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1.
Elife ; 92020 02 03.
Article in English | MEDLINE | ID: covidwho-774702

ABSTRACT

Bats host virulent zoonotic viruses without experiencing disease. A mechanistic understanding of the impact of bats' virus hosting capacities, including uniquely constitutive immune pathways, on cellular-scale viral dynamics is needed to elucidate zoonotic emergence. We carried out virus infectivity assays on bat cell lines expressing induced and constitutive immune phenotypes, then developed a theoretical model of our in vitro system, which we fit to empirical data. Best fit models recapitulated expected immune phenotypes for representative cell lines, supporting robust antiviral defenses in bat cells that correlated with higher estimates for within-host viral propagation rates. In general, heightened immune responses limit pathogen-induced cellular morbidity, which can facilitate the establishment of rapidly-propagating persistent infections within-host. Rapidly-transmitting viruses that have evolved with bat immune systems will likely cause enhanced virulence following emergence into secondary hosts with immune systems that diverge from those unique to bats.


Subject(s)
Chiroptera/virology , Disease Reservoirs/veterinary , Virus Diseases/veterinary , Viruses/growth & development , Zoonoses/virology , Animals , Cell Line , Chiroptera/immunology , Disease Reservoirs/virology , Host Microbial Interactions , Humans , Immunity, Cellular , Kinetics , Models, Biological , Phenotype , Risk Assessment , Virulence , Virus Diseases/immunology , Virus Diseases/transmission , Virus Diseases/virology , Viruses/immunology , Viruses/pathogenicity , Zoonoses/immunology , Zoonoses/transmission
3.
Viruses ; 12(4)2020 04 20.
Article in English | MEDLINE | ID: covidwho-771435

ABSTRACT

Viral outbreaks of varying frequencies and severities have caused panic and havoc across the globe throughout history. Influenza, small pox, measles, and yellow fever reverberated for centuries, causing huge burden for economies. The twenty-first century witnessed the most pathogenic and contagious virus outbreaks of zoonotic origin including severe acute respiratory syndrome coronavirus (SARS-CoV), Ebola virus, Middle East respiratory syndrome coronavirus (MERS-CoV) and Nipah virus. Nipah is considered one of the world's deadliest viruses with the heaviest mortality rates in some instances. It is known to cause encephalitis, with cases of acute respiratory distress turning fatal. Various factors contribute to the onset and spread of the virus. All through the infected zone, various strategies to tackle and enhance the surveillance and awareness with greater emphasis on personal hygiene has been formulated. This review discusses the recent outbreaks of Nipah virus in Malaysia, Bangladesh and India, the routes of transmission, prevention and control measures employed along with possible reasons behind the outbreaks, and the precautionary measures to be ensured by private-public undertakings to contain and ensure a lower incidence in the future.


Subject(s)
Encephalitis, Viral/epidemiology , Encephalitis, Viral/transmission , Henipavirus Infections/epidemiology , Henipavirus Infections/transmission , Nipah Virus/classification , Animals , Bangladesh/epidemiology , Chiroptera/virology , Disease Outbreaks , Encephalitis, Viral/prevention & control , Henipavirus Infections/prevention & control , Humans , India/epidemiology , Infection Control , Malaysia/epidemiology , Nipah Virus/genetics , Viral Structural Proteins/genetics
4.
Cell Metab ; 32(1): 31-43, 2020 07 07.
Article in English | MEDLINE | ID: covidwho-635840

ABSTRACT

For centuries, people believed that bats possessed sinister powers. Bats are thought to be ancestral hosts to many deadly viruses affecting humans including Ebola, rabies, and most recently SARS-CoV-2 coronavirus. However, bats themselves tolerate these viruses without ill effects. The second power that bats have is their longevity. Bats live much longer than similar-sized land mammals. Here we review how bats' ability to control inflammation may be contributing to their longevity. The underlying mechanisms may hold clues to developing new treatments for age-related diseases. Now may be the time to use science to exploit the secret powers of bats for human benefit.


Subject(s)
Aging/physiology , Betacoronavirus/immunology , Chiroptera/physiology , Longevity/physiology , Aging/immunology , Animals , Chiroptera/immunology , Chiroptera/virology , Coronavirus Infections/immunology , Humans , Inflammation/immunology , Pandemics , Pneumonia, Viral/immunology , Telomere Homeostasis/genetics
5.
Infez Med ; 28(3): 302-311, 2020 Sep 01.
Article in English | MEDLINE | ID: covidwho-757657

ABSTRACT

SARS-CoV-2 has created a global disaster by infecting millions of people and causing thousands of deaths across hundreds of countries. Currently, the infection is in its exponential phase in several countries and there is no sign of immediate relief from this deadly virus. At the same time, some "conspiracy theories" have arisen on the origin of this virus due to the lack of a "definite origin". To understand if this controversy is also reflected in scientific publications, here, we reviewed the key articles published at initial stages of the COVID-19 pandemic (January 01, 2020 to April 30, 2020) related to the zoonotic origin of SARS-CoV-2 and the articles opposing the "conspiracy theories". We also provide an overview on the current knowledge on SARS-CoV-2 Spike as well as the Coronavirus research domain. Furthermore, a few important points related to the "conspiracy theories" such as "laboratory engineering" or "bioweapon" aspects of SARS-CoV-2 are also reviewed. In this article, we have only considered the peer-reviewed publications that are indexed in PubMed and other official publications, and we have directly quoted the authors' statements from their respective articles to avoid any controversy.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Genetic Engineering/methods , Pneumonia, Viral/virology , Selection, Genetic , Animals , Biohazard Release , Biological Warfare Agents , Chiroptera/virology , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Dissent and Disputes , Eutheria/classification , Eutheria/virology , Global Health/statistics & numerical data , Humans , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Recombination, Genetic , Sequence Alignment , Zoonoses/virology
7.
Indian J Med Microbiol ; 38(2): 210-212, 2020.
Article in English | MEDLINE | ID: covidwho-745217

ABSTRACT

Recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and subsequent containment procedures have impacted the world as never seen before. Therefore, there is considerable curiosity about the genome evolution related to the origin, transmission and vaccine impact of this virus. We have analysed genome sequences of SARS-CoV-2 isolated from Indian patients to gain an in-depth understanding of genomic evolution and transmission in India. Phylogenetic analysis and mutation profiling revealed major lineages being evolved by characteristic mutations. As the mutation frequency in spike protein is comparatively lesser, the candidate vaccines expected to have wide coverage worldwide including India.


Subject(s)
Antigens, Viral/genetics , Betacoronavirus/genetics , Coronavirus Infections/prevention & control , Genome, Viral , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Spike Glycoprotein, Coronavirus/genetics , Viral Vaccines/genetics , Animals , Antigens, Viral/immunology , Antigens, Viral/metabolism , Betacoronavirus/classification , Betacoronavirus/immunology , Betacoronavirus/pathogenicity , Chiroptera/virology , Coronavirus Infections/epidemiology , Coronavirus Infections/genetics , Coronavirus Infections/immunology , Coronavirus Infections/transmission , Disease Reservoirs/virology , Eutheria/virology , Evolution, Molecular , Humans , India/epidemiology , Mutation , Phylogeny , Pneumonia, Viral/epidemiology , Pneumonia, Viral/immunology , Pneumonia, Viral/transmission , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Viral Vaccines/biosynthesis , Viral Vaccines/immunology
8.
PLoS Pathog ; 16(9): e1008758, 2020 09.
Article in English | MEDLINE | ID: covidwho-742547

ABSTRACT

The COVID-19 pandemic highlights the substantial public health, economic, and societal consequences of virus spillover from a wildlife reservoir. Widespread human transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) also presents a new set of challenges when considering viral spillover from people to naïve wildlife and other animal populations. The establishment of new wildlife reservoirs for SARS-CoV-2 would further complicate public health control measures and could lead to wildlife health and conservation impacts. Given the likely bat origin of SARS-CoV-2 and related beta-coronaviruses (ß-CoVs), free-ranging bats are a key group of concern for spillover from humans back to wildlife. Here, we review the diversity and natural host range of ß-CoVs in bats and examine the risk of humans inadvertently infecting free-ranging bats with SARS-CoV-2. Our review of the global distribution and host range of ß-CoV evolutionary lineages suggests that 40+ species of temperate-zone North American bats could be immunologically naïve and susceptible to infection by SARS-CoV-2. We highlight an urgent need to proactively connect the wellbeing of human and wildlife health during the current pandemic and to implement new tools to continue wildlife research while avoiding potentially severe health and conservation impacts of SARS-CoV-2 "spilling back" into free-ranging bat populations.


Subject(s)
Animals, Wild/virology , Betacoronavirus/pathogenicity , Coronavirus Infections/virology , Pneumonia, Viral/virology , Animals , Chiroptera/virology , Genome, Viral/genetics , Host Specificity/physiology , Humans , Pandemics
9.
Nat Commun ; 11(1): 4235, 2020 08 25.
Article in English | MEDLINE | ID: covidwho-738373

ABSTRACT

Bats are presumed reservoirs of diverse coronaviruses (CoVs) including progenitors of Severe Acute Respiratory Syndrome (SARS)-CoV and SARS-CoV-2, the causative agent of COVID-19. However, the evolution and diversification of these coronaviruses remains poorly understood. Here we use a Bayesian statistical framework and a large sequence data set from bat-CoVs (including 630 novel CoV sequences) in China to study their macroevolution, cross-species transmission and dispersal. We find that host-switching occurs more frequently and across more distantly related host taxa in alpha- than beta-CoVs, and is more highly constrained by phylogenetic distance for beta-CoVs. We show that inter-family and -genus switching is most common in Rhinolophidae and the genus Rhinolophus. Our analyses identify the host taxa and geographic regions that define hotspots of CoV evolutionary diversity in China that could help target bat-CoV discovery for proactive zoonotic disease surveillance. Finally, we present a phylogenetic analysis suggesting a likely origin for SARS-CoV-2 in Rhinolophus spp. bats.


Subject(s)
Chiroptera/virology , Coronavirus Infections/veterinary , Coronavirus/genetics , Evolution, Molecular , Zoonoses/transmission , Animals , Bayes Theorem , Betacoronavirus/classification , Betacoronavirus/genetics , Biodiversity , China , Chiroptera/classification , Coronavirus/classification , Coronavirus Infections/transmission , Coronavirus Infections/virology , Humans , Pandemics , Phylogeny , Phylogeography , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Zoonoses/virology
10.
J Virol ; 94(12)2020 06 01.
Article in English | MEDLINE | ID: covidwho-736044

ABSTRACT

The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that recently emerged in China is thought to have a bat origin, as its closest known relative (BatCoV RaTG13) was described previously in horseshoe bats. We analyzed the selective events that accompanied the divergence of SARS-CoV-2 from BatCoV RaTG13. To this end, we applied a population genetics-phylogenetics approach, which leverages within-population variation and divergence from an outgroup. Results indicated that most sites in the viral open reading frames (ORFs) evolved under conditions of strong to moderate purifying selection. The most highly constrained sequences corresponded to some nonstructural proteins (nsps) and to the M protein. Conversely, nsp1 and accessory ORFs, particularly ORF8, had a nonnegligible proportion of codons evolving under conditions of very weak purifying selection or close to selective neutrality. Overall, limited evidence of positive selection was detected. The 6 bona fide positively selected sites were located in the N protein, in ORF8, and in nsp1. A signal of positive selection was also detected in the receptor-binding motif (RBM) of the spike protein but most likely resulted from a recombination event that involved the BatCoV RaTG13 sequence. In line with previous data, we suggest that the common ancestor of SARS-CoV-2 and BatCoV RaTG13 encoded/encodes an RBM similar to that observed in SARS-CoV-2 itself and in some pangolin viruses. It is presently unknown whether the common ancestor still exists and, if so, which animals it infects. Our data, however, indicate that divergence of SARS-CoV-2 from BatCoV RaTG13 was accompanied by limited episodes of positive selection, suggesting that the common ancestor of the two viruses was poised for human infection.IMPORTANCE Coronaviruses are dangerous zoonotic pathogens; in the last 2 decades, three coronaviruses have crossed the species barrier and caused human epidemics. One of these is the recently emerged SARS-CoV-2. We investigated how, since its divergence from a closely related bat virus, natural selection shaped the genome of SARS-CoV-2. We found that distinct coding regions in the SARS-CoV-2 genome evolved under conditions of different degrees of constraint and are consequently more or less prone to tolerate amino acid substitutions. In practical terms, the level of constraint provides indications about which proteins/protein regions are better suited as possible targets for the development of antivirals or vaccines. We also detected limited signals of positive selection in three viral ORFs. However, we warn that, in the absence of knowledge about the chain of events that determined the human spillover, these signals should not be necessarily interpreted as evidence of an adaptation to our species.


Subject(s)
Betacoronavirus/genetics , Evolution, Molecular , Selection, Genetic , Amino Acid Sequence , Animals , Betacoronavirus/classification , Chiroptera/virology , Coronavirus Infections/virology , Genome, Viral/genetics , Humans , Models, Molecular , Open Reading Frames/genetics , Pandemics , Phylogeny , Pneumonia, Viral/virology , Viral Proteins/chemistry , Viral Proteins/genetics
11.
BMC Res Notes ; 13(1): 398, 2020 Aug 27.
Article in English | MEDLINE | ID: covidwho-733023

ABSTRACT

OBJECTIVE: In December 2019 a novel coronavirus (SARS-CoV-2) that is causing the current COVID-19 pandemic was identified in Wuhan, China. Many questions have been raised about its origin and adaptation to humans. In the present work we performed a genetic analysis of the Spike glycoprotein (S) of SARS-CoV-2 and other related coronaviruses (CoVs) isolated from different hosts in order to trace the evolutionary history of this protein and the adaptation of SARS-CoV-2 to humans. RESULTS: Based on the sequence analysis of the S gene, we suggest that the origin of SARS-CoV-2 is the result of recombination events between bat and pangolin CoVs. The hybrid SARS-CoV-2 ancestor jumped to humans and has been maintained by natural selection. Although the S protein of RaTG13 bat CoV has a high nucleotide identity with the S protein of SARS-CoV-2, the phylogenetic tree and the haplotype network suggest a non-direct parental relationship between these CoVs. Moreover, it is likely that the basic function of the receptor-binding domain (RBD) of S protein was acquired by the SARS-CoV-2 from the MP789 pangolin CoV by recombination and it has been highly conserved.


Subject(s)
Betacoronavirus/genetics , Coronaviridae/genetics , Recombination, Genetic , Spike Glycoprotein, Coronavirus/genetics , Adaptation, Biological/genetics , Animals , Binding Sites/genetics , Chiroptera/virology , Eutheria/virology , Evolution, Molecular , Furin/metabolism , Host Specificity , Humans , Peptidyl-Dipeptidase A/metabolism , Phylogeny , Selection, Genetic , Spike Glycoprotein, Coronavirus/metabolism
13.
Open Vet J ; 10(2): 164-177, 2020 08.
Article in English | MEDLINE | ID: covidwho-724486

ABSTRACT

Viruses are having great time as they seem to have bogged humans down. Severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and novel coronavirus (COVID-19) are the three major coronaviruses of present-day global human and animal health concern. COVID-19 caused by SARS-CoV-2 is identified as the newest disease, presumably of bat origin. Different theories on the evolution of viruses are in circulation, yet there is no denying the fact that the animal source is the skeleton. The whole world is witnessing the terror of the COVID-19 pandemic that is following the same path of SARS and MERS, and seems to be more severe. In addition to humans, several species of animals are reported to have been infected with these life-threatening viruses. The possible routes of transmission and their zoonotic potentialities are the subjects of intense research. This review article aims to overview the link of all these three deadly coronaviruses among animals along with their phylogenic evolution and cross-species transmission. This is essential since animals as pets or food are said to pose some risk, and their better understanding is a must in order to prepare a possible plan for future havoc in both human and animal health. Although COVID-19 is causing a human health hazard globally, its reporting in animals are limited compared to SARS and MERS. Non-human primates and carnivores are most susceptible to SARS-coronavirus and SARS-CoV-2, respectively, whereas the dromedary camel is susceptible to MERS-coronavirus. Phylogenetically, the trio viruses are reported to have originated from bats and have special capacity to undergo mutation and genomic recombination in order to infect humans through its reservoir or replication host. However, it is difficult to analyze how the genomic pattern of coronaviruses occurs. Thus, increased possibility of new virus-variants infecting humans and animals in the upcoming days seems to be the biggest challenge for the future of the world. One health approach is portrayed as our best way ahead, and understanding the animal dimension will go a long way in formulating such preparedness plans.


Subject(s)
Betacoronavirus/classification , Coronavirus Infections/veterinary , Middle East Respiratory Syndrome Coronavirus/classification , Pandemics/veterinary , Pneumonia, Viral/veterinary , SARS Virus/classification , Severe Acute Respiratory Syndrome/veterinary , Animals , Animals, Wild , Betacoronavirus/genetics , Camelids, New World/virology , Camelus/virology , Cats , Chiroptera/virology , Coronavirus Infections/immunology , Coronavirus Infections/transmission , Disease Susceptibility/veterinary , Dogs , Eutheria/virology , Ferrets/virology , Humans , Lions/virology , Middle East Respiratory Syndrome Coronavirus/genetics , Phylogeny , Pneumonia, Viral/immunology , Pneumonia, Viral/transmission , Primates/virology , Raccoon Dogs/virology , SARS Virus/genetics , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/transmission , Snakes/virology , Tigers/virology , Viverridae/virology
14.
Emerg Microbes Infect ; 9(1): 1567-1579, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-707709

ABSTRACT

Diverse SARS-like coronaviruses (SL-CoVs) have been identified from bats and other animal species. Like SARS-CoV, some bat SL-CoVs, such as WIV1, also use angiotensin converting enzyme 2 (ACE2) from human and bat as entry receptor. However, whether these viruses can also use the ACE2 of other animal species as their receptor remains to be determined. We report herein that WIV1 has a broader tropism to ACE2 orthologs than SARS-CoV isolate Tor2. Among the 9 ACE2 orthologs examined, human ACE2 exhibited the highest efficiency to mediate the infection of WIV1 pseudotyped virus. Our findings thus imply that WIV1 has the potential to infect a wide range of wild animals and may directly jump to humans. We also showed that cell entry of WIV1 could be restricted by interferon-induced transmembrane proteins (IFITMs). However, WIV1 could exploit the airway protease TMPRSS2 to partially evade the IFITM3 restriction. Interestingly, we also found that amphotericin B could enhance the infectious entry of SARS-CoVs and SL-CoVs by evading IFITM3-mediated restriction. Collectively, our findings further underscore the risk of exposure to animal SL-CoVs and highlight the vulnerability of patients who take amphotericin B to infection by SL-CoVs, including the most recently emerging (SARS-CoV-2).


Subject(s)
Betacoronavirus/physiology , Chiroptera/virology , Membrane Proteins/metabolism , Peptidyl-Dipeptidase A/metabolism , RNA-Binding Proteins/metabolism , Receptors, Virus/metabolism , Serine Endopeptidases/metabolism , Virus Internalization , Animals , Betacoronavirus/classification , HEK293 Cells , Humans , Rats , SARS Virus/physiology , Viverridae
15.
Viruses ; 12(8)2020 08 05.
Article in English | MEDLINE | ID: covidwho-696041

ABSTRACT

Zoonoses can constitute a threat for public health that can have a global importance, as seen with the current COVID-19 pandemic of severe acute respiratory syndrome coronavirus (SARS-CoV2). Bats have been recognized as an important reservoir of zoonotic coronaviruses (CoVs). In West Africa, where there is a high diversity of bat species, little is known on the circulation of CoVs in these hosts, especially at the interface with human populations. In this study, in Guinea, we tested a total of 319 bats belonging to 14 genera and six families of insectivorous and frugivorous bats across the country, for the presence of coronaviruses. We found CoVs in 35 (11%) of the tested bats-in three insectivorous bat species and five fruit bat species that were mostly captured close to human habitat. Positivity rates varied from 5.7% to 100%, depending on bat species. A wide diversity of alpha and beta coronaviruses was found across the country, including three sequences belonging to SarbeCoVs and MerbeCoVs subgenera known to harbor highly pathogenic human coronaviruses. Our findings suggest that CoVs are widely spread in West Africa and their circulation should be assessed to evaluate the risk of exposure of potential zoonotic CoVs to humans.


Subject(s)
Chiroptera/virology , Coronavirus Infections/veterinary , Coronavirus Infections/virology , Coronavirus/classification , Coronavirus/genetics , Animals , Betacoronavirus/isolation & purification , Biodiversity , Coronavirus/isolation & purification , Female , Genome, Viral , Guinea , Humans , Male , Pandemics , Phylogeny , Pilot Projects , Pneumonia, Viral/veterinary , Pneumonia, Viral/virology , Zoonoses/virology
16.
Clin Sci (Lond) ; 134(15): 1991-2017, 2020 08 14.
Article in English | MEDLINE | ID: covidwho-694110

ABSTRACT

The major risk factors to fatal outcome in COVID-19 patients, i.e., elderliness and pre-existing metabolic and cardiovascular diseases (CVD), share in common the characteristic of being chronic degenerative diseases of inflammatory nature associated with defective heat shock response (HSR). The molecular components of the HSR, the principal metabolic pathway leading to the physiological resolution of inflammation, is an anti-inflammatory biochemical pathway that involves molecular chaperones of the heat shock protein (HSP) family during homeostasis-threatening stressful situations (e.g., thermal, oxidative and metabolic stresses). The entry of SARS coronaviruses in target cells, on the other hand, aggravates the already-jeopardized HSR of this specific group of patients. In addition, cellular counterattack against virus involves interferon (IFN)-mediated inflammatory responses. Therefore, individuals with impaired HSR cannot resolve virus-induced inflammatory burst physiologically, being susceptible to exacerbated forms of inflammation, which leads to a fatal "cytokine storm". Interestingly, some species of bats that are natural reservoirs of zoonotic viruses, including SARS-CoV-2, possess an IFN-based antiviral inflammatory response perpetually activated but do not show any sign of disease or cytokine storm. This is possible because bats present a constitutive HSR that is by far (hundreds of times) more intense and rapid than that of human, being associated with a high core temperature. Similarly in humans, fever is a physiological inducer of HSR while antipyretics, which block the initial phase of inflammation, impair the resolution phase of inflammation through the HSR. These findings offer a rationale for the reevaluation of patient care and fever reduction in SARS, including COVID-19.


Subject(s)
Betacoronavirus/physiology , Chiroptera/immunology , Coronavirus Infections/immunology , Heat-Shock Response , Pneumonia, Viral/immunology , Animals , Betacoronavirus/genetics , Chiroptera/virology , Coronavirus Infections/drug therapy , Coronavirus Infections/genetics , Coronavirus Infections/physiopathology , Heat-Shock Proteins/genetics , Heat-Shock Proteins/immunology , Humans , Interferons/immunology , Pandemics , Pneumonia, Viral/drug therapy , Pneumonia, Viral/genetics , Pneumonia, Viral/physiopathology
17.
Arch Virol ; 165(10): 2341-2348, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-690501

ABSTRACT

Much remains unknown concerning the origin of the novel pandemic coronavirus that has raged across the globe since emerging in Wuhan of Hubei province, near the center of the People's Republic of China, in December of 2019. All current members of the family Coronaviridae have arisen by a combination of incremental adaptive mutations, against the backdrop of many recombinational events throughout the past, rendering each a unique mosaic of RNA sequences from diverse sources. The consensus among virologists is that the base sequence of the novel coronavirus, designated SARS-CoV-2, was derived from a common ancestor of a bat coronavirus, represented by the strain RaTG13, isolated in Yunnan province in 2013. Into that ancestral genetic background, several recombination events have since occurred from other divergent bat-derived coronaviruses, resulting in localized discordance between the two. One such event left SARS-CoV-2 with a receptor binding domain (RBD) capable of binding the human ACE-2 receptor lacking in RaTG13, and a second event uniquely added to SARS-CoV-2 a site specific for furin, capable of efficient endoproteolytic cleavage and activation of the spike glycoprotein responsible for virus entry and cell fusion. This paper demonstrates by bioinformatic analysis that such recombinational events are facilitated by short oligonucleotide "breakpoint sequences", similar to CAGAC, that direct recombination naturally to certain positions in the genome at the boundaries between blocks of RNA code and potentially RNA structure. This "breakpoint sequence hypothesis" provides a natural explanation for the biogenesis of SARS-CoV-2 over time and in the wild.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Inverted Repeat Sequences , Pneumonia, Viral/virology , RNA, Viral/genetics , Amino Acid Sequence , Animals , Base Sequence , Betacoronavirus/classification , China/epidemiology , Chiroptera/virology , Coronaviridae/classification , Coronaviridae/genetics , Coronavirus Infections/epidemiology , Evolution, Molecular , Genome, Viral , Host Microbial Interactions/genetics , Humans , Pandemics , Phylogeny , Pneumonia, Viral/epidemiology , Recombination, Genetic , Sequence Alignment
19.
Am J Trop Med Hyg ; 103(3): 955-959, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-671152

ABSTRACT

The COVID-19 pandemic is among the deadliest infectious diseases to have emerged in recent history. As with all past pandemics, the specific mechanism of its emergence in humans remains unknown. Nevertheless, a large body of virologic, epidemiologic, veterinary, and ecologic data establishes that the new virus, SARS-CoV-2, evolved directly or indirectly from a ß-coronavirus in the sarbecovirus (SARS-like virus) group that naturally infect bats and pangolins in Asia and Southeast Asia. Scientists have warned for decades that such sarbecoviruses are poised to emerge again and again, identified risk factors, and argued for enhanced pandemic prevention and control efforts. Unfortunately, few such preventive actions were taken resulting in the latest coronavirus emergence detected in late 2019 which quickly spread pandemically. The risk of similar coronavirus outbreaks in the future remains high. In addition to controlling the COVID-19 pandemic, we must undertake vigorous scientific, public health, and societal actions, including significantly increased funding for basic and applied research addressing disease emergence, to prevent this tragic history from repeating itself.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/etiology , Pneumonia, Viral/etiology , Animals , Betacoronavirus/classification , Betacoronavirus/genetics , Chiroptera/virology , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Humans , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Public Health
20.
J Virol ; 94(15)2020 07 16.
Article in English | MEDLINE | ID: covidwho-661225

ABSTRACT

The emergence of a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), resulted in a pandemic. Here, we used X-ray structures of human ACE2 bound to the receptor-binding domain (RBD) of the spike protein (S) from SARS-CoV-2 to predict its binding to ACE2 proteins from different animals, including pets, farm animals, and putative intermediate hosts of SARS-CoV-2. Comparing the interaction sites of ACE2 proteins known to serve or not serve as receptors allows the definition of residues important for binding. From the 20 amino acids in ACE2 that contact S, up to 7 can be replaced and ACE2 can still function as the SARS-CoV-2 receptor. These variable amino acids are clustered at certain positions, mostly at the periphery of the binding site, while changes of the invariable residues prevent S binding or infection of the respective animal. Some ACE2 proteins even tolerate the loss or acquisition of N-glycosylation sites located near the S interface. Of note, pigs and dogs, which are not infected or are not effectively infected and have only a few changes in the binding site, exhibit relatively low levels of ACE2 in the respiratory tract. Comparison of the RBD of S of SARS-CoV-2 with that from bat coronavirus strain RaTG13 (Bat-CoV-RaTG13) and pangolin coronavirus (Pangolin-CoV) strain hCoV-19/pangolin/Guangdong/1/2019 revealed that the latter contains only one substitution, whereas Bat-CoV-RaTG13 exhibits five. However, ACE2 of pangolin exhibits seven changes relative to human ACE2, and a similar number of substitutions is present in ACE2 of bats, raccoon dogs, and civets, suggesting that SARS-CoV-2 may not be especially adapted to ACE2 of any of its putative intermediate hosts. These analyses provide new insight into the receptor usage and animal source/origin of SARS-CoV-2.IMPORTANCE SARS-CoV-2 is threatening people worldwide, and there are no drugs or vaccines available to mitigate its spread. The origin of the virus is still unclear, and whether pets and livestock can be infected and transmit SARS-CoV-2 are important and unknown scientific questions. Effective binding to the host receptor ACE2 is the first prerequisite for infection of cells and determines the host range. Our analysis provides a framework for the prediction of potential hosts of SARS-CoV-2. We found that ACE2 from species known to support SARS-CoV-2 infection tolerate many amino acid changes, indicating that the species barrier might be low. Exceptions are dogs and especially pigs, which revealed relatively low ACE2 expression levels in the respiratory tract. Monitoring of animals is necessary to prevent the generation of a new coronavirus reservoir. Finally, our analysis also showed that SARS-CoV-2 may not be specifically adapted to any of its putative intermediate hosts.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/virology , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Spike Glycoprotein, Coronavirus/metabolism , Virus Attachment , Animals , Animals, Domestic , Betacoronavirus/metabolism , Chiroptera/virology , Coronavirus Infections/metabolism , Dogs , Glycosylation , Host-Pathogen Interactions , Humans , Models, Animal , Pandemics , Pets , Pneumonia, Viral/metabolism , Protein Binding , Protein Conformation , Protein Interaction Domains and Motifs , Raccoons/virology , Sequence Alignment , Sequence Analysis, Protein , Swine , Viverridae/virology
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