Canine enteric coronaviruses: emerging viral pathogens with distinct recombinant spike proteins

Phylogenetic Analysis of Porcine Epidemic Diarrhea Virus (PEDV) during 2020-2022 and Isolation of a Variant Recombinant PEDV Strain

Porcine epidemic diarrhea (PED) is an acute, highly contagious, and infectious disease caused by porcine epidemic diarrhea virus (PEDV). PEDV can affect pigs of all ages, with 50~100% mortality in neonatal piglets and substantial economic losses in the swine industry. In the present study, 347 fecal and intestinal samples were collected from seven regions in China during 2020-2022. A comprehensive molecular investigation of the spike (S) gene of PEDV strains was carried out, which included phylogenetic analysis of the obtained PEDV sequences. Epidemiological surveillance data indicate that the GIIc subgroup strains are widely distributed among pigs. A PEDV strain was successfully isolated from positive small intestine samples and identified through RT-PCR detection using specific N gene primers of PEDV, indirect immunofluorescence assay (IFA), TEM analysis, genome sequencing, and full-length S gene analysis, named PEDV/SC/2022. RDP and SimPlot analysis showed that the isolate originated from the recombination of PEDV/AH2012 and PEDV/AJ1102. In conclusion, our findings contribute to the current understanding of PEDV epidemiology and provide valuable information for the control of PED outbreaks in China.

Genetic and Evolutionary Analysis of Canine Coronavirus in Guangxi Province, China, for 2021-2024

Canine coronavirus (CCoV) is an important gastrointestinal pathogen that causes serious harm to pet dogs worldwide. Here, 1791 clinical samples were collected from pet dogs in different pet hospitals in Guangxi Province, southern China, for the 2021-2024 period and detected for CCoV by a multiplex RT-qPCR. The results showed that 8.43% (151/1791) of samples were positive for CCoV. Sixty-five positive samples were selected to amplify, sequence, and analyze S, M, and N genes. A sequence comparison revealed that the nucleotide and amino acid similarities of the S, M, and N genes were 94.86% and 94.62%, 96.85% and 97.80%, and 96.85% and 97.80%, respectively. Phylogenetic analysis indicated that 65 CCoV strains obtained in this study belonged to the CCoV-II genotype, of which 56 CCoV strains belonged to the CCoV-IIa subtype and 9 CCoV strains belonged to the CCoV-IIb subtype. A potential recombination event analysis of S gene sequences indicated that two CCoV strains, i.e., GXBSHM0328-34 and GXYLAC0318-35, have recombination signals. A Bayesian analysis indicated that the evolutionary rates of the S, M, and N genes were 1.791 × 10-3, 6.529 × 10-4, and 4.775 × 10-4 substitutions/site/year, respectively. The population size grew slowly before 1980 and then began to shrink slowly; it then shrank rapidly in 2005 and expanded sharply in 2020, leveling off thereafter. These results indicated the CCoV strains prevalent in Guangxi Province, southern China, showed a high level of genetic diversity and maintained continuous variation among clinical epidemic strains.

Cellular dynamics shape recombination frequency in coronaviruses

Coronavirus genomes have evolutionary histories shaped extensively by recombination. Yet, how often recombination occurs at a cellular level, or the factors that regulate recombination rates, are poorly understood. Utilizing experimental co-infections with pairs of genetically distinct coronaviruses, we found that recombination is both frequent and rare during coinfection. Recombination occurred in every instance of co-infection yet resulted in relatively few recombinant RNAs. By integrating a discrete-time Susceptible-Infected-Removed (SIR) model, we found that rates of recombination are determined primarily by rates of cellular co-infection, rather than other possible barriers such as RNA compartmentalization. By staggering the order and timing of infection with each virus we also found that rates of co-infection are themselves heavily influenced by genetic and ecological mechanisms, including superinfection exclusion and the relative fitness of competing viruses. Our study highlights recombination as a potent yet regulated force: frequent enough to ensure a steady influx of genetic variation but also infrequent enough to maintain genomic integrity. As recombination is thought to be an important driver of host-switching and disease emergence, our study provides new insights into the factors that regulate coronavirus recombination and evolution more broadly.

Development of multiplex real-time PCR for simultaneous detection of SARS-CoV-2, CCoV, and FIPV

Introduction

Coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), canine coronavirus (CCoV), and feline infectious peritonitis virus (FIPV), have the potential for interspecies transmission. These viruses can be present in complex environments where humans, dogs, and cats coexist, posing a significant threat to both human and animal safety.

Methods and results

In this study, we developed a novel multiplex TaqMan-probe-based real-time PCR assay for the simultaneous detection and differentiation of SARS-CoV-2, CCoV, and FIPV. Specific primers and TaqMan fluorescent probes were designed based on the N region of SARS-CoV-2 and FIPV, as well as the S region of CCoV, which demonstrated a remarkable sensitivity and specificity toward the targeted viruses, as few as 21.83, 17.25 and 9.25 copies/μL for SARS-CoV-2, CCoV and FIPV, respectively. The standard curve constructed by the optimized method in our present study showed a high amplification efficiency within or near the optimal range of 91% to 116% and R(2) values were at least 0.95 for the abovementioned coronaviruses. A total of 91 samples, including six plasmid mixed mock samples, four virus fluid mixing simulated samples, and 81 clinical samples, were analyzed using this method. Results demonstrated strong agreement with conventional approaches.

Discussion

By enabling the simultaneous detection of three viruses, this method enhances testing efficiency while decreasing costs. Importantly, it provides a valuable tool for the prevalence and geographical distribution of suspected and co-infected animals, ultimately contributing to the advancement of both animal and public health.

Epidemiological investigation of enteric canine coronaviruses in domestic dogs: A systematic review and meta-analysis

Canine enteric coronavirus (CeCoV) is a globally distributed enteric pathogen that causes significant harm to canines. The objective of this systematic review was to examine the global dissemination of CeCoV and assess the potential for infected canines to be exposed to various CeCoV genotypes and subtypes. With an aggregated prevalence of 18.8%, the study predicted regional variations, indicating that CeCoV is an exceptionally prevalent disease. The increased likelihood that infected canines will be asymptomatic is a significant cause for concern, as undetected cases of CeCoV infection could persist and spread the disease. This underscores the significance of ongoing surveillance of CeCoV in order to avert its transmission. Nevertheless, further investigation is necessary in order to ascertain the moderators that significantly impact the prevalence and distribution of distinct subtypes and genotypes of CeCoV. Hence, it is imperative to undertake randomized clinical trials in order to acquire a more accurate understanding of the variables that influence the prevalence of CeCoV. By conducting ongoing surveillance, regional variations in the prevalence of CeCoV in canines can be accounted for, thereby enhancing our comprehension of the illness and ultimately impeding its transmission.

Feline Infectious Peritonitis mRNA Vaccine Elicits Both Humoral and Cellular Immune Responses in Mice

Feline infectious peritonitis (FIP) is a devastating and often fatal disease caused by feline coronavirus (FCoV). Currently, there is no widely used vaccine for FIP, and many attempts using a variety of platforms have been largely unsuccessful due to the disease's highly complicated pathogenesis. One such complication is antibody-dependent enhancement (ADE) seen in FIP, which occurs when sub-neutralizing antibody responses to viral surface proteins paradoxically enhance disease. A novel vaccine strategy is presented here that can overcome the risk of ADE by instead using a lipid nanoparticle-encapsulated mRNA encoding the transcript for the internal structural nucleocapsid (N) FCoV protein. Both wild type and, by introduction of silent mutations, GC content-optimized mRNA vaccines targeting N were developed. mRNA durability in vitro was characterized by quantitative reverse-transcriptase PCR and protein expression by immunofluorescence assay for one week after transfection of cultured feline cells. Both mRNA durability and protein production in vitro were improved with the GC-optimized construct as compared to wild type. Immune responses were assayed by looking at N-specific humoral (by ELISA) and stimulated cytotoxic T cell (by flow cytometry) responses in a proof-of-concept mouse vaccination study. These data together demonstrate that an LNP-mRNA FIP vaccine targeting FCoV N is stable in vitro, capable of eliciting an immune response in mice, and provides justification for beginning safety and efficacy trials in cats.

Emerging Variants of Canine Enteric Coronavirus Associated with Outbreaks of Gastroenteric Disease

A 2022 canine gastroenteritis outbreak in the United Kingdom was associated with circulation of a new canine enteric coronavirus closely related to a 2020 variant with an additional spike gene recombination. The variants are unrelated to canine enteric coronavirus-like viruses associated with human disease but represent a model for coronavirus population adaptation.

Development of a time-resolved fluorescence immunoassay kit for detecting canine coronavirus and parvovirus through double labeling

OBJECTIVE

Canine enteric coronavirus (CCV) and canine parvovirus type 2 (CPV-2) are the main pathogens responsible for acute gastroenteritis in dogs, and both single and mixed infections are common. This study aimed to establish a double-labeling time-resolved fluorescence immunoassay (TRFIA) to test and distinguish CCV and CPV-2 diseases.

METHODS

A sandwich double-labeling TRFIA method was established and optimized using europium(III) (Eu3+)/samarium(III) (Sm3+) chelates. CCV/CPV-2 antigens were first captured by the immobilized antibodies. Then, combined with Eu3+/Sm3+-labeled paired antibodies, the Eu3+/Sm3+ fluorescence values were detected after dissociation to calculate the CCV/CPV-2 ratios. The performance, clinical performance and methodology used for laboratory (sensitivity, specificity, accuracy and stability) testing were evaluated.

RESULTS

A double-label TRFIA for CCV and CPV-2 detection was optimized and established. The sensitivity of this TRFIA kit was 0.51 ng/mL for CCV and 0.80 ng/mL for CPV-2, with high specificity for CCV and CPV-2. All the accuracy data were less than 10%, and the recovery ranged from 101.21 to 110.28%. The kits can be temporarily stored for 20 days at 4 °C and can be stored for 12 months at temperatures less than - 20 °C. Based on a methodology comparison of 137 clinically suspected patients, there was no statistically significant difference between the TRFIA kit and the PCR method. Additionally, for CCV detection, the clinical sensitivity was 95.74%, and the clinical specificity was 93.33%. For CPV-2 detection, the clinical sensitivity was 92.86%, and the clinical specificity was 96.97%.

CONCLUSION

In this study, a double-label TRFIA kit was prepared for CCV and CPV-2 detection with high laboratory sensitivity, specificity, accuracy, stability, clinical sensitivity and specificity. This kit provides a new option for screening/distinguishing between CCV and CPV-2 and may help improve strategies to prevent and control animal infectious diseases in the future.

Investigation of circulating infectious agents in experimental Beagle dogs of a production colony and three research facilities in China from June 2021 to May 2022

To understand the epizootiologic characteristics of pathogens and opportunistic infections in one Beagle dog production colony and three research facilities, viruses and mycoplasma were detected in 1777 samples collected from Beagle dogs in China by polymerase chain reaction/reverse transcription polymerase chain reaction, and bacteria were isolated and identified by 16S rRNA sequence analysis. In addition, genotyping of the major circulating viruses was carried out by amplification of gene fragments and homology analysis. Canine coronavirus (CCoV), Escherichia coli, canine parvovirus (CPV), Bordetella bronchiseptica, Clostridium perfringens, Mycoplasma cynos, Klebsiella pneumoniae, Streptococcus canis, canine astrovirus (CaAstV), canine kobuvirus (CaKV), Pseudomonas aeruginosa, Proteus mirabilis, Macrococcus canis, Pasteurella canis, canine bocavirus (CBoV) and canine adenovirus (CAdV) were detected in the samples. Single, double, triple and quadruple infections accounted for 6.6%, 1.4%, 1.2% and 0.96% of samples, respectively. CCoV strains in 81 samples included three genotypes, CCoV-I, CCoV-IIa and CCoV-IIb, by analysis of S gene. The rate of single infection of CCoV-I, CCoV-IIa or CCoV-IIb was 19%, 38% or 7.4% respectively. The double and triple infection rates of CCoV were 32.8% and 2.5% respectively. All CPV strains in 36 samples belonged to CPV-2c. There were three amino acid differences in the Fiber protein of CAdV-positive sample QD2022, compared with the reference strain Toronto A26/61 and the vaccine strain YCA-18. These results suggest that CCoV and CPV are primary infectious agents, and that these two viruses were often identified in mixed infections, or coinfections alongside mycoplasma or other bacteria. These results will provide the basis for improvements in prevention and control of naturally occurring infectious diseases in Beagle dog production colonies and research facilities.

The risk of pet animals in spreading severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and public health importance: An updated review

Since the outbreak of SARS-CoV-2 was first identified in 2019, it has been reported that the virus could infect a variety of animals either naturally or experimentally. This review discusses the occurrence SARS-CoV-2 in dogs and cats and the role of these animals in transmitting coronavirus disease 2019 (COVID-19) to their owners. The data were collected from epidemiological studies and case reports that focused on studying the occurrence of SARS-CoV-2 in pet animals and their owners. Epidemiological studies and case reports indicate that dogs and cats are infected with SARS-CoV-2 either naturally or experimentally; however, the global number of naturally infected animals is far lower than the number of people who have COVID-19. These studies demonstrate that pet animals acquire the infection from direct contact with COVID-19-infected owners. Currently, there are no studies reporting that dogs and cats can transmit SARS-CoV-2 to other animals and humans, under natural conditions. The emergence of SARS-CoV-2 infection in companion animals (dogs and cats) in different countries worldwide raises concerns that pets are at higher risk for spreading and transmitting SARS-CoV-2 to humans and other animals, which poses a hazard to the public health. Therefore, investigating the role of dogs and cats in the transmission and epidemiology of SARS-CoV-2 will help us to design and implement appropriate preventive measures against the further transmission of SARS-CoV-2.

Lack of detection of SARS-CoV-2 in British wildlife 2020-21 and first description of a stoat (Mustela erminea) Minacovirus

Repeat spillover of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into new hosts has highlighted the critical role of cross-species transmission of coronaviruses and establishment of new reservoirs of virus in pandemic and epizootic spread of coronaviruses. Species particularly susceptible to SARS-CoV-2 spillover include Mustelidae (mink, ferrets and related animals), cricetid rodents (hamsters and related animals), felids (domestic cats and related animals) and white-tailed deer. These predispositions led us to screen British wildlife with sarbecovirus-specific quantitative PCR and pan coronavirus PCR assays for SARS-CoV-2 using samples collected during the human pandemic to establish if widespread spillover was occurring. Fourteen wildlife species (n=402) were tested, including: two red foxes (Vulpes vulpes), 101 badgers (Meles meles), two wild American mink (Neogale vison), 41 pine marten (Martes martes), two weasels (Mustela nivalis), seven stoats (Mustela erminea), 108 water voles (Arvicola amphibius), 39 bank voles (Myodes glareolous), 10 field voles (Microtus agrestis), 15 wood mice (Apodemus sylvaticus), one common shrew (Sorex aranaeus), two pygmy shrews (Sorex minutus), two hedgehogs (Erinaceus europaeus) and 75 Eurasian otters (Lutra lutra). No cases of SARS-CoV-2 were detected in any animals, but a novel minacovirus related to mink and ferret alphacoronaviruses was detected in stoats recently introduced to the Orkney Islands. This group of viruses is of interest due to pathogenicity in ferrets. The impact of this virus on the health of stoat populations remains to be established.

Screening for canine coronavirus, canine influenza virus, and severe acute respiratory syndrome coronavirus 2 in dogs during the coronavirus disease-2019 pandemic

Background and Aim

Although most cases of coronavirus disease-2019 (COVID-19) are in humans, there is scientific evidence to suggest that the virus can also infect dogs and cats. This study investigated the circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), canine coronavirus (CCV), and canine influenza virus (CIV) in domiciled and/or stray dogs from different locations in the State of Minas Gerais, Brazil, during the COVID-19 pandemic.

Materials and Methods

In total, 86 dogs living in homes, on the streets, or in shelters in the cities of Taiobeiras, Salinas, Araçuaí, and Almenara were randomly selected for this study. The COVID Ag Detect® Self-Test was used to detect SARS-CoV-2. The ACCUVET CCV AG TEST - CANINE CORONAVIROSIS® was used to detect CCV, whereas canine influenza was detected using the ACCUVET CIV AG TEST - INFLUENZA CANINA®. All collected data were mapped using QGIS 3.28.1 for spatial data analysis and the identification of disease distribution patterns. Descriptive analysis of the collected data, prevalence calculations, odds ratios (ORs), and 95% confidence intervals, when possible, was performed.

Results

Of the 86 animals tested, only one dog tested positive for SARS-CoV-2 using the rapid test for viral antigen detection. No animals tested positive for CIV. Canine coronavirus was detected in almost half of the animals tested in Almenara. Severe acute respiratory syndrome-CoV-2 had a low prevalence (1.16%), versus 15.62% for CCV. Although the results were not significant, the age and breed of animals appeared to be associated with the occurrence of CCV. The results indicated that younger animals were 2.375-fold more likely to be infected. Likewise, purebred animals were more likely to contract the disease (OR = 1.944).

Conclusion

The results indicate the need to maintain preventive measures against CCV, canine influenza, and SARS-CoV-2 in dogs. More studies are needed to better elucidate the panorama of these diseases in dogs, mainly in underdeveloped and developing countries.

The coronavirus recombination pathway

Recombination is thought to be a mechanism that facilitates cross-species transmission in coronaviruses, thus acting as a driver of coronavirus spillover and emergence. Despite its significance, the mechanism of recombination is poorly understood, limiting our potential to estimate the risk of novel recombinant coronaviruses emerging in the future. As a tool for understanding recombination, here, we outline a framework of the recombination pathway for coronaviruses. We review existing literature on coronavirus recombination, including comparisons of naturally observed recombinant genomes as well as in vitro experiments, and place the findings into the recombination pathway framework. We highlight gaps in our understanding of coronavirus recombination illustrated by the framework and outline how further experimental research is critical for disentangling the molecular mechanism of recombination from external environmental pressures. Finally, we describe how an increased understanding of the mechanism of recombination can inform pandemic predictive intelligence, with a retrospective emphasis on SARS-CoV-2.

Molecular epidemiology and genetic diversity of canine coronavirus from domestic dogs in Chengdu, China from 2020 to 2021 using a multiplex RT-PCR

Recent reports on identification of canine coronavirus (CCoV) in humans have emphasized the urgency to strengthen surveillance of animal CoVs. The fact that recombinations between CCoV with feline, porcine CoVs brought about new types of CoVs indicated that more attention should be paid to domestic animals like dogs, cats and pigs, and the CoVs they carried. However, there are about ten kinds of CoVs that infect above animals, and thus representative CoVs with zoonotic potentials were considered in this study. Multiplex RT-PCR against CCoV, Feline coronavirus (FCoV), porcine deltacoronavirus and porcine acute diarrhea syndrome coronavirus was developed to investigate the prevalence of CoVs from domestic dogs in Chengdu, Southwest China. Samples from a total of 117 dogs were collected from a veterinary hospital, and only CCoV (34.2%, 40/117) was detected. Therefore, this study focused on CCoV and its characteristics of S, E, M, N and ORF3abc genes. Compared with CoVs that are capable of infecting humans, CCoV strains showed highest nucleotide identity with the novel canine-feline recombinants detected from humans (CCoV-Hupn-2018). Based on S gene, CCoV strains were not only clustered with CCoV-II strains, but also closely related to FCoV-II strains ZJU1617 and SMU-CD59/2018. As for assembled ORF3abc, E, M, N sequences, CCoV strains had the closest relationship with CCoV-II (B203_GZ_2019, B135_JS_2018 and JS2103). What's more, specific amino acid variations were found, especially in S and N proteins, and some mutations were consistent with FCoV, TGEV strains. Altogether, this study provided a novel insight into the identification, diversification and evolution of CoVs from domestic dogs. It is of top priority to recognize zoonotic potential of CoVs, and continued comprehensive surveillance will help better understand the emergence, spreading, and ecology of animal CoVs.

Roles of host proteases in the entry of SARS-CoV-2

The spike protein (S) of SARS-CoV-2 is responsible for viral attachment and entry, thus a major factor for host susceptibility, tissue tropism, virulence and pathogenicity. The S is divided with S1 and S2 region, and the S1 contains the receptor-binding domain (RBD), while the S2 contains the hydrophobic fusion domain for the entry into the host cell. Numerous host proteases have been implicated in the activation of SARS-CoV-2 S through various cleavage sites. In this article, we review host proteases including furin, trypsin, transmembrane protease serine 2 (TMPRSS2) and cathepsins in the activation of SARS-CoV-2 S. Many betacoronaviruses including SARS-CoV-2 have polybasic residues at the S1/S2 site which is subjected to the cleavage by furin. The S1/S2 cleavage facilitates more assessable RBD to the receptor ACE2, and the binding triggers further conformational changes and exposure of the S2' site to proteases such as type II transmembrane serine proteases (TTPRs) including TMPRSS2. In the presence of TMPRSS2 on the target cells, SARS-CoV-2 can utilize a direct entry route by fusion of the viral envelope to the cellular membrane. In the absence of TMPRSS2, SARS-CoV-2 enter target cells via endosomes where multiple cathepsins cleave the S for the successful entry. Additional host proteases involved in the cleavage of the S were discussed. This article also includes roles of 3C-like protease inhibitors which have inhibitory activity against cathepsin L in the entry of SARS-CoV-2, and discussed the dual roles of such inhibitors in virus replication.

Cross-species transmission of coronaviruses with a focus on severe acute respiratory syndrome coronavirus 2 infection in animals: a review for the veterinary practitioner

AbstractIn 2019 a novel coronavirus termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged from an unidentified source and spread rapidly among humans worldwide. While many human infections are mild, some result in severe clinical disease that in a small proportion of infected people is fatal. The pandemic spread of SARS-CoV-2 has been facilitated by efficient human-to-human transmission of the virus, with no data to indicate that animals contributed to this global health crisis. However, a range of domesticated and wild animals are also susceptible to SARS-CoV-2 infection under both experimental and natural conditions. Humans are presumed to be the source of most animal infections thus far, although natural transmission between mink and between free-ranging deer has occurred, and occasional natural transmission between cats cannot be fully excluded. Considering the ongoing circulation of the virus among people, together with its capacity to evolve through mutation and recombination, the risk of the emergence of animal-adapted variants is not negligible. If such variants remain infectious to humans, this could lead to the establishment of an animal reservoir for the virus, which would complicate control efforts. As such, minimising human-to-animal transmission of SARS-CoV-2 should be considered as part of infection control efforts. The aim of this review is to summarise what is currently known about the species specificity of animal coronaviruses, with an emphasis on SARS-CoV-2, in the broader context of factors that facilitate cross-species transmission of viruses.

Prevalence and genetic diversity of canine coronavirus in northeastern China during 2019-2021

Canine coronavirus (CCoV) is associated with diarrhea in dogs, with a high incidence and sometimes even death. However, there is currently limited information about its prevalence and molecular characterization in northeastern China. Therefore, in this study, we examined 325 canine fecal specimens in four provinces in northeastern China from 2019 to 2021. PCR results revealed that 57 out of 325 (17.5%) samples were found to be positive for CCoV, and the positive rate varies obviously with city, season, age and so on. High incidence (65%) of viral co-infection was detected in the diarrhea samples and mixed infection of distinct CCoV genotypes occurs extensively. More importantly, sequence analysis showed that the S gene has a strong mutation. Phylogenetic analysis demonstrated that CCoV-I and CCoV-II strains has different origins. In particular, we found the CCoV-IIa strains of S gene sequenced and the reference strain B906_ZJ_2019 were highly clustered, and the reference strain was a recombinant strain of CCoV-I and CCoV-II. Our findings provide useful orienting clues for evaluating the pathogenic potential of CCoV in canines, and point out more details on characterization in northeastern China. Further work is required to determine the significance and continuous genetic evolution of CCoV.

Coronaviruses: Troubling Crown of the Animal Kingdom

The existence of coronaviruses has been known for many years. These viruses cause significant disease that primarily seems to affect agricultural species. Human coronavirus disease due to the 2002 outbreak of Severe Acute Respiratory Syndrome and the 2012 outbreak of Middle East Respiratory Syndrome made headlines; however, these outbreaks were controlled, and public concern quickly faded. This complacency ended in late 2019 when alarms were raised about a mysterious virus responsible for numerous illnesses and deaths in China. As we now know, this novel disease called Coronavirus Disease 2019 (COVID-19) was caused by Severe acute respiratory syndrome-related-coronavirus-2 (SARS-CoV-2) and rapidly became a worldwide pandemic. Luckily, decades of research into animal coronaviruses hastened our understanding of the genetics, structure, transmission, and pathogenesis of these viruses. Coronaviruses infect a wide range of wild and domestic animals, with significant economic impact in several agricultural species. Their large genome, low dependency on host cellular proteins, and frequent recombination allow coronaviruses to successfully cross species barriers and adapt to different hosts including humans. The study of the animal diseases provides an understanding of the virus biology and pathogenesis and has assisted in the rapid development of the SARS-CoV-2 vaccines. Here, we briefly review the classification, origin, etiology, transmission mechanisms, pathogenesis, clinical signs, diagnosis, treatment, and prevention strategies, including available vaccines, for coronaviruses that affect domestic, farm, laboratory, and wild animal species. We also briefly describe the coronaviruses that affect humans. Expanding our knowledge of this complex group of viruses will better prepare us to design strategies to prevent and/or minimize the impact of future coronavirus outbreaks.

Molecular screening of SARS-CoV-2 in dogs and cats from households with infected owners diagnosed with COVID-19 during Delta and Omicron variant waves in Iran

OBJECTIVE

The emergence of SARS-CoV-2 infection in dogs and cats in different countries worldwide raises concerns that pets are at a higher risk for spreading or transmitting of SARS-CoV-2 to humans and other pets and increased the research works about the zoonotic aspects and natural routes of infection in companion animals. The current study aimed to detect the SARS-CoV-2 in household dogs and cats living with COVID-19 positive owners.

METHODS

Deep oropharyngeal and rectal swabs were collected from 30 household pets (20 cats and 10 dogs) living with COVID-19 positive owners from April 2021 to 2022 in Kerman, Iran. All dogs' and cats' samples were tested by real-time reverse transcription polymerase chain reaction for detection of SARS-CoV-2.

RESULTS

Two household cats out of 20 examined (10%) were positive for SARS-CoV-2, whereas none of the examined dogs were positive for SARS-CoV-2. The two cats positive for SARS-CoV-2 were symptomatic and suffered from severe anorexia with maximum contact with their infected owners.

CONCLUSION

This study reported the presence of SARS-CoV-2 in household cats in close contact with COVID-19 positive owners during the circulation of new SARS-CoV-2 variants (Delta and Omicron) in Iran and suggested that the transmission may have occurred from owners to their cats. Therefore, infected owners should eagerly limit close contact with their pets during COVID-19 illness.

Conserved recombination patterns across coronavirus subgenera

Recombination contributes to the genetic diversity found in coronaviruses and is known to be a prominent mechanism whereby they evolve. It is apparent, both from controlled experiments and in genome sequences sampled from nature, that patterns of recombination in coronaviruses are non-random and that this is likely attributable to a combination of sequence features that favour the occurrence of recombination break points at specific genomic sites, and selection disfavouring the survival of recombinants within which favourable intra-genome interactions have been disrupted. Here we leverage available whole-genome sequence data for six coronavirus subgenera to identify specific patterns of recombination that are conserved between multiple subgenera and then identify the likely factors that underlie these conserved patterns. Specifically, we confirm the non-randomness of recombination break points across all six tested coronavirus subgenera, locate conserved recombination hot- and cold-spots, and determine that the locations of transcriptional regulatory sequences are likely major determinants of conserved recombination break-point hotspot locations. We find that while the locations of recombination break points are not uniformly associated with degrees of nucleotide sequence conservation, they display significant tendencies in multiple coronavirus subgenera to occur in low guanine-cytosine content genome regions, in non-coding regions, at the edges of genes, and at sites within the Spike gene that are predicted to be minimally disruptive of Spike protein folding. While it is apparent that sequence features such as transcriptional regulatory sequences are likely major determinants of where the template-switching events that yield recombination break points most commonly occur, it is evident that selection against misfolded recombinant proteins also strongly impacts observable recombination break-point distributions in coronavirus genomes sampled from nature.

More efforts are needed for background surveys of zoonotic coronaviruses in animals

Recently, a novel dog-origin coronavirus has been found in humans. The low similarity between the receptor-binding domain from this novel virus and other human-infecting coronaviruses in genus Alphacoronavirus suggests it might use a novel receptor or mechanism to enter human cells and also might trigger a novel immune response.

Novel Canine Coronavirus Isolated from a Hospitalized Patient With Pneumonia in East Malaysia

BACKGROUND

During the validation of a highly sensitive panspecies coronavirus (CoV) seminested reverse-transcription polymerase chain reaction (RT-PCR) assay, we found canine CoV (CCoV) RNA in nasopharyngeal swab samples from 8 of 301 patients (2.5%) hospitalized with pneumonia during 2017-2018 in Sarawak, Malaysia. Most patients were children living in rural areas with frequent exposure to domesticated animals and wildlife.

METHODS

Specimens were further studied with universal and species-specific CoV and CCoV 1-step RT-PCR assays, and viral isolation was performed in A72 canine cells. Complete genome sequencing was conducted using the Sanger method.

RESULTS

Two of 8 specimens contained sufficient amounts of CCoVs as confirmed by less-sensitive single-step RT-PCR assays, and 1 specimen demonstrated cytopathic effects in A72 cells. Complete genome sequencing of the virus causing cytopathic effects identified it as a novel canine-feline recombinant alphacoronavirus (genotype II) that we named CCoV-human pneumonia (HuPn)-2018. Most of the CCoV-HuPn-2018 genome is more closely related to a CCoV TN-449, while its S gene shared significantly higher sequence identity with CCoV-UCD-1 (S1 domain) and a feline CoV WSU 79-1683 (S2 domain). CCoV-HuPn-2018 is unique for a 36-nucleotide (12-amino acid) deletion in the N protein and the presence of full-length and truncated 7b nonstructural protein, which may have clinical relevance.

CONCLUSIONS

This is the first report of a novel canine-feline recombinant alphacoronavirus isolated from a human patient with pneumonia. If confirmed as a pathogen, it may represent the eighth unique coronavirus known to cause disease in humans. Our findings underscore the public health threat of animal CoVs and a need to conduct better surveillance for them.

Detection and Molecular Characterization of Canine Alphacoronavirus in Free-Roaming Dogs, Bangladesh

Canine coronavirus (CCoV) is widespread among the dog population and causes gastrointestinal disorders, and even fatal cases. As the zoonotic transmission of viruses from animals to humans has become a worldwide concern nowadays, it is necessary to screen free-roaming dogs for their common pathogens due to their frequent interaction with humans. We conducted a cross-sectional study to detect and characterize the known and novel Corona, Filo, Flavi, and Paramyxoviruses in free-roaming dogs in Bangladesh. Between 2009-10 and 2016-17, we collected swab samples from 69 dogs from four districts of Bangladesh, tested using RT-PCR and sequenced. None of the samples were positive for Filo, Flavi, and Paramyxoviruses. Only three samples (4.3%; 95% CI: 0.9-12.2) tested positive for Canine Coronavirus (CCoV). The CCoV strains identified were branched with strains of genotype CCoV-II with distinct distances. They are closely related to CCoVs from the UK, China, and other CoVs isolated from different species, which suggests genetic recombination and interspecies transmission of CCoVs. These findings indicate that CCoV is circulating in dogs of Bangladesh. Hence, we recommend future studies on epidemiology and genetic characterization with full-genome sequencing of emerging coronaviruses in companion animals in Bangladesh.

SARS-CoV-2 antibodies seroprevalence in dogs from France using ELISA and an automated western blotting assay

Dogs are occasionally susceptible to SARS-CoV-2, developing few or no clinical signs. Epidemiological surveillance of SARS-CoV-2 in dogs requires testing to distinguish it from other canine coronaviruses. In the last year, significant advances have been made in the diagnosis of SARS-CoV-2, allowing its surveillance in both human and animal populations. Here, using ELISA and automated western blotting (AWB) assays, we performed a longitudinal study on 809 apparently healthy dogs from different regions of France to investigate anti-SARS-CoV-2 antibodies. There were three main groups: (i) 356 dogs sampled once before the pandemic, (ii) 235 dogs sampled once during the pandemic, and (iii) 218 dogs, including 82 dogs sampled twice (before and during the pandemic), 125 dogs sampled twice during the pandemic and 11 dogs sampled three times (once before and twice during the pandemic). Using ELISA, seroprevalence was significantly higher during the pandemic [5.5% (25/453)] than during the pre-pandemic period [1.1% (5/449)]. Among the 218 dogs sampled twice, at least 8 ELISA-seroconversions were observed. ELISA positive pre-pandemic sera were not confirmed in serial tests by AWB, indicating possible ELISA cross-reactivity, probably with other canine coronaviruses. A significant difference was observed between these two serological tests (Q = 88, p = 0.008). A clear correlation was observed between SARS-CoV-2 seroprevalence in dogs and the incidence of SARS-CoV-2 infection in human population from the same area. AWB could be used as a second line assay to confirm the doubtful and discrepant ELISA results in dogs. Our results confirm the previous experimental models regarding the susceptibility of dogs to SARS-CoV-2, suggesting that viral transmission from and between dogs is weak or absent. However, the new variants with multiple mutations could adapt to dogs; this hypothesis cannot be ruled out in the absence of genomic data on SARS-CoV-2 from dogs.

Identification and phylogenetic analysis of two canine coronavirus strains

Canine coronavirus (CCoV), a member of the genus Alphacoronavirus, is an enveloped, single-stranded positive-sense RNA virus that responsible for gastroenteritis in dogs. In this study, two CCoV isolates were successfully propagated from 53 CCoV-positive clinical specimens by serial passaging in A-72 cells. These two strains, CCoV JS1706 and CCoV JS1712, caused cytopathic effects in A-72 cells. The sizes of virus plaque formed by them differed in early passages. Electron microscopy revealed a large quantity of typical coronavirus particles with 80–120 nm in diameter in cell culture media and cytoplasm of infected cells, in which they appeared as inclusion bodies. RT-PCR analysis of S gene indicated that these two isolates were belonged to CCoV IIa subtype. Homology of RdRp, S, M and N proteins between the two strains were 100, 99.6, 99.2 and 100.0%, respectively, whereas they were 99.4–100%, 83.1–95.2%, 88.5–99.2% and 91.9–99.7% identity compared to CCoV II reference strains. Phylogenetic analysis of RdRp, S, M and N protein showed that they were closely related to CCoV II strains. These two subtype IIa isolates will be useful for evaluating the pathogenesis and evolution of CCoV and for developing diagnostic reagents and vaccines.

Identification of a canine coronavirus in Australian racing Greyhounds

Coronavirus infection can cause a range of syndromes, which in dogs can include mild-to-severe enteritis that generally resolves rapidly. Fatalities can occur from coinfection with other pathogens, including canine parvovirus. Between late December 2019 and April 2020, canine coronavirus (CCoV) was detected in Australian racing Greyhounds that displayed signs of gastrointestinal disease. The CCoV was genotyped using high-throughput sequencing, recovering 98.3% of a type IIb CCoV, generally thought to cause a mild but highly contagious enteric disease. The Australian CCoV was almost identical (99.9%, whole-genome sequence) to another CCoV associated with an outbreak of severe vomiting in dogs in the United Kingdom at the same time (December 2019-March 2020).

A meta-analysis of cross-sectional studies on the frequency and risk factors associated with canine morbillivirus infection in China

BACKGROUND

The canine morbillivirus, previously known as canine distemper virus (CDV), is a pathogen which infects dogs worldwide and causes fatal disease. CDV has a broad range of hosts and can infect at least six orders and more than 20 mammalian families. Domestic dogs are the main hosts of CDV and play a central role in the transmission of the virus. However, the prevalence of CDV infection in China remains unknown since there are only a few studies which systematically analysed the prevalence of CDV in domestic dogs in the country. Therefore, we conducted a systematic review and meta-analysis of the frequency of CDV positivity and associated risk factors of CDV in Chinese domestic dogs.

METHODS

We systematically searched for studies on the frequency of CDV in Chinese domestic dogs published in English and Chinese to conduct a meta-analysis using the random-effects model with a forest plot with a 95% confidence interval.

RESULTS

The overall estimated frequency of CDV positivity in Chinese domestic dogs was 22%. In addition, our data show that sampling season, age, breed, and immunisation status are associated with CDV infection frequency.

CONCLUSION

In a word, CDV is circulating in domestic dogs in China. Continued intervention strategies based on risk factors are necessary to reduce the frequency of CDV infection, especially in endemic regions.

Cross-Species Transmission of Coronaviruses in Humans and Domestic Mammals, What Are the Ecological Mechanisms Driving Transmission, Spillover, and Disease Emergence?

Coronaviruses cause respiratory and digestive diseases in vertebrates. The recent pandemic, caused by the novel severe acute respiratory syndrome (SARS) coronavirus 2, is taking a heavy toll on society and planetary health, and illustrates the threat emerging coronaviruses can pose to the well-being of humans and other animals. Coronaviruses are constantly evolving, crossing host species barriers, and expanding their host range. In the last few decades, several novel coronaviruses have emerged in humans and domestic animals. Novel coronaviruses have also been discovered in captive wildlife or wild populations, raising conservation concerns. The evolution and emergence of novel viruses is enabled by frequent cross-species transmission. It is thus crucial to determine emerging coronaviruses' potential for infecting different host species, and to identify the circumstances under which cross-species transmission occurs in order to mitigate the rate of disease emergence. Here, I review (broadly across several mammalian host species) up-to-date knowledge of host range and circumstances concerning reported cross-species transmission events of emerging coronaviruses in humans and common domestic mammals. All of these coronaviruses had similar host ranges, were closely related (indicative of rapid diversification and spread), and their emergence was likely associated with high-host-density environments facilitating multi-species interactions (e.g., shelters, farms, and markets) and the health or well-being of animals as end- and/or intermediate spillover hosts. Further research is needed to identify mechanisms of the cross-species transmission events that have ultimately led to a surge of emerging coronaviruses in multiple species in a relatively short period of time in a world undergoing rapid environmental change.

Evolution, Interspecies Transmission, and Zoonotic Significance of Animal Coronaviruses

Coronaviruses are single-stranded RNA viruses that affect humans and a wide variety of animal species, including livestock, wild animals, birds, and pets. These viruses have an affinity for different tissues, such as those of the respiratory and gastrointestinal tract of most mammals and birds and the hepatic and nervous tissues of rodents and porcine. As coronaviruses target different host cell receptors and show divergence in the sequences and motifs of their structural and accessory proteins, they are classified into groups, which may explain the evolutionary relationship between them. The interspecies transmission, zoonotic potential, and ability to mutate at a higher rate and emerge into variants of concern highlight their importance in the medical and veterinary fields. The contribution of various factors that result in their evolution will provide better insight and may help to understand the complexity of coronaviruses in the face of pandemics. In this review, important aspects of coronaviruses infecting livestock, birds, and pets, in particular, their structure and genome organization having a bearing on evolutionary and zoonotic outcomes, have been discussed.

Nanotechnology-based therapeutic formulations in the battle against animal coronaviruses: an update

Outbreak of infectious diseases imposes a serious threat to human population and also causes a catastrophic impact on global economy. Animal coronaviruses remain as one of the intriguing problems, known to cause deadly viral diseases on economically important animal population, and also these infections may spread to other animals and humans. Through isolation of the infected animals from others and providing appropriate treatment using antiviral drugs, it is possible to prevent the virus transmission from animals to other species. In recent times, antiviral drug-resistant strains are being emerged as a deadly virus which are known to cause pandemic. To overcome this, nanoparticles-based formulations are developed as antiviral agent which attacks the animal coronaviruses at multiple sites in the virus replication cycle. Nanovaccines are also being formulated to protect the animals from coronaviruses. Nanoformulations contain particles of one or more dimensions in nano-scale (few nanometers to 1000 nm), which could be inorganic or organic in nature. This review presents the comprehensive outline of the nanotechnology-based therapeutics formulated against animal coronaviruses, which includes the nanoparticles-based antiviral formulations and nanoparticles-based adjuvant vaccines. The mechanism of action of these nanoparticles-based antivirals against animal coronavirus is also discussed using relevant examples. In addition, the scope of repurposing the existing nano-enabled antivirals and vaccines to combat the coronavirus infections in animals is elaborated.

Prevalence and molecular characteristics of feline coronavirus in southwest China from 2017 to 2020

Feline coronavirus (FCoV) is the causative agent of feline infectious peritonitis and diarrhoea in kittens worldwide. In this study, a total of 173 feline diarrhoeal faecal and ascetic samples were collected from 15 catteries and six veterinary hospitals in southwest China from 2017 to 2020. FCoV was detected in 80.35 % (139/173) of the samples using the RT-nPCR method; these included infections with 122 type I FCoV and 57 type II FCoV. Interestingly, 51 cases had co-infection with types I and II, the first such report in mainland China. To further analyse the genetic diversity of FCoV, we amplified 23 full-length spike (S) genes, including 18 type I and five type II FCoV. The type I FCoV and type II FCoV strains shared 85.5-98.7% and 97.4-98.9% nucleotide (nt) sequence identities between one another, respectively. The N-terminal domain (NTD) of 23 FCoV strains showed a high degree of variation (73.6-80.3 %). There was six type I FCoV strains with two amino acid insertions (159HL160) in the NTD. In addition, 18 strains of type I FCoV belonged to the Ie cluster, and five strains of type II FCoV were in the IIb cluster based on phylogenetic analysis. Notably, it was first time that two type I FCoV strains had recombination in the NTD, and the recombination regions was located 140-857 nt of the S gene. This study constitutes a systematic investigation of the current infection status and molecular characteristics of FCoV in southwest China.

Coronavirus disease 2019 and its potential animal reservoirs: A review

In the 21st century, the world has been plagued by coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a virus of the family Coronaviridae epidemiologically suspected to be linked to a wet market in Wuhan, China. The involvement of wildlife and wet markets with the previous outbreaks simultaneously has been brought into sharp focus. Although scientists are yet to ascertain the host range and zoonotic potential of SARS-CoV-2 rigorously, information about its two ancestors, SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV), is a footprint for research on COVID-19. A 96% genetic similarity with bat coronaviruses and SARS-CoV-2 indicates that the bat might be a potential reservoir of SARS-CoV-2 just like SARS-CoV and MERS-CoV, where civets and dromedary camels are considered the potential intermediate host, respectively. Perceiving the genetic similarity between pangolin coronavirus and SARS-CoV-2, many scientists also have given the scheme that the pangolin might be the intermediate host. The involvement of SARS-CoV-2 with other animals, such as mink, snake, and turtle has also been highlighted in different research articles based on the interaction between the key amino acids of S protein in the receptor-binding domain and angiotensin-converting enzyme II (ACE2). This study highlights the potential animal reservoirs of SARS-CoV-2 and the role of wildlife in the COVID-19 pandemic. Although different causes, such as recurring viral genome recombination, wide genetic assortment, and irksome food habits, have been blamed for this emergence, basic research studies and literature reviews indicate an enormous consortium between humans and animals for the COVID-19 pandemic.

The Gut Viral Metagenome Analysis of Domestic Dogs Captures Snapshot of Viral Diversity and Potential Risk of Coronavirus

The close relations between dogs (Canis lupus familiaris) and humans lay a foundation for cross species transmissions of viruses. The co-existence of multiplex viruses in the host accelerate viral variations. For effective prediction and prevention of potential epidemic or even pandemic, the metagenomics method was used to investigate the gut virome status of 45 domestic healthy dogs which have extensive contact with human beings. A total of 248.6 GB data (505, 203, 006 valid reads, 150 bp in length) were generated and 325, 339 contigs, which were best matched with viral genes, were assembled from 46, 832, 838 reads. In the aggregate, 9,834 contigs (3.02%) were confirmed for viruses. The top 30 contigs with the most reads abundance were mapped to DNA virus families Circoviridae, Parvoviridae and Herpesviridae; and RNA virus families Astroviridae, Coronaviridae and Picornaviridae, respectively. Numerous sequences were assigned to animal virus families of Astroviridae, Coronaviridae, Circoviridae, etc.; and phage families of Microviridae, Siphoviridae, Ackermannviridae, Podoviridae, Myoviridae and the unclassified phages. Further, several sequences were homologous with the insect and plant viruses, which reflects the diet and habitation of dogs. Significantly, canine coronavirus was uniquely identified in all the samples with high abundance, and the phylogenetic analysis therefore showed close relationship with the human coronavirus strain 229E and NL63, indicating the potential risk of canine coronavirus to infect humans by obtaining the ability of cross-species transmission. This study emphasizes the high detection frequency of virus harbored in the enteric tract of healthy contacted animal, and expands the knowledge of the viral diversity and the spectrum for further disease-association studies, which is meaningful for elucidating the epidemiological and biological role of companion animals in public health.

Applied Proteomics in 'One Health'

‘One Health’ summarises the idea that human health and animal health are interdependent and bound to the health of ecosystems. The purpose of proteomics methodologies and studies is to determine proteins present in samples of interest and to quantify changes in protein expression during pathological conditions. The objectives of this paper are to review the application of proteomics technologies within the One Health concept and to appraise their role in the elucidation of diseases and situations relevant to One Health. The paper develops in three sections. Proteomics Applications in Zoonotic Infections part discusses proteomics applications in zoonotic infections and explores the use of proteomics for studying pathogenetic pathways, transmission dynamics, diagnostic biomarkers and novel vaccines in prion, viral, bacterial, protozoan and metazoan zoonotic infections. Proteomics Applications in Antibiotic Resistance part discusses proteomics applications in mechanisms of resistance development and discovery of novel treatments for antibiotic resistance. Proteomics Applications in Food Safety part discusses the detection of allergens, exposure of adulteration, identification of pathogens and toxins, study of product traits and characterisation of proteins in food safety. Sensitive analysis of proteins, including low-abundant ones in complex biological samples, will be achieved in the future, thus enabling implementation of targeted proteomics in clinical settings, shedding light on biomarker research and promoting the One Health concept.

The spike glycoprotein genes of porcine epidemic diarrhea viruses isolated in China

The porcine epidemic diarrhea virus (PEDV) causes a highly contagious disease in pigs, which is one of the most devastating viral diseases of swine in the world. In China, PEDV was first confirmed in 1984 and PEDV infections occurred sporadically from 1984 to early 2010. From late 2010 until present, PEDV infections have swept every province or region in China. In this study, we analyzed a total of 186 full-length spike genes and deduced proteins of all available complete genomes of PEDVs isolated in China during 2007–2019. A total of 28 potential recombination events were identified in the spike genes of PEDVs in China. Spike gene recombination not only expanded the genetic diversity of PEDVs in the GII genogroup, but also resulted in the emergence of a new evolutional branch GI-c during 2016–2018. In addition, comparative analysis of spike proteins between GI-a prototype virulent CV777 and GII strain AJ1102 reveals that the amino acid variations could affect 20 potential linear B cell epitopes, demonstrating a dramatic antigen drift in the spike protein. These results provide a thorough view of the information about the genetic and antigenic diversity of PEDVs circulating in China and therefore could benefit the development of suitable strategies for disease control.

Molecular biology of the SARs-CoV-2 spike protein: A review of current knowledge

The global coronavirus disease 2019 (COVID‐19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has led to an unprecedented worldwide public health emergency. Despite the concerted efforts of the scientific field, by April 25, 2021, SARS‐CoV‐2 had spread to over 192 countries/regions, causing more than 146 million confirmed cases including 31 million deaths. For now, an established treatment for patients with COVID‐19 remains unavailable. The key to tackling this pandemic is to understand the mechanisms underlying its infectivity and pathogenicity. As a predominant focus, the coronavirus spike (S) protein is the key determinant of host range, infectivity, and pathogenesis. Thereby comprehensive understanding of the sophisticated structure of SARS‐CoV‐2 S protein may provide insights into possible intervention strategies to fight this ongoing global pandemic. Herein, we summarize the current knowledge of the molecular structural and functional features of SARS‐CoV‐2 S protein as well as recent updates on the cell entry mechanism of the SARS‐CoV‐2, paving the way for exploring more structure‐guided strategies against SARS‐CoV‐2.

Amachawadi R, Dash AP, Yadav MP, Prasad KS, P S, Jain AS, Shivamallu C. COVID-19 PANDEMIC: A SYSTEMATIC REVIEW ON THE CORONAVIRUSES OF ANIMALS AND SARS-CoV-2

Coronaviruses (CoVs), classified into four genera, viz., alpha-, beta-, gamma-, and Delta- CoV, represent an important group of diverse transboundary pathogens that can infect a variety of mammalian and avian species including humans, animals, poultry, and non-poultry birds. CoVs primarily infect lung and gut epithelial cells, besides monocytes and macrophages. CoVs have high mutation rates causing changes in host specificity, tissue tropism, and mode of virus excretion and transmissions. The recent CoV zoonoses are SARS, MERS, and COVID-19 that are caused by the transmission of beta-CoVs of bats to humans. Recently, reverse zoonoses of the COVID-19 virus have been detected in dogs, tigers, and minks. Beta-CoV strains also infect bovine (BCoV) and canine species (CRCoV); both these beta-CoVs might have originated from a common ancestor. Despite the high genetic similarity between BCoV, CRCoV, and HCoV-OC43, these differ in species specificity. Alpha-CoV strains infect canine (CCoV), feline (FIPV), swine (TGEV and PEDV), and humans (HCoV229E and NL63). Six coronavirus species are known to infect and cause disease in pigs, seven in human beings, and two in dogs. The high mutation rate in CoVs is attributed to error-prone 3′-5′ exoribonuclease (NSP 14), and genetic recombination to template shift by the polymerase. The present compilation describes the important features of the CoVs and diseases caused in humans, animals, and birds that are essential in surveillance of diverse pool of CoVs circulating in nature, and monitoring interspecies transmission, zoonoses, and reverse zoonoses.

Genome-wide comparison of coronaviruses derived from veterinary animals: A canine and feline perspective

Feline- and canine-derived coronaviruses (FCoVs and CCoVs) are widespread among dog and cat populations. This study was to understand the route of disease origin and viral transmission in veterinary animals and in human through comparative pan-genomic analysis of coronavirus sequences, especially retrieved from genomes of FCoV and CCoV. Average nucleotide identity based on complete genomes might clustered CoV strains according to their infected host, with an exception of type II of CCoV (accession number KC175339) that was clustered closely to virulent FCoVs. In contrast, the hierarchical clustering based on gene repertories retrieved from pan-genome analysis might divided the examined coronaviruses into host-independent clusters, and formed obviously the cluster of Alphacoronaviruses into sub-clusters of feline-canine, only feline, feline-canine-human coronavirus. Also, functional analysis of genomic subsets might help to divide FCoV and CCoV pan-genomes into (i) clusters of core genes encoding spike, membrane, nucleocapsid proteins, and ORF1ab polyprotein; (ii) clusters of core-like genes encoding nonstructural proteins; (iii) clusters of accessory genes encoding the ORF1A; and (iv) two singleton genes encoding nonstructural protein and polyprotein 1ab. Seven clusters of gene repertories were categorized as common to the FCoV and/or CCoV genomes including pantropic and high virulent strains, illustrating that distinct core-like genes/accessory genes concerning to their pathogenicity should be exploited in further biotype analysis of new isolate. In conclusion, the phylogenomic analyses have allowed the identification of trends in the viral genomic data, especially in developing a specific control measures against coronavirus disease, such as the selection of good markers for differentiating new species from common and/or pantropic isolates.

Animal Reservoirs and Hosts for Emerging Alphacoronaviruses and Betacoronaviruses

The ongoing global pandemic caused by coronavirus disease has once again demonstrated the role of the family Coronaviridae in causing human disease outbreaks. Because severe acute respiratory syndrome coronavirus 2 was first detected in December 2019, information on its tropism, host range, and clinical manifestations in animals is limited. Given the limited information, data from other coronaviruses might be useful for informing scientific inquiry, risk assessment, and decision-making. We reviewed endemic and emerging infections of alphacoronaviruses and betacoronaviruses in wildlife, livestock, and companion animals and provide information on the receptor use, known hosts, and clinical signs associated with each host for 15 coronaviruses detected in humans and animals. This information can be used to guide implementation of a One Health approach that involves human health, animal health, environmental, and other relevant partners in developing strategies for preparedness, response, and control to current and future coronavirus disease threats.

Clinical and molecular aspects of veterinary coronaviruses

Coronaviruses are a large group of RNA viruses that infect a wide range of animal species. The replication strategy of coronaviruses involves recombination and mutation events that lead to the possibility of cross-species transmission. The high plasticity of the viral receptor due to a continuous modification of the host species habitat may be the cause of cross-species transmission that can turn into a threat to other species including the human population. The successive emergence of highly pathogenic coronaviruses such as the Severe Acute Respiratory Syndrome (SARS) in 2003, the Middle East Respiratory Syndrome Coronavirus in 2012, and the recent SARS-CoV-2 has incentivized a number of studies on the molecular basis of the coronavirus and its pathogenesis. The high degree of interrelatedness between humans and wild and domestic animals and the modification of animal habitats by human urbanization, has favored new viral spreads. Hence, knowledge on the main clinical signs of coronavirus infection in the different hosts and the distinctive molecular characteristics of each coronavirus is essential to prevent the emergence of new coronavirus diseases. The coronavirus infections routinely studied in veterinary medicine must be properly recognized and diagnosed not only to prevent animal disease but also to promote public health.

Molecular survey of parvovirus, astrovirus, coronavirus, and calicivirus in symptomatic dogs

Gastrointestinal disorders caused by enteric viruses are frequently reported in dogs worldwide, with significant mortality rates in unvaccinated individuals. This study reports the identification and molecular characterization of Canine parvovirus (CPV-2), Canine coronavirus (CcoV), Canine astrovirus (AstV), and Canine calicivirus (CcaV) in a panel of dogs showing severe enteric clinical signs sampled in a typical Mediterranean environment (Sardinia, Italy). At least one of these viral species was detected in 92.3% samples. CPV-2 was the most frequently detected virus (87.2%), followed by AsTv (20.5%), CCoV-IIa (18%), and CCoV-I (10.3%). CCoV-IIb and CaCV were not detected in any sample. Single infection was detected in 24 samples (66.7%), mainly related to CPV-2 (91.7%). Coinfections were present in 33.3% samples with constant detection of CPV-2. Canine coronavirus was present only in coinfected animals. The VP2 sequence analysis of CPV-2 positive samples confirmed the presence of all variants, with CPV-2b most frequently detected. Phylogeny based on the CcoV-IIa spike protein (S) gene allowed to identify 2 different clades among Sardinian isolates but failed to distinguish enteric from pantropic viruses. Study on presence and prevalence of enteroviruses in dogs increase our knowledge about the circulation of these pathogens in the Mediterranean area and highlight the need for dedicated routine vaccine prophylaxis. Molecular analyses of enteric viruses are fundamental to avoid failure of vaccines caused by frequent mutations observed in these enteroviruses.

COVID-19: animals, veterinary and zoonotic links

Coronavirus disease 2019 (COVID-19), has spread over 210 countries and territories beyond China shortly. On February 29, 2020, the World Health Organization (WHO) denoted it in a high-risk category, and on March 11, 2020, this virus was designated pandemic, after its declaration being a Public Health International Emergency on January 30, 2020. World over high efforts are being made to counter and contain this virus. The COVID-19 outbreak once again proves the potential of the animal-human interface to act as the primary source of emerging zoonotic diseases. Even though the circumstantial evidence suggests the possibility of an initial zoonotic emergence, it is too early to confirm the role of intermediate hosts such as snakes, pangolins, turtles, and other wild animals in the origin of SARS-CoV-2, in addition to bats, the natural hosts of multiple coronaviruses such as SARS-CoV and MERS-CoV. The lessons learned from past episodes of MERS-CoV and SARS-CoV are being exploited to retort this virus. Best efforts are being taken up by worldwide nations to implement effective diagnosis, strict vigilance, heightened surveillance, and monitoring, along with adopting appropriate preventive and control strategies. Identifying the possible zoonotic emergence and the exact mechanism responsible for its initial transmission will help us to design and implement appropriate preventive barriers against the further transmission of SARS-CoV-2. This review discusses in brief about the COVID-19/SARS-CoV-2 with a particular focus on the role of animals, the veterinary and associated zoonotic links along with prevention and control strategies based on One-health approaches.

Feline infectious peritonitis (FIP) and coronavirus disease 19 (COVID-19): Are they similar?

SARS‐CoV‐2 has radically changed our lives causing hundreds of thousands of victims worldwide and influencing our lifestyle and habits. Feline infectious peritonitis (FIP) is a disease of felids caused by the feline coronaviruses (FCoV). FIP has been considered irremediably deadly until the last few years. Being one of the numerous coronaviruses that are well known in veterinary medicine, information on FCoV could be of interest and might give suggestions on pathogenic aspects of SARS‐CoV‐2 that are still unclear. The authors of this paper describe the most important aspects of FIP and COVID‐19 and the similarities and differences between these important diseases. SARS‐CoV‐2 and FCoV are taxonomically distant viruses, and recombination events with other coronaviruses have been reported for FCoV and have been suggested for SARS‐CoV‐2. SARS‐CoV‐2 and FCoV differ in terms of some pathogenic, clinical and pathological features. However, some of the pathogenic and immunopathogenic events that are well known in cats FIP seem to be present also in people with COVID‐19. Moreover, preventive measures currently recommended to prevent SARS‐CoV‐2 spreading have been shown to allow eradication of FIP in feline households. Finally, one of the most promising therapeutic compounds against FIP, GS‐441524, is the active form of Remdesivir, which is being used as one therapeutic option for COVID‐19.

Coronaviruses and gastrointestinal diseases

The effects of coronaviruses on the respiratory system are of great concern, but their effects on the digestive system receive much less attention. Coronaviruses that infect mammals have shown gastrointestinal pathogenicity and caused symptoms such as diarrhea and vomiting. Available data have shown that human coronaviruses, including the newly emerged SARS-CoV-2, mainly infect the respiratory system and cause symptoms such as cough and fever, while they may generate gastrointestinal symptoms. However, there is little about the relation between coronavirus and digestive system. This review specifically addresses the effects of mammalian and human coronaviruses, including SARS-CoV-2, on the digestive tract, helping to cope with the new virus infection-induced disease, COVID-19.

Animal coronaviruses and coronavirus disease 2019: Lesson for One Health approach

Coronaviruses are a group of enveloped, single-stranded, positive-sense RNA viruses that are broadly classified into alpha, beta, gamma, and delta coronavirus genera based on the viral genome. Coronavirus was not thought to be a significant problem in humans until the outbreak of severe acute respiratory syndrome in 2002, but infections in animals, including pigs, cats, dogs, and poultry, have been problematic for a long time. The outbreak of coronavirus disease 2019 in December 2019 in Wuhan, China, drew special attention towards this virus once again. The intermediate host of this novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is yet to be determined, but it has a very close genomic relationship with the bat coronavirus (Bat-CoV), RaTG13 strain, and the pangolin coronaviruses. As veterinary medicine has a long-term experience dealing with coronaviruses, this could be helpful in better understanding and detecting the origin of SARS-CoV-2 and drive human medicine towards the development of vaccines and antiviral drugs through the collaborative and transdisciplinary approaches of One Health.

Coronavirus Disease 2019-COVID-19

SUMMARYIn recent decades, several new diseases have emerged in different geographical areas, with pathogens including Ebola virus, Zika virus, Nipah virus, and coronaviruses (CoVs). Recently, a new type of viral infection emerged in Wuhan City, China, and initial genomic sequencing data of this virus do not match with previously sequenced CoVs, suggesting a novel CoV strain (2019-nCoV), which has now been termed severe acute respiratory syndrome CoV-2 (SARS-CoV-2). Although coronavirus disease 2019 (COVID-19) is suspected to originate from an animal host (zoonotic origin) followed by human-to-human transmission, the possibility of other routes should not be ruled out. Compared to diseases caused by previously known human CoVs, COVID-19 shows less severe pathogenesis but higher transmission competence, as is evident from the continuously increasing number of confirmed cases globally. Compared to other emerging viruses, such as Ebola virus, avian H7N9, SARS-CoV, and Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV-2 has shown relatively low pathogenicity and moderate transmissibility. Codon usage studies suggest that this novel virus has been transferred from an animal source, such as bats. Early diagnosis by real-time PCR and next-generation sequencing has facilitated the identification of the pathogen at an early stage. Since no antiviral drug or vaccine exists to treat or prevent SARS-CoV-2, potential therapeutic strategies that are currently being evaluated predominantly stem from previous experience with treating SARS-CoV, MERS-CoV, and other emerging viral diseases. In this review, we address epidemiological, diagnostic, clinical, and therapeutic aspects, including perspectives of vaccines and preventive measures that have already been globally recommended to counter this pandemic virus.