Coronaviruses in humans and animals: the role of bats in viral evolution

Identification of common human infectious and potentially zoonotic novel genotypes of Enterocytozoon bieneusi in cavernicolous bats in Thailand

Enterocytozoon bieneusi is a common cause of human microsporidiosis and can infect a variety of animal hosts worldwide. In Thailand, previous studies have shown that this parasite is common in domestic animals. However, information on the prevalence and genotypes of this parasite in other synanthropic wildlife, including bats, remains limited. Several pathogens have been previously detected in bats, suggesting that bats may serve as a reservoir for this parasite. In this study, a total of 105 bat guano samples were collected from six different sites throughout Thailand. Of these, 16 from Chonburi (eastern), Ratchaburi (western), and Chiang Rai (northern) provinces tested positive for E. bieneusi, representing an overall prevalence of 15.2%. Based on ITS1 sequence analysis, 12 genotypes were identified, including two known genotypes (D and type IV) frequently detected in humans and ten novel potentially zoonotic genotypes (TBAT01-TBAT10), all belonging to zoonotic group 1. Lyle's flying fox (Pteropus lylei), commonly found in Southeast Asia, was identified as the host in one sample that was also positive for E. bieneusi. Network analysis of E. bieneusi sequences detected in this study and those previously reported in Thailand also revealed intraspecific divergence and recent population expansion, possibly due to adaptive evolution associated with host range expansion. Our data revealed, for the first time, multiple E. bieneusi genotypes of zoonotic significance circulating in Thai bats and demonstrated that bat guano fertilizer may be a vehicle for disease transmission.

A Nasal Vaccine Candidate, Containing Three Antigenic Regions from SARS-CoV-2, to Induce a Broader Response

A chimeric protein, formed by two fragments of the conserved nucleocapsid (N) and S2 proteins from SARS-CoV-2, was obtained as a recombinant construct in Escherichia coli. The N fragment belongs to the C-terminal domain whereas the S2 fragment spans the fibre structure in the post-fusion conformation of the spike protein. The resultant protein, named S2NDH, was able to form spherical particles of 10 nm, which forms aggregates upon mixture with the CpG ODN-39M. Both preparations were recognized by positive COVID-19 human sera. The S2NDH + ODN-39M formulation administered by the intranasal route resulted highly immunogenic in Balb/c mice. It induced cross-reactive anti-N humoral immunity in both sera and bronchoalveolar fluids, under a Th1 pattern. The cell-mediated immunity (CMI) was also broad, with positive response even against the N protein of SARS-CoV-1. However, neither neutralizing antibodies (NAb) nor CMI against the S2 region were obtained. As alternative, the RBD protein was included in the formulation as inducer of NAb. Upon evaluation in mice by the intranasal route, a clear adjuvant effect was detected for the S2NDH + ODN-39M preparation over RBD. High levels of NAb were induced against SARS-CoV-2 and SARS-CoV-1. The bivalent formulation S2NDH + ODN-39M + RBD, administered by the intranasal route, constitutes an attractive proposal as booster vaccine of sarbecovirus scope.

Psychological repercussions of COVID-19 on health care workers, Sudan

Healthcare workers around the world were confronted with innumerable torments with the emergence of COVID-19. Amid the pandemic, frontline healthcare personnel serve crucial responsibilities and endure significant social, psychological and economic consequences. This cross-sectional study collected demographic data for 1 year from 385 healthcare officials from all the hospitals spread across the state of Khartoum to research the factors that affected the healthcare workers and doctors who were on the frontline to diagnose and treat the patients with potential or confirmed COVID-19. The degree of symptoms of depression, anxiety and insomnia was also assessed through validated measurement tools. The female participants showed more vulnerability to depression, anxiety and insomnia than their male counterparts. It was reported by the end of the study that the healthcare workers in Sudan are under immense psychological hazards.

Antivirals for Broader Coverage against Human Coronaviruses

Coronaviruses (CoVs) are enveloped positive-sense single-stranded RNA viruses with a genome that is 27-31 kbases in length. Critical genes include the spike (S), envelope (E), membrane (M), nucleocapsid (N) and nine accessory open reading frames encoding for non-structural proteins (NSPs) that have multiple roles in the replication cycle and immune evasion (1). There are seven known human CoVs that most likely appeared after zoonotic transfer, the most recent being SARS-CoV-2, responsible for the COVID-19 pandemic. Antivirals that have been approved by the FDA for use against COVID-19 such as Paxlovid can target and successfully inhibit the main protease (MPro) activity of multiple human CoVs; however, alternative proteomes encoded by CoV genomes have a closer genetic similarity to each other, suggesting that antivirals could be developed now that target future CoVs. New zoonotic introductions of CoVs to humans are inevitable and unpredictable. Therefore, new antivirals are required to control not only the next human CoV outbreak but also the four common human CoVs (229E, OC43, NL63, HKU1) that circulate frequently and to contain sporadic outbreaks of the severe human CoVs (SARS-CoV, MERS and SARS-CoV-2). The current study found that emerging antiviral drugs, such as Paxlovid, could target other CoVs, but only SARS-CoV-2 is known to be targeted in vivo. Other drugs which have the potential to target other human CoVs are still within clinical trials and are not yet available for public use. Monoclonal antibody (mAb) treatment and vaccines for SARS-CoV-2 can reduce mortality and hospitalisation rates; however, they target the Spike protein whose sequence mutates frequently and drifts. Spike is also not applicable for targeting other HCoVs as these are not well-conserved sequences among human CoVs. Thus, there is a need for readily available treatments globally that target all seven human CoVs and improve the preparedness for inevitable future outbreaks. Here, we discuss antiviral research, contributing to the control of common and severe CoV replication and transmission, including the current SARS-CoV-2 outbreak. The aim was to identify common features of CoVs for antivirals, biologics and vaccines that could reduce the scientific, political, economic and public health strain caused by CoV outbreaks now and in the future.

Comparison of ordinary reverse transcription real-time polymerase chain reaction (qRT-PCR) with a newly developed one-step single-tube nested real-time RT-PCR (OSN-qRT-PCR) for sensitive detection of SARS-CoV-2 in wastewater

Wastewater monitoring has proven to be an important approach to detecting and controlling the development of the SARS-CoV-2 pandemic. Various tests based on reverse transcription real-time PCR (qRT-PCR) have been developed and used for the detection of SARS-CoV-2 in wastewater samples. In this study, we attempted to increase the sensitivity of qRT-PCR by developing a one-step single-tube nested qRT-PCR assay (OSN-qRT-PCR). Two variants were developed, oriented to nucleocapsid phosphoprotein gene (N) and to spike protein gene (S), respectively. The performance of conventional qRT-PCR assays oriented to these genes with two novel OSN-qRT-PCR assays were firstly optimized using wastewater artificially contaminated with two encapsidated RNA mimic systems harboring a portion either N or S gene (ENRM and ESRM, respectively). The assays were coupled to a polyethylene glycol-based RNA precipitation/extraction method and applied to detect SARS-CoV-2 in wastewater samples from four cities in Slovakia. Both novel OSN-qRT-PCR assays demonstrated higher detection rates than the ordinary qRT-PCR counterparts. The virus levels in the analyzed wastewater samples had a high or very high relation with the numbers of clinical cases in the monitored regions. In fact, correlation with a 3-, 4-, or 5-day temporal offset was revealed. The OSN-qRT-PCR assays demonstrated robustness, mainly in samples with low viral loads.

A SARS-CoV-2: Companion Animal Transmission and Variants Classification

The continuous emergence of novel viruses and their diseases are a threat to global public health as there have been three outbreaks of coronaviruses that are highly pathogenic to humans in the span of the last two decades, severe acute respiratory syndrome (SARS)-CoV in 2002, Middle East respiratory syndrome (MERS)-CoV in 2012, and novel SARS-CoV-2 which emerged in 2019. The unprecedented spread of SARS-CoV-2 worldwide has given rise to multiple SARS-CoV-2 variants that have either altered transmissibility, infectivity, or immune escaping ability, causing diseases in a broad range of animals including human and non-human hosts such as companion, farm, zoo, or wild animals. In this review, we have discussed the recent SARS-CoV-2 outbreak, potential animal reservoirs, and natural infections in companion and farm animals, with a particular focus on SARS-CoV-2 variants. The expeditious development of COVID-19 vaccines and the advancements in antiviral therapeutics have contained the COVID-19 pandemic to some extent; however, extensive research and surveillance concerning viral epidemiology, animal transmission, variants, or seroprevalence in diverse hosts are essential for the future eradication of COVID-19.

Canine Coronavirus Infection Modulates the Biogenesis and Composition of Cell-Derived Extracellular Vesicles

Coronavirus (CoV) has persistently become a global health concern causing various diseases in a wide variety of hosts, including humans, birds, and companion animals. However, the virus-mediated responses in animal hosts have not been studied extensively due to pathogenesis complexity and disease developments. Extracellular vesicles (EVs) are widely explored in viral infections for their intercellular communication, nanocarrier, and immunomodulatory properties. We proposed that coronavirus hijacks the host exosomal pathway and modulates the EV biogenesis, composition, and protein trafficking in the host. In the present study, Crandell-Rees feline kidney (CRFK) cells were infected with canine coronavirus (CCoV) in an exosome-free medium at the multiplicity of infection (MOI) of 400 infectious units (IFU) at various time points. The cell viability was significantly decreased over time, as determined by the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Post-infection EVs were isolated, and transmission electron microscopy (TEM) showed the presence of small EVs (sEVs) after infection. NanoSight particle tracking analysis (NTA) revealed that EV sizes averaged between 100 and 200 nm at both incubation times; however, the mean size of infection-derived EVs was significantly decreased at 48 h when compared to uninfected control EVs. Quantitative analysis of protein levels performed by dot blot scanning showed that the expression levels of ACE-2, annexin-V, flotillin-1, TLR-7, LAMP, TNF-α, caspase-1, caspase-8, and others were altered in EVs after infection. Our findings suggested that coronavirus infection impacts cell viability, modulates EV biogenesis, and alters cargo composition and protein trafficking in the host, which could impact viral progression and disease development. Future experiments with different animal CoVs will provide a detailed understanding of host EV biology in infection pathogenesis and progression. Hence, EVs could offer a diagnostic and therapeutic tool to study virus-mediated host responses that could be extended to study the interspecies jump of animal CoVs to cause infection in humans.

Interactions between Humans and Dogs during the COVID-19 Pandemic: Recent Updates and Future Perspectives

COVID-19 is one of the deadliest epidemics. This pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the role of dogs in spreading the disease in human society is poorly understood. This review sheds light on the limited susceptibility of dogs to COVID-19 infections which is likely attributed to the relatively low levels of angiotensin-converting enzyme 2 (ACE2) in the respiratory tract and the phylogenetic distance of ACE2 in dogs from the human ACE2 receptor. The low levels of ACE2 affect the binding affinity between spike and ACE2 proteins resulting in it being uncommon for dogs to spread the disease. To demonstrate the role of dogs in spreading COVID-19, we reviewed the epidemiological studies and prevalence of SARS-CoV-2 in dogs. Additionally, we discussed the use of detection dogs as a rapid and reliable method for effectively discriminating between SARS-CoV-2 infected and non-infected individuals using different types of samples (secretions, saliva, and sweat). We considered the available information on COVID-19 in the human-dog interfaces involving the possibility of transmission of COVID-19 to dogs by infected individuals and vice versa, the human-dog behavior changes, and the importance of preventive measures because the risk of transmission by domestic dogs remains a concern.

Clinical Features of COVID-19 and Differentiation from Other Causes of CAP

Community-acquired pneumonia (CAP) is a significant cause of morbidity and mortality, one of the most common reasons for infection-related death worldwide. Causes of CAP include numerous viral, bacterial, and fungal pathogens, though frequently no specific organism is found. Beginning in 2019, the COVID-19 pandemic has caused incredible morbidity and mortality. COVID-19 has many features typical of CAP such as fever, respiratory distress, and cough, and can be difficult to distinguish from other types of CAP. Here, we highlight unique clinical features of COVID-19 pneumonia such as olfactory and gustatory dysfunction, lymphopenia, and distinct imaging appearance.

Genomic representation predicts an asymptotic host adaptation of bat coronaviruses using deep learning

Introduction

Coronaviruses (CoVs) are naturally found in bats and can occasionally cause infection and transmission in humans and other mammals. Our study aimed to build a deep learning (DL) method to predict the adaptation of bat CoVs to other mammals.

Methods

The CoV genome was represented with a method of dinucleotide composition representation (DCR) for the two main viral genes, ORF1ab and Spike. DCR features were first analyzed for their distribution among adaptive hosts and then trained with a DL classifier of convolutional neural networks (CNN) to predict the adaptation of bat CoVs.

Results and discussion

The results demonstrated inter-host separation and intra-host clustering of DCR-represented CoVs for six host types: Artiodactyla, Carnivora, Chiroptera, Primates, Rodentia/Lagomorpha, and Suiformes. The DCR-based CNN with five host labels (without Chiroptera) predicted a dominant adaptation of bat CoVs to Artiodactyla hosts, then to Carnivora and Rodentia/Lagomorpha mammals, and later to primates. Moreover, a linear asymptotic adaptation of all CoVs (except Suiformes) from Artiodactyla to Carnivora and Rodentia/Lagomorpha and then to Primates indicates an asymptotic bats-other mammals-human adaptation.

Conclusion

Genomic dinucleotides represented as DCR indicate a host-specific separation, and clustering predicts a linear asymptotic adaptation shift of bat CoVs from other mammals to humans via deep learning.

RNA structure-altering mutations underlying positive selection on Spike protein reveal novel putative signatures to trace crossing host-species barriers in Betacoronavirus

Similar to other RNA viruses, the emergence of Betacoronavirus relies on cross-species viral transmission, which requires careful health surveillance monitoring of protein-coding information as well as genome-wide analysis. Although the evolutionary jump from natural reservoirs to humans may be mainly traced-back by studying the effect that hotspot mutations have on viral proteins, it is largely unexplored if other impacts might emerge on the structured RNA genome of Betacoronavirus. In this survey, the protein-coding and viral genome architecture were simultaneously studied to uncover novel insights into cross-species horizontal transmission events. We analysed 1,252,952 viral genomes of SARS-CoV, MERS-CoV, and SARS-CoV-2 distributed across the world in bats, intermediate animals, and humans to build a new landscape of changes in the RNA viral genome. Phylogenetic analyses suggest that bat viruses are the most closely related to the time of most recent common ancestor of Betacoronavirus, and missense mutations in viral proteins, mainly in the S protein S1 subunit: SARS-CoV (G > T; A577S); MERS-CoV (C > T; S746R and C > T; N762A); and SARS-CoV-2 (A > G; D614G) appear to have driven viral diversification. We also found that codon sites under positive selection on S protein overlap with non-compensatory mutations that disrupt secondary RNA structures in the RNA genome complement. These findings provide pivotal factors that might be underlying the eventual jumping the species barrier from bats to intermediate hosts. Lastly, we discovered that nearly half of the Betacoronavirus genomes carry highly conserved RNA structures, and more than 90% of these RNA structures show negative selection signals, suggesting essential functions in the biology of Betacoronavirus that have not been investigated to date. Further research is needed on negatively selected RNA structures to scan for emerging functions like the potential of coding virus-derived small RNAs and to develop new candidate antiviral therapeutic strategies.

Virtual screening based on the structure of more than 105 compounds against four key proteins of SARS-CoV-2: MPro, SRBD, RdRp, and PLpro

Background

SARS-CoV-2 initially originated in Wuhan (China) around December 2019, and spread all over the world. Currently, WHO (Word Health Organization) has licensed several vaccines for this viral infection. However, not everyone can be vaccinated. People with underlying health conditions that weaken their immune systems or those with severe allergies to some vaccine components, may not be able to be vaccinated. Moreover, no vaccination is 100% safe, and the emergence of new SARS-CoV-2 mutations may reduce the efficacy of immunizations. Therefore, it is urgent to develop effective drugs to protect people against this virus.

Material and method

We performed structure-based virtual screening (SBVS) of a library that was built from ChemDiv and PubChem databases against four SARS-CoV-2 target proteins: S-protein (spike), main protease (M_Pro), RNA-dependent RNA polymerase, and PL_pro. A virtual screening study was performed using PyRx and AutoDock tools.

Results

Our results suggest that twenty-five top-ranked drugs with the highest energy binding as the potential inhibitors against four SARS-CoV-2 targets, relative to the reference molecules. Based on the energy binding, we suggest that these compounds could be used to produce effective anti-viral drugs against SARS-CoV-2.

Conclusion

The discovery of novel compounds for COVID-19 using computer-aided drug discovery tools requires knowledge of the structure of coronavirus and various target proteins of the virus. These compounds should be further assessed in experimental assays and clinical trials to validate their actual activity against the disease. These findings may contribute to the drug design studies against COVID-19.

Transmission dynamics and susceptibility patterns of SARS-CoV-2 in domestic, farmed and wild animals: Sustainable One Health surveillance for conservation and public health to prevent future epidemics and pandemics

The exact origin of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and source of introduction into humans has not been established yet, though it might be originated from animals. Therefore, we conducted a study to understand the putative reservoirs, transmission dynamics, and susceptibility patterns of SARS-CoV-2 in animals. Rhinolophus bats are presumed to be natural progenitors of SARS-CoV-2-related viruses. Initially, pangolin was thought to be the source of spillover to humans, but they might be infected by human or other animal species. So, the virus spillover pathways to humans remain unknown. Human-to-animal transmission has been testified in pet, farmed, zoo and free-ranging wild animals. Infected animals can transmit the virus to other animals in natural settings like mink-to-mink and mink-to-cat transmission. Animal-to-human transmission is not a persistent pathway, while mink-to-human transmission continues to be illuminated. Multiple companions and captive wild animals were infected by an emerging alpha variant of concern (B.1.1.7 lineage) whereas Asiatic lions were infected by delta variant, (B.1.617.2). To date, multiple animal species - cat, ferrets, non-human primates, hamsters and bats - showed high susceptibility to SARS-CoV-2 in the experimental condition, while swine, poultry, cattle showed no susceptibility. The founding of SARS-CoV-2 in wild animal reservoirs can confront the control of the virus in humans and might carry a risk to the welfare and conservation of wildlife as well. We suggest vaccinating pets and captive animals to stop spillovers and spillback events. We recommend sustainable One Health surveillance at the animal-human-environmental interface to detect and prevent future epidemics and pandemics by Disease X.

Cinema's Terrifying Realities: Pandemics, Zombification, and SARS-COV-2

Contagion is a function of the properties of the pathogen, social interactions, and personal relationships in the society it attacks. Filmmakers in the horror genre were inspired by the idea of rabies as a virus that could mutate into something more dangerous. Fictional epidemics of scavenging undead were often attributed to encephalitis caused by rabies or a mutated rabies virus. During the early months of the SARS-COV-2 pandemic, there was a spike in streaming of Contagion that portrays a viral infectious disease modeled after a bat virus that spreads at an alarming rate, unleashing a global public panic and a clueless governmental response. We wanted to trace how filmmakers used rabies pathology as source material for their plots. We searched internet film databases and reviewed fictional films that utilized this plot device. Many dystopic, rabies-induced pandemic scenarios - mostly from the zombie genre - reveal parallels to the COVID-19 pandemic. Many zombie films, despite their absurd premise, anticipated the realities of future pandemics.

Possible internal viral shedding and interferon production after clinical recovery from COVID-19: Case report

A 70-year-old man underwent off-pump coronary artery bypass grafting 28 days after his recovery from coronavirus disease 2019 (COVID-19), which was confirmed by a negative polymerase chain reaction (PCR) test result for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a nasopharyngeal swab. The PCR test result was also negative for nasopharyngeal sampling 5 days prior to the surgery. However, his redundant saphenous vein and sputum through the endotracheal tube that was taken on the operative day showed the presence of SARS-CoV-2 by PCR. Immunohistochemical analysis of Spike and Nucleoprotein of the saphenous vein showed small clusters of each antigen-positive speckle. Ultrastructural imaging of the saphenous vein showed virus-like particles. The cell-based assay suggested that the patient’s serum contained a higher concentration of type-I interferons than that of healthy control sera. These observations suggest that internal viral shedding and, to some extent, innate immune responses continue after COVID-19 recovery.

Longitudinal Survey of Coronavirus Circulation and Diversity in Insectivorous Bat Colonies in Zimbabwe

Background: Studies have linked bats to outbreaks of viral diseases in human populations such as SARS-CoV-1 and MERS-CoV and the ongoing SARS-CoV-2 pandemic. Methods: We carried out a longitudinal survey from August 2020 to July 2021 at two sites in Zimbabwe with bat–human interactions: Magweto cave and Chirundu farm. A total of 1732 and 1866 individual bat fecal samples were collected, respectively. Coronaviruses and bat species were amplified using PCR systems. Results: Analysis of the coronavirus sequences revealed a high genetic diversity, and we identified different sub-viral groups in the Alphacoronavirus and Betacoronavirus genus. The established sub-viral groups fell within the described Alphacoronavirus sub-genera: Decacovirus, Duvinacovirus, Rhinacovirus, Setracovirus and Minunacovirus and for Betacoronavirus sub-genera: Sarbecoviruses, Merbecovirus and Hibecovirus. Our results showed an overall proportion for CoV positive PCR tests of 23.7% at Chirundu site and 16.5% and 38.9% at Magweto site for insectivorous bats and Macronycteris gigas, respectively. Conclusions: The higher risk of bat coronavirus exposure for humans was found in December to March in relation to higher viral shedding peaks of coronaviruses in the parturition, lactation and weaning months of the bat populations at both sites. We also highlight the need to further document viral infectious risk in human/domestic animal populations surrounding bat habitats in Zimbabwe.

Theoretical Investigation of the Coronavirus SARS-CoV-2 (COVID-19) Infection Mechanism and Selectivity

The SARS-CoV-2 virus, commonly known as COVID-19, first occurred in December 2019 in Wuhan, Hubei Province, China. Since then, it has become a tremendous threat to human health. With a pandemic threat, it is in the significant interest of the scientific world to establish its method of infection. In this manuscript, we combine knowledge of the infection mechanism with theoretical methods to answer the question of the virus’s selectivity. We proposed a two-stage infection mechanism. In the first step, the virus interacts with the ACE2 receptor, with the “proper strength”. When the interaction is too strong, the virus will remain in an “improper position”; if the interaction is too weak, the virus will “run away” from the cell. We also indicated three residues (positions 30, 31, and 353) located on the ACE2 protein-binding interface, which seems to be crucial for successful infection. Our results indicate that these residues are necessary for the initiation of the infection process.

Cannabidiol and SARS-CoV-2 Infection

Cannabidiol (CBD) can prevent the inflammatory response of SARS-CoV-2 spike protein in Caco-2-cells. This action is coupled with the inhibition of IL-1beta, IL-6, IL-18, and TNF-alpha, responsible for the inflammatory process during SARS-CoV-2 infection. CBD can act on the different proteins encoded by SARS-CoV-2 and as an antiviral agent to prevent the viral infection. Furthermore, recent studies have shown the possible action of CBD as an antagonist of cytokine release syndromes. In the SARS-CoV-2 pathophysiology, the angiotensin-converting enzyme 2 (ACE2) seems to be the key cell receptor for SARS-CoV-2 infection. The WNT/β-catenin pathway and PPARγ interact in an opposite manner in many diseases, including SARS-CoV-2 infection. CBD exerts its activity through the interaction with PPARγ in SARS-CoV-2 infection. Thus, we can hypothesize that CBD may counteract the inflammatory process of SARS-CoV-2 by its interactions with both ACE2 and the interplay between the WNT/β-catenin pathway and PPARγ. Vaccines are the only way to prevent COVID-19, but it appears important to find therapeutic complements to treat patients already affected by SARS-CoV-2 infection. The possible role of CBD should be investigated by clinical trials to show its effectiveness.

Borderline microscopic organism and lockdown impacted across the borders-global shakers

Viruses are the potential cause of several diseases including novel corona virus-19, flu, small pox, chicken pox, acquired immunodeficiency syndrome, severe acute respiratory syndrome etc. The objectives of this review article are to summarize the reasons behind the epidemics caused by several emerging viruses and bacteria, how to control the infection and preventive strategies. We have explained the causes of epidemics along with their preventive measures, the impact of lockdown on the health of people and the economy of a country. Several reports have revealed the transmission of infection during epidemic from the contact of an infected person to the public that can be prevented by implementing the lockdown by the government of a country. Though lockdown has been considered as one of the significant parameters to control the diseases, however, it has some negative consequences on the health of people as they can be more prone to other ailments like obesity, diabetes, cardiac problems etc. and drastic decline in the economy of a country. Therefore, the transmission of diseases can be prevented by warning the people about the severity of diseases, avoiding their public transportation, keeping themselves isolated, strictly following the guidelines of lockdown and encouraging regular exercise.

Reprogrammed Pteropus Bat Stem Cells as A Model to Study Host-Pathogen Interaction during Henipavirus Infection

Bats are natural hosts for numerous zoonotic viruses, including henipaviruses, which are highly pathogenic for humans, livestock, and other mammals but do not induce clinical disease in bats. Pteropus bats are identified as a reservoir of henipaviruses and the source of transmission of the infection to humans over the past 20 years. A better understanding of the molecular and cellular mechanisms allowing bats to control viral infections requires the development of relevant, stable, and permissive cellular experimental models. By applying a somatic reprogramming protocol to Pteropus bat primary cells, using a combination of ESRRB (Estrogen Related Receptor Beta), CDX2 (Caudal type Homeobox 2), and c-MYC (MYC proto-oncogene) transcription factors, we generated bat reprogrammed cells. These cells exhibit stem cell-like characteristics and neural stem cell molecular signature. In contrast to primary fibroblastic cells, these reprogrammed stem cells are highly permissive to henipaviruses and exhibit specific transcriptomic profiles with the particular expression of certain susceptibility factors such as interferon-stimulated genes (ISG), which may be related to viral infection. These Pteropus bat reprogrammed stem cells should represent an important experimental tool to decipher interactions during henipaviruses infection in Pteropus bats, facilitate isolation and production of bat-borne viruses, and to better understand the bat biology.

Is COVID-19 associated with latent toxoplasmosis?

The present study aimed to evaluate the possible association between coronavirus disease 2019 (COVID-19) and latent Toxoplasma gondii infection in a group of patients and healthy individuals. Blood samples were obtained from 269 PCR-positive COVID-19 patients. The serum was separated and tested for the existence of anti-T. gondii antibodies (IgG) using a commercial enzyme-linked immunosorbent assay kit. The prevalence of latent toxoplasmosis between a subgroup of the patients (aged under 55 years old) and COVID-19 negative individuals was compared. Anti-T. gondii antibodies were found in 226/269 (84.0%) patients with COVID-19. Anti-Toxoplasma antibodies were detected in 72/91 (79.1%) cases and 96/123 (78.0%) COVID-19 negative individuals (odd ratio = 1.1; 95% confidence interval: 0.55-2.07, P = 0.85). The median and interquartile range (IQR) of the IgG titer were not statistically significant different between case (97.3 [31.0-133.5]) and control groups (34.4 [13.0-144.5]) (P = 0.10). These findings demonstrated that latent Toxoplasma infection is prevalent amongst the COVID-19 patients. It also did not find any significant association between chronic toxoplasmosis and COVID-19.

Rapid determination of infectious SARS-CoV-2 in PCR-positive samples by SDS-PMA assisted RT-qPCR

The ongoing COVID-19 pandemic has generated a global health crisis that needs well management of not only patients but also environments to reduce SARS-CoV-2 transmission. The gold standard RT-qPCR method is sensitive and rapid to detect SARS-CoV-2 nucleic acid, but does not answer if PCR-positive samples contain infectious virions. To circumvent this problem, we report an SDS-propidium monoazide (PMA) assisted RT-qPCR method that enables rapid discrimination of live and dead SARS-CoV-2 within 3 h. PMA, a photo-reactive dye, can react with viral RNA released or inside inactivated SARS-CoV-2 virions under assistance of 0.005% SDS, but not viral RNA inside live virions. Formation of PMA-RNA conjugates prevents PCR amplification, leaving only infectious virions to be detected. Under optimum conditions, RT-qPCR detection of heat-inactivated SARS-CoV-2 resulted in larger than 9 Ct value differences between PMA-treated and PMA-free groups, while less than 0.5 Ct differences were observed in the detection of infectious SARS-CoV-2 ranging from 20 to 5148 viral particles. Using a cutoff Ct difference of 8.6, this method could differentiate as low as 8 PFU live viruses in the mixtures of live and heat-inactivated virions. Further experiments showed that this method could successfully monitor the natural inactivation process of SARS-CoV-2 on plastic surfaces during storage with comparable results to the gold standard plaque assay. We believe that the culture-free method established here could be used for rapid and convenient determination of infectious SARS-CoV-2 virions in PCR-positive samples, which will facilitate better control of SARS-CoV-2 transmission.

The contribution of bovines to human health against viral infections

In the last 40 years, novel viruses have evolved at a much faster pace than other pathogens. Viral diseases pose a significant threat to public health around the world. Bovines have a longstanding history of significant contributions to human nutrition, agricultural, industrial purposes, medical research, drug and vaccine development, and livelihood. The life cycle, genomic structures, viral proteins, and pathophysiology of bovine viruses studied in vitro paved the way for understanding the human counterparts. Calf model has been used for testing vaccines against RSV, papillomavirus vaccines and anti-HCV agents were principally developed after using the BPV and BVDV model, respectively. Some bovine viruses-based vaccines (BPIV-3 and bovine rotaviruses) were successfully developed, clinically tried, and commercially produced. Cows, immunized with HIV envelope glycoprotein, produced effective broadly neutralizing antibodies in their serum and colostrum against HIV. Here, we have summarized a few examples of human viral infections for which the use of bovines has contributed to the acquisition of new knowledge to improve human health against viral infections covering the convergence between some human and bovine viruses and using bovines as disease models. Additionally, the production of vaccines and drugs, bovine-based products were covered, and the precautions in dealing with bovines and bovine-based materials.

Cannabinoids for SARS-CoV-2 and is there evidence of their therapeutic efficacy?

To combat the coronaviruses and their novel variants, therapeutic drugs and the development of vaccines that are to be effective throughout human life are urgently needed. The endocannabinoid system (ECS) acts as a modulator in the activation of the microcirculation, immune system, and autonomic nervous system, along with controlling pharmacological functions such as emotional responses, homeostasis, motor functions, cognition, and motivation. The ECS contains endogenous cannabinoids, cannabinoid receptor (CBRs), and enzymes that regulate their biosynthesis, transport, and degradation. Moreover, phytocannabinoids and synthetic cannabinoids that mimic the action of endocannabinoids also play an essential role in the modulation of the ECS. Cannabinoids, the main constituents of cannabis (Cannabis sativa L.), are therapeutic compounds that have received international attention in the health field due to their therapeutic properties. Recently, they have been tested for the treatment of COVID-19 due to their antiviral properties. Indeed, cannabinoid-type compounds, and in particular cannabidiol (CBD), isolated from glandular trichomes found in the calyx of cannabis flowers with reported antiviral properties is hypothesized to be a therapeutic option in the ministration of SARS-CoV-2 consorted with COVID-19 disease. The relevant articles were determined from the database search published mainly in Web of Science, Google scholar, PubMed, Crossref, and ClinicalTrials.gov database during the pandemic period. The articles were evaluated for the therapeutic potentials, mechanisms of action of cannabinoids, the roles of the ECS in the immune system, impact of cannabinoids in SARS-CoV-2 septic, especially if they address the application of cannabinoids as drugs for the curability and management of SARS-CoV-2 and its novel variants. Although the evidence needed to be considered using cannabinoids in the control and treatment of viral diseases is currently in its infancy, they already offer an opportunity for clinicians due to their effects in relieving pain, improving appetite, and improving childhood epilepsy, especially in cancer and human immunodeficiency virus (HIV/AIDS) patients. In addition to these, the most recent scientific evidence emphasizes their use in the treatment of the coronavirus infected patients. In brief, all preclinic and clinic studies that have been reported show that, through the cannabinoid system, cannabinoids, particularly CBD, have many mechanisms that are effective in the treatment of patients infected by SARS-CoV-2. Thus, more extensive studies are necessary in this area to fully identify the effects of cannabinoids on SARS-CoV-2.

An overview of the preclinical discovery and development of remdesivir for the treatment of coronavirus disease 2019 (COVID-19)

Introduction

Remdesivir (RDV) is an inhibitor of the viral RNA-dependent RNA polymerases that are active in some RNA viruses, including the Ebola virus and zoonotic coronaviruses. When severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) was identified as the etiologic agent of the coronavirus disease 2019 (COVID-19), several investigations have assessed the potential activity of RDV in inhibiting viral replication, giving rise to hope for an effective treatment.

Areas covered

In this review, the authors describe the main investigations leading to the discovery of RDV and its subsequent development as an antiviral agent, focusing on the main clinical trials investigating its efficacy in terms of symptom resolution and mortality reduction.

Expert opinion

RDV is the most widely investigated antiviral drug for the treatment of COVID-19. This attention on RDV activity against SARS-CoV-2 is justified by promising in vitro studies, which demonstrated that RDV was able to suppress viral replication without significant toxicity. Such activity was confirmed by an investigation in an animal model and by the results of preliminary clinical investigations. Nevertheless, the efficacy of RDV in reducing mortality has not been clearly demonstrated.

Clinical, Biochemical and Molecular Evaluations of Ivermectin Mucoadhesive Nanosuspension Nasal Spray in Reducing Upper Respiratory Symptoms of Mild COVID-19

BACKGROUND

Ivermectin is an FDA-approved broad-spectrum anti-parasitic agent that has been shown to inhibit SARS-CoV-2 replication in vitro.

OBJECTIVE

We aimed to assess the therapeutic efficacy of ivermectin mucoadhesive nanosuspension intranasal spray in treatment of patients with mild COVID-19.

METHODS

This clinical trial included 114 patients diagnosed as mild COVID-19. Patients were divided randomly into two age and sex-matched groups; group A comprising 57 patients received ivermectin nanosuspension nasal spray twice daily plus the Egyptian protocol of treatment for mild COVID-19 and group B comprising 57 patients received the Egyptian protocol for mild COVID-19 only. Evaluation of the patients was performed depending on improvement of presenting manifestations, negativity of two consecutive pharyngeal swabs for the COVID-19 nucleic acid via rRT-PCR and assessments of hematological and biochemical parameters in the form of complete blood counts, C-reactive protein, serum ferritin and d-dimer which were performed at presentation and 7 days later.

RESULTS

Of the included patients confirmed with mild COVID-19, 82 were males (71.9%) and 32 females (28.1%) with mean age 45.1 ± 18.9. In group A, 54 patients (94.7%) achieved 2 consecutive negative PCR nasopharyngeal swabs in comparison to 43 patients (75.4%) in group B with P = 0.004. The durations of fever, cough, dyspnea and anosmia were significantly shorter in group A than group B, without significant difference regarding the duration of gastrointestinal symptoms. Duration taken for nasopharyngeal swab to be negative was significantly shorter in group A than in group B (8.3± 2.8 days versus 12.9 ± 4.3 days; P = 0.0001).

CONCLUSION

Local use of ivermectin mucoadhesive nanosuspension nasal spray is safe and effective in treatment of patients with mild COVID-19 with rapid viral clearance and shortening the anosmia duration.

CLINICALTRIALSGOV IDENTIFIER

NCT04716569; https://clinicaltrials.gov/ct2/show/NCT04716569.