstrated a critical role for intermediate hosts (respectively, palm civets and camels) in their evolutionary history of zoonotic emergence (106)(107)(108). Given the high endemicity and biodiversity characteristic of Madagascar's mammalian fauna, the island abounds with opportunities for CoV recombination with unique viruses in unique hosts.…”

The Remarkable Evolutionary Plasticity of Coronaviruses by Mutation and Recombination: Insights for the COVID-19 Pandemic and the Future Evolutionary Paths of SARS-CoV-2

“…CoVs have become a focal point of virus research, especially after the 2002-2003 SARS-CoV-1 epidemic. Data collected over the last two decades show that bats and rodents serve as reservoirs for the Alpha and Beta CoV genera, whereas wild birds probably serve as reservoirs for the Gamma and Delta CoV genera [28][29][30][31]. The human CoVs have a zoonotic origin, where bats and rodents seem to be the key reservoirs [32,33] with intermediate hosts, such as civets, raccoon dogs, camels, and possibly (the evidence here is weak) pangolins, playing a role in cross-species transmission [31,[34][35][36].…”

“…Data collected over the last two decades show that bats and rodents serve as reservoirs for the Alpha and Beta CoV genera, whereas wild birds probably serve as reservoirs for the Gamma and Delta CoV genera [28][29][30][31]. The human CoVs have a zoonotic origin, where bats and rodents seem to be the key reservoirs [32,33] with intermediate hosts, such as civets, raccoon dogs, camels, and possibly (the evidence here is weak) pangolins, playing a role in cross-species transmission [31,[34][35][36]. The recent detection of porcine delta coronavirus (PDCoV) and a feline-canine recombinant Alpha-genus CoV in human patients demonstrate that many more animals may actually serve as either reservoirs or intermediate hosts [37,38].…”

“…The animal receptors to which CoVs bind, such as angiotensin-converting enzyme 2 (ACE2) and aminopeptidase N (APN), are highly conserved in evolutionary terms, and this leads to a high incidence of cross-species infection including from birds to mammals. Such transmission events may either be direct or happen via a number of hosts at intermediate points on the evolutionary scale [31,[40][41][42][43][44][45][46]. Spill-back infections from humans to other animals (domesticated or wild) that are termed reverse zoonoses have been reported and should be monitored thoroughly [47].…”

“…Spill-back infections from humans to other animals (domesticated or wild) that are termed reverse zoonoses have been reported and should be monitored thoroughly [47]. For example, SARS-CoV-2 is able to infect gorillas, dogs, cats, lions, tigers, pumas, cougars, snow leopards, ferrets, deer, and minks [31,48]. There have been cases of SARS-CoV-2 transmission from humans to minks and back to humans [49].…”