Corona Viruses: Emergence, Evolution, and Recurrence

Corona viruses (CoVs) are enveloped RNA viruses that infect a broad array of avian and mammalian species, including humans. The existence of these viruses is believed to have occurred thousands of years ago as animal CoVs;bats, birds, rodents were reported to be natural reservoirs. They garnered scientific attention after their emergence as human pathogens, till date, seven corona viruses were reported to infect humans, with mild to moderate and/or severe respiratory illness. The ongoing pandemic COVID-19 is caused by one of such Corona viruses named Severe Acute Respiratory Syndrome Corona Virus -2 (SARS-CoV-2), which surprised all with its unprecedented transmission dynamics and etiology. This virus surged twice within a gap of a year all over the world and became a major health concern to many nations. Most of these Corona viruses transferred to humans through intermediate hosts. Here, in this chapter, we summarized the structural and genomic features of the Coronaviruses in general and emphasizing the SARS CoV-2 and added an account of the different vaccines and their production platforms in combating the pandemic. We briefly discussed the evolution of new variants of SARS-CoV-2 and their role in the surge of COVID-19 infections. We tried to give a brief account of the historical aspects, cross-species transmission, mutations/recombinations scenarios of CoVs with a note on their emergence as human pathogens and future prospects of recurrence. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2021.

The Calculating Methods of Economic Burden of Covid -19 Disease: A Systematic Review

Background and aims: The Covid 19 epidemic has become one of the most important health system challenges in the world. This epidemic, in addition to death and disability, has come at a high cost. The aim of this study was to identify the methods of calculating the burden of Covid 19 disease. Methods: The present study performed by systematic review method. All articles related to the Covid disease burden reviewed in five databases and two search engines. Nine articles analyzed in the final analysis. Results: Nine studies from December 2019 to April 2021 examined and calculated the burden of Covid-19 disease. 5 studies were published in 2020 and 4 studies in 2021. The studies were conducted in China, the United States, Saudi Arabia, Italy, Brazil and Iran. The costs of this disease were classified into medical and non-medical costs. Due to the emergence of this disease and the lack of sufficient knowledge about this disease, there are fundamental limitations in conducting economic burden studies of this epidemic. Conclusion: Access to information is the most important prerequisite for these studies. Therefore, the method of disease management, information and diagnostic cases at the national level is very effective in calculating the economic burden of this disease. The requirements, limitations and basic framework of calculations in estimating the economic burden of this disease should be considered by researchers and policy makers of the health system. © 2022 Iran University of Medical Sciences. All rights reserved.

A mathematical-based epidemic model to prevent and control outbreak of corona virus 2019 (COVID-19)

COVID-19 is the seventh member of the Coronaviridae family and this virus will spread quickly in humans, birds and other animals. Human infections are the major source of spreading this virus, it causes mainly respiratory and neurological diseases. In the month of December 2019 there were an increased number of patients reported to hospitals in Wuhan, China. They identified this virus as a novel Corona virus, named as COVID-19. Due to this uncontrollable virus two major challenges are faced by mankind. First, abnormal growth of COVID-19 cases is leading to insufficient medical resources and second, emergency protocols (such as lockdowns) are imposed as preventive measures. we provide a preliminary evolutionary graph theory based mathematical model was designed for control and prevention of COVID-19. In the proposed model, well known technique of social distancing with different variations are implemented. Lockdown by many countries leads to the decrease of Gross Domestic Product (GDP) and increase in mental problems in citizens. These two problems can be solved by the administration of anti virus in some form to the public as a counterpart to the virus. This model works more effectively with high percolation of antiviral nodes in a population and over a period of time. © 2022 Scrivener Publishing LLC.

Engineered nanomaterials as fighters against SARS-CoV-2: The way to control and treat pandemics.

In this editorial trend, we aim to collect and present recently available data about the characteristics of SARS-CoV-2 virus, severity, infection, replication, diagnosis, and current medications. In addition, we propose the role of nanomaterials in controlling and treating COVID-19 through their antiviral and antibacterial potential with suggested action mechanisms indicating the capability of interaction between these nanomaterials and SARS-CoV-2. These nanomaterials might be among the possible and most effective cures against coronavirus.

A comprehensive account of SARS-CoV-2 genome structure, incurred mutations, lineages and COVID-19 vaccination program.

This review collates information on the onset of COVID-19, SARS-CoV-2 genome architecture, emergence of novel viral lineages that drove multiple waves of infection around the world and standard and fast track development of vaccines. With the passage of time, the continuously evolving SARS-CoV-2 has acquired an expanded mutational landscape. The functional characterization of spike protein mutations, the primary target of diagnostics, therapeutics and vaccines has revealed increased transmission, pathogenesis and immune escape potential in the variant lineages of the virus. The incurred mutations have also resulted in substantial viral neutralization escape to vaccines, monoclonal, polyclonal and convalescent antibodies presently in use. The present situation suggests the need for development of precise next-generation vaccines and therapeutics by targeting the more conservative genomic viral regions for providing adequate protection.

Prevention, treatment and potential mechanism of herbal medicine for Corona viruses: A review.

The pandemic of coronavirus disease 2019 (COVID-19) caused by the SARS-coronavirus 2(SARS-CoV-2) virus has become the greatest global public health crisis in recent years,and the COVID-19 epidemic is still continuing. However, due to the lack of effectivetherapeutic drugs, the treatment of corona viruses is facing huge challenges. In thiscontext, countries with a tradition of using herbal medicine such as China have beenwidely using herbal medicine for prevention and nonspecific treatment of corona virusesand achieved good responses. In this review, we will introduce the application of herbalmedicine in the treatment of corona virus patients in China and other countries, andreview the progress of related molecular mechanisms and antiviral activity ingredients ofherbal medicine, in order to provide a reference for herbal medicine in the treatment ofcorona viruses. We found that herbal medicines are used in the prevention and fightagainst COVID-19 in countries on all continents. In China, herbal medicine has beenreported to relieve some of the clinical symptoms of mild patients and shorten the length of hospital stay. However, as most herbal medicines for the clinical treatment of COVID-19still lack rigorous clinical trials, the clinical and economic value of herbal medicines in theprevention and treatment of COVID-19 has not been fully evaluated. Future work basedon large-scale randomized, double-blind clinical trials to evaluate herbal medicines andtheir active ingredients in the treatment of new COVID-19 will be very meaningful.

In Vitro Rapid Antigen Test Performance with the SARS-CoV-2 Variants of Concern B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta).

Rapid antigen tests (RATs) are an integral part of SARS-CoV-2 containment strategies. As emerging variants of concern (VOCs) displace the initially circulating strains, it is crucial that RATs do not fail to detect these new variants. In this study, four RATs for nasal swab testing were investigated using cultured strains of B.1.1 (non-VOC), B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta). Based on dilution series in cell culture medium and pooled saliva, the limit of detection of these RATs was determined in a laboratory setting. Further investigations on cross-reactivity were conducted using recombinant N-protein from seasonal human coronaviruses (hCoVs). RATs evaluated showed an overall comparable performance with cultured strains of the non-VOC B.1.1 and the VOCs Alpha, Beta, Gamma, and Delta. No cross-reactivity was detected with recombinant N-protein of the hCoV strains HKU1, OC43, NL63, and 229E. A continuous evaluation of SARS-CoV-2 RAT performance is required, especially with regard to evolving mutations. Moreover, cross-reactivity and interference with pathogens and other substances on the test performance of RATs should be consistently investigated to ensure suitability in the context of SARS-CoV-2 containment.

Bats and viruses: a death-defying friendship.

Bats have a primeval evolutionary origin and have adopted various survival methods. They have played a central role in the emergence of various viral diseases. The sustenance of a plethora of virus species inside them has been an earnest area of study. This review explains how the evolution of viruses in bats has been linked to their metabolic pathways, flight abilities, reproductive abilities and colonization behaviors. The utilization of host immune response by DNA and RNA viruses is a commencement of the understanding of differences in the impact of viral infection in bats from other mammals. Rabies virus and other lyssa viruses have had long documented history as bat viruses. While many others like Ebola virus, Nipah virus, Hantavirus, SARS-CoV, MERS-CoV and other new emerging viruses like Sosuga virus, Menangle and Tioman virus are now being studied extensively for their transmission in new hosts. The ongoing pandemic SARS-CoV-2 virus has also been implicated to be originated from bats. Certain factors have been linked to spillover events while the scope of entitlement of other conditions in the spread of diseases from bats still exists. However, certain physiological and ecological parameters have been linked to specific transmission patterns, and more definite proofs are awaited for establishing these connections.

siRNA as a Potential Therapy for COVID-19.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) is a highly contagious virus causing COVID-19 disease that severely impacted the world health, education, and economy systems in 2020. The numbers of infection cases and reported deaths are still increasing with no specific treatment identified yet to halt this pandemic. Currently, several proposed treatments are under preclinical and clinical investigations now, alongside the race to vaccinate as many individuals as possible. The genome of SARS-CoV2 shares a similar gene organization as other viruses in the Coronaviridae family. It is a positive-sense, single-stranded RNA. This feature suggests that RNA interference (RNAi) is an attractive prophylactic and therapeutic option for the control of this pandemic and other possible future pandemics of the corona viruses. RNAi utilizes the use of siRNA molecules, which are 21-29 nt duplexes RNA molecules that intervene with targeted gene expression in the cytoplasm by a specific mechanism of complementary destruction of mRNA. Previous experience with SARS-CoV and the Middle East respiratory syndrome (MERS) showed that siRNA molecules were effective against these viruses in vitro and in vivo. Moreover, there have been extensive advances in siRNA technology in the past decade from chemistry and target selection considerations; which concluded with the successful approval of two commercial products based on siRNA technology. In addition, the current knowledge of the genome structure and functionality of the corona viruses enables the recognition of conserved sequences to optimize siRNA targeting and avoid viral escape through mutations, either for the current SARS-CoV2 as well as future corona viruses.

Morbidity and mortality trends of Covid 19 in top 10 countries.

The present article highlights morbidity and mortality trends of Covid 19 in the last 3 months in top 10 countries of the world. In spite of efforts being undertaken, all countries are showing an increasing trend in terms of morbidity and mortality. The order of countries in terms of mortality and morbidity has changed in the last 3 months. Various efforts are being undertaken by WHO and other agencies world over including the vaccine development initiative.

The renin-angiotensin system in COVID-19: Why ACE2 targeting by coronaviruses produces higher mortality in elderly hypertensive patients?

This renin-angiotensin system (RAS) interpretation is focused on differences in tissue dependence on RAS and on the topological hierarchy that allows mediators to act only on downstream tissues. Dependence of tissues on RAS: Tested by expectation maximization clustering of the RNA human tissue expression (https://biogps.org/). ACE and vasoconstrictive AT1R clustered with the prorenin receptor. ACE2 and dilatory MAS1 clustered with nine RAS-related genes, highly expressed in: Liver; Cardiac_Myocytes; Skeletal_Muscle; Uterus; Kidney; Lung; Small_Intestine; Smooth_Muscle. RAS and stress accumulation: While prorenin is active after binding to its receptor, binding of soluble renin increases its enzymatic activity several times. Increased renin secretion multiplies the overall capacity for producing Ang I, leading to hypertension and increased vascular resistance. Coronavirus infection and comorbidities: Cardiorespiratory failure during infection is linked to the previously altered RAS role in lungs and myocardium. Reduced vasodilation by ACE2 lead to vasoconstriction and suboptimal tissue perfusion patterns. Also see the video abstract here https://www.youtube.com/watch?v=Jf0Iped-Mws.

Is it time for microbiome-based therapies in viral infections?

Infectious diseases related to viruses, as well as bacterial pathogens, abound in all parts of the world, burdening health and economy. Thus, there is a dire need to find new prevention and treatment strategies to improve clinical practices related to viral infections. Human gut contains trillions of bacteria which have regulatory roles in immune development, homeostasis, and body metabolism. Today, it is difficult to find any prominent viral infection that hasn't had any link with the human gut microbiota. In this opinion-based review article, I argued the significance of manipulating human gut microbiota as novel therapeutics through probiotics or FMT in alleviating complexities related to viral infections, and pinpointed bottlenecks involved in this research.