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Tracking A Killer (contact Tracing) - Health - Nairaland

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Tracking A Killer (contact Tracing) by efezizi: 1:14pm On Jun 13, 2020
Tracking a killer
Investigating an outbreak is not unlike the work of any detective. It’s a race to the scene of the crime before any evidence disappears; witnesses are interviewed - and then the chase begins, to track down and contain the killer before they strike again.
But despite rallying an unrivalled international effort, coronavirus continues to advance, killing thousands of people everyday.
Six months on, what have scientists discovered whilst trying to contain coronavirus?
Raising the alarm
Understanding the origins of any virus is crucial, in order to predict how it will impact our health, and how fast it might spread. But, from the very beginning, coronavirus took everyone by surprise.
As much of the world prepared to welcome in the new year, Dr Li Wenliang was working in the emergency department of Wuhan Central Hospital where seven patients, all suffering from pneumonia - an infection of the lungs - had been quarantined.
Group messaging his colleagues in a private WeChat on 30 December, he shared his worst fears - was he witnessing a new wave of Sars (Severe Acute Respiratory Syndrome)?
Sars, another type of coronavirus, first emerged in China in 2003 and spread to 26 countries, infecting more than 8000 people.
However, what Dr Li had identified was not a second wave of Sars, but the first wave of the Covid-19 virus (Sars-Cov-2).

Dr Li Wenliang
Three days after texting his peers, warning of a possible outbreak, Dr Li was detained by police, along with eight others, for “spreading rumours”, according to Chinese media.
Shortly after returning to work, Dr Li contracted Covid-19. He died on 7 February, aged 34, leaving behind his son and pregnant wife.

Scene of the crime
Situated in the newer part of town, Huanan Seafood Market was a hubbub of small stallholders, selling everything from live poultry, to fish, reptiles and wild game.
But throughout the last weeks of December 2019, as more and more doctors and nurses began to warn of a possible viral outbreak, it was health workers who first realised the connection - that the majority of their patients worked at Huanan Seafood Market.
On 31 December, Wuhan’s Health Commission filed their first official report to Beijing. The following day, the market was quarantined.
Police officers outside Huanan Seafood Market
Today, scientists are unanimous in believing a large outbreak took place at the seafood market, but whether it was the place where the virus first emerged now looks unlikely.
Samples taken from both people and live animals at the market have since tested positive for Covid-19. Yet, according to medical researchers in Wuhan, the earliest human case of the coronavirus disease has subsequently been found to have occurred almost four weeks earlier than the outbreak at the market: an elderly man from Wuhan who developed symptoms as early as 1 December 2019 and had no conclusive links to Huanan Seafood Market.
Symptomatic cases of Covid-19 have now been discovered as early as 1 December
Back in January, as health workers in Wuhan began to witness an explosion of cases across the city's hospitals, no one predicted the devastating speed with which the virus would spread, not only across China, but across the Asian continent.
Just nine days after the first reported death of a patient with Covid-19, on 11 January, new cases had already crossed from China to Japan, South Korea and Thailand.
And thus began the chase after a killer, in which, despite all the world’s advances in medicine and technology, we were always one step behind…

Profiling a killer
“Our first question is always, what is it?” says Professor of Immunology Kristian Andersen
Andersen's laboratory specialises in infectious disease genomics. They investigate how viruses jump from animals to humans and cause large-scale outbreaks.
Along with over a third of world's population, Professor Kristian Andersen is also living and working under lockdown
Back in late December, within hours of those first cases being admitted to hospital, nasal swabs of the mystery virus were being analysed by scientists at the Wuhan Institute of Virology.
They were looking for its genome - its complete genetic code - which would reveal exactly what it was and how it might spread.
Genomes are essentially a long string of letters - the human genome, for example, is made up of over three billion genetic letters. A common flu virus is more like 15,000 letters, and encoded within this chain are all the instructions a virus might need to replicate itself millions of times over, resulting in the spread of disease and infection.
Deciphering the genome of a virus usually takes months, even years, to complete. However, with exceptional speed, on 10 January, scientists at the Wuhan Institute of Virology - led by Professor Yong-Zhen Zhang - published the first genomic sequence of Covid-19, the first, and arguably the most crucial, piece of the puzzle.
A single coronavirus
“As soon as we saw that first sequence, we knew immediately that it was a type of coronavirus - and that it was 80% identical to Sars,” says Professor Andersen.
Coronaviruses are a large family of viruses, hundreds of which are known to circulate among animals such as pigs, camels, bats and cats. Covid-19 is only the seventh coronavirus believed to have jumped from another animal to a human.
“Our second question is how can we diagnose it - which leads to testing and understanding the way the virus transmits,” says Prof Andersen.
“And the third question is how can we develop vaccines against it? All of which can be answered with the genetics as a blueprint for the virus.”
Professor Anderson says there is overwhelming evidence the virus originated in a bat.
“This ultimately started in a bat. We know this is a fully natural virus, because there are so many similar viruses found in bats,” he explains. “What we don’t know is how it got into the human population.”
Andersen’s team has studied another coronavirus found in a bat, which was 96% identical to Covid-19 . They have also seen strong similarities with another corona-like virus found in pangolins, one of the most trafficked mammals in Asia.
Could the virus have jumped from a bat, to another intermediary animal such as a pangolin, where it picked up some extra proteins, before finally jumping to a human? For scientists, the investigation continues.
In China, just two days after sharing the first genetic sequence of Covid-19 with the world, Professor Zhang’s laboratory was closed by local authorities and their research licence revoked. According to Chinese media, no official reason was ever given - but the team’s contribution to the world had already taken root.
“Without that first sequence, we couldn't have started any of this work,” says Prof Andersen. “It’s all thanks to these scientists delivering crucial information at an unbelievable speed.”
Track, trace, isolate
As the pandemic took hold, efforts shifted from investigating the origins of the virus to containing the outbreak.
Contact tracers
South Korea, a nation of 51 million people, stands out as one of the most successful countries in the world in managing to contain Covid-19.
Much of this success has been attributed to the country’s ability to mobilise a small army of contact tracers: detectives trained to connect the dots between a positive Covid-19 case and all their most recent contacts. The tracers must then decide who should be instructed to self-isolate, or, in some cases, whether to quarantine an entire building or organisation, such as a hospital, care home or office.
New daily cases of Covid-19 in South Korea
With only a handful of cases throughout January and early February, many South Koreans thought perhaps a large outbreak had been avoided. However, in late February, from a single city, came a sudden escalation of thousands of cases reported within the space of only a few days.
The outbreak in Daegu city has since been attributed to the movements of one single person, South Korea’s superspreader - the now infamous patient 31.
The city of Daegu accounts for more than 60% of all of the country's cases
Patient 31 tested positive for coronavirus on 17 February. It was only thanks to the work of contract tracers, that all her most recent contacts - which, shockingly, turned out to be more than 1,000 people in the space of 10 days - were tracked down and instructed to self-isolate, thus avoiding an even bigger outbreak.
As deputy of Daegu’s epidemiology team, Professor Kim Jong-Yeon is responsible for the city’s infantry of contact tracers - often former government employees, as well as junior doctors. He says only if people are evasive, do they use more rigorous methods - such as investigating their credit card transactions and their phone or GPS history. People such as patient 31.
Professor Kim Jong-Yeon in Daegu City
“Patient 31, at first she didn't tell us she was from the Shincheonji Church. It was us, the contact tracers, who later discovered she was a member,” says Prof Kim.
With approximately 300,000 members nationwide, the doctrine of Shincheonji Church of Jesus claims their founder, Lee Man-hee, is the second coming of Jesus Christ and that only he can interpret the Bible. Many mainstream Christian churches in South Korea consider the group to be a cult and have long criticised their aggressive recruitment of young people.
A service at Shincheonji Gyeonggi-do Church. Source: Shincheonji
But patient 31 has not become infamous simply for covering up her affiliation with Shincheonji Church. As contact tracers uncovered, in the 10 days prior to being tested - despite showing symptoms - she travelled around the city of Daegu coming into contact with more than 1,000 people.
After being involved in a car accident on 6 February, patient 31 was admitted to hospital on 7 February, where she came into close contact with an estimated 128 people. She then temporarily discharged herself in order to return home to collect personal belongings, a two-and-a-half-hour round-trip, before returning to hospital. Later that week she discharged herself multiple times, once going for lunch with a friend, and twice in order to attend a a two-hour church service with a 1000-strong congregation.
Due to the secretive nature of the Shincheonji Church, Prof Kim says the hardest part of the investigation was trying to establish who also visited the church during that week.
“We finally secured a list of all 9,000 members of the church. At first, we started to call and ask all of them if they had any symptoms. About 1200 people told us they did, but some people refused to get tested and self-quarantine.”
With hundreds of individuals reluctant to reveal their association with the secretive church, the professor says they were left with no choice.
“It became a matter of how quickly we could separate those church members from the rest of Daegu’s citizens. So the government issued an executive order for all church members to self-isolate.”
Thousands of students of the Shincheonji Church celebrate their in-house graduation. Source: Shincheonji
The city’s rigorous investigation of all new cases, combined with comprehensive testing, quickly curbed the spread of the virus - and by early April, the city of Daegu reported zero new cases of Covid-19.
However, elsewhere in the world, the virus continued to advance unabated. For the scientific community, it became vital to track the virus, not only over borders, but across continents.
The answer to this problem lay in the genome, clues left behind in the genetic code of the virus as it began to replicate and spread.
Efosa imalerio is a Pharmaceutical Biochemist from lahor Biomedical Research laboratories Benin City.
Additional reporting by - Bugyeong Jung

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