Another Decade, Another CoronavirusMay. 8,2020
For the third time in as many decades, a zoonotic coronavirus has crossed species to infect human populations. This virus, named COVID-19 by WHO, The initial outbreak occurred in Wuhan, China. The rapid response of the Chinese public health, clinical, and scientific communities facilitated recognition of the clinical disease and initial understanding of the epidemiology of the infection. First reports indicated that human-to-human transmission was limited or nonexistent, but we now know that such transmission occurs, although to what extent remains unknown. Like outbreaks caused by two other pathogenic human respiratory coronaviruses (severe acute respiratory syndrome coronavirus [SARS-CoV] and Middle East respiratory syndrome coronavirus [MERS-CoV]), 2019-nCoV causes respiratory disease that is often severe. As of January 24, 2020, there were more than 800 reported cases, with a mortality rate of 3%.
Much still needs to be learned about this infection. Most important, the extent of interhuman transmission and the spectrum of clinical disease need to be determined. And identification of the zoonotic origin of the virus.
Stanley Perlman from University of Iowa, published his article Another Decade, Another Coronavirus on The New England journal of Medicine
The results reveal that 1. Transmission of SARS-CoV and MERS-CoV occurred to a large extent by means of superspreading events. SARS-CoV mutated over the 2002–2004 epidemic to better bind to its cellular receptor and to optimize replication in human cells, enhancing virulence. Adaptation readily occurs because coronaviruses have error-prone RNA-dependent RNA polymerases, making mutations and recombination events frequent. It is likely that 2019-nCoV will behave more like SARS-CoV and further adapt to the human host, with enhanced binding to hACE2. 2. Given its close similarity to bat coronaviruses, it is likely that bats are the primary reservoir for the virus.
The author pointed out that transmission of 2019-nCoV probably occurs by means of large droplets and contact and less so by means of aerosols and fomites, on the basis of our experience with SARS-CoV and MERS-CoV. Public health measures, including quarantining in the community as well as timely diagnosis and strict adherence to universal precautions in healthcare settings, were critical in controlling SARS and MERS. Institution of similar measures will be important and, it is hoped, successful in reducing the transmission of 2019-nCoV.
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