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Stability of SARS Coronavirus in Human Specimens and Environment and Its Sensitivity to Heating and UV Irradiation
Abstract
The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was studied.
Using a SARS coronavirus strain CoV-P9, which was isolated from pharyngeal swab of a probable SARS case in Beijing, its stability in mimic human specimens and in mimic environment including surfaces of commonly used materials or in household conditions, as well as its resistance to temperature and UV irradiation were analyzed. A total of 10(6) TCID50 viruses were placed in each tested condition, and changes of the viral infectivity in samples after treatments were measured by evaluating cytopathic effect (CPE) in cell line Vero-E6 at 48 h after infection.
The results showed that SARS coronavirus in the testing condition could survive in serum, 1:20 diluted sputum and feces for at least 96 h, whereas it could remain alive in urine for at least 72 h with a low level of infectivity. The survival abilities on the surfaces of eight different materials and in water were quite comparable, revealing reduction of infectivity after 72 to 96 h exposure. Viruses stayed stable at 4 degrees C, at room temperature (20 degrees C) and at 37 degrees C for at least 2 h without remarkable change in the infectious ability in cells, but were converted to be non-infectious after 90-, 60- and 30-min exposure at 56 degrees C, at 67 degrees C and at 75 degrees C, respectively. Irradiation of UV for 60 min on the virus in culture medium resulted in the destruction of viral infectivity at an undetectable level.
The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.
... The detection of RNA or even viable viruses on surfaces suggests that contaminated fomites may harbor viral material; however, this detection does not confirm that the virus remains infectious in real-world conditions. Furthermore, it should be taken into account that environmental factors like temperature, humidity, and UV light degrade viral particles over time [33,34]. Contact tracing and epidemiological studies [35] have found that most COVID-19 transmission events are associated with close person-to-person contact or shared airspace, rather than surface contact [36]. ...
... However, environmental resistance varies significantly between enveloped and non-enveloped viruses due to differences in their structural composition (Table 1) [46]. These differences influence their survival on surfaces, resistance to disinfectants, and vulnerability to environmental factors like temperature [47], humidity, and UV light [33]. Enveloped viruses, such as coronaviruses, possess a protective lipid bilayer envelope surrounding the protein capsid and nucleic acid. ...
The increasing need for effective antiviral strategies has led to the development of innovative surface coatings to combat the transmission of viruses via fomites. The aim of this review is to critically assess the efficacy of antiviral coatings in mitigating virus transmission, particularly those activated by visible light. The alarm created by the COVID-19 pandemic, including the initial uncertainty about the mechanisms of its spread, attracted attention to fomites as a possible source of virus transmission. However, later research has shown that surface-dependent infection mechanisms need to be carefully evaluated experimentally. By briefly analyzing virus–surface interactions and their implications, this review highlights the importance of shifting to innovative solutions. In particular, visible-light-activated antiviral coatings that use reactive oxygen species such as singlet oxygen to disrupt viral components have emerged as promising options. These coatings can allow for obtaining safe, continuous, and long-term active biocidal surfaces suitable for various applications, including healthcare environments and public spaces. This review indicates that while the significance of fomite transmission is context-dependent, advances in material science provide actionable pathways for designing multifunctional, visible-light-activated antiviral coatings. These innovations align with the lessons learned from the COVID-19 pandemic and pave the way for sustainable, broad-spectrum antiviral solutions capable of addressing future public health challenges.
... Secretory autophagy is known to promote viral maturation, egress, and cell-cell spreading and is initiated by SFTSV infection. In addition, the SFTSV infection did not exhibit a cytopathic effect, similar to some other viruses such as the SARS coronavirus [34]. Instead of merely observing a static state, the study revealed a dynamic morphological transformation (Supplementary Figure S1) over two days, marked by the emergence of multinucleated cells and a sharp increase in the concentration of the virus by the third day after infection. ...
In our prior investigations, we elucidated the role of the tryptophan-to-tyrosine substitution at the 61st position in the nonstructural protein NSsW61Y in diminishing the interaction between nonstructural proteins (NSs) and nucleoprotein (NP), impeding viral replication. In this study, we focused on the involvement of NSs in replication via the modulation of autophagosomes. Initially, we examined the impact of NP expression levels, a marker for replication, upon the infection of HeLa cells with severe fever thrombocytopenia syndrome virus (SFTSV), with or without the inhibition of NP binding. Western blot analysis revealed a reduction in NP levels in NSsW61Y-expressing conditions. Furthermore, the expression levels of the canonical autophagosome markers p62 and LC3 decreased in HeLa cells expressing NSsW61Y, revealing the involvement of individual viral proteins on autophagy. Subsequent experiments confirmed that NSsW61Y perturbs autophagy flux, as evidenced by reduced levels of LC3B and p62 upon treatment with chloroquine, an inhibitor of autophagosome–lysosome fusion. LysoTracker staining demonstrated a decrease in lysosomes in cells expressing the NS mutant compared to those expressing wild-type NS. We further explored the mTOR-associated regulatory pathway, a key regulator affected by NS mutant expression. The observed inhibition of replication could be linked to conformational changes in the NSs, impairing their binding to NP and altering mTOR regulation, a crucial upstream signaling component in autophagy. These findings illuminate the intricate interplay between NSsW61Y and the suppression of host autophagy machinery, which is crucial for the generation of autophagosomes to facilitate viral replication.
... Chin et al. reported that after 2 days, no infective SARS-CoV-2 was detected on the treated wood surface in their experiments (room temperature, RH 65%) while Duan et al. reported that SARS-CoV stayed infectious for 4−5 days at room temperature on wood board. 16,23 In our studies, we simulated standardized test conditions by incubating the virus on the surface at room temperature and over 90% RH. Additionally, it was important to note that indoor humidity levels can vary significantly, especially in Nordic countries. ...
The ongoing challenge of viral transmission, exemplified by the Covid pandemic and recurrent viral outbreaks, necessitates the exploration of sustainable antiviral solutions. This study investigates the underexplored antiviral potential of wooden surfaces. We evaluated the antiviral efficacy of various wood types, including coniferous and deciduous trees, against enveloped coronaviruses and nonenveloped enteroviruses like coxsackie virus A9. Our findings revealed excellent antiviral activity manifesting already within 10 to 15 min in Scots pine and Norway spruce, particularly against enveloped viruses. In contrast, other hardwoods displayed varied efficacy, with oak showing effectiveness against the enterovirus. This antiviral activity was consistently observed across a spectrum of humidity levels (20 to 90 RH%), while the antiviral efficacy manifested itself more rapidly at 37 °C vs 21 °C. Key to our findings is the chemical composition of these woods. Resin acids and terpenes were prevalent in pine and spruce, correlating with their antiviral performance, while oak’s high phenolic content mirrored its efficacy against enterovirus. The pine surface absorbed a higher fraction of the coronavirus in contrast to oak, whereas enteroviruses were not absorbed on those surfaces. Thermal treatment of wood or mixing wood with plastic, such as in wood-plastic composites, strongly compromised the antiviral functionality of wood materials. This study highlights the role of bioactive chemicals in the antiviral action of wood and opens new avenues for employing wood surfaces as a natural and sustainable barrier against viral transmissions.
... Furthermore, freezing temperatures can aggravate diarrhea, easily causing winter dysentery. However, other studies have shown that BCoV-induced diarrhea was not correlated with low temperatures [30,33,46]. HE and S are critical for BCoV invasion and cellular release and are critical antibodyneutralization epitopes. ...
Simple Summary
Bovine coronavirus (BCoV), bovine rotavirus, bovine viral diarrhea virus, and bovine astrovirus are the most common intestinal pathogenic viruses causing diarrhea in cattle. BCoV was the major pathogen detected, with a positive rate of 34.02% (560/1646) from January 2020 to August 2023. The asymptomatic BCoV-infected rate (351/1646) was higher than the diarrhea BCoV-infected rate (209/1646). Studying the relevance of diarrhea associated with BCoV has shown that the onset of diarrheal symptoms post-infection is strongly correlated with the cattle’s age and may also be related to the breed. One the other hand, we amplified and sequenced the hemagglutinin esterase (HE), spike protein, and whole genomes of the partially positive samples and obtained six complete HE sequences, seven complete spike sequences, and six whole genomes. The results of molecular characterization revealed that six strains were in the GⅡb subgroup, and HBSJZ2202 and JSYZ2209 had four amino acid insertions on HE. We also analyzed ORF1a and found disparities across various regions within GIIb, which were positioned on separate branches within the phylogenetic tree. This work provides data for further investigating the epidemiology of BCoV and for understanding and analyzing BCoV distribution and dynamics.
Abstract
Bovine coronavirus (BCoV), bovine rotavirus, bovine viral diarrhea virus, and bovine astrovirus are the most common intestinal pathogenic viruses causing diarrhea in cattle. We collected 1646 bovine fecal samples from January 2020 to August 2023. BCoV was the major pathogen detected, with a positive rate of 34.02% (560/1646). Of the 670 diarrheal samples and 976 asymptomatic samples, 209 and 351 were BCoV-positive, respectively. Studying the relevance of diarrhea associated with BCoV has shown that the onset of diarrheal symptoms post-infection is strongly correlated with the cattle’s age and may also be related to the breed. We amplified and sequenced the hemagglutinin esterase (HE), spike protein, and whole genomes of the partially positive samples and obtained six complete HE sequences, seven complete spike sequences, and six whole genomes. Molecular characterization revealed that six strains were branched Chinese strains, Japanese strains, and partial American strains from the GⅡb subgroup. Strains HBSJZ2202 and JSYZ2209 had four amino acid insertions on HE. We also analyzed ORF1a and found disparities across various regions within GIIb, which were positioned on separate branches within the phylogenetic tree. This work provides data for further investigating the epidemiology of BCoV and for understanding and analyzing BCoV distribution and dynamics.
O surgimento do SARS-CoV-2 trouxe desafios significativos para a Odontologia, especialmente por se tratar de uma profissão que exige proximidade física entre o profissional e o paciente, além da produção constante de aerossóis durante os procedimentos. Esses fatores aumentam o risco de transmissão de doenças infecciosas, especialmente em ambientes como consultórios odontológicos, onde as principais vias de contágio – boca, nariz e olhos – ficam constantemente expostas. Diante desse cenário, tornou-se essencial investigar estratégias eficazes de prevenção da contaminação cruzada, como o uso de enxaguatórios bucais antivirais, métodos de desinfecção de superfícies e a atualização dos equipamentos de proteção individual. Para isso, foi realizada uma pesquisa eletrônica na base de dados PubMed, com artigos publicados até agosto de 2020, utilizando os termos “Covid-19” + “Dentistry” e “SARS-CoV-2” + “Dentistry”. Inicialmente, foram encontrados 537 estudos. Após análise de títulos e resumos, 92 foram selecionados, e, desses, 67 apresentaram relação direta com o escopo da revisão. Os resultados demonstraram que o peróxido de hidrogênio a 1% e a iodopovidona a 0,2% foram os enxaguatórios bucais mais eficazes na redução da carga viral. Já na desinfecção de superfícies, soluções à base de álcool e hipoclorito mostraram efeito significativo na inativação do vírus. Esses achados reforçam a importância de medidas preventivas rigorosas na rotina odontológica. A implementação de protocolos baseados em evidências científicas, aliada à disseminação de orientações claras aos profissionais da área, é fundamental para reduzir os riscos de contaminação e, consequentemente, controlar a curva de infecção no ambiente clínico.
Digital transformation has disruptive effects on science and science communication. In digital and social media, traditional allocation of roles in the relation between science and public are called into question and bring forth new formats and practices of science communication. On the basis of three selected digital science communication formats from the domain of the COVID19 pandemic, this contribution shows how the popularizing translations between specialized and everyday discourses are transmedially organized and invite retranslations. It proposes the media-theoretical concept of transcriptivity for the theoretical version of such discourse movements, which also allows to grasp the follow-up communications. Finally, it is argued that science communication and its transcriptive procedures are organized in communication arenas that replace the traditional vertical model science communication.
Millions of discarded single-use and medical waste generated plastics (masks, gloves, aprons and sanitizer bottles etc.) during the COVID-19 pandemic have been added to the terrestrial environment. It is estimated that 1.6 million tons of plastic waste have been generated worldwide since the outbreak. The unexpected incidence of an epidemic of this scale has resulted in unbearable levels of plastic wastes. Thus, the plastic system has been burdened with much inefficiency due to the outbreak of the Corona virus (SARS-CoV2) pandemic. It emphasizes that it is risky to think of plastic waste management as a limited and linear problem, because of the complexity and interrelationships of the various parts of the plastics system that are influenced by interconnected processes, stakeholders and values. Investing in circular technologies such as feedstock recycling and improving the environmental viability of existing techniques could be critical in dealing with plastic waste fluxes during a crisis. The three R’s (reduce, reuse and recycle) efforts need to be done in an effective manner to promote better plastic waste management. We then explain the present pathways for reduce, reuse and recycling of plastic waste during the COVID-19 pandemic via mechanical, physical and chemical processes and what steps should be taken to improve the three R’s rates in order to promote sustainability in the plastics industry. This chapter aims to raise awareness about the importance of implementing three R’s targeted dynamic plastic waste management strategies to reduce environmental pollution caused by the COVID-19 pandemic.
In healthcare settings, contaminated surfaces play an important role in the transmission of nosocomial pathogens potentially resulting in healthcare-associated infections (HAI). Pathogens can be transmitted directly from frequent hand-touch surfaces close to patients or indirectly by staff and visitors. HAI risk depends on exposure, extent of contamination, infectious dose (ID), virulence, hygiene practices, and patient vulnerability. This review attempts to close a gap in previous reviews on persistence/tenacity by only including articles ( n = 171) providing quantitative data on re-cultivable pathogens from fomites for a better translation into clinical settings. We have therefore introduced the new term “replication capacity” (RC). The RC is affected by the degree of contamination, surface material, temperature, relative humidity, protein load, organic soil, UV-light (sunlight) exposure, and pH value. In general, investigations into surface RC are mainly performed in vitro using reference strains with high inocula. In vitro data from studies on 14 Gram-positive, 26 Gram-negative bacteria, 18 fungi, 4 protozoa, and 37 viruses. It should be regarded as a worst-case scenario indicating the upper bounds of risks when using such data for clinical decision-making. Information on RC after surface contamination could be seen as an opportunity to choose the most appropriate infection prevention and control (IPC) strategies. To help with decision-making, pathogens characterized by an increased nosocomial risk for transmission from inanimate surfaces (“fomite-borne”) are presented and discussed in this systematic review. Thus, the review offers a theoretical basis to support local risk assessments and IPC recommendations.
The current pandemic generates plastic waste from the medical field, mainly consisting of polystyrene, polypropylene, polyethylene terephthalate, nylon, and polyethylene. COVID-19 outbreak has become a universal health hazard, leading to severe human respiratory tract infections via droplets, infected palms, or surfaces. Personal protection equipment (PPE) must be worn at all times to avoid contracting COVID, which creates a huge problem for the PPE supply chain made of single-use plastic. The greatest challenge is to minimize the decontaminated PPE waste generated with the help of the reuse and recycling of PPEs so that the abandoned PPE waste can be minimized. Because new research has recently improved the reliability of reprocessing technologies, reusing PPE could be a viable short-term solution to the COVID-19 epidemic. These include vaporized hydrogen peroxide disinfecting techniques, ultraviolet light disinfecting techniques, thermal disinfecting techniques like pyrolysis, a microwave technique, and many more. The study's main objective is to generate a list of all the relevant literature on various PPE sterilizing processes in order to assist readers in determining their best options.
This review provides an overview of the inactivation of pathogenic microorganisms using deep-UV light. Specifically, it discusses bacteria and viruses, presenting inactivation mechanisms and outlining key considerations for evaluating the effectiveness of inactivation. In addition, it also presents the actual inactivation effect of viruses using deep-UV LEDs, which have garnered significant attention in recent years.
In March 2003, a novel coronavirus (SARS-CoV) was discovered in association with cases of severe acute respiratory syndrome (SARS). The sequence of the complete genome of SARS-CoV was determined, and the initial characterization of the viral genome is presented in this report. The genome of SARS-CoV is 29,727 nucleotides in length and has 11 open reading frames, and its genome organization is similar to that of other coronaviruses. Phylogenetic analyses and sequence comparisons showed that SARS-CoV is not closely related to any of the previously characterized coronaviruses.
Information on the clinical features of the severe acute respiratory syndrome (SARS) will be of value to physicians caring for patients suspected of having this disorder.
We abstracted data on the clinical presentation and course of disease in 10 epidemiologically linked Chinese patients (5 men and 5 women 38 to 72 years old) in whom SARS was diagnosed between February 22, 2003, and March 22, 2003, at our hospitals in Hong Kong, China.
Exposure between the source patient and subsequent patients ranged from minimal to that between patient and health care provider. The incubation period ranged from 2 to 11 days. All patients presented with fever (temperature, >38 degrees C for over 24 hours), and most presented with rigor, dry cough, dyspnea, malaise, headache, and hypoxemia. Physical examination of the chest revealed crackles and percussion dullness. Lymphopenia was observed in nine patients, and most patients had mildly elevated aminotransferase levels but normal serum creatinine levels. Serial chest radiographs showed progressive air-space disease. Two patients died of progressive respiratory failure; histologic analysis of their lungs showed diffuse alveolar damage. There was no evidence of infection by Mycoplasma pneumoniae, Chlamydia pneumoniae, or Legionella pneumophila. All patients received corticosteroid and ribavirin therapy a mean (+/-SD) of 9.6+/-5.42 days after the onset of symptoms, and eight were treated earlier with a combination of beta-lactams and macrolide for 4+/-1.9 days, with no clinical or radiologic efficacy.
SARS appears to be infectious in origin. Fever followed by rapidly progressive respiratory compromise is the key complex of signs and symptoms from which the syndrome derives its name. The microbiologic origins of SARS remain unclear.
There has been an outbreak of the severe acute respiratory syndrome (SARS) worldwide. We report the clinical, laboratory, and radiologic features of 138 cases of suspected SARS during a hospital outbreak in Hong Kong.
From March 11 to 25, 2003, all patients with suspected SARS after exposure to an index patient or ward were admitted to the isolation wards of the Prince of Wales Hospital. Their demographic, clinical, laboratory, and radiologic characteristics were analyzed. Clinical end points included the need for intensive care and death. Univariate and multivariate analyses were performed.
There were 66 male patients and 72 female patients in this cohort, 69 of whom were health care workers. The most common symptoms included fever (in 100 percent of the patients); chills, rigors, or both (73.2 percent); and myalgia (60.9 percent). Cough and headache were also reported in more than 50 percent of the patients. Other common findings were lymphopenia (in 69.6 percent), thrombocytopenia (44.8 percent), and elevated lactate dehydrogenase and creatine kinase levels (71.0 percent and 32.1 percent, respectively). Peripheral air-space consolidation was commonly observed on thoracic computed tomographic scanning. A total of 32 patients (23.2 percent) were admitted to the intensive care unit; 5 patients died, all of whom had coexisting conditions. In a multivariate analysis, the independent predictors of an adverse outcome were advanced age (odds ratio per decade of life, 1.80; 95 percent confidence interval, 1.16 to 2.81; P=0.009), a high peak lactate dehydrogenase level (odds ratio per 100 U per liter, 2.09; 95 percent confidence interval, 1.28 to 3.42; P=0.003), and an absolute neutrophil count that exceeded the upper limit of the normal range on presentation (odds ratio, 1.60; 95 percent confidence interval, 1.03 to 2.50; P=0.04).
SARS is a serious respiratory illness that led to significant morbidity and mortality in our cohort.
A worldwide outbreak of severe acute respiratory syndrome (SARS) has been associated with exposures originating from a single ill health care worker from Guangdong Province, China. We conducted studies to identify the etiologic agent of this outbreak.
We received clinical specimens from patients in seven countries and tested them, using virus-isolation techniques, electron-microscopical and histologic studies, and molecular and serologic assays, in an attempt to identify a wide range of potential pathogens.
None of the previously described respiratory pathogens were consistently identified. However, a novel coronavirus was isolated from patients who met the case definition of SARS. Cytopathological features were noted in Vero E6 cells inoculated with a throat-swab specimen. Electron-microscopical examination revealed ultrastructural features characteristic of coronaviruses. Immunohistochemical and immunofluorescence staining revealed reactivity with group I coronavirus polyclonal antibodies. Consensus coronavirus primers designed to amplify a fragment of the polymerase gene by reverse transcription-polymerase chain reaction (RT-PCR) were used to obtain a sequence that clearly identified the isolate as a unique coronavirus only distantly related to previously sequenced coronaviruses. With specific diagnostic RT-PCR primers we identified several identical nucleotide sequences in 12 patients from several locations, a finding consistent with a point-source outbreak. Indirect fluorescence antibody tests and enzyme-linked immunosorbent assays made with the new isolate have been used to demonstrate a virus-specific serologic response. This virus may never before have circulated in the U.S. population.
A novel coronavirus is associated with this outbreak, and the evidence indicates that this virus has an etiologic role in SARS. Because of the death of Dr. Carlo Urbani, we propose that our first isolate be named the Urbani strain of SARS-associated coronavirus.
We sequenced the 29,751-base genome of the severe acute respiratory syndrome (SARS)-associated coronavirus known as the Tor2 isolate. The genome sequence reveals that this coronavirus is only moderately related to other known coronaviruses, including two human coronaviruses, HCoV-OC43 and HCoV-229E. Phylogenetic analysis of the predicted viral proteins indicates that the virus does not closely resemble any of the three previously known groups of coronaviruses. The genome sequence will aid in the diagnosis of SARS virus infection in humans and potential animal hosts (using polymerase chain reaction and immunological tests), in the development of antivirals (including neutralizing antibodies), and in the identification of putative epitopes for vaccine development.
The susceptibility of laboratory mice to intranasal and contact infection with mouse hepatitis virus (MHV)-related coronaviruses was tested in infant CD1 mice. One day old mouse pups were inoculated intranasally with respiratory MHV-S, enteric MHV-Y, rat sialodacryoadenitis virus (SDAV), human coronavirus OC43 (HCV-OC43) or bovine coronavirus (BCV). Twenty-four hours later, they were placed in direct contact with age matched sham inoculated pups. Indices of infection in virus inoculated mice included lesions by histopathology and viral antigen by immunoperoxidase histochemistry in brain, lung, liver and intestine at 3 days after inoculation. Indices of infection in contact mice included mortality or seroconversion by 21 days after exposure. Infant mice were susceptible to infection with all five viruses. Transmission by direct contact exposure occurred with MHV and SDAV, but not HCV or BCV. Furthermore, adult mice were not susceptible to infection with HCV. Tissue distribution of lesions and antigen varied markedly among viruses, indicating that they do not induce the same disease as MHV. This study demonstrates that although these coronaviruses are antigenically closely related, they are biologically different viruses and disease patterns in susceptible infant mice can be used to differentiate viruses.
Rhinoviruses are picornaviruses that cause colds. They are naturally temperature sensitive and highly adapted to grow in respiratory epithelium. Coronaviruses are structurally quite different, being enveloped viruses but are also adapted to grow in respiratory epithelium and also cause colds.
The quasispecies nature of three animal pathogenic RNA viruses of field origin was examined by testing variants of classical swine fever virus (CSFV) originating from geographically different areas, feline coronavirus (FCoV) detected from the same animal by successive sampling, and rabbit haemorrhagic disease virus (RHDV) originating from successive outbreaks in the same geographic area. Clinical samples were investigated using reverse transcriptase polymerase chain reaction (RT-PCR) and ensuing single strand conformational polymorphism (SSCP) assay. By the combination of these methods even subtle differences could be detected among the amplified fragments of the same virus species of different origin. FCoV proved to comprise the most and CSFV the less heterogeneous virus quasispecies. The results show that the combination of RT-PCR and SSCP provides novel and highly sensitive means for the characterisation of RNA viruses, with special regard to genome composition, evolution, features of pathogenicity and molecular epizootiology.
An outbreak of severe acute respiratory syndrome (SARS) has been reported in Hong Kong. We investigated the viral cause and clinical presentation among 50 patients.
We analysed case notes and microbiological findings for 50 patients with SARS, representing more than five separate epidemiologically linked transmission clusters. We defined the clinical presentation and risk factors associated with severe disease and investigated the causal agents by chest radiography and laboratory testing of nasopharyngeal aspirates and sera samples. We compared the laboratory findings with those submitted for microbiological investigation of other diseases from patients whose identity was masked.
Patients' age ranged from 23 to 74 years. Fever, chills, myalgia, and cough were the most frequent complaints. When compared with chest radiographic changes, respiratory symptoms and auscultatory findings were disproportionally mild. Patients who were household contacts of other infected people and had older age, lymphopenia, and liver dysfunction were associated with severe disease. A virus belonging to the family Coronaviridae was isolated from two patients. By use of serological and reverse-transcriptase PCR specific for this virus, 45 of 50 patients with SARS, but no controls, had evidence of infection with this virus.
A coronavirus was isolated from patients with SARS that might be the primary agent associated with this disease. Serological and molecular tests specific for the virus permitted a definitive laboratory diagnosis to be made and allowed further investigation to define whether other cofactors play a part in disease progression.