A new infectious disease challenge: Urbani severe acute respiratory syndrome (SARS) associated coronavirus

Predicting the number of COVID-19 infections and deaths in USA

BACKGROUND

Uncertainties surrounding the 2019 novel coronavirus (COVID-19) remain a major global health challenge and requires attention. Researchers and medical experts have made remarkable efforts to reduce the number of cases and prevent future outbreaks through vaccines and other measures. However, there is little evidence on how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection entropy can be applied in predicting the possible number of infections and deaths. In addition, more studies on how the COVID-19 infection density contributes to the rise in infections are needed. This study demonstrates how the SARS-COV-2 daily infection entropy can be applied in predicting the number of infections within a given period. In addition, the infection density within a given population attributes to an increase in the number of COVID-19 cases and, consequently, the new variants.

RESULTS

Using the COVID-19 initial data reported by Johns Hopkins University, World Health Organization (WHO) and Global Initiative on Sharing All Influenza Data (GISAID), the result shows that the original SAR-COV-2 strain has R0<1 with an initial infection growth rate entropy of 9.11 bits for the United States (U.S.). At close proximity, the average infection time for an infected individual to infect others within a susceptible population is approximately 7 minutes. Assuming no vaccines were available, in the U.S., the number of infections could range between 41,220,199 and 82,440,398 in late March 2022 with approximately, 1,211,036 deaths. However, with the available vaccines, nearly 48 Million COVID-19 cases and 706, 437 deaths have been prevented.

CONCLUSION

The proposed technique will contribute to the ongoing investigation of the COVID-19 pandemic and a blueprint to address the uncertainties surrounding the pandemic.

A Throat Lozenge Containing Amyl Meta Cresol and Dichlorobenzyl Alcohol Has a Direct Virucidal Effect on Respiratory Syncytial Virus, Influenza a and SARS-CoV

A potent virucidal mixture containing amyl metacresol and dichlorobenzyl alcohol at low pH inactivated enveloped respiratory viruses influenza A, respiratory synctial virus (RSV) and severe acute respiratory syndrome coronavirus (SARS-CoV) but not viruses with icosahedral symmetry, such as adenoviruses or rhinoviruses. A titre of approximately 3.5 log10 TCID50 was reduced to below the level of detection within two minutes. Electron microscopy of purified influenza A virus showed extensive clumping and morphological changes in spike configuration after contact with the virucidal mixture, but no overt destruction of the viral membrane. We conclude that, formulated as a lozenge, the mixture could have significant effects in reducing the infectivity of certain infectious viruses in the throat and presumably in cough droplets, thus reducing, theoretically, opportunities for person-to-person transmission.

Recent developments in anti-severe acute respiratory syndrome coronavirus chemotherapy

Severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in early 2003 to cause a very severe acute respiratory syndrome, which eventually resulted in a 10% case-fatality rate. Owing to excellent public health measures that isolated focus cases and their contacts, and the use of supportive therapies, the epidemic was suppressed to the point that further cases have not appeared since 2005. However, despite intensive research since then (over 3500 publications), it remains an untreatable disease. The potential for re-emergence of the SARS-CoV or a similar virus with unknown but potentially serious consequences remains high. This is due in part to the extreme genetic variability of RNA viruses such as the coronaviruses, the many animal reservoirs that seem to be able host the SARS-CoV in which reassortment or recombination events could occur and the ability coronaviruses have to transmit relatively rapidly from species to species in a short period of time. Thus, it seems prudent to continue to explore and develop antiviral chemotherapies to treat SARS-CoV infections. To this end, the various efficacious anti-SARS-CoV therapies recently published from 2007 to 2010 are reviewed in this article. In addition, compounds that have been tested in various animal models and were found to reduce virus lung titers and/or were protective against death in lethal models of disease, or otherwise have been shown to ameliorate the effects of viral infection, are also reported.

Spatio-temporal evolution of Beijing 2003 SARS epidemic

Studying spatio-temporal evolution of epidemics can uncover important aspects of interaction among people, infectious diseases, and the environment, providing useful insights and modeling support to facilitate public health response and possibly prevention measures. This paper presents an empirical spatio-temporal analysis of epidemiological data concerning 2321 SARS-infected patients in Beijing in 2003. We mapped the SARS morbidity data with the spatial data resolution at the level of street and township. Two smoothing methods, Bayesian adjustment and spatial smoothing, were applied to identify the spatial risks and spatial transmission trends. Furthermore, we explored various spatial patterns and spatio-temporal evolution of Beijing 2003 SARS epidemic using spatial statistics such as Moran's I and LISA. Part of this study is targeted at evaluating the effectiveness of public health control measures implemented during the SARS epidemic. The main findings are as follows. (1) The diffusion speed of SARS in the northwest-southeast direction is weaker than that in northeast-southwest direction. (2) SARS's spread risk is positively spatially associated and the strength of this spatial association has experienced changes from weak to strong and then back to weak during the lifetime of the Beijing SARS epidemic. (3) Two spatial clusters of disease cases are identified: one in the city center and the other in the eastern suburban area. These two clusters followed different evolutionary paths but interacted with each other as well. (4) Although the government missed the opportunity to contain the early outbreak of SARS in March 2003, the response strategies implemented after the mid of April were effective. These response measures not only controlled the growth of the disease cases, but also mitigated the spatial diffusion.

Outbreak Investigations

The aim of outbreak epidemiology is to study an epidemic in order to gain control over it and to prevent further spread of the disease. Generally outbreak means a “sudden occurrence,” while in the epidemiological sense an outbreak is defined as a sudden increase in the disease frequency, related to time, place, and observed population. Thousands of outbreaks among humans and animals have been reported and investigated during the last two centuries, among them the most numerous being outbreaks of cholera, plague, malaria, smallpox, influenza, SARS, measles, salmonella, chikungunya, and various foodborne outbreaks.

PLP2, a potent deubiquitinase from murine hepatitis virus, strongly inhibits cellular type I interferon production

Infections by coronaviruses such as severe acute respiratory syndrome (SARS) coronavirus (SCoV) and mouse hepatitis virus A59 (MHV-A59) result in very little type I interferon (IFN) production by host cells, which is potentially responsible for the rapid viral growth and severe immunopathology associated with SARS. However, the molecular mechanisms for the low IFN production in cells infected with coronaviruses remain unclear. Here, we provide evidence that Papain-like protease domain 2 (PLP2), a catalytic domain of the nonstructural protein 3 (nsp3) of MHV-A59, can bind to IRF3, cause its deubiquitination and prevent its nuclear translocation. As a consequence, co-expression of PLP2 strongly inhibits CARDIF-, TBK1- and IRF3-mediated IFNbeta reporter activities. In addition, we show that wild-type PLP2 but not the mutant PLP2 lacking the deubiquitinase (DUB) activity can reduce IFN induction and promote viral growth in cells infected with VSV. Thus, our study uncovered a viral DUB which coronaviruses may use to escape from the host innate antiviral responses.

New antiviral drugs, vaccines and classic public health interventions against SARS coronavirus

Severe acute respiratory syndrome (SARS) is caused by one of two recently discovered coronaviruses. The virus is emergent from South East (SE) Asian mammals: either the civet cat, a related species or a rat species. The virus has a long incubation period and low reproduction number (R0 value) and hence the first outbreak in 2004 was controlled by hygiene and quarantine. However, the healthcare system was compromised and the economic cost was extremely high. Fortunately, the virus is easily cultivated in Vero E6 cells and therefore the search for new antivirals and vaccines was initiated within weeks of the discovery of the virus using classic techniques of cell culture and electron microscopy. Molecular diagnostics facilitated rapid and accurate diagnosis, a key factor in containing the outbreak. The broad-spectrum molecule ribavirin was used in SE Asia in infected patients alongside corticosteroids. In retrospect, many patients survived due to careful nursing. The only currently accepted intervention is interferon. Coronavirus replicon systems should facilitate rapid screening of new inhibitors and the complex mechanism of viral replication will ensure that drugs are developed against at least five molecular targets, in particular the viral protease.

Evolutional insights on uncharacterized SARS coronavirus genes

The complete genome of the severe acute respiratory syndrome coronavirus (SARS-CoV) and many of its variants has been determined by several laboratories. The genome contains fourteen predicted open reading frames (ORFs). However, a function had been clearly assigned for only six of these ORFs, in the viral replication, transcription and structural constituents. The others are herein referred to as uncharacterized ORFs (UC-ORFs). Here, we try to provide a relational insight on those UC-ORFs, suggesting that a number of them are remotely related to structural proteins of coronaviruses and other viruses infecting mammalian hosts. Surprisingly, several of the UC-ORFs exhibit considerable similarity with other SARS-CoV ORFs. These observations may provide clues on the evolution and genome dynamics of the SARS-CoV.

Molecular mechanisms of severe acute respiratory syndrome (SARS)

Severe acute respiratory syndrome (SARS) is a new infectious disease caused by a novel coronavirus that leads to deleterious pulmonary pathological features. Due to its high morbidity and mortality and widespread occurrence, SARS has evolved as an important respiratory disease which may be encountered everywhere in the world. The virus was identified as the causative agent of SARS due to the efforts of a WHO-led laboratory network. The potential mutability of the SARS-CoV genome may lead to new SARS outbreaks and several regions of the viral genomes open reading frames have been identified which may contribute to the severe virulence of the virus. With regard to the pathogenesis of SARS, several mechanisms involving both direct effects on target cells and indirect effects via the immune system may exist. Vaccination would offer the most attractive approach to prevent new epidemics of SARS, but the development of vaccines is difficult due to missing data on the role of immune system-virus interactions and the potential mutability of the virus. Even in a situation of no new infections, SARS remains a major health hazard, as new epidemics may arise. Therefore, further experimental and clinical research is required to control the disease.

A new millennium conundrum: how to use a powerful class of influenza anti-neuraminidase drugs (NAIs) in the community

Influenza A and B viruses cause serious medical problems and social disruption every year in particular countries of the world. The virus is notoriously fickle and may attack citizens in say two adjacent countries but not the third. More rarely a global pandemic virus emerges causing millions of deaths worldwide. The SARS outbreak has illuminated weaknesses in planning for sudden outbreaks of disease in a modern society and in particular how panic can grip and cause intense economic disruption. Many communities in the world are neither prepared for a global pandemic nor a very acute epidemic of influenza. The neuraminidase inhibitors (NAIs) are a new class of antiviral drug targeting a viral influenza enzyme, the neuraminidase, which acts both to facilitate virus infection of cells by clearing a passage through otherwise protective respiratory fluids and also by helping release of the virus by cutting the chemical umbilical cord which links up the virus to the infected cell. Extensive laboratory studies of the two molecules zanamivir and oseltamivir have shown that they block all influenza A and B viruses yet tested and would, in theory, even inhibit the 1918 pandemic virus. Both drugs can be used prophylactically to prevent spread of infection in families and communities where 80-90% protection has been documented. The therapeutic effects are also strong in adults and children abbreviating infection, reducing quantities of excreted virus and reducing antibiotic prescriptions. The drugs have to be taken within 48 h of the onset of symptoms. Drug resistance is not a problem at present because although such mutants occur the mutants are compromised and are less virulent than their drug-sensitive parents and they spread less easily. The two drugs could be stockpiled to prepare for an influenza pandemic but, importantly, clinical and scientific experience need to be gained by using these inhibitors in the yearly conflagrations of epidemic influenza, which unchecked do great harm to our communities.

Severe acute respiratory syndrome: global initiatives for disease diagnosis

We present a retrospective analysis of the available articles on severe acute respiratory syndrome (SARS) published since the outbreak of the disease. SARS is a new infectious disease caused by a novel coronavirus. Originating in Guangdong, Southern China, at the end of 2002, it has spread to regions all over the world, affecting more than 8000 people. With high morbidity and mortality, SARS is an important respiratory disease which may be encountered world-wide. The causative virus was identified by a WHO-led network of laboratories, which identified the genome sequence and developed the first molecular assays for diagnosis. For the respiratory physician, detecting SARS in its earliest stages, identifying pathways of transmission, and implementing preventive and therapeutic strategies are all important. The WHO and the CDC have published helpful definitions of 'suspected' and 'probable' cases. However, the symptoms of the disease may change, and laboratory tests and definitions are still limited. Even in a situation of no new cases of infection, SARS remains a major respiratory health hazard. As with influenza virus outbreaks, new epidemics may arise at the end of each year.