Emergence of Bat-Related Betacoronaviruses: Hazard and Risks

Abstract

The current Coronavirus Disease 2019 (COVID-19) pandemic, with more than 111 million reported cases and 2,500,000 deaths worldwide (mortality rate currently estimated at 2.2%), is a stark reminder that coronaviruses (CoV)-induced diseases remain a major threat to humanity. COVID-19 is only the latest case of betacoronavirus (β-CoV) epidemics/pandemics. In the last 20 years, two deadly CoV epidemics, Severe Acute Respiratory Syndrome (SARS; fatality rate 9.6%) and Middle East Respiratory Syndrome (MERS; fatality rate 34.7%), plus the emergence of HCoV-HKU1 which causes the winter common cold (fatality rate 0.5%), were already a source of public health concern. Betacoronaviruses can also be a threat for livestock, as evidenced by the Swine Acute Diarrhea Syndrome (SADS) epizootic in pigs. These repeated outbreaks of β-CoV-induced diseases raise the question of the dynamic of propagation of this group of viruses in wildlife and human ecosystems. SARS-CoV, SARS-CoV-2, and HCoV-HKU1 emerged in Asia, strongly suggesting the existence of a regional hot spot for emergence. However, there might be other regional hot spots, as seen with MERS-CoV, which emerged in the Arabian Peninsula. β-CoVs responsible for human respiratory infections are closely related to bat-borne viruses. Bats are present worldwide and their level of infection with CoVs is very high on all continents. However, there is as yet no evidence of direct bat-to-human coronavirus infection. Transmission of β-CoV to humans is considered to occur accidentally through contact with susceptible intermediate animal species. This zoonotic emergence is a complex process involving not only bats, wildlife and natural ecosystems, but also many anthropogenic and societal aspects. Here, we try to understand why only few hot spots of β-CoV emergence have been identified despite worldwide bats and bat-borne β-CoV distribution. In this work, we analyze and compare the natural and anthropogenic environments associated with the emergence of β-CoV and outline conserved features likely to create favorable conditions for a new epidemic. We suggest monitoring South and East Africa as well as South America as these regions bring together many of the conditions that could make them future hot spots.

Species-specific molecular barriers to SARS-CoV-2 replication in bat cells

“…Species belonging to the Rhinolophus genus, including R. ferrumequinum , are known natural hosts for numerous SARS-CoV-related betacoronaviruses [9,31]. Alphacoronaviruses [10,32,33], and possibly betacoronaviruses [8], circulate in species belonging to the Myotis genera. Primary cells generated from wing biopsies of R. ferrumequinum , M. myotis , M. nattereri and M. brandtii (table 1) were subjected to infection by SARS-CoV-2 at a multiplicity of infection (MOI) of 1.…”

“…First, comparison of ACE2 protein sequences from 37 bat species, including species of the genus Rhinolophus, predicted a low or very low ability to interact with viral S proteins [20]. Second, expressing ACE2 from dozen bat species in non-permissive mammalian cells possibly betacoronaviruses [8], circulate in species belonging to the Myotis genera. Primary cells generated from wing biopsies of R. ferrumequinum, M. myotis, M. nattereri and M. brandtii (table 1) were subjected to infection by SARS-CoV-2 at a multiplicity of infection (MOI) of 1.…”

The land use–food–coronavirus nexus

“…Rulli and co-authors acknowledge that follow-up analyses should consider climate change impacts on bat habitats 10 -entailing more complex feedback with ecosystems 11 , as well as trade-offs and synergies among dietary shifts, food security, wild meat trade and food system shocks 12,13 . Indeed, any zoonotic disease emergence is a complex process also involving societal and economic aspects 14 . In the context of COVID-19, development of therapeutic options, surveillance systems and vaccines are urgent, but strategic actions related to intersectoral collaboration, collective education and awareness raising about the multiple benefits of the One Health approach implementation 15 can mitigate risks associated with anthropized environments 16 .…”

Biomimetics provides lessons from nature for contemporary ways to improve human health

“…It was recently reported that the Southeast Asian region is a global hotspot of climate change-driven increase in bat-borne coronaviruses [134]. It has also been suggested that there is a need to monitor Southeast Africa and South America for future pandemics, as these regions amalgamate many of the circumstances that could create a perfect storm for new hotspots [135]. For the prevention and treatment of viral pandemics, much can be learned from nature.…”