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Post by Admin on May 19, 2020 7:33:40 GMT
In a paper published today by the journal Nature, a team including researchers from the University of Washington reports that the antibody, known as S309, can neutralize the virus that causes COVID-19 in lab experiments. “We still need to show that this antibody is protective in living systems, which has not yet been done,” David Veesler, a biochemist at the UW School of Medicine who’s one of the paper’s senior authors, said in a news release.
S309 was one of several promising monoclonal antibodies identified in the memory B cells of a patient who survived Severe Acute Respiratory Syndrome. No cases of SARS have been reported since 2004. Like COVID-19, SARS was caused by a type of coronavirus, which led researchers to check for therapeutic crossover effects.
Combining the S309 antibody with other antibodies identified in the SARS patient’s blood sample enhanced the neutralization effect on the COVID-19 virus, known as SARS-CoV-2. Medications that make use of the antibodies are now on a fast-track development and testing path at California-based Vir Biotechnology in collaboration with GlaxoSmithKline, in preparation for clinical trials. Veesler and Davide Corti are senior authors of the Nature study, titled “Cross-Neutralization of SARS-CoV-2 by a human monoclonal SARS-CoV Antibody.” Lead authors are Dora Pinto, Young-Jun Park, Martina Beltramello and Alexandra Walls. There are 19 additional co-authors.
Cross-neutralization of SARS-CoV-2 by a human monoclonal SARS-CoV antibody
Abstract SARS-CoV-2 is a newly emerged coronavirus responsible for the current COVID-19 pandemic that has resulted in more than 3.7 million infections and 260,000 deaths as of 6 May 20201,2. Vaccine and therapeutic discovery efforts are paramount to curb the pandemic spread of this zoonotic virus. The SARS-CoV-2 spike (S) glycoprotein promotes entry into host cells and is the main target of neutralizing antibodies. Here we describe multiple monoclonal antibodies targeting SARS-CoV-2 S identified from memory B cells of an individual who was infected with SARS-CoV in 2003. One antibody, named S309, potently neutralizes SARS-CoV-2 and SARS-CoV pseudoviruses as well as authentic SARS-CoV-2 by engaging the S receptor-binding domain. Using cryo-electron microscopy and binding assays, we show that S309 recognizes a glycan-containing epitope that is conserved within the sarbecovirus subgenus, without competing with receptor attachment. Antibody cocktails including S309 along with other antibodies identified here further enhanced SARS-CoV-2 neutralization and may limit the emergence of neutralization-escape mutants. These results pave the way for using S309- and S309-containing antibody cocktails for prophylaxis in individuals at high risk of exposure or as a post-exposure therapy to limit or treat severe disease.
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Post by Admin on May 20, 2020 0:34:35 GMT
Cats can spread the new coronavirus to other cats without any of them ever having symptoms, a lab experiment suggests.
Scientists who led the work, reported on Wednesday, say it shows the need for more research into whether the virus can spread from people to cats to people again.
Health experts have downplayed that possibility. The American Veterinary Medical Association said in a new statement that just because an animal can be deliberately infected in a lab “does not mean that it will easily be infected with that same virus under natural conditions.”
Anyone concerned about that risk should use “common sense hygiene,” said virus expert Peter Halfmann. Don’t kiss your pets and keep surfaces clean to cut the chances of picking up any virus an animal might shed, he said.
He and colleagues at the University of Wisconsin School of Veterinary Medicine led the lab experiment and published results Wednesday in the New England Journal of Medicine. Federal grants paid for the work.
Researchers took coronavirus from a human patient and infected three cats with it. Each cat then was housed with another cat that was free of infection. Within five days, coronavirus was found in all three of the newly exposed animals.
None of the six cats ever showed any symptoms.
“There was no sneezing, no coughing, they never had a high body temperature or lost any weight,” Halfmann said. “If a pet owner looked at them ... they wouldn’t have noticed anything.”
Last month, two domestic cats in different parts of New York state tested positive for the coronavirus after mild respiratory illnesses. They were thought to have picked it up from people in their homes or neighborhoods.
Some tigers and lions at the Bronx Zoo also have tested positive for the virus, as have a small number of other animals around the world.
Those cases and the new lab experiment show “there is a public health need to recognize and further investigate the potential chain of human-cat-human transmission,” the authors wrote.
Guidelines from the U.S. Centers for Disease Control and Prevention say that based on the limited information available so far, the risk of pets spreading coronavirus to people “is considered to be low.”
The veterinary medicine group says “there is no evidence to suggest that animals, including pets, that may be incidentally infected by humans are playing a role in the spread of COVID-19.” It stressed that person-to-person transmission was driving the global pandemic.
However, the group noted that many diseases spread between pets and people, so hygiene is always important: Wash your hands before and after touching pets, and keep your pet and its food and water bowls clean.
Halfmann, whose two cats sleep near him, said the worry may be greater for animal shelters, where one infected animal could pass the virus to many others.
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Post by Admin on May 21, 2020 5:38:34 GMT
Chinese doctors are seeing the coronavirus manifest differently among patients in its new cluster of cases in the northeast region compared to the original outbreak in Wuhan, suggesting that the pathogen may be changing in unknown ways and complicating efforts to stamp it out. Patients found in the northern provinces of Jilin and Heilongjiang appear to carry the virus for a longer period of time and take longer to test negative, Qiu Haibo, one of China’s top critical care doctors, told state television on Tuesday. Patients in the northeast also appear to be taking longer than the one to two weeks observed in Wuhan to develop symptoms after infection, and this delayed onset is making it harder for authorities to catch cases before they spread, said Qiu, who is now in the northern region treating patients. “The longer period during which infected patients show no symptoms has created clusters of family infections,” said Qiu, who was earlier sent to Wuhan to help in the original outbreak. Some 46 cases have been reported over the past two weeks spread across three cities -- Shulan, Jilin city and Shengyang -- in two provinces, a resurgence of infection that sparked renewed lockdown measures over a region of 100 million people. Qiu said that doctors have also noticed patients in the northeast cluster seem to have damage mostly in their lungs, whereas patients in Wuhan suffered multi-organ damage across the heart, kidney and gut. Officials now believe that the new cluster stemmed from contact with infected arrivals from Russia, which has one of the worst outbreaks in Europe. Genetic sequencing has showed a match between the northeast cases and Russian-linked ones, said Qiu. Among the northeast cluster, only 10% have turned critical and 26 are hospitalized. Over 100 Million in China’s Northeast Face Renewed Lockdown China is moving aggressively to stem the spread of the new cluster ahead of its annual political gathering in Beijing scheduled to start this week. As thousands of delegates stream into the capital to endorse the government’s agenda, China’s central leadership is determined to project stability and control. The northeast provinces have ordered a return of lockdown measures, halting train services, closing schools and sealing off residential compounds, dismaying residents who had thought the worst was over. “People should not assume the peak has passed or let down their guard,” Wu Anhua, a senior infectious disease doctor, said on state television on Tuesday. “It’s totally possible that the epidemic will last for a long time.”
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Post by Admin on Jun 5, 2020 1:15:46 GMT
An international team of physicists, led by Pennsylvania State University (Penn State) in Philadelphia1, believes that manufacturers could incorporate UV LEDs made with the new material into lamps that are lighter, cheaper, and more efficient than the UV lamps people currently use for disinfection. The idea of using UV light to kill microbes has been around since at least 1877, when the British chemists Arthur Downes and Thomas Blunt published a paper in the journal Nature reporting that sunlight inhibits the growth of bacteria. Some people hope that increased amounts of sunlight during the summer months in Europe and the United States will slow the spread of the new coronavirus. However, in a recent article in The Lancet Microbe2, microbiologists point out that by the time sunlight reaches the ground, it no longer contains the shorter wavelengths of UV light that destroy the genetic material in viruses. A future staple in operating theaters? The UV systems that health professionals use to sanitize areas such as hospital operating theaters deploy these shorter wavelengths. Known as UVC, they are in the range of 200–280 nanometers. Research from 2016 found that UVC is highly effective at deactivating coronaviruses closely related to SARS-CoV-2. To deliver sufficient doses, the UV sources in these systems are usually mercury-containing lamps. However, these are expensive and bulky and use a lot of power. LEDs that emit UV would make a cheap, lightweight, and energy-efficient alternative, but current versions are not powerful enough to deliver a knockout blow to viruses. Their power output is limited by the necessity for LEDs to use electrodes that are transparent to the wavelengths of light they emit. At present, the best available material that is transparent to UV at the right wavelengths is a poor conductor of electricity. “You have to ensure a sufficient UV light dose to kill all the viruses,” says senior study author Roman Engel-Herbert, an associate professor of materials science, physics, and chemistry at Penn State. “This means you need a high performance UV LED emitting a high intensity of UV light, which is currently limited by the transparent electrode material being used.” To develop LED computer screens, smartphones, tablets, and light bulbs, scientists have had to develop materials that not only conduct well but are also transparent to visible light. If anything, the challenge has proved even greater for scientists trying to develop better conductors that are transparent to UV at shorter wavelengths. “There is simply no good material choice for a UV-transparent conductor material that has been identified,” says study co-author Joseph Roth, a doctoral candidate in materials science and engineering at Penn State. 1. www.nature.com/articles/016218a02. www.thelancet.com/journals/lanmic/article/PIIS2666-5247(20)30013-6/fulltext#%20
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Post by Admin on Jun 5, 2020 7:02:16 GMT
Solar ultraviolet radiation sensitivity of SARS-CoV-2 Ayse Seyer Tamer Sanlidag
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can be life-threatening; the outbreak of this disease was characterised as a pandemic by WHO on March 11, 2020.1 COVID-19 is currently a global health issue and governments are taking a series of measures to reduce the spread of the virus among communities. Factors affecting the survival of SARS-CoV-2 need to be clarified and the effect of solar ultraviolet radiation is one subject under discussion.2
The output of both the popular and scientific press have included hopeful speeches by politicians or scientists suggesting that the transmission of SARS-CoV-2 will be contained within the coming months because of increasing temperatures and solar ultraviolet radiation during the summer season in countries in the northern hemisphere. However, solar ultraviolet radiation and ultraviolet germicidal irradiation (UVGI) are not the same. To evaluate effectiveness of ultraviolet radiation, we need to consider the virology of SARS-CoV-2, an enveloped, single stranded RNA virus. SARS-CoV-2 is a novel betacoronavirus and showed 88% genome similarity with two SARS-like coronaviruses (SL-CoV) found in bats: SL-CoV-ZC45 and SL-CoVZXC21.3 Human-to-human transmission occurs via droplets (by direct or indirect contact)4 and viral droplets can survive on various surfaces for several hours, despite reductions in the viral load.2 This information shows that, despite their enveloped structure, SARS-CoV-2 is quite resistant to environmental conditions.
During epidemics and pandemics, disinfection of environments is crucial, particularly for airborne diseases.5 The advantages offered by ultraviolet radiation make UVGI (ultraviolet disinfection) a very effective disinfection tool.6 Ultraviolet light can be classified into three subtypes by radiation wavelengths: ultraviolet A (320-400 nm), ultraviolet B (280–320 nm) and ultraviolet C (200–280 nm).7 The commonly used wavelength for UVGI is ultraviolet C because its germicidal effectiveness peak wavelength is 260–265 nm, which is equivalent to the peak of ultraviolet radiation absorption of nucleic acids.7 It is known that as the ultraviolet wavelength decreases, the germicidal effect of ultraviolet radiation increases.8 Therefore, ultraviolet wavelengths below 320 nm are classed as actinic—ie, causing photochemical reactions. Since ultraviolet A radiation is insufficiently absorbed by viral nucleic acid, ultraviolet A radiation is not considered germicidal.7
Unfortunately, ultraviolet A is the major ultraviolet component of sunlight reaching the ground.8 Ultraviolet B radiation can also have a small germicidal effect,7 but only a small portion of it reaches the Earth's surface as most is absorbed by the atmosphere.8 Ultraviolet radiation that is totally absorbed by the ozone layer is accepted as having the optimum germicidal wavelength—ie, ultraviolet C radiation.8 Unifying all these principles, it is clear that sunlight reaching the ground lacks germicidal ultraviolet C radiation.7, 8 Studies show that UVGI methods can be used effectively to eliminate viruses—eg, in health-care facilities, schools, indoors, etc—by using special ultraviolet radiation systems (ultraviolet C lamps, chambers). Also, it is known that the ultraviolet absorption peak of RNA viruses is around 250 nm wavelength.7 Therefore, the germicidal effectiveness of ultraviolet C radiation is limited to such applications and sunlight is not an alternative. However, some studies based on SARS-CoV, have shown that at least 60°C (which the earth does not reach to this temperature) and a minimum of 90 min are required to inactivate SARS-CoV-2.9
In the absence of scientific evidence showing ultraviolet B radiation's germicidal effectiveness on SARS-CoV-2, both politicians and scientists should avoid voicing assumptions on the effect of sunlight on viral transmission. Such uninformed statements can promoted misunderstanding and offer unrealistic hope to communities. This misunderstanding can also cause lethargy with regard to the government measurements in place in the community. Further studies should be done by simulating complex environmental conditions, in which a number of variables will test the effectiveness of ultraviolet B radiation against environmental SARS-CoV-2.
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