Undoubtedly, the most important public health news in the world is the appearance of the new coronavirus in China. Baptized as 2019-nCoV, until the end of this edition, The virus has caused 2,744 confirmed cases and 82 deaths in the Asian country, and thanks to the airplanes, isolated cases have been presented in 13 other nations. In this article we will see what is known about this unprecedented infectious agent and how modern genetics can help in its control.
Coronavirus
Coronavirus – named for the way it looks when viewed through an electron microscope – is a family of six viruses that cause respiratory infections, including the common cold and pneumonia. The two most famous members of this group are severe acute respiratory syndrome (SARS), which appeared in China in 2002, and Middle Eastern respiratory syndrome (MERS), detected in the Middle East in 2012. Both caused epidemics.
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The current coronavirus is the seventh member of this family, has an incubation period of 1 to 14 days and is spread from person to person, even before presenting symptoms.
Origin
On December 30, 2019, an outbreak of severe pneumonia was announced in a group of workers in the animal market of the city of Wuhan, in central China. There were 44 affected and 7 deaths. The first case appeared on December 8, and a virus originated in one of the animals sold in that market was suspected.
Contagion
The contagiousness of a virus is measured with the basic play number (R0), which is defined as the number of people who can be infected by another patient. The virus with the highest R0 is that of measles, which reaches 18. The mumps is 10, that of SARS and that of HIV is 4, that of Ebola and that of norovirus is 2. That of influenza is 1.3 , Y The new 2019-nCoV has been estimated between 1.4 and 2.5, which would indicate that it is more contagious than the common flu.
Lethality
Defined as the proportion of patients dying of the infection, it is known that the most lethal viruses are rabies (almost 100%), Ebola (80%), Marburg and Lassa (50%), the Hantavirus (36%) and Dengue (20%). The flu has a lethality of 0.1% (the 1918 pandemic had 2.5%). The SARS and MERS reached 15% and 40%, respectively. The lethality of the new coronavirus has not yet been estimated, but considering the 2,744 confirmed cases and 80 deaths, would be 2.8%.
Genome
Because the genome study is now a very fast and cheap test, this advance will allow an advanced fight against the coronavirus. Until last week, there were already 24 tests that had been done on his genome.
Monitoring the viral genome in real time will allow two things. The first is to know the possible origin of the virus; that is to say, to determine if to reach the human being he needed a single animal or it was first necessary that it mutated in several species. The second is to monitor the mutations that occur as the virus spreads and infects more and more people. With that knowledge, it will be possible to design vaccines or specific treatments, especially considering that viral genomes are published in the GenBank, a cyber repository that interested scientists can freely access.
So far, the results indicate a virus with very little genetic variation, so that this infectious agent would have passed very quickly from the animal to the human being, without the need for intermediate hosts, and it is thought that –like the SARS and the MERS– originated in a bat. It is also not known in which animal (intermediate host) it mutated before passing to the human being. The SARS did it on the civet, a rodent mammal that the Chinese eat, while the MERS did it on a camel.
Scientists estimate that the new coronavirus passed from the animal to the first human being (patient zero) between October 30 and November 29, 2019, and that that first patient would have infected other people in the Wuhan market.
The little genetic variation of the viral genome also indicates that the main method of the virus to maintain the infection in a city is the contagion between human beings, and that reducing that transmission by 60% could stop the epidemic.
Similarly, the modern Crispr genetic editing method (which was not available in previous epidemics) will expedite diagnostic tests, allowing instant identification of the virus and replacing current chain polymerase (PCR) tests, the result of which ID takes one to three days.
Corollary
Undoubtedly, humanity is facing a new virus, which – due to the information available at the moment – is moderately contagious, low lethality and does not represent, according to the World Health Organization (WHO), an international public health emergency, as the emergency is confined in China.
Intercontinental flights have caused cases to be found in more than a dozen countries, and what happens in these territories will be important to know if the virus is capable of causing a pandemic, or if the epidemic will remain localized in China.
If the new cases outside the Asian country are self-limited, we will be – as the WHO says – facing a localized epidemic; vice versa, if these are counted in hundreds or thousands, we would be facing an unpredictable forecast pandemic
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