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News Medical (Austrália)

Two genome sequences of coronavirus (COVID-19) show possible internal transmission

Publicado em 04 março 2020

Por Angela Betsaida B. Laguipo

The coronavirus disease (COVID-19) is rapidly spreading around the globe. With the high infection rate and spread of the virus to more than 80 countries, scientists are racing to study the nature of the virus, in the hopes of finding new vaccines and therapeutics.

Now, scientists have published two genome sequences for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Coronavirus disease (COVID-19) is an infectious disease caused by SARS-CoV-2.

The scientists, which were from the Adolfo Lutz Institute (IAL), the University of São Paulo (USP) in Brazil and the University of Oxford in the United Kingdom, published their study on Virological.org, which is a forum for discussion and date shared by virologists, public health specialists, and epidemiologists across the globe.

Different genomes

The team has found that the genome sequence of the coronavirus sampled from the first confirmed case in Brazil is different from the one acquired from the second confirmed case in the country. Further, the two complete genome sequences were different from the patients in China.

The scientific discovery has been added to an international database where about 22 countries have sequenced the virus genomes, to help them understand and know the nature of the virus. In understanding how the virus behaves and how it affects the health of those infected according to the genetic characteristics of each population, better therapeutics and potential vaccines can be developed.

China has published the complete genome of the coronavirus 2019, now officially called SARS-CoV-2, which served as the basis for diagnostic methods that are now being used across the globe. The findings of the genome analysis have also led to scientists formulating potential vaccines that can help stem the spread of the virus.

Now, this new genomic analysis of the two patients in Brazil will shed light on how the virus affects each country’s population. The activity of the virus may affect the population of each country differently. Also, the genome analysis in each country can help determine how the virus moves, leads to unrelated cases, and where originated.

Novel Coronavirus SARS-CoV-2: This scanning electron microscope image shows SARS-CoV-2 (round gold objects) emerging from the surface of cells cultured in the lab. SARS-CoV-2, also known as 2019-nCoV, is the virus that causes COVID-19. The virus shown was isolated from a patient in the U.S. The first Brazilian sequence closely resembles the samples sequenced in Germany. The second Brazilian genome is more similar to the genome sequenced in the United Kingdom. Credit: NIAID-RML

A step closer

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“By sequencing the genome, we’ve come closer to finding out the origin of the epidemic. We know the confirmed cases in Brazil came from Italy, but the Italians don’t yet know the origin of the outbreak in Lombardy as they have yet to sequence their samples. They haven’t identified patient zero and don’t know whether he or she came from China directly or via other countries,” Ester Sabino, head of USP’s Tropical Medicine Institute (IMT), said.

Further, Sabino added that the first Brazilian sequence closely resembles the samples found in Germany and is different from those in Wuhan, China, the outbreak’s epicenter where the virus emerged in late December 2019.

However, the second genome from Brazil is more similar to the genome from the UK, suggesting that internal transmission is happening in European countries.

Ongoing monitoring progress

The ongoing monitoring progress will help scientists identify the specific regions of the viral genome that mutate least, a pivotal step in developing vaccines, diagnostic tests, and therapeutics. This way, when scientists perform testing in a region that mutates frequently, it can have a high loss of sensitivity.

The new project in determining genomic sequences of the virus can help combine the expertise of many scientists in responding to outbreaks, including studying epidemiological data in real-time.

“We began partnering with the IAL team and training researchers to use MinION, a portable, low-cost sequencing technology. We used this methodology to monitor the evolution of the Zika virus in the Americas, but in that case, we were able to trace the origin of the virus and the dissemination route only a year after the epidemic ended. This time the team went into action as soon as the first case was confirmed,” Sabino said.

At the moment, the researchers urge other scientists in the field in other countries to perform genome sequences of their confirmed cases. With the vast data about the virus, it can shed light on its mechanism, making it easier to develop antivirals and possible vaccines.

Coronavirus outbreak magnitude

The coronavirus disease (COVID-19) is rapidly spreading across continents. Globally, the total number of coronavirus disease cases is 95,120, and it is increasing by the minute. The death toll has reached 3,254. China has reported the highest number of infections and deaths, with 80,270 cases.

Outside mainland China, South Korea, Italy, and Iran have reported high infection rates. South Korea has 5,621 confirmed cases, while Italy has 3,089 cases, and Iran has 2,922 cases. Italy and Iran have reported the greatest number of deaths outside mainland China with 107 and 92 deaths, respectively.

Sources:

Agência FAPESP. First cases of coronavirus disease (COVID-19) in Brazil, South America (2 genomes, 3rd March 2020). http://virological.org/t/first-cases-of-coronavirus-disease-covid-19-in-brazil-south-america-2-genomes-3rd-march-2020/409 Coronavirus COVID-19 Global Cases by Johns Hopkins CSSE - https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6 Technology used to sequence coronavirus in Brazil will enable scientists to monitor epidemic in real time - http://agencia.fapesp.br/technology-used-to-sequence-coronavirus-in-brazil-will-enable-scientists-to-monitor-epidemic-in-real-time/32656/