How the new coronavirus was discovered

As the new coronavirus spreads further, scientists in China and around the world are working togetherĀ  to start a “second battleground” against the virus outside hospitals. On January 24, the National Pathogen Microbiology Library released a photo of China’s first new coronavirus electroscope isolated by the China Center for Disease Control and Prevention.

In the early hours of the 25th, Beijing time, the authoritative medical journal New England Journal of Medicine published a related research paper led by Gao Fu, director of the China Center for Disease Control and Prevention, revealing the whole process of Chinese scientists discovering and isolating the new coronavirus (2019-nCov).

By sequencing the entire genome of samples from three patients with the new coronavirus pneumonia that was found early, The team found a never-before-seen beta coronavirus virus. The virus is isolated from the epithelial cells of an infected person and later named 2019-nCoV, a subspecies of the Sarbe virus, a coronavirus subdivision, but forms another cluster of evolutionary branches. Unlike MERS-CoV and SARS-CoV, 2019-nCoV is the seventh member of the coronavirus family that can infect humans.

In a paper, The New England Journal of Medicine Chinese edition of NEJM Medical Frontiers, Gao Fu’s team disclosed in its paper that in late December 2019, several local health authorities reported a group of unexplained pneumonia patients who were epidemiologically linked to a wholesale seafood and wet animal market in Wuhan. On December 31, the China Center for Disease Control and Prevention sent a rapid emergency response team to conduct epidemiological and pathogenic investigations with health agencies in Hubei province and Wuhan.

According to the study, on December 27, 2019, three adult patients with severe pneumonia symptoms were admitted to a hospital in Wuhan. Patients 1 were 49-year-old women, patients 2 were 61-year-old males and patients 3 were 32-year-old males. The team collected a medical history of patients 1 and 2: Patient 1 had no potential chronic underlying medical history, but developed fever (body temperature 37-38 degrees C), cough and chest discomfort on 23 December 2019. Cough and lung discomfort worsened 4 days after the oncoming clinical symptoms, but the fever symptoms eased and pneumonia was diagnosed based on the results of CT scans. The patient’s occupation is a retail vendor at the seafood market.

Patient 2 Initial symptoms begin on December 20, 2019 with fever and cough. Breathing difficulties occurred 7 days after the onset of the disease and the subsequent 2 days of sexual aggravation (chest information as shown in Figure 1), during which mechanical ventilation was carried out. The patient had frequently visited the seafood market. Patients 1 and 3 were discharged on 16 January 2020 after treatment, but Patient 2 died on 9 January 2020 without collecting tissue samples from the patient.

How the new coronavirus was discovered

Chest

On December 30, 2019, they received alveolar irrigationĀ  of the three patients from Wuhan Jinyintan Hospital, the team said. The new coronavirus was then isolated from all three patients. Although 2019-nCov is similar to the type B coronavirus isolated in bats, it is different from SARS coronavirus and MERS coronavirus, the paper said. The three new 2019 coronaviruses from Wuhan and two SARS-like strains from bats form a new branch in the Sarbe coronavirus subgenutb B lineage; THE SARS-like coronavirus together forms another branch of the Sarbe coronavirus subspecies.

In an editorial published at the same time, NEJM Medical Frontiers noted that following the outbreak of severe acute respiratory syndrome (SARS-CoV) in 2002 and merS-CoV in the Middle East in 2012, 2019- nCoV is the third pathogenic coronavirus to appear in humans in the past 20 years.

The latest information from China, Thailand, South Korea and Japan indicates that diseases associated with 2019-nCoVĀ  appear to be relatively mild compared to SARS and MERS , and that 2019-nCoV appears to be less pathogenic than MERS-CoV and SARS-CoV. However, this also raises the important question of what impact will be on containing new viruses and preventing their widespread spread.

The editorial points out that efficient human-to-human transmission is a necessary condition for the large-scale spread of the new virus. However, if the virus infection does not cause serious illness, the infected person is likely not to seek medical attention. Instead, they may go to work and travel, which may spread the virus to contacts and may even spread internationally. If many infected people have no symptoms or only mild symptoms (assuming they can spread the virus), it is much more complicated to identify the chain of transmission and to track the follow-up contact.

The editorial also said it was not yet known where the new virus was located in 2019-nCoV within the entire range of the virus’s ability to spread from person to person. But it is essentially possible to assume that if the virus can spread efficiently, its seemingly low pathogenicity relative to SARS may instead lead to large-scale transmission. In this way, viruses that pose a lower health threat at the individual level can pose a higher risk at the population level and may result in damage and economic loss to the global public health system.

Another expert, Stanley Perlman of the University of Iowa, noted in a commentary published in the journal that there is still a lot of information to be learned about the new virus infection. Most importantly, there is a need to determine the degree of human-to-human transmission and the various manifestations of clinical diseases, to obtain as many timely and geographically unrelated clinical isolates as possible to assess the extent of viral mutations and to assess whether these mutations indicate adaptability to human hosts. In addition, the source of the virus’s zoonotic pathogens should be determined as soon as possible.