SARS-CoV-2 infection in farmed minks, the Netherlands, April and May 2020

Original Hosts, Clinical Features, Transmission Routes, and Vaccine Development for Coronavirus Disease (COVID-19)

The pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to public concern worldwide. Although a variety of hypotheses about the hosts of SARS-CoV-2 have been proposed, an exact conclusion has not yet been reached. Initial clinical manifestations associated with COVID-19 are similar to those of other acute respiratory infections, leading to misdiagnoses and resulting in the outbreak at the early stage. SARS-CoV-2 is predominantly spread by droplet transmission and close contact; the possibilities of fecal-oral, vertical, and aerosol transmission have not yet been fully confirmed or rejected. Besides, COVID-19 cases have been reported within communities, households, and nosocomial settings through contact with confirmed COVID-19 patients or asymptomatic individuals. Environmental contamination is also a major driver for the COVID-19 pandemic. Considering the absence of specific treatment for COVID-19, it is urgent to decrease the risk of transmission and take preventive measures to control the spread of the virus. In this review, we summarize the latest available data on the potential hosts, entry receptors, clinical features, and risk factors of COVID-19 and transmission routes of SARS-CoV-2, and we present the data about development of vaccines.

Multi-species ELISA for the detection of antibodies against SARS-CoV-2 in animals

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic with millions of infected humans and hundreds of thousands of fatalities. As the novel disease - referred to as COVID-19 - unfolded, occasional anthropozoonotic infections of animals by owners or caretakers were reported in dogs, felid species and farmed mink. Further species were shown to be susceptible under experimental conditions. The extent of natural infections of animals, however, is still largely unknown. Serological methods will be useful tools for tracing SARS-CoV-2 infections in animals once test systems are evaluated for use in different species. Here, we developed an indirect multi-species ELISA based on the receptor-binding domain (RBD) of SARS-CoV-2. The newly established ELISA was evaluated using 59 sera of infected or vaccinated animals, including ferrets, raccoon dogs, hamsters, rabbits, chickens, cattle and a cat, and a total of 220 antibody-negative sera of the same animal species. Overall, a diagnostic specificity of 100.0% and sensitivity of 98.31% were achieved, and the functionality with every species included in this study could be demonstrated. Hence, a versatile and reliable ELISA protocol was established that enables high-throughput antibody detection in a broad range of animal species, which may be used for outbreak investigations, to assess the seroprevalence in susceptible species or to screen for reservoir or intermediate hosts.

Testing at scale during the COVID-19 pandemic

Assembly and publication of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome in January 2020 enabled the immediate development of tests to detect the new virus. This began the largest global testing programme in history, in which hundreds of millions of individuals have been tested to date. The unprecedented scale of testing has driven innovation in the strategies, technologies and concepts that govern testing in public health. This Review describes the changing role of testing during the COVID-19 pandemic, including the use of genomic surveillance to track SARS-CoV-2 transmission around the world, the use of contact tracing to contain disease outbreaks and testing for the presence of the virus circulating in the environment. Despite these efforts, widespread community transmission has become entrenched in many countries and has required the testing of populations to identify and isolate infected individuals, many of whom are asymptomatic. The diagnostic and epidemiological principles that underpin such population-scale testing are also considered, as are the high-throughput and point-of-care technologies that make testing feasible on a massive scale.

Aleutian mink disease: Spatio-temporal variation of prevalence and influence on the feral American mink

Pathogens are one of the factors driving wildlife population dynamics. The spread of pathogens in wildlife is currently highly related to the transmission of pathogens from farmed animals, which has increased with the constant development of farming. Here, we analysed the spatio-temporal variation in the prevalence of Aleutian mink disease virus (AMDV) antibodies in feral American mink (Neovison vison) populations in Poland (1,153 individuals from nine sites) in relation to mink farming intensity. AMDV was detected in feral mink at all study sites and the prevalence ranged from 0.461 in the northern region to 0.826 in the western region. Mink males and adults were infected more often than females and subadults; the infection was also more frequent during the mink breeding season than during non-breeding. The prevalence of AMDV changed non-linearly in consecutive years and the peak of prevalence was every 3-4 years. The predicted AMDV prevalence was low at sites where the number of farmed mink was also low and increased linearly with the increase in the number of mink kept on farms. The predicted AMDV prevalence at sites with low mink farming intensity strongly varied between years, whereas at sites with high mink farming intensity, the predicted prevalence did not change significantly. AMDV infection affected the mink's body condition and caused an increase in the size of the spleen, liver and kidneys. This study shows that Aleutian mink disease strongly affects feral mink but the spatio-temporal variation of its prevalence is complex and partly related to the transmission of the virus from farmed mink to feral populations. The study highlights the complexity of AMDV circulation in feral mink populations and implicates a potential spillover of the virus to native species.

Potential zoonotic sources of SARS-CoV-2 infections

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causing coronavirus disease-2019 (COVID-19) likely has evolutionary origins in other animals than humans based on genetically related viruses existing in rhinolophid bats and pangolins. Similar to other animal coronaviruses, SARS-CoV-2 contains a functional furin cleavage site in its spike protein, which may broaden the SARS-CoV-2 host range and affect pathogenesis. Whether ongoing zoonotic infections are possible in addition to efficient human-to-human transmission remains unclear. In contrast, human-to-animal transmission can occur based on evidence provided from natural and experimental settings. Carnivores, including domestic cats, ferrets and minks, appear to be particularly susceptible to SARS-CoV-2 in contrast to poultry and other animals reared as livestock such as cattle and swine. Epidemiologic evidence supported by genomic sequencing corroborated mink-to-human transmission events in farm settings. Airborne transmission of SARS-CoV-2 between experimentally infected cats additionally substantiates the possibility of cat-to-human transmission. To evaluate the COVID-19 risk represented by domestic and farmed carnivores, experimental assessments should include surveillance and health assessment of domestic and farmed carnivores, characterization of the immune interplay between SARS-CoV-2 and carnivore coronaviruses, determination of the SARS-CoV-2 host range beyond carnivores and identification of human risk groups such as veterinarians and farm workers. Strategies to mitigate the risk of zoonotic SARS-CoV-2 infections may have to be developed in a One Health framework and non-pharmaceutical interventions may have to consider free-roaming animals and the animal farming industry.

Review: SARS-CoV-2 infection in farmed minks - an overview of current knowledge on occurrence, disease and epidemiology

Coronaviruses (CoVs), which are enveloped, positive-sense RNA viruses, may cause infections in mammals and birds. Apart from the respiratory manifestations, CoVs are also responsible for infections of the gastrointestinal tract and nervous systems. Their propensity to recombine allows them to easily transmit and adapt to new hosts. The emergence of a new CoV in humans, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is attributed to a zoonotic origin, has provoked numerous studies to assess its pathogenicity for different animal species (pets, farm and wild animals). Available results indicate that numerous animal species are susceptible to infection with SARS-CoV-2. From April 2020, when the first SARS-CoV-2 infection in minks was reported in the Netherlands, to the end of January 2021, further outbreaks have been confirmed in Denmark, Italy, Spain, Sweden, the United States, Greece, France, Canada, Lithuania and Poland. It has also been established that human-to-minks and minks-to-human transmission may occur. The results obtained to date indicate that the virus was originally introduced into the minks population by humans, possibly at the start of the pandemic and had been circulating in the population for several weeks before detection. Recent data indicate that minks are highly susceptible to SARS-CoV-2 infection, but the route or routes of virus transmission between farms, other than by direct contact with infected humans, have not been identified. In minks, infection can occur in clinical and subclinical form, making it possibly difficult to detect. Therefore, minks could represent potentially dangerous, not always recognized, animal reservoir for SARS-CoV-2. The current data indicate that further studies on minks and other Mustelidae are needed to clarify whether they may be a potential reservoir for SARS-CoV-2, and if so, how and whether this can be prevented.

Predicted occurrence, ecotoxicological risk and environmentally acquired resistance of antiviral drugs associated with COVID-19 in environmental waters

Antiviral drugs have been used to treat the ever-growing number of coronavirus disease, 2019 (COVID-19) patients. Consequently, unprecedented amounts of such drug residues discharging into ambient waters raise concerns on the potential ecotoxicological effects to aquatic lives, as well as development of antiviral drug-resistance in wildlife. Here, we estimated the occurrence, fate and ecotoxicological risk of 11 therapeutic agents suggested as drugs for COVID-19 treatment and their 13 metabolites in wastewater and environmental waters, based on drug consumption, physical-chemical property, and ecotoxicological and pharmacological data for the drugs, with the aid of quantitative structure-activity relationship (QSAR) modelling. Our results suggest that the removal efficiencies at conventional wastewater treatment plants will remain low (<20%) for half of the substances, and consequently, high drug residues (e.g. 7402 ng/L ribavirin, 4231 ng/L favipiravir, 730 ng/L lopinavir, 319 ng/L remdesivir; each combined for both unchanged forms and metabolites; and when each drug is administered to 100 patients out of 100,000 populations on a day) can be present in secondary effluents and persist in the environmental waters. Ecotoxicological risk in receiving river waters can be high (risk quotient >1) by a use of favipiravir, lopinavir, umifenovir and ritonavir, and medium (risk quotient >0.1) by a use of chloroquine, hydroxychloroquine, remdesivir, and ribavirin, while the risk will remain low (risk quotient <0.1) for dexamethasone and oseltamivir. The potential of wild animals acquiring antiviral drug resistance was estimated to be low. Our prediction suggests a pressing need for proper usage and waste management of antiviral drugs as well as for improving removal efficiencies of drug residues in wastewater.

Severe acute respiratory syndrome coronavirus-2 natural animal reservoirs and experimental models: systematic review

The current severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) outbreak has been rapidly spreading worldwide, causing serious global concern. The role that animal hosts play in disease transmission is still understudied and researchers wish to find suitable animal models for fundamental research and drug discovery. In this systematic review, we aimed to compile and discuss all articles that describe experimental or natural infections with SARS-CoV-2, from the initial discovery of the virus in December 2019 through to October 2020. We systematically searched four databases (Scopus, PubMed, Science Direct and Web of Science). The following data were extracted from the included studies: type of infection (natural or experimental), age, sample numbers, dose, route of inoculation, viral replication, detection method, clinical symptoms and transmission. Fifty-four studies were included, of which 34 were conducted on animal reservoirs (naturally or experimentally infected), and 20 involved models for testing vaccines and therapeutics. Our search revealed that Rousettus aegyptiacus (fruit bats), pangolins, felines, mink, ferrets and rabbits were all susceptible to SARS-CoV-2, while dogs were weakly susceptible and pigs, poultry, and tree shrews were not. In addition, virus replication in mice, mink, hamsters and ferrets resembled subclinical human infection, so these animals might serve as useful models for future studies to evaluate vaccines or antiviral agents and to study host-pathogen interactions. Our review comprehensively summarized current evidence on SARS-CoV-2 infection in animals and their usefulness as models for studying vaccines and antiviral drugs. Our findings may direct future studies for vaccine development, antiviral drugs and therapeutic agents to manage SARS-CoV-2-caused diseases.

Susceptibility of Well-Differentiated Airway Epithelial Cell Cultures from Domestic and Wild Animals to Severe Acute Respiratory Syndrome Coronavirus 2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally, and the number of worldwide cases continues to rise. The zoonotic origins of SARS-CoV-2 and its intermediate and potential spillback host reservoirs, besides humans, remain largely unknown. Because of ethical and experimental constraints and more important, to reduce and refine animal experimentation, we used our repository of well-differentiated airway epithelial cell (AEC) cultures from various domesticated and wildlife animal species to assess their susceptibility to SARS-CoV-2. We observed that SARS-CoV-2 replicated efficiently only in monkey and cat AEC culture models. Whole-genome sequencing of progeny viruses revealed no obvious signs of nucleotide transitions required for SARS-CoV-2 to productively infect monkey and cat AEC cultures. Our findings, together with previous reports of human-to-animal spillover events, warrant close surveillance to determine the potential role of cats, monkeys, and closely related species as spillback reservoirs for SARS-CoV-2.

The Precautionary Principle in Zoonotic Disease Control

The COVID-19 pandemic has shown that zoonotic diseases are a great threat for humanity. During the course of such a pandemic, public health authorities often apply the precautionary principle to justify disease control measures. However, evoking this principle is not without ethical implications. Especially within a One Health strategy, that requires us to balance public health benefits against the health interests of animals and the environment, unrestricted use of the precautionary principle can lead to moral dilemmas. In this article, we analyze the ethical dimensions of the use of the precautionary principle in zoonotic disease control and formulate criteria to protect animals and the environment against one-sided interpretations. Furthermore, we distinguish two possible conceptions of the precautionary principle. First, we notice that because of the unpredictable nature of zoonotic diseases, public health authorities in general focus on the idea of precaution as preparedness. This reactive response often leads to difficult trade-offs between human and animal health. We therefore argue that this policy should always be accompanied by a second policy, that we refer to as precaution as prevention. Although zoonotic diseases are part of our natural world, we have to acknowledge that their origin and global impact are often a consequence of our disturbed relation with animals and the environment.

SARS-CoV-2 and hypertension

The objective of this review is to give an overview of the pathophysiological effects of the Coronavirus Disease 2019 (COVID-19) in relation to hypertension (HT), with a focus on the Renin-Angiotensin-Aldosterone System (RAAS) and the MAS receptor. HT is a multifactorial disease and a public health burden, as it is a risk factor for diseases like stroke, coronary artery disease, and heart failure, leading to 10.4 million deaths yearly. Blood pressure is regulated by the RAAS. The system consists of two counter-regulatory axes: ACE/ANG-II/AT₁ R and ACE2/ANG-(1-7)/MAS. The main regulatory protein in balancing the RAAS is angiotensin-converting enzyme 2 (ACE2). The protein also functions as the main mediator of endocytosis of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the host cell. SARS-CoV-2 is the cause of COVID-19 and has caused a worldwide pandemic; however, the treatment and prophylaxis of COVID-19 are limited. Several drugs and vaccines are currently being tested in clinical trials with a few already approved by EMA and FDA. HT is a major risk factor regarding the severity and fatality of COVID-19, and the RAAS plays an important role in COVID-19 infection since SARS-CoV-2 can lead to a dysregulation of the system by reducing the ACE2 expression. The exact mechanisms of HT in relation to COVID-19 remain uncertain, and more research is needed for further elucidation.

Predicting the zoonotic capacity of mammals to transmit SARS-CoV-2

Back and forth transmission of SARS-CoV-2 between humans and animals may lead to wild reservoirs of virus that can endanger efforts toward long-term control of COVID-19 in people, and protecting vulnerable animal populations that are particularly susceptible to lethal disease. Predicting high risk host species is key to targeting field surveillance and lab experiments that validate host zoonotic potential. A major bottleneck to predicting animal hosts is the small number of species with available molecular information about the structure of ACE2, a key cellular receptor required for viral cell entry. We overcome this bottleneck by combining species' ecological and biological traits with 3D modeling of virus and host cell protein interactions using machine learning methods. This approach enables predictions about the zoonotic capacity of SARS-CoV-2 for over 5,000 mammals - an order of magnitude more species than previously possible. The high accuracy predictions achieved by this approach are strongly corroborated by in vivo empirical studies. We identify numerous common mammal species whose predicted zoonotic capacity and close proximity to humans may further enhance the risk of spillover and spillback transmission of SARS-CoV-2. Our results reveal high priority areas of geographic overlap between global COVID-19 hotspots and potential new mammal hosts of SARS-CoV-2. With molecular sequence data available for only a small fraction of potential host species, predictive modeling integrating data across multiple biological scales offers a conceptual advance that may expand our predictive capacity for zoonotic viruses with similarly unknown and potentially broad host ranges.

In vitro Characterization of Fitness and Convalescent Antibody Neutralization of SARS-CoV-2 Cluster 5 Variant Emerging in Mink at Danish Farms

In addition to humans, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can transmit to animals that include hamsters, cats, dogs, mink, ferrets, tigers, lions, cynomolgus macaques, rhesus macaques, and treeshrew. Among these, mink are particularly susceptible. Indeed, 10 countries in Europe and North America reported SARS-CoV-2 infection among mink on fur farms. In Denmark, SARS-CoV-2 spread rapidly among mink farms and spilled-over back into humans, acquiring mutations/deletions with unknown consequences for virulence and antigenicity. Here we describe a mink-associated SARS-CoV-2 variant (Cluster 5) characterized by 11 amino acid substitutions and four amino acid deletions relative to Wuhan-Hu-1. Temporal virus titration, together with genomic and subgenomic viral RNA quantitation, demonstrated a modest in vitro fitness attenuation of the Cluster 5 virus in the Vero-E6 cell line. Potential alterations in antigenicity conferred by amino acid changes in the spike protein that include three substitutions (Y453F, I692V, and M1229I) and a loss of two amino acid residues 69 and 70 (ΔH69/V70), were evaluated in a virus microneutralization assay. Compared to a reference strain, the Cluster 5 variant showed reduced neutralization in a proportion of convalescent human COVID-19 samples. The findings underscore the need for active surveillance SARS-CoV-2 infection and virus evolution in susceptible animal hosts.

The zoonotic and natural foci characteristics of SARS-CoV-2

The origin of SARS-CoV-2 is still an unresolved mystery. In this study, we systematically reviewed the main research progress of wild animals carrying virus highly homologous to SARS-CoV-2 and analyzed the natural foci characteristics of SARS-CoV-2. The complexity of SARS-CoV-2 origin in wild animals and the possibility of SARS-CoV-2 long-term existence in human populations are also discussed. The joint investigation of corona virus carried by wildlife, as well as the ecology and patho-ecology of bats and other wildlife, are key measures to further clarify the characteristics of natural foci of SARS-CoV-2 and actively defend against future outbreaks of emerging zoonotic diseases.

Heparan Sulfate Proteoglycans as Attachment Factor for SARS-CoV-2

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) is causing an unprecedented global pandemic demanding the urgent development of therapeutic strategies. Microarray binding experiments, using an extensive heparan sulfate (HS) oligosaccharide library, showed that the receptor binding domain (RBD) of the spike of SARS-CoV-2 can bind HS in a length- and sequence-dependent manner. A hexasaccharide composed of IdoA2S-GlcNS6S repeating units was identified as the minimal binding epitope. Surface plasmon resonance showed the SARS-CoV-2 spike protein binds with a much higher affinity to heparin (K D = 55 nM) compared to the RBD (K D = 1 μM) alone. It was also found that heparin does not interfere in angiotensin-converting enzyme 2 (ACE2) binding or proteolytic processing of the spike. However, exogenous administered heparin or a highly sulfated HS oligosaccharide inhibited RBD binding to cells. Furthermore, an enzymatic removal of HS proteoglycan from physiological relevant tissue resulted in a loss of RBD binding. The data support a model in which HS functions as the point of initial attachment allowing the virus to travel through the glycocalyx by low-affinity high-avidity interactions to reach the cell membrane, where it can engage with ACE2 for cell entry. Microarray binding experiments showed that ACE2 and HS can simultaneously engage with the RBD, and it is likely no dissociation between HS and RBD is required for binding to ACE2. The results highlight the potential of using HS oligosaccharides as a starting material for therapeutic agent development.

SARS-CoV-2 neutralising antibodies in Dogs and Cats in the United Kingdom

Companion animals are susceptible to SARS-CoV-2 infection and sporadic cases of pet infections have occurred in the United Kingdom. Here we present the first large-scale serological survey of SARS-CoV-2 neutralising antibodies in dogs and cats in the UK. Results are reported for 688 sera (454 canine, 234 feline) collected by a large veterinary diagnostic laboratory for routine haematology during three time periods; pre-COVID-19 (January 2020), during the first wave of UK human infections (April-May 2020) and during the second wave of UK human infections (September 2020-February 2021). Both pre-COVID-19 sera and those from the first wave tested negative. However, in sera collected during the second wave, 1.4% (n=4) of dogs and 2.2% (n=2) cats tested positive for neutralising antibodies. The low numbers of animals testing positive suggests pet animals are unlikely to be a major reservoir for human infection in the UK. However, continued surveillance of in-contact susceptible animals should be performed as part of ongoing population health surveillance initiatives.

Update on Potentially Zoonotic Viruses of European Bats

Bats have been increasingly gaining attention as potential reservoir hosts of some of the most virulent viruses known. Numerous review articles summarize bats as potential reservoir hosts of human-pathogenic zoonotic viruses. For European bats, just one review article is available that we published in 2014. The present review provides an update on the earlier article and summarizes the most important viruses found in European bats and their possible implications for Public Health. We identify the research gaps and recommend monitoring of these viruses.

Susceptibility to SARS-CoV-2 of Cell Lines and Substrates Commonly Used to Diagnose and Isolate Influenza and Other Viruses

Co-infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other viruses has been reported. We evaluated cell lines commonly used to isolate viruses and diagnose related diseases for their susceptibility to SARS-CoV-2. Although multiple kidney cell lines from monkeys were susceptible to SARS-CoV-2, we found many cell types derived from humans, dogs, minks, cats, mice, and chicken were not. We analyzed MDCK cells, which are most commonly used for surveillance and study of influenza viruses, and found that they were not susceptible to SARS-CoV-2. The low expression level of the angiotensin converting enzyme 2 receptor and lower receptor affinity to SARS-CoV-2 spike, which could be overcome by overexpression of canine angiotensin converting enzyme 2 in trans, strengthened the cellular barrier to productive infection. Moreover, a D614G mutation in the spike protein did not appear to affect SARS-CoV-2 cell tropism. Our findings should help avert inadvertent propagation of SARS-CoV-2 from diagnostic cell lines.

Serologic Screening of Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Cats and Dogs during First Coronavirus Disease Wave, the Netherlands

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect many animal species, including minks, cats, and dogs. To gain insights into SARS-CoV-2 infections in cats and dogs, we developed and validated a set of serologic assays, including ELISA and virus neutralization. Evaluation of samples from animals before they acquired coronavirus disease and samples from cats roaming SARS-CoV-2–positive mink farms confirmed the suitability of these assays for specific antibody detection. Furthermore, our findings exclude SARS-CoV-2 nucleocapsid protein as an antigen for serologic screening of cat and dog samples. We analyzed 500 serum samples from domestic cats and dogs in the Netherlands during April–May 2020. We showed 0.4% of cats and 0.2% of dogs were seropositive. Although seroprevalence in cats and dogs that had unknown SARS-CoV-2 exposure was low during the first coronavirus disease wave, our data stress the need for development of continuous serosurveillance for SARS-CoV-2 in these 2 animal species.

Current State of Knowledge about Role of Pets in Zoonotic Transmission of SARS-CoV-2

Pets play a crucial role in the development of human feelings, social life, and care. However, in the era of the prevailing global pandemic of COVID-19 disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many questions addressing the routes of the virus spread and transmission to humans are dramatically emerging. Although cases of SARS-CoV-2 infection have been found in pets including dogs, cats, and ferrets, to date there is no strong evidence for pet-to-human transmission or sustained pet-to-pet transmission of SARS-CoV-2. However, an increasing number of studies reporting detection of SARS-CoV-2 in farmed minks raises suspicion of potential viral transmission from these animals to humans. Furthermore, due to the high susceptibility of cats, ferrets, minks and hamsters to COVID-19 infection under natural and/or experimental conditions, these animals have been extensively explored as animal models to study the SARS-CoV-2 pathogenesis and transmission. In this review, we present the latest reports focusing on SARS-CoV-2 detection, isolation, and characterization in pets. Moreover, based on the current literature, we document studies aiming to broaden the knowledge about pathogenicity and transmissibility of SARS-CoV-2, and the development of viral therapeutics, drugs and vaccines. Lastly, considering the high rate of SARS-CoV-2 evolution and replication, we also suggest routes of protection against the virus.

SARS-CoV-2 infection and transmission in the North American deer mouse

Widespread circulation of SARS-CoV-2 in humans raises the theoretical risk of reverse zoonosis events with wildlife, reintroductions of SARS-CoV-2 into permissive nondomesticated animals. Here we report that North American deer mice (Peromyscus maniculatus) are susceptible to SARS-CoV-2 infection following intranasal exposure to a human isolate, resulting in viral replication in the upper and lower respiratory tract with little or no signs of disease. Further, shed infectious virus is detectable in nasal washes, oropharyngeal and rectal swabs, and viral RNA is detectable in feces and occasionally urine. We further show that deer mice are capable of transmitting SARS-CoV-2 to naïve deer mice through direct contact. The extent to which these observations may translate to wild deer mouse populations remains unclear, and the risk of reverse zoonosis and/or the potential for the establishment of Peromyscus rodents as a North American reservoir for SARS-CoV-2 remains unknown.

High-throughput quantitation of SARS-CoV-2 antibodies in a single-dilution homogeneous assay

SARS-CoV-2 emerged in late 2019 and has since spread around the world, causing a pandemic of the respiratory disease COVID-19. Detecting antibodies against the virus is an essential tool for tracking infections and developing vaccines. Such tests, primarily utilizing the enzyme-linked immunosorbent assay (ELISA) principle, can be either qualitative (reporting positive/negative results) or quantitative (reporting a value representing the quantity of specific antibodies). Quantitation is vital for determining stability or decline of antibody titers in convalescence, efficacy of different vaccination regimens, and detection of asymptomatic infections. Quantitation typically requires two-step ELISA testing, in which samples are first screened in a qualitative assay and positive samples are subsequently analyzed as a dilution series. To overcome the throughput limitations of this approach, we developed a simpler and faster system that is highly automatable and achieves quantitation in a single-dilution screening format with sensitivity and specificity comparable to those of ELISA.

Zoonotic and Reverse Zoonotic Transmissibility of SARS-CoV-2

The Coronavirus Disease 2019 (COVID-19) is the first known pandemic caused by a coronavirus. Its causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), appears to be capable of infecting different mammalian species. Recent detections of this virus in pet, zoo, wild, and farm animals have compelled inquiry regarding the zoonotic (animal-to-human) and reverse zoonotic (human-to-animal) transmissibility of SARS-CoV-2 with the potential of COVID-19 pandemic evolving into a panzootic.

It is important to monitor the global spread of disease and to assess the significance of genomic changes to support prevention and control efforts during a pandemic. An understanding of the SARS-CoV-2 epidemiology provides opportunities to prevent the risk of repeated re-infection of humans and requires a robust One Health-based investigation. This review paper describes the known properties and the existing gaps in scientific knowledge about the zoonotic and reverse zoonotic transmissibility of the novel virus SARS-CoV-2 and the COVID-19 disease it causes.

Assessing the extent of community spread caused by mink-derived SARS-CoV-2 variants

SARS-CoV-2 has recently been found to have spread from humans to minks and then to have transmitted back to humans. However, it is unknown to what extent the human-to-human transmission caused by the variant has reached. Here, we used publicly available SARS-CoV-2 genomic sequences from both humans and minks collected in Denmark and the Netherlands, and combined phylogenetic analysis with Bayesian inference under an epidemiological model, to trace the possibility of person-to-person transmission. The results showed that at least 12.5% of all people being infected with dominated mink-derived SARS-CoV-2 variants in Denmark and the Netherlands were caused by human-to-human transmission, indicating that this “back-to-human” SARS-CoV-2 variant has already caused human-to-human transmission. Our study also indicated the need for monitoring this mink-derived and other animal source “back-to-human” SARS-CoV-2 in future and that prevention and control measures should be tailored to avoid large-scale community transmission caused by the virus jumping between animals and humans.

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SARS-CoV-2 transmission from human to mink is not lineage specific

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Mink-derived SARS-CoV-2 variants keep human-to-human transmission

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At least 12.5% of patients with mink-derived SARS-CoV-2 were caused by human-to-human transmission

SARS-CoV-2 infection in cats and dogs in infected mink farms

Animals like mink, cats and dogs are susceptible to SARS‐CoV‐2 infection. In the Netherlands, 69 out of 127 mink farms were infected with SARS‐CoV‐2 between April and November 2020 and all mink on infected farms were culled after SARS‐CoV‐2 infection to prevent further spread of the virus. On some farms, (feral) cats and dogs were present. This study provides insight into the prevalence of SARS‐CoV‐2‐positive cats and dogs in 10 infected mink farms and their possible role in transmission of the virus. Throat and rectal swabs of 101 cats (12 domestic and 89 feral cats) and 13 dogs of 10 farms were tested for SARS‐CoV‐2 using PCR. Serological assays were performed on serum samples from 62 adult cats and all 13 dogs. Whole Genome Sequencing was performed on one cat sample. Cat‐to‐mink transmission parameters were estimated using data from all 10 farms. This study shows evidence of SARS‐CoV‐2 infection in 12 feral cats and 2 dogs. Eleven cats (18%) and two dogs (15%) tested serologically positive. Three feral cats (3%) and one dog (8%) tested PCR‐positive. The sequence generated from the cat throat swab clustered with mink sequences from the same farm. The calculated rate of mink‐to‐cat transmission showed that cats on average had a chance of 12% (95%CI 10%–18%) of becoming infected by mink, assuming no cat‐to‐cat transmission. As only feral cats were infected it is most likely that infections in cats were initiated by mink, not by humans. Whether both dogs were infected by mink or humans remains inconclusive. This study presents one of the first reports of interspecies transmission of SARS‐CoV‐2 that does not involve humans, namely mink‐to‐cat transmission, which should also be considered as a potential risk for spread of SARS‐CoV‐2.

Effect of COVID-19 on the livestock sector in Bangladesh and recommendations

COVID-19 and its accompanying effects have severely affected an estimated 0.3 million dairy farms and 65-70 thousand commercial poultry farms in Bangladesh. Many of them closed down or halted productions due to the burden of continuous losses. Reports showed that about 12-15 million liters of milk have remained unsold, which has caused a daily loss of 570 million Bangladeshi Taka (6.7 million USD) in the dairy sector only. Furthermore, the poultry sector has also encountered a loss of a minimum of 115 billion Bangladeshi Taka (1.35 billion USD) within just two weeks from March 20 to April 4, 2020. The situation might accelerate the arising food crisis due to the collapse of the livestock sector during the COVID-19 pandemic and turn it into a humanitarian catastrophe. Hence, the government should retaliate through the provision of financial assistance to livestock farmers, and the proclamation of emergency veterinary services on the earliest basis. In addition to that, the government could develop long-term, sustainable strategies and projects through multi-sectoral engagement to ensure further capacity building of farmers and other stakeholders.

The contribution of veterinary public health to the management of the COVID-19 pandemic from a One Health perspective

The human coronavirus disease 2019 (COVID-19) pandemic represents one of the greatest public health crises in recent history, which has caused unprecedented and massive disruptions of social and economic life globally, and the biggest communication challenges for public information-sharing. While there is strong evidence that bats are the animal source of SARS-CoV-2, the causative agent of COVID-19, there are many uncertainties around the epidemiology, the intermediate animal species, and potential animal routes of SARS-Cov-2 transmission to humans. While it has also long been known that coronaviruses circulate among different animal species, including SARS-CoV and MERS-CoV, responsible for the pandemics of severe acute respiratory syndrome and Middle East respiratory syndrome endemic in Middle Eastern countries in 2002-2003 and 2012 respectively, the way this pandemic is being managed tends to downplay or neglect the veterinary contribution, which is not in line with the One Health approach, if we consider that the genesis of the COVID-19 pandemic, likewise SARS and MERS lies on a close and interdependent links of humans, animals and the environment. To overcome this flaw, and to better operationalize the One Health approach, there are several lines of contributions the veterinary profession might provide to manage the COVID-19 pandemic in the framework of interventions jointly concerted in the veterinary and medical domains, notably: the experience in dealing with past animal epidemics, the skills in conducting wildlife surveillance targeting emerging pathogens at risky hot spots, and with the aim to predict and prevent future pandemics, the laboratory support for the diagnosis and molecular characterization of SARS-CoV-2 and human samples testing, and animal import risk assessment to define COVID-19 risk strategy for international air travel. The veterinary profession presents itself ontologically with a strong One Health accent and all the related valuable knowledge can be properly integrated within centralised multidisciplinary task-forces set up at the national and international level, with a renewed role in the management and monitoring structures required for managing the COVID-19 pandemic.

COVID-19 and Domestic Animals: Exploring the Species Barrier Crossing, Zoonotic and Reverse Zoonotic Transmission of SARS-CoV-2

BACKGROUND

To date, more than thirty animals have been tested positive for SARS-CoV-2; all of them infected by humans with COVID-19. Some animal experiments suggested the possibility of animal to animal transmission of SARS-CoV-2 that was seen in some cases of infected animals. Animal to human transmission was considered unlikely until investigations revealed the possibility of mink to human transmission of SARS-CoV-2 in the Netherlands.

OBJECTIVE

The current study aims at highlighting the predominance of SARS-CoV-2 infection in various animal species, reverse zoonotic transmission and proposing possible animal models that might aid in the study and development of a vaccine against Covid-19.

METHODS

The authors have gathered information on various animal species infected with SARS-CoV-2 and possible tests conducted via online news reports, websites and Scopus indexed journals.

RESULTS

The study of the susceptibility of SARS-CoV-2 to domestic animals concluded that pigs, chicken, and ducks were not vulnerable to Covid-19; dogs showed less susceptibility to SARS-CoV-2 and cats as well as ferrets were seen susceptible to Covid-19. SARS-CoV-2 has been seen crossing the species barrier, infecting humans from the wild with the yet unclear source, spreading from humans to humans quickly, humans to animals, animals to animals, and is likely to spread from animals to humans even though minimally. Animals appear somewhat resistant to SARS-CoV-2 transmission compared to humans who globally crossed eight million infection cases, and the infected animals mostly do not show many complications and recover quickly.

CONCLUSION

Precautions are advised to prevent human to animal transmission of the virus, and in some areas, to avoid animal to human spread of the virus. Further monitoring is required to assess the SARS-CoV-2 infection in animals as COVID-19 is a rapidly evolving condition worldwide. Cats and ferrets have physiological resemblance and genome sequencing studies propose the possibility of these species to be used as animal models for investigating the SARS-CoV-2 infection and this might aid in further studies and vaccine development against Covid-19.

Exploration of hosts and transmission traits for SARS-CoV-2 based on the k-mer natural vector

A severe respiratory pneumonia COVID-19 has raged all over the world, and a coronavirus named SARS-CoV-2 is blamed for this global pandemic. Despite intensive research into the origins of the COVID-19 pandemic, the evolutionary history of its agent SARS-CoV-2 remains unclear, which is vital to control the pandemic and prevent another round of outbreak. Coronaviruses are highly recombinogenic, which are not well handled with alignment-based method. In addition, deletions have been found in the genomes of several SARS-CoV-2, which cannot be resolved with current phylogenetic methods. Therefore, the k-mer natural vector is proposed to explore hosts and transmission traits for SARS-CoV-2 using strict phylogenetic reconstruction. SARS-CoV-2 clustering with bat-origin coronaviruses strongly suggests bats to be the natural reservoir of SARS-CoV-2. By building bat-to-human transmission route, pangolin is identified as an intermediate host, and civet is predicted as a possible candidate. We speculate that SARS-CoV-2 undergoes cross-species recombination between bat and pangolin coronaviruses. This study also demonstrates transmission mode and features of SARS-CoV-2 in the COVID-19 pandemic when it broke out early around the world.

Evolution, Ecology, and Zoonotic Transmission of Betacoronaviruses: A Review

Coronavirus infections have been a part of the animal kingdom for millennia. The difference emerging in the twenty-first century is that a greater number of novel coronaviruses are being discovered primarily due to more advanced technology and that a greater number can be transmitted to humans, either directly or via an intermediate host. This has a range of effects from annual infections that are mild to full-blown pandemics. This review compares the zoonotic potential and relationship between MERS, SARS-CoV, and SARS-CoV-2. The role of bats as possible host species and possible intermediate hosts including pangolins, civets, mink, birds, and other mammals are discussed with reference to mutations of the viral genome affecting zoonosis. Ecological, social, cultural, and environmental factors that may play a role in zoonotic transmission are considered with reference to SARS-CoV, MERS, and SARS-CoV-2 and possible future zoonotic events.

Comparative analyses of ACE2 and TMPRSS2 gene: Implications for the risk to which vertebrate animals are susceptible to SARS-CoV-2

Along with the control and prevention of coronavirus disease 2019 transmission, infected animals might have potential to carry the virus to spark new outbreaks. However, very few studies explore the susceptibility of animals to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Viral attachment as a crucial step for cross-species infection requires angiotensin-converting enzyme 2 (ACE2) as a receptor and depends on TMPRSS2 protease activity. Here, we searched the genomes of metazoans from different classes using an extensive BLASTP survey and found ACE2 and TMPRSS2 occur in vertebrates, but some vertebrates lack Tmprss2. We identified 6 amino acids among 25 known human ACE2 residues are highly associated with the binding of ACE2 to SARS-CoV-2 (p value < .01) by Fisher exact test, and following this, calculated the probability of viral attachment within each species by the randomForest function from R randomForest library. Furthermore, we observed that Ace2 selected from seven animals based on the above analysis lack the hydrophobic contacts identified on human ACE2, indicating less affinity of SARS-CoV-2 to Ace2 in animals than humans. Finally, the alignment of 3D structure between human ACE2 and other animals by I-TASSER and TM-align displayed a reasonable structure for viral attachment within these species. Taken together, our data may shed light on the human-to-animal transmission of SARS-CoV-2.

Wildlife rehabilitation centers as a potential source of transmission of SARS-CoV-2 into native wildlife of Latin America

The COVID-19 pandemic has impacted the entire world, causing a great number of mortality of humans and affecting the economy, while conservation efforts are finally recognized to prevent further pandemics. The wildlife rehabilitation centers (WRCs) play a relevant role in animal welfare; nevertheless, they also represent an imminent risk of pathogen transmission between humans-to-animals and between animals. Moreover, WRCs could spread pathogens into natural habitats through the reintroduction of infectious individuals. These biosafety concerns at WRCs may increase as the economic and social impact of the COVID-19 extends. We explored the current situation of Latin American WRCs under the COVID-19 pandemic to determine the feasibility of SARS-CoV-2 introduction, amplification, and spread within these institutions. We surveyed WRCs from eight Latin American countries. We found that pandemic is affecting these institutions in many aspects: workers with symptoms compatible with COVID-19, reduced economic resources, and lack of information and support from governmental authorities. These have forced WRCs to reduce the workforce, veterinary visits, and animal food rations and to increase the number of animals released. This scenario generates a risky environment for the transmission of SARS-CoV-2, especially for felids, mustelids, and non-human primates. Therefore, it is imperative to respect quarantine periods, monitor incoming patients, increase biosecurity measures, develop and apply guidelines and recommendations for the protection of personnel and biosafety of enclosures and instruments. It is of utmost importance the proper and safer reintroduction of recovered wildlife.

First Description of SARS-CoV-2 Infection in Two Feral American Mink (Neovison vison) Caught in the Wild

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19, is considered a pathogen of animal origin that is mainly transmitted from human to human. Several animal species can be naturally or experimentally infected by SARS-CoV-2, with compelling evidence that mink is highly susceptible to SARS-CoV-2 infection. Human-to-mink infection cases have been reported and there are also suggestions that mink-to-human infection occurs. Mink infections have been reported to date only on fur farms, except for one infected free- ranging wild mink near a Utah (USA) fur farm, which suggests a transmission pathway from farms to wild mink. We now report the detection of SARS-CoV-2 in 2 of 13 feral dark brown American mink (Neovison vison) trapped in the Valencian Community (Eastern Spain), during an invasive species trapping campaign. They were trapped in riverbeds in sparsely inhabited rural areas known to harbor self-sustained feral mink populations. The closest fur farm is about 20 km away. SARS-CoV-2 RNA was detected by two-step RT-PCR in these animals' mesenteric lymph nodes and was confirmed by sequencing a 397-nucleotide amplified region of the S gene, yielding identical sequences in both animals. A molecular phylogenetic analysis was run on this sequence, which was found to correspond to the consensus SARS-CoV-2 sequence from Wuhan. Our findings appear to represent the first example of SARS-CoV-2 acquired in the wild by feral mink in self-sustained populations.

First Description of SARS-CoV-2 Infection in Two Feral American Mink (Neovison vison) Caught in the Wild

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19, is considered a pathogen of animal origin that is mainly transmitted from human to human. Several animal species can be naturally or experimentally infected by SARS-CoV-2, with compelling evidence that mink is highly susceptible to SARS-CoV-2 infection. Human-to-mink infection cases have been reported and there are also suggestions that mink-to-human infection occurs. Mink infections have been reported to date only on fur farms, except for one infected free- ranging wild mink near a Utah (USA) fur farm, which suggests a transmission pathway from farms to wild mink. We now report the detection of SARS-CoV-2 in 2 of 13 feral dark brown American mink (Neovison vison) trapped in the Valencian Community (Eastern Spain), during an invasive species trapping campaign. They were trapped in riverbeds in sparsely inhabited rural areas known to harbor self-sustained feral mink populations. The closest fur farm is about 20 km away. SARS-CoV-2 RNA was detected by two-step RT-PCR in these animals' mesenteric lymph nodes and was confirmed by sequencing a 397-nucleotide amplified region of the S gene, yielding identical sequences in both animals. A molecular phylogenetic analysis was run on this sequence, which was found to correspond to the consensus SARS-CoV-2 sequence from Wuhan. Our findings appear to represent the first example of SARS-CoV-2 acquired in the wild by feral mink in self-sustained populations.

Susceptibility of white-tailed deer (Odocoileus virginianus) to SARS-CoV-2

The origin of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing the global coronavirus disease 19 (COVID-19) pandemic, remains a mystery. Current evidence suggests a likely spillover into humans from an animal reservoir. Understanding the host range and identifying animal species that are susceptible to SARS-CoV-2 infection may help to elucidate the origin of the virus and the mechanisms underlying cross-species transmission to humans. Here we demonstrated that white-tailed deer (Odocoileus virginianus), an animal species in which the angiotensin converting enzyme 2 (ACE2) - the SARS-CoV-2 receptor - shares a high degree of similarity to humans, are highly susceptible to infection. Intranasal inoculation of deer fawns with SARS-CoV-2 resulted in established subclinical viral infection and shedding of infectious virus in nasal secretions. Notably, infected animals transmitted the virus to non-inoculated contact deer. Viral RNA was detected in multiple tissues 21 days post-inoculation (pi). All inoculated and indirect contact animals seroconverted and developed neutralizing antibodies as early as day 7 pi. The work provides important insights into the animal host range of SARS-CoV-2 and identifies white-tailed deer as a susceptible wild animal species to the virus.IMPORTANCEGiven the presumed zoonotic origin of SARS-CoV-2, the human-animal-environment interface of COVID-19 pandemic is an area of great scientific and public- and animal-health interest. Identification of animal species that are susceptible to infection by SARS-CoV-2 may help to elucidate the potential origin of the virus, identify potential reservoirs or intermediate hosts, and define the mechanisms underlying cross-species transmission to humans. Additionally, it may also provide information and help to prevent potential reverse zoonosis that could lead to the establishment of a new wildlife hosts. Our data show that upon intranasal inoculation, white-tailed deer became subclinically infected and shed infectious SARS-CoV-2 in nasal secretions and feces. Importantly, indirect contact animals were infected and shed infectious virus, indicating efficient SARS-CoV-2 transmission from inoculated animals. These findings support the inclusion of wild cervid species in investigations conducted to assess potential reservoirs or sources of SARS-CoV-2 of infection.

The PRRA insert at the S1/S2 site modulates cellular tropism of SARS-CoV-2 and ACE2 usage by the closely related Bat RaTG13

Biochemical and structural analyses suggest that SARS-CoV-2 is well-adapted to infecting humans and the presence of four residues (PRRA) at the S1/S2 site within the spike (S) protein, which may lead to unexpected tissue or host tropism. Here we report that SARS-CoV-2 efficiently utilized ACE2 of 9 species to infect 293T cells. Similarly, pseudoviruses bearing S protein derived from either the bat RaTG13 or pangolin GX, two closely related animal coronaviruses, utilized ACE2 of a diverse range of animal species to gain entry. Removal of PRRA from SARS-CoV-2 S protein displayed distinct effects on pseudoviral entry into different cell types. Unexpectedly, insertion of PRRA into the RaTG13 S protein selectively abrogated the usage of horseshoe bat and pangolin ACE2 but enhanced the usage of mouse ACE2 by the relevant pseudovirus to enter cells. Together, our findings identified a previously unrecognized effect of the PRRA insert on SARS-CoV-2 and RaTG13 S proteins.ImportanceThe four-residue insert (PRRA) at the boundary between the S1and S2 subunits of SARS-CoV-2 has been widely recognized since day 1 for its role in SARS-CoV-2 S protein processing and activation. As this PRRA insert is unique to SARS-CoV-2 among group b betacoronaviruses, it is thought to affect the tissue and species tropism of SARS-CoV-2. We compared the usage of 10 ACE2 orthologs and found that the presence of PRRA not only affects the cellular tropism of SARS-CoV-2 but also modulates the usage of ACE2 orthologs by the closely related bat RaTG13 S protein. The binding of pseudovirions carrying RaTG13 S with a PRRA insert to mouse ACE2 was nearly 2-fold higher than that of pseudovirions carrying RaTG13 S.

Host barriers to SARS-CoV-2 demonstrated by ferrets in a high-exposure domestic setting

Ferrets (Mustela putorius furo) are mustelids of special relevance to laboratory studies of respiratory viruses and have been shown to be susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and onward transmission. Here, we report the results of a natural experiment where 29 ferrets in one home had prolonged, direct contact and constant environmental exposure to two humans with symptomatic disease, one of whom was confirmed positive for SARS-CoV-2. We observed no evidence of SARS-CoV-2 transmission from humans to ferrets based on viral and antibody assays. To better understand this discrepancy in experimental and natural infection in ferrets, we compared SARS-CoV-2 sequences from natural and experimental mustelid infections and identified two surface glycoprotein Spike (S) mutations associated with mustelids. While we found evidence that angiotensin-converting enzyme II provides a weak host barrier, one mutation only seen in ferrets is located in the novel S1/S2 cleavage site and is computationally predicted to decrease furin cleavage efficiency. These data support the idea that host factors interacting with the novel S1/S2 cleavage site may be a barrier in ferret SARS-CoV-2 susceptibility and that domestic ferrets are at low risk of natural infection from currently circulating SARS-CoV-2. We propose two mechanistically grounded hypotheses for mustelid host adaptation of SARS-CoV-2, with possible effects that require additional investigation.

COVID-19 and Hypertension: The What, the Why, and the How

It has been a year since the coronavirus disease 2019 (COVID-19) was declared pandemic and wreak havoc worldwide. Despite meticulous research has been done in this period, there are still much to be learn from this novel coronavirus. Globally, observational studies have seen that majority of the patients with COVID-19 have preexisting hypertension. This raises the question about the possible relationship between COVID-19 and hypertension. This review summarizes the current understanding of the link between hypertension and COVID-19 and its underlying mechanisms.

SARS-CoV-2-Morphology, Transmission and Diagnosis during Pandemic, Review with Element of Meta-Analysis

The outbreak of Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2). Thus far, the virus has killed over 2,782,112 people and infected over 126,842,694 in the world (state 27 March 2021), resulting in a pandemic for humans. Based on the present data, SARS-CoV-2 transmission from animals to humans cannot be excluded. If mutations allowing breaking of the species barrier and enhancing transmissibility occurred, next changes in the SARS-CoV-2 genome, leading to easier spreading and greater pathogenicity, could happen. The environment and saliva might play an important role in virus transmission. Therefore, there is a need for strict regimes in terms of personal hygiene, including hand washing and surface disinfection. The presence of viral RNA is not an equivalent of active viral infection. The positive result of the RT-PCR method may represent either viral residues or infectious virus particles. RNA-based tests should not be used in patients after the decline of disease symptoms to confirm convalescence. It has been proposed to use the test based on viral, sub-genomic mRNA, or serological methods to find the immune response to infection. Vertical transmission of SARS-CoV-2 is still a little-known issue. In our review, we have prepared a meta-analysis of the transmission of SARS-CoV-2 from mother to child depending on the type of delivery. Our study indicated that the transmission of the virus from mother to child is rare, and the infection rate is not higher in the case of natural childbirth, breastfeeding, or contact with the mother. We hope that this review and meta-analysis will help to systemize knowledge about SARS-CoV-2 with an emphasis on diagnostic implications and transmission routes, in particular, mother-to-child transmission.

Monitoring SARS-CoV-2 Circulation and Diversity through Community Wastewater Sequencing, the Netherlands and Belgium

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become a major global health problem, and public health surveillance is crucial to monitor and prevent virus spread. Wastewater-based epidemiology has been proposed as an addition to disease-based surveillance because virus is shed in the feces of ≈40% of infected persons. We used next-generation sequencing of sewage samples to evaluate the diversity of SARS-CoV-2 at the community level in the Netherlands and Belgium. Phylogenetic analysis revealed the presence of the most prevalent clades (19A, 20A, and 20B) and clustering of sewage samples with clinical samples from the same region. We distinguished multiple clades within a single sewage sample by using low-frequency variant analysis. In addition, several novel mutations in the SARS-CoV-2 genome were detected. Our results illustrate how wastewater can be used to investigate the diversity of SARS-CoV-2 viruses circulating in a community and identify new outbreaks.

SARS-CoV-2 infection, neuropathogenesis and transmission among deer mice: Implications for spillback to New World rodents

Coronavirus disease-19 (COVID-19) emerged in late 2019 in China and rapidly became pandemic. As with other coronaviruses, a preponderance of evidence suggests the virus originated in horseshoe bats (Rhinolophus spp.) and may have infected an intermediate host prior to spillover into humans. A significant concern is that SARS-CoV-2 could become established in secondary reservoir hosts outside of Asia. To assess this potential, we challenged deer mice (Peromyscus maniculatus) with SARS-CoV-2 and found robust virus replication in the upper respiratory tract, lungs and intestines, with detectable viral RNA for up to 21 days in oral swabs and 6 days in lungs. Virus entry into the brain also occurred, likely via gustatory-olfactory-trigeminal pathway with eventual compromise to the blood-brain barrier. Despite this, no conspicuous signs of disease were observed, and no deer mice succumbed to infection. Expression of several innate immune response genes were elevated in the lungs, including IFNα, IFNβ, Cxcl10, Oas2, Tbk1 and Pycard. Elevated CD4 and CD8β expression in the lungs was concomitant with Tbx21, IFNγ and IL-21 expression, suggesting a type I inflammatory immune response. Contact transmission occurred from infected to naive deer mice through two passages, showing sustained natural transmission and localization into the olfactory bulb, recapitulating human neuropathology. In the second deer mouse passage, an insertion of 4 amino acids occurred to fixation in the N-terminal domain of the spike protein that is predicted to form a solvent-accessible loop. Subsequent examination of the source virus from BEI Resources determined the mutation was present at very low levels, demonstrating potent purifying selection for the insert during in vivo passage. Collectively, this work has determined that deer mice are a suitable animal model for the study of SARS-CoV-2 respiratory disease and neuropathogenesis, and that they have the potential to serve as secondary reservoir hosts in North America.

Animal coronaviruses and SARS-CoV-2

COVID-19 is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has rapidly spread to 216 countries and territories since first outbreak in December of 2019, posing a substantial economic losses and extraordinary threats to the public health worldwide. Although bats have been suggested as the natural host of SARS-CoV-2, transmission chains of this virus, role of animals during cross-species transmission, and future concerns remain unclear. Diverse animal coronaviruses have extensively been studied since the discovery of avian coronavirus in 1930s. The current article comprehensively reviews and discusses the current understanding about animal coronaviruses and SARS-CoV-2 for their emergence, transmission, zoonotic potential, alteration of tissue/host tropism, evolution, status of vaccines and surveillance. This study aims at providing guidance for control of COVID-19 and preventative strategies for possible future outbreaks of zoonotic coronavirus via cross-species transmission.

Monitoring SARS-CoV-2 Circulation and Diversity through Community Wastewater Sequencing, the Netherlands and Belgium

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become a major global health problem, and public health surveillance is crucial to monitor and prevent virus spread. Wastewater-based epidemiology has been proposed as an addition to disease-based surveillance because virus is shed in the feces of ≈40% of infected persons. We used next-generation sequencing of sewage samples to evaluate the diversity of SARS-CoV-2 at the community level in the Netherlands and Belgium. Phylogenetic analysis revealed the presence of the most prevalent clades (19A, 20A, and 20B) and clustering of sewage samples with clinical samples from the same region. We distinguished multiple clades within a single sewage sample by using low-frequency variant analysis. In addition, several novel mutations in the SARS-CoV-2 genome were detected. Our results illustrate how wastewater can be used to investigate the diversity of SARS-CoV-2 viruses circulating in a community and identify new outbreaks.

Monitoring SARS-CoV-2 Circulation and Diversity through Community Wastewater Sequencing, the Netherlands and Belgium

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become a major global health problem, and public health surveillance is crucial to monitor and prevent virus spread. Wastewater-based epidemiology has been proposed as an addition to disease-based surveillance because virus is shed in the feces of ≈40% of infected persons. We used next-generation sequencing of sewage samples to evaluate the diversity of SARS-CoV-2 at the community level in the Netherlands and Belgium. Phylogenetic analysis revealed the presence of the most prevalent clades (19A, 20A, and 20B) and clustering of sewage samples with clinical samples from the same region. We distinguished multiple clades within a single sewage sample by using low-frequency variant analysis. In addition, several novel mutations in the SARS-CoV-2 genome were detected. Our results illustrate how wastewater can be used to investigate the diversity of SARS-CoV-2 viruses circulating in a community and identify new outbreaks.

Risk assessment of SARS-CoV-2 infection in free-ranging wild animals in Belgium

The aim of this review paper is to evaluate the putative susceptibilities of different free-ranging wild animal species in Belgium to SARS-CoV-2 and provide a risk assessment of SARS-CoV-2 infection in those animals. Since the onset of the COVID-19 pandemic, natural SARS-CoV-2 infections have mainly been confirmed in domestic and production animals, and in wild animals kept in captivity, although the numbers remain limited when compared to human cases. Recently, the first SARS-CoV-2 infections in presumably escaped minks found in the wild have been detected, further addressing the much-feared scenario of transmission of the virus to animals living in the wild and its consequences. Considering the most likely origin of the virus being a wild animal and the putative susceptibilities of free-ranging wild animal species to SARS-CoV-2, the risk of infection with possible establishment of the virus in these populations has to be investigated closely. The authors conclude that most attention should be given to surveillance and awareness-raising activities for SARS-CoV-2 infection in wild mustelids, bats, wild canids and felids, particularly these collected in wildlife rescue centres. People involved in frequent and close contact with wild animals should take all necessary precautionary measures to protect wild animals against exposure to the virus. More than one year after the first detection of SARS-CoV-2 in humans, the time has come to increase investments in research and surveillance activities in animals, including in free-ranging wild animals, as part of a One Health control of this pandemic. This study focussing on Belgium could be helpful for other countries with similar animal densities and ecosystems.

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.

Clinicopathologic features of a feline SARS-CoV-2 infection model parallel acute COVID-19 in humans

The emergence and ensuing dominance of COVID-19 on the world stage has emphasized the urgency of efficient animal models for the development of therapeutics and assessment of immune responses to SARS-CoV-2 infection. Shortcomings of current animal models for SARS-CoV-2 include limited lower respiratory disease, divergence from clinical COVID-19 disease, and requirements for host genetic modifications to permit infection. This study validates a feline model for SARS-CoV-2 infection that results in clinical disease and histopathologic lesions consistent with severe COVID-19 in humans. Intra-tracheal inoculation of concentrated SARS-CoV-2 caused infected cats to develop clinical disease consistent with that observed in the early exudative phase of COVID-19. A novel clinical scoring system for feline respiratory disease was developed and utilized, documenting a significant degree of lethargy, fever, dyspnea, and dry cough in infected cats. In addition, histopathologic pulmonary lesions such as diffuse alveolar damage, hyaline membrane formation, fibrin deposition, and proteinaceous exudates were observed due to SARS-CoV-2 infection, imitating lesions identified in people hospitalized with ARDS from COVID-19. A significant correlation exists between the degree of clinical disease identified in infected cats and pulmonary lesions. Viral loads and ACE2 expression were quantified in nasal turbinates, distal trachea, lung, and various other organs. Natural ACE2 expression, paired with clinicopathologic correlates between this feline model and human COVID-19, encourage use of this model for future translational studies.