how long does coronavirus remain stable  on surfaces?

Stability and infectivity of coronaviruses in inanimate environments

Coronaviruses widespread on nonliving surfaces: important questions and promising answers.

The world is facing, while writing this review, a global pandemic due to one of the types of the coronaviruses (i.e., COVID-19), which is a new virus. Among the most important reasons for the transmission of infection between humans is the presence of this virus active on the surfaces and materials. Here, we addressed important questions such as do coronaviruses remain active on the inanimate surfaces? Do the types of inanimate surfaces affect the activity of coronaviruses? What are the most suitable ingredients that used to inactivate viruses? This review article addressed many of the works that were done in the previous periods on the survival of many viruses from the coronaviruses family on various surfaces such as steel, glass, plastic, Teflon, ceramic tiles, silicon rubber and stainless steel copper alloys, Al surface, sterile sponges, surgical gloves and sterile latex. The impacts of environmental conditions such as temperature and humidity were presented and discussed. The most important active ingredients that can deactivate viruses on the surfaces were reported here. We hope that these active ingredients will have the same effect on COVID-19.

Coronaviruses widespread on nonliving surfaces: important questions and promising answers

Stability of bovine coronavirus on lettuce surfaces under household refrigeration conditions

Fecal suspensions with an aerosol route of transmission were responsible for a cluster of severe acute respiratory syndrome (SARS) cases in 2003 in Hong Kong. Based on that event, the World Health Organization recommended that research be implemented to define modes of transmission of SARS coronavirus through sewage, feces, food and water. Environmental studies have shown that animal coronaviruses remain infectious in water and sewage for up to a year depending on the temperature and humidity. In this study, we examined coronavirus stability on lettuce surfaces. A cell culture adapted bovine coronavirus, diluted in growth media or in bovine fecal suspensions to simulate fecal contamination was used to spike romaine lettuce. qRT-PCR detected viral RNA copy number ranging from 6.6 × 10(4) to 1.7 × 10(6) throughout the experimental period of 30 days. Whereas infectious viruses were detected for at least 14 days, the amount of infectious virus varied, depending upon the diluent used for spiking the lettuce. UV and confocal microscopic observation indicated attachment of residual labeled virions to the lettuce surface after the elution procedure, suggesting that rates of inactivation or detection of the virus may be underestimated. Thus, it is possible that contaminated vegetables may be potential vehicles for coronavirus zoonotic transmission to humans.

How long do nosocomial pathogens persist on inanimate surfaces? A systematic review

BACKGROUND: Inanimate surfaces have often been described as the source for outbreaks of nosocomial infections. The aim of this review is to summarize data on the persistence of different nosocomial pathogens on inanimate surfaces. METHODS: The literature was systematically reviewed in MedLine without language restrictions. In addition, cited articles in a report were assessed and standard textbooks on the topic were reviewed. All reports with experimental evidence on the duration of persistence of a nosocomial pathogen on any type of surface were included. RESULTS: Most gram-positive bacteria, such as Enterococcus spp. (including VRE), Staphylococcus aureus (including MRSA), or Streptococcus pyogenes, survive for months on dry surfaces. Many gram-negative species, such as Acinetobacter spp., Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Serratia marcescens, or Shigella spp., can also survive for months. A few others, such as Bordetella pertussis, Haemophilus influenzae, Proteus vulgaris, or Vibrio cholerae, however, persist only for days. Mycobacteria, including Mycobacterium tuberculosis, and spore-forming bacteria, including Clostridium difficile, can also survive for months on surfaces. Candida albicans as the most important nosocomial fungal pathogen can survive up to 4 months on surfaces. Persistence of other yeasts, such as Torulopsis glabrata, was described to be similar (5 months) or shorter (Candida parapsilosis, 14 days). Most viruses from the respiratory tract, such as corona, coxsackie, influenza, SARS or rhino virus, can persist on surfaces for a few days. Viruses from the gastrointestinal tract, such as astrovirus, HAV, polio- or rota virus, persist for approximately 2 months. Blood-borne viruses, such as HBV or HIV, can persist for more than one week. Herpes viruses, such as CMV or HSV type 1 and 2, have been shown to persist from only a few hours up to 7 days. CONCLUSION: The most common nosocomial pathogens may well survive or persist on surfaces for months and can thereby be a continuous source of transmission if no regular preventive surface disinfection is performed.

How long does Coronavirus survive on different surfaces?

Dental practices now need to be more vigilant than ever and pay extra attention to hygiene in the surgery Hospitals are currently operating an hourly total clean policy and it would be prudent for dental practices to look to operate something similar to reduce the possibility of viral transmission The Government is encouraging people to stay at home and maintain social distancing during the pandemic However, key workers must go to work, use public transport and mix with high risk people People also need to go to supermarkets to get their groceries The surfaces in these public places are likely to be contaminated;these germs can then be brought into homes or dental practices

Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents

Summary Currently, the emergence of a novel human coronavirus, SARS-CoV-2, has become a global health concern causing severe respiratory tract infections in humans. Human-to-human transmissions have been described with incubation times between 2-10 days, facilitating its spread via droplets, contaminated hands or surfaces. We therefore reviewed the literature on all available information about the persistence of human and veterinary coronaviruses on inanimate surfaces as well as inactivation strategies with biocidal agents used for chemical disinfection, e.g. in healthcare facilities. The analysis of 22 studies reveals that human coronaviruses such as Severe Acute Respiratory Syndrome (SARS) coronavirus, Middle East Respiratory Syndrome (MERS) coronavirus or endemic human coronaviruses (HCoV) can persist on inanimate surfaces like metal, glass or plastic for up to 9 days, but can be efficiently inactivated by surface disinfection procedures with 62–71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite within 1 minute. Other biocidal agents such as 0.05–0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate are less effective. As no specific therapies are available for SARS-CoV-2, early containment and prevention of further spread will be crucial to stop the ongoing outbreak and to control this novel infectious thread.

Another Decade, Another Coronavirus

Isothermal evaporation rate of deposited liquid aerosols and the SARS-CoV-2 coronavirus survival

It is shown that the evaporation rate of a liquid sample containing the culture of coronavirus affects its survival on a substrate. Possible mechanisms of such influence can be due to the appearance of large, about 140 bar, non comprehensive capillary pressures and the associated dynamic forces during the movement of the evaporation front in a sample with the virus. A simulation of isothermal evaporation of a thin liquid sample based on the Stefan problem was performed. The comparison of simulation data and recent experiments on the coronavirus survival on various surfaces showed that the rate of isothermal evaporation of aqueous samples, which is higher for heat-conducting materials, correlates well with the lifetime of the coronavirus on these surfaces.

Currently, the emergence of a novel human coronavirus, SARS-CoV-2, has become a global health concern causing severe respiratory tract infections in humans. Human-to-human transmissions have been described with incubation times between 2-10 days, facilitating its spread via droplets, contaminated hands or surfaces. We therefore reviewed the literature on all available information about the persistence of human and veterinary coronaviruses on inanimate surfaces as well as inactivation strategies with biocidal agents used for chemical disinfection, e.g. in healthcare facilities. The analysis of 22 studies reveals that human coronaviruses such as Severe Acute Respiratory Syndrome (SARS) coronavirus, Middle East Respiratory Syndrome (MERS) coronavirus or endemic human coronaviruses (HCoV) can persist on inanimate surfaces like metal, glass or plastic for up to 9 days, but can be efficiently inactivated by surface disinfection procedures with 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite within 1 minute. Other biocidal agents such as 0.05-0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate are less effective. As no specific therapies are available for SARS-CoV-2, early containment and prevention of further spread will be crucial to stop the ongoing outbreak and to control this novel infectious thread.

Genome analyses help track coronavirus' moves

Genome analyses help track coronavirus' moves.

Bovine coronavirus mRNA replication continues throughout persistent infection in cell culture.

The existence of viral mRNA replicons was demonstrated in cells infected with the bovine coronavirus by showing a minus-strand counterpart and a corresponding replicative intermediate for each subgenomic mRNA species. mRNA replication is thus a universal property of coronaviruses, since this is now the third coronavirus for which it has been demonstrated. During the acute phase of infection (first 48 h), minus and plus strands accumulated at the same rate initially, but maximal accumulation of minus strands peaked earlier than that for plus strands, indicating that minus- and plus-strand levels are differentially regulated. In addition, packaged (input) mRNAs appeared to serve as templates for their own early replication. mRNA replication continued throughout establishment and maintenance of persistent infection (studied for 120 days), which is consistent with our hypothesis that mRNA replication contributes mechanistically to virus persistence. A replication-defective (potentially interfering) species of RNA existed transiently (beginning at day 2 and ending before day 76 postinfection), but because of its transient nature it cannot be considered essential to the long-term maintenance of virus persistence.

Adaptation of coronavirus JHM to persistent infection of murine sac(-) cells.

Coronaviruses can establish persistent infections in the central nervous system of rodents, and these are associated with demyelinating encephalomyelitis. The effects of persistence on the virus are difficult to study in vivo but may have a crucial influence on the course of infection. We therefore produced a persistent infection in vitro using the neurotropic coronavirus JHM, in order to investigate the events underlying the establishment of such an infection and the adaptation of the virus to persistence. The persistent infection was maintained for over 115 passages and continued to release high levels of infectious virus. During the 18 months of culture the number of cells expressing virus antigen detected by indirect immune fluorescence decreased to 40%. Analysis showed that the carried virus contained a significant proportion of heterogeneous temperature-sensitive mutants. All virus clones isolated possessed the capacity to induce a more productive growth cycle, a less pronounced cytopathic effect and showed a much reduced neurovirulence when inoculated into newborn and weanling rats. Evidence for structural changes involving the surface peplomer protein (E2) was obtained using hybridoma antibodies, which neutralized the parental JHM virus but not the JHM-Pi virus. Defective interfering particles and interferon activities have been excluded as possible agents instrumental in the establishment and maintenance of the chronic infection, and we suggest that the emergence of virus variants of lowered virulence is central to these processes.

The Effects of Temperature and Relative Humidity on the Viability of the SARS Coronavirus

The main route of transmission of SARS CoV infection is presumed to be respiratory droplets. However the virus is also detectable in other body fluids and excreta. The stability of the virus at different temperatures and relative humidity on smooth surfaces were studied. The dried virus on smooth surfaces retained its viability for over 5 days at temperatures of 22–25°C and relative humidity of 40–50%, that is, typical air-conditioned environments. However, virus viability was rapidly lost (>3 log(10)) at higher temperatures and higher relative humidity (e.g., 38°C, and relative humidity of >95%). The better stability of SARS coronavirus at low temperature and low humidity environment may facilitate its transmission in community in subtropical area (such as Hong Kong) during the spring and in air-conditioned environments. It may also explain why some Asian countries in tropical area (such as Malaysia, Indonesia or Thailand) with high temperature and high relative humidity environment did not have major community outbreaks of SARS.

Calling all coronavirus researchers: keep sharing, stay open.

Establishment and maintenance of a persistent infection of L132 cells by human coronavirus strain 229E

A persistent infection by human coronavirus 229E (HCV/229E) was established in a human continuous cell line (L132). Following the initial infection with stock HCV/229E, several cultures were established of which two (HV1 and HV4) have been maintained by continuous passage for two years. These cultures have shed high titres of infectious virus continuously into the supernatant fluid since their initiation. The persistently infected cells were resistant to homologous super-infection but supported polio virus replication to normal titres. Preliminary tests indicated that 50–100 percent of the cells contain virus. Neither interferon nor reverse transcriptase could be detected in these cultures and the presence of defective interfering particles could not be demonstrated. VH1 and VH4 coronaviruses, isolated from these persistently infected cultures (HV) and identified by 229E antiserum neutralization, were more cytocidal than the parent virus as judged by plaque characteristics and CPE however, they were indistinguishable on the basis of density, EM morphology, and genome size. Present evidence indicates that temperature plays an important but as yet undetermined role in the establishment and maintenance of stable 229E persistently infected cell cultures.

Coronavirus in water environments: Occurrence, persistence and concentration methods - A scoping review

Coronaviruses (CoV) are a large family of viruses causing a spectrum of disease ranging from the common cold to more severe diseases as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV). The recent outbreak of coronavirus disease 2019 (COVID-19) has become a public health emergency worldwide. SARS-CoV-2, the virus responsible for COVID-19, is spread by human-to-human transmission via droplets or direct contact. However, since SARS-CoV-2 (as well as other coronaviruses) has been found in the fecal samples and anal swabs of some patients, the possibility of fecal-oral (including waterborne) transmission need to be investigated and clarified. This scoping review was conducted to summarize research data on CoV in water environments. A literature survey was conducted using the electronic databases PubMed, EMBASE, and Web Science Core Collection. This comprehensive research yielded more than 3000 records, but only 12 met the criteria and were included and discussed in this review. In detail, the review captured relevant studies investigating three main areas: 1) CoV persistence/survival in waters; 2) CoV occurrence in water environments; 3) methods for recovery of CoV from waters. The data available suggest that: i) CoV seems to have a low stability in the environment and is very sensitive to oxidants, like chlorine; ii) CoV appears to be inactivated significantly faster in water than non-enveloped human enteric viruses with known waterborne transmission; iii) temperature is an important factor influencing viral survival (the titer of infectious virus declines more rapidly at 23°C-25 °C than at 4 °C); iv) there is no current evidence that human coronaviruses are present in surface or ground waters or are transmitted through contaminated drinking-water; v) further research is needed to adapt to enveloped viruses the methods commonly used for sampling and concentration of enteric, non enveloped viruses from water environments. The evidence-based knowledge reported in this paper is useful to support risk analysis processes within the drinking and wastewater chain (i.e., water and sanitation safety planning) to protect human health from exposure to coronavirus through water.

Calling all coronavirus researchers: keep sharing, stay open

Abstract Coronaviruses (CoV) are a large family of viruses causing a spectrum of disease ranging from the common cold to more severe diseases as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV). The recent outbreak of coronavirus disease 2019 (COVID-19) has become a public health emergency worldwide. SARS-CoV-2, the virus responsible for COVID-19, is spread by human-to-human transmission via droplets or direct contact. However, since SARS-CoV-2 (as well as other coronaviruses) has been found in the fecal samples and anal swabs of some patients, the possibility of fecal-oral (including waterborne) transmission need to be investigated and clarified. This scoping review was conducted to summarize research data on CoV in water environments. A literature survey was conducted using the electronic databases PubMed, EMBASE, and Web Science Core Collection. This comprehensive research yielded more than 3000 records, but only 12 met the criteria and were included and discussed in this review. In detail, the review captured relevant studies investigating three main areas: 1) CoV persistence/survival in waters; 2) CoV occurrence in water environments; 3) methods for recovery of CoV from waters. The data available suggest that: i) CoV seems to have a low stability in the environment and is very sensitive to oxidants, like chlorine; ii) CoV appears to be inactivated significantly faster in water than non-enveloped human enteric viruses with known waterborne transmission; iii) temperature is an important factor influencing viral survival (the titer of infectious virus declines more rapidly at 23°C–25 °C than at 4 °C); iv) there is no current evidence that human coronaviruses are present in surface or ground waters or are transmitted through contaminated drinking-water; v) further research is needed to adapt to enveloped viruses the methods commonly used for sampling and concentration of enteric, non enveloped viruses from water environments. The evidence-based knowledge reported in this paper is useful to support risk analysis processes within the drinking and wastewater chain (i.e., water and sanitation safety planning) to protect human health from exposure to coronavirus through water.

Droplet evaporation residue indicating SARS-COV-2 survivability on surfaces

SARS-CoV-2 survives and remains viable on surfaces for several days under different environments as reported in recent studies. However, it is unclear how the viruses survive for such a long time and why their survivability varies across different surfaces. To address these questions, we conduct systematic experiments investigating the evaporation of droplets produced by a nebulizer and human-exhaled gas on surfaces. We found that these droplets do not disappear with evaporation, but instead shrink to a size of a few micrometers (referred to as residues), persist for more than 24 hours, and are highly durable against changes of environmental conditions. The characteristics of these residues change significantly across surface types. Specifically, surfaces with high thermal conductivity like copper do not leave any resolvable residues, while stainless steel, plastic, and glass surfaces form residues from a varying fraction of all deposited droplets at 40% relative humidity. Lowering humidity level suppresses the formation of residues while increasing humidity level enhances it. Our results suggest that these microscale residues can potentially insulate the virus against environmental changes, allowing them to survive inhospitable environments and remain infectious for prolonged durations after deposition. Our findings can also be extended to other viruses transmitted through respiratory droplets (e.g., SARS-CoV, flu viruses, etc.), and can thus lead to practical guidelines for disinfecting surfaces and other prevention measures (e.g., humidity control) for limiting viral transmission.

Likelihood of survival of coronavirus in a respiratory droplet deposited on a solid surface

We predict and analyze the drying time of respiratory droplets from a COVID-19 infected subject, which is a crucial time to infect another subject. Drying of the droplet is predicted by using a diffusion-limited evaporation model for a sessile droplet placed on a partially wetted surface with a pinned contact line. The variation in droplet volume, contact angle, ambient temperature, and humidity are considered. We analyze the chances of the survival of the virus present in the droplet based on the lifetime of the droplets under several conditions and find that the chances of the survival of the virus are strongly affected by each of these parameters. The magnitude of shear stress inside the droplet computed using the model is not large enough to obliterate the virus. We also explore the relationship between the drying time of a droplet and the growth rate of the spread of COVID-19 in five different cities and find that they are weakly correlated.

Modeling the Stability of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) on Skin, Currency, and Clothing

A new coronavirus (SARS-CoV-2) emerged in the winter of 2019 in Wuhan, China, and rapidly spread around the world. The extent and efficiency of SARS-CoV-2 pandemic is far greater than previous coronaviruses that emerged in the 21st Century. Here, we modeled stability of SARS-CoV-2 on skin, paper currency, and clothing to determine if these surfaces may factor in the fomite transmission dynamics of SARS-CoV-2. Skin, currency, and clothing samples were exposed to SARS-CoV-2 under laboratory conditions and incubated at three different temperatures (4C, 22C, and 37C). Stability was evaluated at 0 hours (h), 4 h, 8 h, 24 h, 72 h, 96 h, 7 days, and 14 days post-exposure. SARS-CoV-2 was shown to be stable on skin through the duration of the experiment at 4C (14 days). Virus remained stable on skin for at least 96 h at 22C and for at least 8h at 37C. There were minimal differences between the tested currency samples. The virus remained stable on the $1 U.S.A. Bank Note for at least 96 h at 4C while viable virus was not detected on the $20 U.S.A. Bank Note samples beyond 72 h. The virus remained stable on both Bank Notes for at least 8 h at 22C and 4 h at 37C. Clothing samples were similar in stability to the currency with the virus being detected for at least 96 h at 4C and at least 4 h at 22C. No viable virus was detected on clothing samples at 37C after initial exposure. This study confirms the inverse relationship between virus stability and temperature. Furthermore, virus stability on skin demonstrates the need for continued hand hygiene practices to minimize fomite transmission both in the general population as well as workplaces where close contact is common.

Effect of Environmental Conditions on SARS-CoV-2 Stability in Human Nasal Mucus and Sputum

We found that environmental conditions affect the stability of severe acute respiratory syndrome coronavirus 2 in nasal mucus and sputum. The virus is more stable at low-temperature and low-humidity conditions, whereas warmer temperature and higher humidity shortened half-life. Although infectious virus was undetectable after 48 hours, viral RNA remained detectable for 7 days.

Stability of SARS-CoV-2 and other coronaviruses in the environment and on common touch surfaces and the influence of climatic conditions: a review

Although the unprecedented efforts the world has been taking to control the spread of the human coronavirus disease (COVID-19) and its causative etiology [Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2)], the number of confirmed cases has been increasing drastically. Therefore, there is an urgent need for devising more efficient preventive measures, to limit the spread of the infection until an effective treatment or vaccine is available. The preventive measures depend mainly on the understanding of the transmission routes of this virus, its environmental stability, and its persistence on common touch surfaces. Due to the very limited knowledge about SARS-CoV-2, we can speculate its stability in the light of previous studies conducted on other human and animal coronaviruses. In this review, we present the available data on the stability of coronaviruses (CoVs), including SARS-CoV-2, from previous reports to help understand its environmental survival. According to available data, possible airborne transmission of SARS-CoV-2 has been suggested. SARS-CoV-2 and other human and animal CoVs have remarkably short persistence on copper, latex, and surfaces with low porosity as compared to other surfaces like stainless steel, plastics, glass, and highly porous fabrics. It has also been reported that SARS-CoV-2 is associated with diarrhea and that it is shed in the feces of COVID-19 patients. Some CoVs show persistence in human excrement, sewage, and waters for a few days. These findings suggest a possible risk of fecal-oral, foodborne, and waterborne transmission of SARS-CoV-2 in developing countries that often use sewage-polluted waters in irrigation and have poor water treatment systems. CoVs survive longer in the environment at lower temperatures and lower relative humidity. It has been suggested that large numbers of COVID-19 cases are associated with cold and dry climates in temperate regions of the world and that seasonality of the virus spread is suspected.

Effect of Environmental Conditions on SARS-CoV-2 Stability in Human Nasal Mucus and Sputum.

Chaos with Coronavirus

How much is coronavirus spreading under the radar?

Is the coronavirus airborne? Experts can't agree

Coronavirus come of age

Selection of viral variants during persistent infection of insectivorous bat cells with Middle East respiratory syndrome coronavirus

Coronaviruses that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) are speculated to have originated in bats. The mechanisms by which these viruses are maintained in individuals or populations of reservoir bats remain an enigma. Mathematical models have predicted long-term persistent infection with low levels of periodic shedding as a likely route for virus maintenance and spillover from bats. In this study, we tested the hypothesis that bat cells and MERS coronavirus (CoV) can co-exist in vitro. To test our hypothesis, we established a long-term coronavirus infection model of bat cells that are persistently infected with MERS-CoV. We infected cells from Eptesicus fuscus with MERS-CoV and maintained them in culture for at least 126 days. We characterized the persistently infected cells by detecting virus particles, protein and transcripts. Basal levels of type I interferon in the long-term infected bat cells were higher, relative to uninfected cells, and disrupting the interferon response in persistently infected bat cells increased virus replication. By sequencing the whole genome of MERS-CoV from persistently infected bat cells, we identified that bat cells repeatedly selected for viral variants that contained mutations in the viral open reading frame 5 (ORF5) protein. Furthermore, bat cells that were persistently infected with ΔORF5 MERS-CoV were resistant to superinfection by wildtype virus, likely due to reduced levels of the virus receptor, dipeptidyl peptidase 4 (DPP4) and higher basal levels of interferon in these cells. In summary, our study provides evidence for a model of coronavirus persistence in bats, along with the establishment of a unique persistently infected cell culture model to study MERS-CoV-bat interactions.

Uncertainty in the Time of Coronavirus

[Seroepidemiological study of coronavirus infection in children and adults in St. Petersburg].

As the result of prolonged (17 years) observations of patients with acute respiratory infections hospitalized in basic departments of clinics of the Research Institute of Influenza, coronavirus infection was found to be the cause of respiratory diseases, on the average, in 12% of cases (in some years in 6.8% to 28.6% of cases). The analysis of extensive morbidity rates among different age groups of the population showed that children were affected by coronavirus infection 5-7 times more often than adults. Three year cycles of this infection were established. The periods of coronaviruses activation were accompanied by their detection in patient material by electron-microscopy, a sharp increase of immune response of patients as well as in the number of nosocomial infections and the proportion of the monoinfection of the coronavirus nature. Coronaviruses played the leading role among other viruses in the etiology of hospital respiratory infections. Mucosal antibodies to coronaviruses in the secretions of the nasal cavity proved to be more important than serum antibodies not only in protection from infection, but also in the pattern of clinical manifestations of the disease.

COVID-19 Surface Persistence: A Recent Data Summary and Its Importance for Medical and Dental Settings

Recently, due to the coronavirus pandemic, many guidelines and anti-contagion strategies continue to report unclear information about the persistence of coronavirus disease 2019 (COVID-19) in the environment. This certainly generates insecurity and fear in people, with an important psychological component that is not to be underestimated at this stage of the pandemic. The purpose of this article is to highlight all the sources currently present in the literature concerning the persistence of the different coronaviruses in the environment as well as in medical and dental settings. As this was a current study, there are still not many sources in the literature, and scientific strategies are moving towards therapy and diagnosis, rather than knowing the characteristics of the virus. Such an article could be an aid to summarize virus features and formulate new guidelines and anti-spread strategies.

The time course of the immune response to experimental coronavirus infection of man.

After preliminary trials, the detailed changes in the concentration of specific circulating and local antibodies were followed in 15 volunteers inoculated with coronavirus 229E. Ten of them, who had significantly lower concentrations of pre-existing antibody than the rest, became infected and eight of these developed colds. A limited investigation of circulating lymphocyte populations showed some lymphocytopenia in infected volunteers. In this group, antibody concentrations started to increase 1 week after inoculation and reached a maximum about 1 week later. Thereafter antibody titres slowly declined. Although concentrations were still slightly raised 1 year later, this did not always prevent reinfection when volunteers were then challenged with the homologous virus. However, the period of virus shedding was shorter than before and none developed a cold. All of the uninfected group were infected on re-challenge although they also appeared to show some resistance to disease and in the extent of infection. These results are discussed with reference to natural infections with coronavirus and with other infections, such as rhinovirus infections.

Human coronavirus reinfection dynamics: lessons for SARS-CoV-2

In the current SARS-CoV-2 pandemic a key unsolved question is the quality and duration of acquired immunity in recovered individuals. This is crucial to solve, however SARS-CoV-2 has circulated for under five months, precluding a direct study. We therefore monitored 10 subjects over a time span of 35 years (1985-2020), providing a total of 2473 follow up person-months, and determined a) their antibody levels following infection by any of the four seasonal human coronaviruses, and b) the time period after which reinfections by the same virus can occur. An alarmingly short duration of protective immunity to coronaviruses was found by both analyses. We saw frequent reinfections at 12 months post-infection and a substantial reduction in antibody levels as soon as 6 months post-infection.

Photopolarimetrical properties of coronavirus model particles: Spike proteins number influence

Abstract Coronavirus virions have spherical shape surrounded by spike proteins. The coronavirus spike proteins are very effective molecular mechanisms, which provide the coronavirus entrance to the host cell. The number of these spikes is different; it dramatically depends on external conditions and determines the degree of danger of the virus. A larger number of spike proteins makes the virus infectivity stronger. This paper describes a mathematical model of the shape of coronavirus virions. Based on this model, the characteristics of light scattered by the coronavirus virions were calculated. It was found two main features of coronavirus model particles in the spectral region near 200 nm: a minimum of intensity and a sharp leap of the linear polarization degree. The effect of the spike protein number on the intensity and polarization properties of the scattered light was studied. It was determined that when the number of spike proteins decreases, both the intensity minimum and the position of the linear polarization leap shift to shorter wavelengths. This allows us to better evaluate the shape of the coronavirus virion, and, therefore, the infectious danger of the virus. It was shown that the shorter the wavelength of scattered light, the more reliably one can distinguish viruses from non-viruses. The developed model and the light scattering simulations based on it can be applied not only to coronaviruses, but also to other objects of a similar structure, for example, pollen.

Photopolarimetrical properties of coronavirus model particles: spike proteins number influence

Coronavirus virions have spherical shape surrounded by spike proteins. The coronavirus spike proteins are very effective molecular mechanisms, which provide the coronavirus entrance to the host cell. The number of these spikes is different; it dramatically depends on external conditions and determines the degree of danger of the virus. A larger number of spike proteins makes the virus infectivity stronger. This paper describes a mathematical model of the shape of coronavirus virions. Based on this model, the characteristics of light scattered by the coronavirus virions were calculated. It was found two main features of coronavirus model particles in the spectral region near 200nm: a minimum of intensity and a sharp leap of the linear polarization degree. The effect of the spike protein number on the intensity and polarization properties of the scattered light was studied. It was determined that when the number of spike proteins decreases, both the intensity minimum and the position of the linear polarization leap shift to shorter wavelengths. This allows us to better evaluate the shape of the coronavirus virion, and, therefore, the infectious danger of the virus. It was shown that the shorter the wavelength of scattered light, the more reliably one can distinguish viruses from non-viruses. The developed model and the light scattering simulations based on it can be applied not only to coronaviruses, but also to other objects of a similar structure, for example, pollen.

Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation.

OBJECTIVE 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. METHODS 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. RESULTS 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. CONCLUSION 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.

Survival of Coronaviruses in Water and Wastewater

The advent of severe acute respiratory syndrome and its potential environmental transmission indicates the need for more information on the survival of coronavirus in water and wastewater. The survival of representative coronaviruses, feline infectious peritonitis virus, and human coronavirus 229E was determined in filtered and unfiltered tap water (4 and 23°C) and wastewater (23°C). This was compared to poliovirus 1 under the same test conditions. Inactivation of coronaviruses in the test water was highly dependent on temperature, level of organic matter, and presence of antagonistic bacteria. The time required for the virus titer to decrease 99.9% (T(99.9)) shows that in tap water, coronaviruses are inactivated faster in water at 23°C (10 days) than in water at 4°C (>100 days). Coronaviruses die off rapidly in wastewater, with T(99.9) values of between 2 and 4 days. Poliovirus survived longer than coronaviruses in all test waters, except the 4°C tap water.

Coronavirus can infect cats - dogs, not so much.

Coronavirus: the first three months as it happened

Coronavirus, as a source of pandemic pathogens

The coronavirus and the influenza virus have similarities and differences. In order to comprehensively compare them, their genome sequencing data were examined by principal component analysis. Variations in coronavirus were smaller than those in a subclass of the influenza virus. In addition, differences among coronaviruses in a variety of hosts were small. These characteristics may have facilitated the infection of different hosts. Although many of the coronaviruses were more conservative, those repeatedly found among humans showed annual changes. If SARS-CoV-2 changes its genome like the Influenza H type, it will repeatedly spread every few years. In addition, the coronavirus family has many other candidates for subsequent pandemics. One Sentence Summary The genome data of coronavirus were compared to influenza virus, to investigate its spreading mechanism and future status. Coronavirus would repeatedly spread every few years. In addition, the coronavirus family has many other candidates for subsequent pandemics.

Is the coronavirus airborne? Experts can't agree.

Effects of air temperature and relative humidity on coronavirus survival on surfaces.

Assessment of the risks posed by severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) on surfaces requires data on survival of this virus on environmental surfaces and on how survival is affected by environmental variables, such as air temperature (AT) and relative humidity (RH). The use of surrogate viruses has the potential to overcome the challenges of working with SARS-CoV and to increase the available data on coronavirus survival on surfaces. Two potential surrogates were evaluated in this study; transmissible gastroenteritis virus (TGEV) and mouse hepatitis virus (MHV) were used to determine effects of AT and RH on the survival of coronaviruses on stainless steel. At 4 degrees C, infectious virus persisted for as long as 28 days, and the lowest level of inactivation occurred at 20% RH. Inactivation was more rapid at 20 degrees C than at 4 degrees C at all humidity levels; the viruses persisted for 5 to 28 days, and the slowest inactivation occurred at low RH. Both viruses were inactivated more rapidly at 40 degrees C than at 20 degrees C. The relationship between inactivation and RH was not monotonic, and there was greater survival or a greater protective effect at low RH (20%) and high RH (80%) than at moderate RH (50%). There was also evidence of an interaction between AT and RH. The results show that when high numbers of viruses are deposited, TGEV and MHV may survive for days on surfaces at ATs and RHs typical of indoor environments. TGEV and MHV could serve as conservative surrogates for modeling exposure, the risk of transmission, and control measures for pathogenic enveloped viruses, such as SARS-CoV and influenza virus, on health care surfaces.

Keep up with the latest coronavirus research.

The ocular surface, coronaviruses and COVID-19

The ocular surface has been suggested as a site of infection with Coronavirus-2 (SARS-CoV-2) responsible for the coronavirus disease-19 (COVID-19). This review examines the evidence for this hypothesis, and its implications for clinical practice. Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), responsible for the COVID-19 pandemic, is transmitted by person-to-person contact, via airborne droplets, or through contact with contaminated surfaces. SARS-CoV-2 binds to angiotensin converting enzyme-2 (ACE2) to facilitate infection in humans. This review sets out to evaluate evidence for the ocular surface as a route of infection. A literature search in this area was conducted on 15 April 2020 using the Scopus database. In total, 287 results were returned and reviewed. There is preliminary evidence for ACE2 expression on corneal and conjunctival cells, but most of the other receptors to which coronaviruses bind appear to be found under epithelia of the ocular surface. Evidence from animal studies is limited, with a single study suggesting viral particles on the eye can travel to the lung, resulting in very mild infection. Coronavirus infection is rarely associated with conjunctivitis, with occasional cases reported in patients with confirmed COVID-19, along with isolated cases of conjunctivitis as a presenting sign. Coronaviruses have been rarely isolated from tears or conjunctival swabs. The evidence suggests coronaviruses are unlikely to bind to ocular surface cells to initiate infection. Additionally, hypotheses that the virus could travel from the nasopharynx or through the conjunctival capillaries to the ocular surface during infection are probably incorrect. Conjunctivitis and isolation of the virus from the ocular surface occur only rarely, and overwhelmingly in patients with confirmed COVID-19. Necessary precautions to prevent person-to-person transmission should be employed in clinical practice throughout the pandemic, and patients should be reminded to maintain good hygiene practices.

How scientific conferences will survive the coronavirus shock.

What could coronavirus teach us?

No evidence for quasispecies populations during persistence of the coronavirus mouse hepatitis virus JHM: sequence conservation within the surface glycoprotein gene S in Lewis rats.

The surface glycoprotein S (spike) of coronaviruses is believed to be an important determinant of virulence and displays extensive genetic polymorphism in cell culture isolates. This led us to consider whether the observed heterogeneity is reflected by a quasispecies distribution of mutated RNA molecules within the infected organ. Coronavirus infection of rodents is a useful model system for investigating the pathogenesis of virus-induced central nervous system (CNS) disease. Here, we investigated whether genetic changes in the S gene occurred during virus persistence in vivo. We analysed the variability of S gene sequences directly from the brain tissue of Lewis rats infected with the coronavirus mouse hepatitis virus (MHV) variant JHM-Pi using RT-PCR amplification methods. The S gene sequence displayed a remarkable genetic stability in vivo. No evidence for a quasispecies distribution was found by sequence analysis of amplified S gene fragments derived from the CNS of Lewis rats. Furthermore, the S gene also remained conserved under the selection pressure of a neutralizing antibody. Only a few mutations predicted to result in amino acid changes were detected in single clones. The changes were not represented in the consensus sequence. These results indicate that to retain functional proteins under the constraints of a persistent infection in vivo, conservation of sequence can be more important than heterogeneity.

Transmission of SARS and MERS coronaviruses and influenza virus in healthcare settings: the possible role of dry surface contamination

Summary Viruses with pandemic potential including H1N1, H5N1, and H5N7 influenza viruses, and severe acute respiratory syndrome (SARS)/Middle East respiratory syndrome (MERS) coronaviruses (CoV) have emerged in recent years. SARS-CoV, MERS-CoV, and influenza virus can survive on surfaces for extended periods, sometimes up to months. Factors influencing the survival of these viruses on surfaces include: strain variation, titre, surface type, suspending medium, mode of deposition, temperature and relative humidity, and the method used to determine the viability of the virus. Environmental sampling has identified contamination in field-settings with SARS-CoV and influenza virus, although the frequent use of molecular detection methods may not necessarily represent the presence of viable virus. The importance of indirect contact transmission (involving contamination of inanimate surfaces) is uncertain compared with other transmission routes, principally direct contact transmission (independent of surface contamination), droplet, and airborne routes. However, influenza virus and SARS-CoV may be shed into the environment and be transferred from environmental surfaces to hands of patients and healthcare providers. Emerging data suggest that MERS-CoV also shares these properties. Once contaminated from the environment, hands can then initiate self-inoculation of mucous membranes of the nose, eyes or mouth. Mathematical and animal models, and intervention studies suggest that contact transmission is the most important route in some scenarios. Infection prevention and control implications include the need for hand hygiene and personal protective equipment to minimize self-contamination and to protect against inoculation of mucosal surfaces and the respiratory tract, and enhanced surface cleaning and disinfection in healthcare settings.

Effective Heat Inactivation of SARS-CoV-2

The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or 2019-nCoV) has quickly turned into a global pandemic. Infectious viruses had been isolated from oro- or naso-pharyngeal swabs, sputum and possibly stool samples of infected individuals. Handling these clinical specimens therefore poses a biosafety risk to both healthcare professionals and laboratory workers. In this study, we aimed to evaluate the stability of SARS-CoV-2 under different heat conditions and report that the virus is stable at 37 C for at least 24 hours. Heating at 56 C for 30 minutes, however, effectively inactivated the virus while preserved the stability of viral RNA in both human sera and sputum samples. These findings provide critical information regarding the biology of the virus as well as a practical way to inactivate infectious virus that is potentially found in clinical specimens.

Coronavirus can infect cats - dogs, not so much

Are We Ready for the New Coronavirus?

Are we ready for the new coronavirus?

Keep up with the latest coronavirus research

Coronavirus entry and release in polarized epithelial cells: a review

Most coronaviruses cause respiratory or intestinal infections in their animal or human host. Hence, their interaction with polarized epithelial cells plays a critical role in the onset and outcome of infection. In this paper, we review the knowledge regarding the entry and release of coronaviruses, with particular emphasis on the severe acute respiratory syndrome and Middle East respiratory syndrome coronaviruses. As these viruses approach the epithelial surfaces from the apical side, it is not surprising that coronavirus cell receptors are exposed primarily on the apical domain of polarized epithelial cells. With respect to release, all possibilities appear to occur. Thus, most coronaviruses exit through the apical surface, several through the basolateral one, although the Middle East respiratory syndrome coronavirus appears to use both sides. These observations help us understand the local or systematic spread of the infection within its host as well as the spread of the virus within the host population. Copyright © 2014 John Wiley & Sons, Ltd.

Do Humidity and Temperature Impact the Spread of the Novel Coronavirus?

[Acute respiratory disease caused by coronaviruses].

Serological evidence of coronavirus aetiology was found in 11 patients out of 218 persons examined (5%) in the period of 1986-1987, and in 23 cases out of 311 patients (7.4%) in the period of 1987-1988. Antibody titres with a minimum of four-time elevated values in paired sera using the ELISA method were considered conclusive. Coronaviruses 229E and OC43 were employed. During the first period, more persons were infected by coronavirus 229E, while in the second period, by coronavirus OC43. The disease was equally spread over all the months of the years. For example, in the 1987-1988 period, most infections occurred in February, when out of 60 examined patients, 9 were coronavirus positive (15%).

Modelling the thermal inactivation of viruses from the Coronaviridae family in suspensions or on surfaces with various relative humidities.

Temperature and relative humidity are major factors determining virus inactivation in the environment. This article reviews inactivation data of coronaviruses on surfaces and in liquids from published studies and develops secondary models to predict coronaviruses inactivation as a function of temperature and relative humidity. A total of 102 D-values (time to obtain a log10 reduction of virus infectivity), including values for SARS-CoV-2, were collected from 26 published studies. The values obtained from the different coronaviruses and studies were found to be generally consistent. Five different models were fitted to the global dataset of D-values. The most appropriate model considered temperature and relative humidity. A spreadsheet predicting the inactivation of coronaviruses and the associated uncertainty is presented and can be used to predict virus inactivation for untested temperatures, time points or new coronavirus strains.

How scientific conferences will survive the coronavirus shock

Why does the coronavirus spread so easily between people?

Purified coronavirus Spike protein nanoparticles induce coronavirus neutralizing antibodies in mice

Development of vaccination strategies for emerging pathogens are particularly challenging because of the sudden nature of the emergence of these viruses and the long process needed for traditional vaccine development. Therefore, there is a need for development of a rapid method of vaccine development that can respond to emerging pathogens in a short time frame. The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) in 2003 and Middle East respiratory syndrome (MERS-CoV) in late 2012 demonstrate the importance of coronaviruses as emerging pathogens. The spike glycoproteins of coronaviruses reside on the surface of the virion and are responsible for virus entry. The spike glycoprotein is the major immunodominant antigen of coronaviruses and has proven to be an excellent target for vaccine designs that seek to block coronavirus entry and promote antibody targeting of infected cells. Vaccination strategies for coronaviruses have involved live attenuated virus, recombinant viruses, non-replicative virus-like particles expressing coronavirus proteins or DNA plasmids expressing coronavirus genes. None of these strategies has progressed to an approved human coronavirus vaccine in the ten years since SARS-CoV emerged. Here we describe a novel method for generating MERS-CoV and SARS-CoV full-length spike nanoparticles, which in combination with adjuvants are able to produce high titer antibodies in mice.

As We Went to Press: COVID-19 Continues to Spread

Updates on the coronavirus.

COVID-19 and Lessons to Be Learned from Prior Coronavirus Outbreaks

The Molecular Biology of Coronaviruses

Publisher Summary This chapter discusses the manipulation of clones of coronavirus and of complementary DNAs (cDNAs) of defective-interfering (DI) RNAs to study coronavirus RNA replication, transcription, recombination, processing and transport of proteins, virion assembly, identification of cell receptors for coronaviruses, and processing of the polymerase. The nature of the coronavirus genome is nonsegmented, single-stranded, and positive-sense RNA. Its size ranges from 27 to 32 kb, which is significantly larger when compared with other RNA viruses. The gene encoding the large surface glycoprotein is up to 4.4 kb, encoding an imposing trimeric, highly glycosylated protein. This soars some 20 nm above the virion envelope, giving the virus the appearance-with a little imagination-of a crown or coronet. Coronavirus research has contributed to the understanding of many aspects of molecular biology in general, such as the mechanism of RNA synthesis, translational control, and protein transport and processing. It remains a treasure capable of generating unexpected insights.

Coronavirus: just imagine

Beyond the science of covid-19

Models of the new coronavirus's spread are imperfect, so factors other than the science play an important role too, says David Adam

Coronavirus?

The molecular biology of intracellular events during Coronavirus infection cycle

CoV-2 which is the causative agent of COVID-19 belongs to genus betacoronaviruses. The sequence analysis of S protein of CoV-2 has shown that it has acquired a 'polybasic cleavage site' consisting of 12 aminoacids that has been predicted to enable its cleavage by other cellular proteases possibly increasing its transmissibility. The aminoacids present in receptor binding domain of S protein of SARS CoV which are critical for its binding to cellular receptor are different in CoV-2. The presence of heptanucleotide slippery sequence in ORF1 resulting in ribosomal frameshifting, and presence of transcription regulatory sequences between ORFs resulting in discontinuous transcription, are peculiar features of Coronavirus infection cycle. The exonuclease activity of nsp14 provides possible proofreading ability to RNA polymerase makes coronaviruses different from other RNA viruses allowing coronaviruses to maintain their relatively large genome size. This mini-review summarizes the peculiar features of Coronaviruses genome and the critical events during the infection cycle with focus on CoV-2.

[Study on the stability of SARS coronavirus].

Coronavirus.

A Surface Coating that Rapidly Inactivates SARS-CoV-2.

SARS-CoV-2, the virus that causes the disease COVID-19, remains viable on solids for periods of up to one week, so one potential route for human infection is via exposure to an infectious dose from a solid. We have fabricated and tested a coating that is designed to reduce the longevity of SARS-CoV-2 on solids. The coating consists of cuprous oxide (Cu2O) particles bound with polyurethane. After one hour on coated glass or stainless steel, the viral titer was reduced by about 99.9% on average compared to the uncoated sample. An advantage of a polyurethane-based coating is that polyurethane is already used to coat a large number of everyday objects. Our coating adheres well to glass and stainless steel, as well as everyday items that people may fear to touch during a pandemic, such as a doorknob, a pen, and a credit card keypad button. The coating performs well in the cross-hatch durability test and remains intact and active after 13 days immersed in water, or after exposure to multiple cycles of exposure to virus and disinfection.

Bovine enteric coronavirus structure as studied by a freeze-drying technique.

A strain of bovine coronavirus (F15) was studied by electron microscopy using a freeze-drying technique. Purified coronavirus preparations show three different categories of image: (i) 'blackberry-like' virions, (ii) virions with a smooth depression at their surface, and (iii) apparently broken particles showing very clearly the areas of spike insertion in the virus membrane. Virus projections resemble 'mushrooms' with the 'stalk' inserted at the virus membrane. A model of the virion structure is proposed.

Properties of Coronavirus and SARS-CoV-2

were identified beginning with the discovery of SARS-CoV in 2002. With the recent detection of SARS-CoV-2, there are now seven human coronaviruses. Those that cause mild diseases are the 229E, OC43, NL63 and HKU1, and the pathogenic species are SARS-CoV, MERS-CoV and SARS-CoV-2 Coronaviruses (order Nidovirales, family Coronaviridae, and subfamily Orthocoronavirinae) are spherical (125nm diameter), and enveloped with club-shaped spikes on the surface giving the appearance of a solar corona. Within the helically symmetrical nucleocapsid is the large positive sense, single stranded RNA. Of the four coronavirus genera (α,ß,Î³,Î´), human coronaviruses (HCoVs) are classified under α-CoV (HCoV-229E and NL63) and ß-CoV (MERS-CoV, SARS-CoV, HCoVOC43 and HCoV-HKU1). SARS-CoV-2 is a ß-CoV and shows fairly close relatedness with two bat-derived CoV-like coronaviruses, bat-SL-CoVZC45 and bat-SL-CoVZXC21. Even so, its genome is similar to that of the typical CoVs. SARS-CoV and MERS-CoV originated in bats, and it appears to be so for SARS-CoV-2 as well. The possibility of an intermediate host facilitating the emergence of the virus in humans has already been shown with civet cats acting as intermediate hosts for SARS-CoVs, and dromedary camels for MERS-CoV. Human-to-human transmission is primarily achieved through close contact of respiratory droplets, direct contact with the infected individuals, or by contact with contaminated objects and surfaces. The coronaviral genome contains four major structural proteins: the spike (S), membrane (M), envelope (E) and the nucleocapsid (N) protein, all of which are encoded within the 3' end of the genome. The S protein mediates attachment of the virus to the host cell surface receptors resulting in fusion and subsequent viral entry. The M protein is the most abundant protein and defines the shape of the viral envelope. The E protein is the smallest of the major structural proteins and participates in viral assembly and budding. The N protein is the only one that binds to the RNA genome and is also involved in viral assembly and budding. Replication of coronaviruses begin with attachment and entry. Attachment of the virus to the host cell is initiated by interactions between the S protein and its specific receptor. Following receptor binding, the virus enters host cell cytosol via cleavage of S protein by a protease enzyme, followed by fusion of the viral and cellular membranes. The next step is the translation of the replicase gene from the virion genomic RNA and then translation and assembly of the viral replicase complexes. Following replication and subgenomic RNA synthesis, encapsidation occurs resulting in the formation of the mature virus. Following assembly, virions are transported to the cell surface in vesicles and released by exocytosis.

Persistence of Bacteriophage Phi 6 on Porous and Non-Porous Surfaces; Potential for use as Ebola or Coronavirus Surrogate.

The infection of healthcare workers during the 2013 -2016 Ebola outbreak raised concerns about fomite transmission. In the wake of the Coronavirus Disease 2019 (COVID-19) pandemic, investigations are ongoing to determine the role of fomites in coronavirus transmission as well. The bacteriophage Phi 6 has a phospholipid envelope and is commonly used in environmental studies as a surrogate for human enveloped viruses. The persistence of Phi 6 was evaluated as a surrogate for EBOV and coronaviruses on porous and nonporous hospital surfaces. Phi 6 was suspended in a body fluid simulant and inoculated onto 1 cm2 coupons of steel, plastic, and two fabric curtain types. The coupons were placed at two controlled absolute humidity (AH) levels; a low AH of 3.0 g/m3 and a high AH of 14.4 g/m3 Phi 6 declined at a slower rate on all materials under low AH conditions with a decay rate of 0.06 log10PFU/d to 0.11 log10PFU/d, as compared to the higher AH conditions with a decay rate of 0.65 log10PFU/h to 1.42 log10PFU/d. There was a significant difference in decay rates between porous and non-porous surfaces at both low AH (P < 0.0001) and high AH (P < 0.0001). Under these laboratory-simulated conditions, Phi 6 was found to be a conservative surrogate for EBOV under low AH conditions, in that it persisted longer than Ebola virus in similar AH conditions. Additionally, some coronaviruses persist longer than phi6 under similar conditions, therefore Phi6 may not be a suitable surrogate for coronaviruses.IMPORTANCE Understanding the persistence of enveloped viruses helps inform infection control practices and procedures in healthcare facilities and community settings. These data convey to public health investigators that enveloped viruses can persist and remain infective on surfaces, thus demonstrating a potential risk for transmission. Under these laboratory-simulated western indoor hospital conditions, Phi 6 was used to assess suitability as a surrogate for environmental persistence research related to enveloped viruses, including EBOV and coronaviruses.

Stability of SARS‐CoV‐2 and other coronaviruses in the environment and on common touch surfaces and the influence of climatic conditions: A review

Although the unprecedented efforts the world has been taking to control the spread of the human coronavirus disease (COVID‐19) and its causative aetiology [severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2)], the number of confirmed cases has been increasing drastically. Therefore, there is an urgent need for devising more efficient preventive measures, to limit the spread of the infection until an effective treatment or vaccine is available. The preventive measures depend mainly on the understanding of the transmission routes of this virus, its environmental stability, and its persistence on common touch surfaces. Due to the very limited knowledge about SARS‐CoV‐2, we can speculate its stability in the light of previous studies conducted on other human and animal coronaviruses. In this review, we present the available data on the stability of coronaviruses (CoVs), including SARS‐CoV‐2, from previous reports to help understand its environmental survival. According to available data, possible airborne transmission of SARS‐CoV‐2 has been suggested. SARS‐CoV‐2 and other human and animal CoVs have remarkably short persistence on copper, latex and surfaces with low porosity as compared to other surfaces like stainless steel, plastics, glass and highly porous fabrics. It has also been reported that SARS‐CoV‐2 is associated with diarrhoea and that it is shed in the faeces of COVID‐19 patients. Some CoVs show persistence in human excrement, sewage and waters for a few days. These findings suggest a possible risk of faecal–oral, foodborne and waterborne transmission of SARS‐CoV‐2 in developing countries that often use sewage‐polluted waters in irrigation and have poor water treatment systems. CoVs survive longer in the environment at lower temperatures and lower relative humidity. It has been suggested that large numbers of COVID‐19 cases are associated with cold and dry climates in temperate regions of the world and that seasonality of the virus spread is suspected.

This newly recognized coronavirus makes one wonder why we were so unprepared

Protection and disinfection policies against SARS-CoV-2 (COVID-19).

In late December 2019, reports from China of the incidence of pneumonia with unknown etiology were sent to the World Health Organization (WHO). Shortly afterwards, the cause of this disease was identified as the novel beta-coronavirus, SARS-CoV-2, and its genetic sequence was published on January 12, 2020. Human-to-human transmission via respiratory droplets and contact with aerosol infected surfaces are the major ways of transmitting this virus. Here we attempted to collect information on virus stability in the air and on surfaces and ways of preventing of SARS-CoV-2 spreading.

Coronavirus 2020.

Preparing for a Surge of Coronavirus Cases

Why more coronavirus testing won't automatically help the hardest hit.

Persistence of Severe Acute Respiratory Syndrome Coronavirus 2 in Aerosol Suspensions

We aerosolized severe acute respiratory syndrome coronavirus 2 and determined that its dynamic aerosol efficiency surpassed those of severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome. Although we performed experiment only once across several laboratories, our findings suggest retained infectivity and virion integrity for up to 16 hours in respirable-sized aerosols.

In Coronavirus Times

Evolution of a coronavirus during persistent infection in vitro.

Preparing for a Surge of Coronavirus Cases.

Persistence of Severe Acute Respiratory Syndrome Coronavirus 2 in Aerosol Suspensions.

Stop the coronavirus stigma now.

Stability and inactivation of SARS coronavirus

The SARS-coronavirus (SARS-CoV) is a newly emerged, highly pathogenic agent that caused over 8,000 human infections with nearly 800 deaths between November 2002 and September 2003. While direct person-to-person transmission via respiratory droplets accounted for most cases, other modes have not been ruled out. Faecal shedding is common and prolonged and has caused an outbreak in Hong Kong. We studied the stability of SARS-CoV under different conditions, both in suspension and dried on surfaces, in comparison with other human-pathogenic viruses, including human coronavirus HCoV-229E. In suspension, HCoV-229E gradually lost its infectivity completely while SARS-CoV retained its infectivity for up to 9 days; in the dried state, survival times were 24 h versus 6 days. Thermal inactivation at 56°C was highly effective in the absence of protein, reducing the virus titre to below detectability; however, the addition of 20% protein exerted a protective effect resulting in residual infectivity. If protein-containing solutions are to be inactivated, heat treatment at 60°C for at least 30 min must be used. Different fixation procedures, e.g. for the preparation of immunofluorescence slides, as well as chemical means of virus inactivation commonly used in hospital and laboratory settings were generally found to be effective. Our investigations confirm that it is possible to care for SARS patients and to conduct laboratory scientific studies on SARS-CoV safely. Nevertheless, the agent’s tenacity is considerably higher than that of HCoV-229E, and should SARS re-emerge, increased efforts need to be devoted to questions of environmental hygiene.

Coronavirus replication factories

Protection and disinfection policies against SARS-CoV-2 (COVID-19)

Coronavirus response: a focus on containment is still apt.

Coronavirus

Effects of temperature on COVID-19 transmission

Coronavirus disease 2019 (COVID19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARSCoV2), it was first identified in 2019 in Wuhan, China and has resulted in the 2019-20 coronavirus pandemic. As of March 1, 2020, 79,968 patients in China and 7169 outside of China had tested positive for COVID19 and a mortality rate of 3.6% has been observed amongst Chinese patients. Its primary mode of transmission is via respiratory droplets from coughs and sneezes. The virus can remain viable for up to three days on plastic and stainless steel or in aerosols for upto 3 hours and is relatively more stable than the known human coronaviruses. It is stable in faeces at room temperature for at least 1-2 days and can be stable in infected patients for up to 4 days. Heat at 56 degree Celsius kills the SARS coronavirus at around 10000 units per 15 minutes. Thus, temperature is an important factor in survival of COVID19 virus and this article focuses on understanding the relationship between temperature and COVID19 transmission from the data available between January-March 2020.

Isolation and identification of human coronavirus 229E from frequently touched environmental surfaces of a university classroom that is cleaned daily

Frequently touched surfaces of a university classroom that is cleaned daily contained viable human coronavirus 229E (CoV-229E). Tests of a CoV-229E laboratory strain under conditions that simulated the ambient light, temperature, and relative humidity conditions of the classroom revealed that some of the virus remained viable on various surfaces for 7 days, suggesting CoV-229E is relatively stable in the environment. Our findings reinforce the notion that contact transmission may be possible for this virus.

Autopsy slowdown hinders quest to determine how coronavirus kills.

Further studies on human enteric coronaviruses

Comparisons were made between human enteric coronaviruses and the enteric coronaviruses of pigs and calves by negative staining. Examination of human intestinal organ culture fluids at various time intervals after inoculation with the human enteric coronavirus showed increasing numbers of particles in the fluids. Thin sections of the columnar epithelial cells of these explants showed a number of features consistent with the replication of known human and animal coronaviruses. Virus particles found in thin sections had a mean diameter of 68 nm. In addition, a structure was found in thin sections which has not been described previously. This structure may represent the viral nucleocapsid.