Overview of Coronaviruses in Veterinary Medicine

Molecular characterization of swine acute diarrhea syndrome coronavirus detected in Vietnamese pigs

Swine acute diarrhea syndrome coronavirus (SADS-CoV) is a novel porcine coronavirus that was recently identified in southern China in 2017. At present, there is a lack of nationwide epidemiological investigations of the newly emerged SADS-CoV. Because Vietnam is geographically adjacent to southern China, many diseases have spread from China to Vietnam. To assess SADS-CoV transmission to Vietnam, we conducted a retrospective study to detect SADS-CoV in samples collected from pig farms in northern Vietnam. Among the 69 fecal samples tested, 5 were positive for SADS-CoV. The spike gene sequence showed high genetic homology with strains circulating in China. Our study is the first to show that SADS-CoV has spread from China to Vietnam and highlights the need for global epidemiological investigations of SADS-CoV.

Insights into the Activation of Unfolded Protein Response Mechanism during Coronavirus Infection

Coronaviruses represent a significant class of viruses that affect both animals and humans. Their replication cycle is strongly associated with the endoplasmic reticulum (ER), which, upon virus invasion, triggers ER stress responses. The activation of the unfolded protein response (UPR) within infected cells is performed from three transmembrane receptors, IRE1, PERK, and ATF6, and results in a reduction in protein production, a boost in the ER's ability to fold proteins properly, and the initiation of ER-associated degradation (ERAD) to remove misfolded or unfolded proteins. However, in cases of prolonged and severe ER stress, the UPR can also instigate apoptotic cell death and inflammation. Herein, we discuss the ER-triggered host responses after coronavirus infection, as well as the pharmaceutical targeting of the UPR as a potential antiviral strategy.

Reversible rearrangement of the cellular cytoskeleton: A key to the broad-spectrum antiviral activity of novel amphiphilic polymers

The battle against emerging viral infections has been uneven, as there is currently no broad-spectrum drug available to contain the spread of novel pathogens throughout the population. Consequently, the pandemic outbreak that occurred in early 2020 laid bare the almost empty state of the pandemic box. Therefore, the development of novel treatments with broad specificity has become a paramount concern in this post-pandemic era. Here, we propose copolymers of poly (sodium 2-(acrylamido)-2-methyl-1-propanesulfonate) (PAMPS) and poly (sodium 11-(acrylamido)undecanoate (AaU), both block (PAMPS75-b-PAaUn) and random (P(AMPSm-co-AaUn)) that show efficacy against a broad range of alpha and betacoronaviruses. Owing to their intricate architecture, these polymers exhibit a highly distinctive mode of action, modulating nano-mechanical properties of cells and thereby influencing viral replication. Through the employment of confocal and atomic force microscopy techniques, we discerned perturbations in actin and vimentin filaments, which correlated with modification of cellular elasticity and reduction of glycocalyx layer. Intriguingly, this process was reversible upon polymer removal from the cells. To ascertain the applicability of our findings, we assessed the efficacy and underlying mechanism of the inhibitors using fully differentiated human airway epithelial cultures, wherein near-complete abrogation of viral replication was documented. Given their mode of action, these polymers can be classified as biologically active nanomaterials that exploit a highly conserved molecular target-cellular plasticity-proffering the potential for truly broad-spectrum activity while concurrently for drug resistance development is minimal.

First Detection of SARS-CoV-2 in White Rhinoceros during a Small-Scale Coronavirus Surveillance in the Bandia Reserve, Senegal

The SARS-CoV-2 pandemic has heightened interest in the monitoring and surveillance of coronaviruses in wildlife. Testing for the virus in animals can provide valuable insights into viral reservoirs, transmission, and pathogenesis. In this study, we present the results of the molecular surveillance project focused on coronaviruses in Senegalese wildlife. During the project, we screened fecal samples of the wild animals living in the Bandia Reserve (ten non-human primates, one giraffe, and two white rhinoceros) and the free-living urban population of African four-toed hedgehogs in Ngaparou. The results showed the absence of coronaviruses in hedgehogs, non-human primates, and a giraffe. A single positive sample was obtained from a white rhinoceros. The sequencing results of amplified RdRp gene confirmed that the detected virus was SARS-CoV-2. This study represents the first documented instance of molecular detection of SARS-CoV-2 in white rhinoceros and, therefore, extends our knowledge of possible SARS-CoV-2 hosts.

Animal Models for the Study of Neurologic Manifestations Of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the worldwide coronavirus (COVID-19) pandemic, has infected an estimated 525 million people with over 6 million deaths. Although COVID-19 is primarily a respiratory disease, an escalating number of neurologic symptoms have been reported in humans. Some neurologic symptoms, such as loss of smell or taste, are mild. However, other symptoms, such as meningoencephalitis or stroke, are potentially fatal. Along with surveys and postmortem evaluations on humans, scientists worked with several animal species to try to elucidate the causes of neurologic symptoms. Neurologic sequelae remain challenging to study due to the complexity of the nervous system and difficulties in identification and quantification of neurologic signs. We reviewed animal models used in the study of neurologic COVID-19, specifically research in mice, hamsters, ferrets, and nonhuman primates. We summarized findings on the presence and pathologic effects of SARS-CoV-2 on the nervous system. Given the need to increase understanding of COVID-19 and its effects on the nervous system, scientists must strive to obtain new information from animals to reduce mortality and morbidity with neurologic complications in humans.

Antiviral Properties of Pennisetum purpureum Extract against Coronaviruses and Enteroviruses

Many severe epidemics are caused by enteroviruses (EVs) and coronaviruses (CoVs), including feline coronavirus (FCoV) in cats, epidemic diarrhea disease virus (PEDV) in pigs, infectious bronchitis virus (IBV) in chickens, and EV71 in human. Vaccines and antiviral drugs are used to prevent and treat the infection of EVs and CoVs, but the effectiveness is affected due to rapidly changing RNA viruses. Many plant extracts have been proven to have antiviral properties despite the continuous mutations of viruses. Napier grass (Pennisetum purpureum) has high phenolic content and has been used as healthy food materials, livestock feed, biofuels, and more. This study tested the antiviral properties of P. purpureum extract against FCoV, PEDV, IBV, and EV71 by in vitro cytotoxicity assay, TCID₅₀ virus infection assay, and chicken embryo infection assay. The findings showed that P. purpureum extract has the potential of being disinfectant to limit the spread of CoVs and EVs because the extract can inhibit the infection of EV71, FCoV, and PEDV in cells, and significantly reduce the severity of symptoms caused by IBV in chicken embryos.