Modeling study estimates spread of 2019 novel coronavirus

Coronavirus diagnosis concept (stock image)

New modelling research, published in The Lancet, estimates that up to 75,800 individuals in the Chinese city of Wuhan may have been infected with 2019 novel coronavirus (2019-nCoV) as of January 25, 2020.

Senior author Professor Gabriel Leung from the University of Hong Kong highlights: "Not everyone who is infected with 2019-nCoV would require or seek medical attention. During the urgent demands of a rapidly expanding epidemic of a completely new virus, especially when system capacity is getting overwhelmed, some of those infected may be undercounted in the official register."

He explains: "The apparent discrepancy between our modelled estimates of 2019-nCoV infections and the actual number of confirmed cases in Wuhan could also be due to several other factors. These include that there is a time lag between infection and symptom onset, delays in infected persons coming to medical attention, and time taken to confirm cases by laboratory testing, which could all affect overall recording and reporting."

The new estimates also suggest that multiple major Chinese cities might have already imported dozens of cases of 2019-nCoV infection from Wuhan, in numbers sufficient to initiate local epidemics.

The early estimates underscore that it will likely take rapid and immediate scale-up of substantial public health control measures to prevent large epidemics in areas outside Wuhan. Further analyses suggest that if transmissibility of 2019-nCoV could be reduced, both the growth rate and size of local epidemics in all cities across China could be reduced.

"If the transmissibility of 2019-nCoV is similar nationally and over time, it is possible that epidemics could be already growing in multiple major Chinese cities, with a time lag of one to two weeks behind the Wuhan outbreak," says lead author Professor Joseph Wu from the University of Hong Kong. "Large cities overseas with close transport links to China could potentially also become outbreak epicentres because of substantial spread of pre-symptomatic cases unless substantial public health interventions at both the population and personal levels are implemented immediately."

According to Professor Gabriel Leung: "Based on our estimates, we would strongly urge authorities worldwide that preparedness plans and mitigation interventions should be readied for quick deployment, including securing supplies of test reagents, drugs, personal protective equipment, hospital supplies, and above all human resources, especially in cities with close ties with Wuhan and other major Chinese cities."

In the study, researchers used mathematical modelling to estimate the size of the epidemic based on officially reported 2019-nCoV case data and domestic and international travel (i.e., train, air, road) data. They assumed that the serial interval estimate (the time it takes for infected individuals to infect other people) for 2019-nCoV was the same as for severe acute respiratory syndrome (SARS: table 1). The researchers also modelled potential future spread of 2019-nCoV in China and internationally, accounting for the potential impact of various public health interventions that were implemented in January 2020 including use of face masks and increased personal hygiene, and the quarantine measures introduced in Wuhan on January 23.

The researchers estimate that in the early stages of the Wuhan outbreak (from December 1, 2019 to January 25, 2020) each person infected with 2019-nCoV could have infected up to 2-3 other individuals on average, and that the epidemic doubled in size every 6.4 days. During this period, up to 75,815 individuals could have been infected in Wuhan.

Additionally, estimates suggest that cases of 2019-nCoV infection may have spread from Wuhan to multiple other major Chinese cities as of January 25, including Guangzhou (111 cases), Beijing (113), Shanghai (98), and Shenzhen (80; figure 3). Together these cities account for over half of all outbound international air travel from China.

While the estimates suggest that the quarantine in Wuhan may not have the intended effect of completely halting the epidemic, further analyses suggest that if transmissibility of 2019-nCoV could be reduced by 25% in all cities nationally with expanded control efforts, both the growth rate and size of local epidemics could be substantially reduced. Moreover, a 50% reduction in transmissibility could shift the current 2019-nCoV epidemic from one that is expanding rapidly, to one that is slowly growing (figure 4).

"It might be possible to reduce local transmissibility and contain local epidemics if substantial, even draconian, measures that limit population mobility in all affected areas are immediately considered. Precisely what and how much should be done is highly contextually specific and there is no one-size-fits-all set of prescriptive interventions that would be appropriate across all settings," says co-author Dr Kathy Leung from the University of Hong Kong. "On top of that, strategies to drastically reduce within-population contact by cancelling mass gatherings, school closures, and introducing work-from-home arrangements could contain the spread of infection so that the first imported cases, or even early local transmission, does not result in large epidemics outside Wuhan."

The authors point to several limitations of their study, including that the accuracy of their estimates depend on their assumption about the zoonotic source of infection in Wuhan. They also highlight that the models assume travel behaviour was not affected by disease status and that all infections eventually have symptoms -- so it is possible that milder cases have gone undetected which could underestimate the size of the outbreak. Lastly, they note that their epidemic forecast was based on inter-city mobility data from 2019, and might not reflect mobility patterns in 2020, particularly in light of the health threat posed by 2019-nCoV.

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Materials provided by The Lancet. Note: Content may be edited for style and length.

Amazon deforestation and number of fires show summer of 2019 not a 'normal' year

Burning in Amazon rainforest

The fires that raged across the Brazilian Amazon this summer were not 'normal' and large increases in deforestation could explain why, scientists show.

The perceived scale of the Amazon blazes received global attention this summer. However, international concerns raised at the time were countered by the Brazilian Government, which claimed the fire situation in August was 'normal' and 'below the historical average'.

An international team of scientists writing in the journal Global Change Biology say the number of active fires in August was actually three times higher than in 2018 and the highest number since 2010.

Although fires in the Amazon can occur in a number of ways, the scientists show that there is strong evidence to link this year's increases to deforestation.

They have used evidence collected from the Brazilian Government's DETER-b deforestation detection system -- which calculates deforestation by interpreting images taken by NASA satellites.

This shows that deforestation in July this year was almost four times the average from the same period in the previous three years. This is important as deforestation is almost always followed by fire -- the cut vegetation is left to dry before being burned.

Professor Jos Barlow, lead author of the paper said: "The marked upturn in both active fire counts and deforestation in 2019 therefore refutes suggestions by the Brazilian Government that August 2019 was a normal fire month in the Amazon."

August's blazes occurred at a time without a strong drought. Droughts can provide conditions favourable to the spreading of human-made fires. The scientists also show that the 'enormous' smoke plumes that reached high into the atmosphere, which were captured by media footage of the blazes, could only have been caused by the combustion of large amounts of biomass.

The researchers acknowledge that the number of active fires decreased in September by 35 per cent. Though they say it is not clear whether that fall is due to rains or President Bolsonaro's two-month moratoria on fires.

Images from DETER-b show that deforestation continued at a rate well above the average in September, despite the President's moratoria.

The extent of August's fires is unclear. Although the numbers of fires are counted, their extent is not, the researchers acknowledge in their paper 'Clarifying Amazonia's burning crisis'.

Dr Erika Berenguer, a Brazilian researcher jointly affiliated with Lancaster University and the University of Oxford, said: "Our paper clearly shows that without tackling deforestation, we will continue to see the largest rainforest in the world being turned to ashes. We must curb deforestation.

"Brazil has for the past decade been an environmental leader, showing to the world that it can successfully reduce deforestation. It is both economically and environmentally unwise to revert this trend."

The paper's authors are Jos Barlow of Lancaster University, Erika Berenguer of Lancaster University and the University of Oxford, Rachel Carmenta of the University of Cambridge, and Filipe França of the Universidade Federal do Pará.

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Materials provided by Lancaster University. Note: Content may be edited for style and length.

Amazon deforestation and number of fires show summer of 2019 not a 'normal' year

Burning in Amazon rainforest

The fires that raged across the Brazilian Amazon this summer were not 'normal' and large increases in deforestation could explain why, scientists show.

The perceived scale of the Amazon blazes received global attention this summer. However, international concerns raised at the time were countered by the Brazilian Government, which claimed the fire situation in August was 'normal' and 'below the historical average'.

An international team of scientists writing in the journal Global Change Biology say the number of active fires in August was actually three times higher than in 2018 and the highest number since 2010.

Although fires in the Amazon can occur in a number of ways, the scientists show that there is strong evidence to link this year's increases to deforestation.

They have used evidence collected from the Brazilian Government's DETER-b deforestation detection system -- which calculates deforestation by interpreting images taken by NASA satellites.

This shows that deforestation in July this year was almost four times the average from the same period in the previous three years. This is important as deforestation is almost always followed by fire -- the cut vegetation is left to dry before being burned.

Professor Jos Barlow, lead author of the paper said: "The marked upturn in both active fire counts and deforestation in 2019 therefore refutes suggestions by the Brazilian Government that August 2019 was a normal fire month in the Amazon."

August's blazes occurred at a time without a strong drought. Droughts can provide conditions favourable to the spreading of human-made fires. The scientists also show that the 'enormous' smoke plumes that reached high into the atmosphere, which were captured by media footage of the blazes, could only have been caused by the combustion of large amounts of biomass.

The researchers acknowledge that the number of active fires decreased in September by 35 per cent. Though they say it is not clear whether that fall is due to rains or President Bolsonaro's two-month moratoria on fires.

Images from DETER-b show that deforestation continued at a rate well above the average in September, despite the President's moratoria.

The extent of August's fires is unclear. Although the numbers of fires are counted, their extent is not, the researchers acknowledge in their paper 'Clarifying Amazonia's burning crisis'.

Dr Erika Berenguer, a Brazilian researcher jointly affiliated with Lancaster University and the University of Oxford, said: "Our paper clearly shows that without tackling deforestation, we will continue to see the largest rainforest in the world being turned to ashes. We must curb deforestation.

"Brazil has for the past decade been an environmental leader, showing to the world that it can successfully reduce deforestation. It is both economically and environmentally unwise to revert this trend."

The paper's authors are Jos Barlow of Lancaster University, Erika Berenguer of Lancaster University and the University of Oxford, Rachel Carmenta of the University of Cambridge, and Filipe França of the Universidade Federal do Pará.

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Story Source:

Materials provided by Lancaster University. Note: Content may be edited for style and length.

Amazon deforestation and number of fires show summer of 2019 not a 'normal' year

Burning in Amazon rainforest 

The fires that raged across the Brazilian Amazon this summer were not 'normal' and large increases in deforestation could explain why, scientists show.

The perceived scale of the Amazon blazes received global attention this summer. However, international concerns raised at the time were countered by the Brazilian Government, which claimed the fire situation in August was 'normal' and 'below the historical average'.

An international team of scientists writing in the journal Global Change Biology say the number of active fires in August was actually three times higher than in 2018 and the highest number since 2010.

Although fires in the Amazon can occur in a number of ways, the scientists show that there is strong evidence to link this year's increases to deforestation.

They have used evidence collected from the Brazilian Government's DETER-b deforestation detection system -- which calculates deforestation by interpreting images taken by NASA satellites.

This shows that deforestation in July this year was almost four times the average from the same period in the previous three years. This is important as deforestation is almost always followed by fire -- the cut vegetation is left to dry before being burned.

Professor Jos Barlow, lead author of the paper said: "The marked upturn in both active fire counts and deforestation in 2019 therefore refutes suggestions by the Brazilian Government that August 2019 was a normal fire month in the Amazon."

August's blazes occurred at a time without a strong drought. Droughts can provide conditions favourable to the spreading of human-made fires. The scientists also show that the 'enormous' smoke plumes that reached high into the atmosphere, which were captured by media footage of the blazes, could only have been caused by the combustion of large amounts of biomass.

The researchers acknowledge that the number of active fires decreased in September by 35 per cent. Though they say it is not clear whether that fall is due to rains or President Bolsonaro's two-month moratoria on fires.

Images from DETER-b show that deforestation continued at a rate well above the average in September, despite the President's moratoria.

The extent of August's fires is unclear. Although the numbers of fires are counted, their extent is not, the researchers acknowledge in their paper 'Clarifying Amazonia's burning crisis'.

Dr Erika Berenguer, a Brazilian researcher jointly affiliated with Lancaster University and the University of Oxford, said: "Our paper clearly shows that without tackling deforestation, we will continue to see the largest rainforest in the world being turned to ashes. We must curb deforestation.

"Brazil has for the past decade been an environmental leader, showing to the world that it can successfully reduce deforestation. It is both economically and environmentally unwise to revert this trend."

The paper's authors are Jos Barlow of Lancaster University, Erika Berenguer of Lancaster University and the University of Oxford, Rachel Carmenta of the University of Cambridge, and Filipe França of the Universidade Federal do Pará.

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Materials provided by Lancaster University. Note: Content may be edited for style and length.

2019 Nobel Prize in Physics: Evolution of the universe and discovery of exoplanet orbiting solar-type star

                                                        illustration of exoplanet orbiting star 

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics 2019 "for contributions to our understanding of the evolution of the universe and Earth's place in the cosmos" with one half to James Peebles of Princeton University, USA, "for theoretical discoveries in physical cosmology" and the other half jointly to Michel Mayor of the University of Geneva, Switzerland, and Didier Queloz of the University of Geneva, Switzerland, and the University of Cambridge, UK, "for the discovery of an exoplanet orbiting a solar-type star."

New perspectives on our place in the universe

This year's Nobel Prize in Physics rewards new understanding of the universe's structure and history, and the first discovery of a planet orbiting a solar-type star outside our solar system.

James Peebles' insights into physical cosmology have enriched the entire field of research and laid a foundation for the transformation of cosmology over the last fifty years, from speculation to science. His theoretical framework, developed since the mid-1960s, is the basis of our contemporary ideas about the universe.

The Big Bang model describes the universe from its very first moments, almost 14 billion years ago, when it was extremely hot and dense. Since then, the universe has been expanding, becoming larger and colder. Barely 400,000 years after the Big Bang, the universe became transparent and light rays were able to travel through space. Even today, this ancient radiation is all around us and, coded into it, many of the universe's secrets are hiding. Using his theoretical tools and calculations, James Peebles was able to interpret these traces from the infancy of the universe and discover new physical processes.

The results showed us a universe in which just five per cent of its content is known, the matter which constitutes stars, planets, trees -- and us. The rest, 95 per cent, is unknown dark matter and dark energy. This is a mystery and a challenge to modern physics.

In October 1995, Michel Mayor and Didier Queloz announced the first discovery of a planet outside our solar system, an exoplanet, orbiting a solar-type star in our home galaxy, the Milky Way. At the Haute-Provence Observatory in southern France, using custom-made instruments, they were able to see planet 51 Pegasi b, a gaseous ball comparable with the solar system's biggest gas giant, Jupiter.

This discovery started a revolution in astronomy and over 4,000 exoplanets have since been found in the Milky Way. Strange new worlds are still being discovered, with an incredible wealth of sizes, forms and orbits. They challenge our preconceived ideas about planetary systems and are forcing scientists to revise their theories of the physical processes behind the origins of planets. With numerous projects planned to start searching for exoplanets, we may eventually find an answer to the eternal question of whether other life is out there.

This year's Laureates have transformed our ideas about the cosmos. While James Peebles' theoretical discoveries contributed to our understanding of how the universe evolved after the Big Bang, Michel Mayor and Didier Queloz explored our cosmic neighbourhoods on the hunt for unknown planets. Their discoveries have forever changed our conceptions of the world.

James Peebles, born 1935 in Winnipeg, Canada. Ph.D. 1962 from Princeton University, USA. Albert Einstein Professor of Science at Princeton University, USA.

Michel Mayor, born 1942 in Lausanne, Switzerland. Ph.D. 1971 from University of Geneva, Switzerland. Professor at University of Geneva, Switzerland.

Didier Queloz, born 1966. Ph.D. 1995 from University of Geneva, Switzerland. Professor at University of Geneva, Switzerland and University of Cambridge, UK.

Prize amount: 9 million Swedish krona, with one half to James Peebles and the other half jointly to Michel Mayor and Didier Queloz

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Materials provided by Nobel Foundation. Note: Content may be edited for style and length.