At the end of 2019 in Wuhan, China, a novel coronavirus, provisionally named 2019-nCoV, was detected. In the first few months of 2020, it has rapidly spread all over the globe, and on March 11 World Health Organization declared a pandemic (WHO Director-General’s opening remarks, 2020). Scientists from all over the world have been working on determining the origin and the main epidemiological and clinical characteristics of the virus in search of the best treatment strategies.
One of the early studies regarding the 2019-nCoV was titled “Genomic characterization and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding.” (Lu et al., 2020). The authors start by providing some background information into coronaviruses. They state that this type of virus has been identified in several avian hosts and some mammals including camels, bats, mice, dogs, and cats (Lu et al., 2020). However, while coronaviruses are increasingly met in mammals, the ones for which humans are susceptible usually have quite mild symptoms (Lu et al., 2020). Nonetheless, there have been a few exceptions: severe acute respiratory syndrome (SARS) which emerged in southern China in 2002 (as cited in Lu et al., 2020), and the Middle East respiratory syndrome (MERS) which was detected in Saudi Arabia in 2012 (as cited in Lu et al., 2020). The authors continue by describing the events following the discovery of 2019-nCoV. In December 2019 epidemiological association with the Huanan seafood market in Wuhan was identified about several patients with severe pneumonia. By the time the article was written, the virus had already been found in South Korea, Thailand, Singapore, South Korea, and the USA; and there were almost 6000 confirmed cases in China (Lu et al., 2020). However, it had not yet spread so dangerously across the globe.
The authors aim to provide the genomic characterization of ten genomes of the novel coronavirus based on the epidemiological data of nine inpatients from at least three Wuhan hospitals
in order to understand the origins and “cell receptor binding of the virus” (Lu et al., 2020, 566). The authors start explaining their methodology by providing the epidemiological characteristics of the patients studied. Eight of them had visited the Huanan market before showing the symptoms of unidentified pneumonia while one stayed in the hotel near the market (Lu et al., 2020). Five of the patients were tested for 18 viruses and four bacteria by the Chinese Center for Disease Control and Prevention (CDC) and were found negative for all common pneumonia pathogens; four of the them were screened for five viruses and one bacterium in BJI (Beijing, China) and showed negative results as well (Lu et al., 2020). Therefore, special-pathogen-free human airway epithelial (HAE) cells were used to isolate the virus (Lu et al., 2020). The samples were, then, sent to BJI, where they undergone several sequencing stages described by the authors in detail. The procedures carried out allowed to create a real-time Polymerase chain reaction (PCR) assays, one in CDC and another in BJI. Then, the original clinic samples in BJI and CDC were tested by these two PCR assays, respectively (Lu et al., 2020, 568). All the samples were found positive for 2019-nCoV.
The results of the analysis concern the comparison between COVID-19 and similar viruses.
The most related viruses available in the GenBank system were “bat-SL-CoVZC45 and another SARS-like betacoronavirus of bat origin, bat-SL-CoVZXC21” (Lu et al., 2020, 570). The lengths of the proteins encoded by those viruses were found comparable (Lu et al., 2020). The genetic similarities of the novel coronavirus and SARS-CoV and MERS-CoV were considerably less significant – 79% and 50%, respectively (Lu et al., 2020). The main difference was in “a longer spike protein of 2019-nCoV compared with the bat SARS-like coronaviruses, SARS-CoV, and MERS-CoV” (Lu et al., 2020, 570).
The authors summarize their findings in the discussion part. They claim that phylogenetic analysis of 2019-nCoV allowed to identify that the virus belongs to the subgenus Sarbecovirus. They emphasize similarities between the 2019-nCoV and bat-derived coronaviruses (bat-SL-CoVZC45 and bat-SL-CoVZXC21) (Lu et al., 2020). They also state that since eight of the patients studied had visited the Huanan seafood market, they most likely were exposed to the pathogen there (Lu et al., 2020). The results make it possible to suggest that contamination could occur through droplet transmission or by yet unidentified source (Lu et al., 2020). The authors also emphasize that the sequences derived from the patients were almost identical. This indicates that the virus “originated from one source within a very short period and was detected relatively rapidly” (Lu et al., 2020, 573). They, however, suggest constant surveillance to see if the virus would mutate (it is considered quite likely). The study also claims that while the novel virus can be traced to bats, another animal might have served as an intermediate host (Lu et al., 2020). The authors highlight the danger connected to “the hidden virus reservoir in wild animals and their potential to occasionally spill over into human populations” (Lu et al., 2020, 774). They emphasize the general threat posed by the novel coronavirus. As it has already been mentioned, by the time of the publication, there has already been enough evidence of human-to-human transmission in China and in other regions, including the US.
The study is accompanied by detailed and well-designed visual information (various charts and tables) supporting the authors claims. The structure of the article is clear; there is a summary at the beginning, including the concise description of the background, methods, and findings of the research. The authors also mention the added value and the implication of their paper.
Several other studies have been dedicated to the same topic. Early research had already pointed out the possibility of the bat-related origin of the virus (Paraskevis et al., 2020). Some studies published previously suggested that the virus might have originated as the results of recent genome recombination (Ji, 2020). However, another study debunked these claims by highlighting the results of several examinations suggesting that there is “a uniform ancestry across the genome” (Paraskevis et al., 2020). Some later studies confirm the findings of the research in question highlighting notable differences in the protein structure of the novel coronavirus and SARS-CoV and MERS-CoV viruses (Wu et al., 2020). Wu et al. also suggest further investigation into how these divergences affect the functionality of the disease. The most recent studies firmly established that bats are the primary host of the virus. They also suggest that despite the relatively low genetic similarity between 2019-nCoV and SARS-CoV, the diseases have several common features, including epidemiology and clinical characteristics (Han et al., 2020). Thus, later studies have confirmed and expanded the findings of the research in question.
Considering the current global coronavirus-related medical crisis, continuous scientific and medical research into the issue is needed. Regular studies aiming to expand and facilitate knowledge of the epidemiological and clinical picture regarding 2019-nCoV should be widely welcomed and adequately funded in order to find ways to ease the current situation. The study in question has, therefore, contributed to a better comprehension of this new danger faced by humanity by analyzing the genomic characteristics of the novel virus at the earliest stages of its spread.
References
- Han, Q., Lin, Q., Jin, S., & You, L. (2020). Coronavirus 2019-nCoV: A brief perspective from the front line. Journal of Infection, 80(4), 373–377.
- Ji, W. (2020). Homologous recombination within the spike glycoprotein of the newly identified coronavirus may boost cross-species transmission from snake to human. Journal of Medical Virology 92(4), 264–266.
- Lu, R., Zhao, X., Li, J., Niu, P., Yang, B., Wu, H., Wang, W., Song, H., Huang, B., Zhu N., Bi Y., Ma, X., Zhan, F., Wang, L., Hu, T., Zhou, H., Hu Z., Zhou, W.,…. Tan, W. (2020). Genomic characterization and epidemiology of 2019 novel coronavirus: Implications for virus origins and receptor binding. The Lancet, 395(10224), 565–574.
- Paraskevis, D., Kostaki, E. G., Magiorkinis, G., Panayiotakopoulos, G., Sourvinos, G., & Tsiodras, S. (2020). Full-genome evolutionary analysis of the novel corona virus (2019-nCoV) rejects the hypothesis of emergence as a result of a recent recombination event. Infection, Genetics and Evolution, 79. DOI: 10.1016/j.meegid.2020.104212
- WHO Director-General’s opening remarks at the media briefing on COVID-19 – March 11 2020. (2020). World Health Organization. Web.
- Wu, A., Peng, Y., Huang, B., Ding, X., Wang, X., Niu, P., Meng, J., Zhu, Z., Zhang, Z., Wang, Z., Sheng, J., Quan, L., Xia, Z., Tan, W., Cheng, G., Jiang, T. (2020). Genome composition and divergence of the novel coronavirus (2019-nCoV) originating in China. Cell Host & Microbe, 27(3), 325-328. DOI: 10.1016/j.chom.2020.02.001