Another virus from China? Real threat or unnecessary panic?

20200111AD, 2019-nCoV, Wuhan, coronavirus:

In the media for several days the topic number one is Wuhan coronavirus. Not only medics write about the pathogen and increased epidemiological risk, and articles on this subject can be found on almost every major news portal. It is worth recalling that this is not the first such situation, and the world has already faced coronaviruses before.
On December 31, 2019, WHO received a report on the spread of an unknown pathogen in the city of Wuhan, Hubei Province, China. His disease was defined as "pneumonia caused by unknown factors". It was pointed out in a fairly short time that this is a new SARS-like coronavirus that is called 2019-nCoV.

What are we fighting with?
Coronaviruses (Coronavirus; HCoV) cause disease worldwide in humans and animals. Human coronaviruses (Human Coronavirus; HCoV) are known primarily as etiological factors of lower and upper respiratory tract infections that can also cause gastrointestinal or nervous system symptoms.

Even in the last century, only two coronaviruses were thought to be pathogenic to humans. It was not until 2003 that another coronavirus causing human disease was identified - SARS-CoV. This virus has been identified as the etiological factor of severe acute respiratory syndrome (SARS). At the turn of 2002 and 2003, it was this virus that caused illnesses in over 8,000 people, of which almost 800 people died of the disease. Hence, SARS-CoV mortality was estimated to be around 10%.

The shape of these viruses in an electron microscope resembles a crown (due to the presence of characteristic protein structures in the form of surface protrusions protruding from the bilayer lipid sheath), hence the name - coronaviruses.

Their diameter is in the range of 60-220 nm. The coronavirus nucleocapsid is coated with a two-layer protein-rich sheath. It is worth noting that coronaviruses have one of the largest genomes among RNA viruses, which, combined with the high variability characteristic of RNA viruses, leads to the accumulation of genome sequence changes, which can result in the formation of different virus variants and a change in cellular tropism. It is this feature that raises the most concerns in scientists and epidemiologists.

Diagnostics:
Even before the 2002 epidemic, the diagnosis of lower respiratory tract infections did not completely include coronaviruses. It was only in connection with the emergence of the new HcoV-SARS species that research into this group was intensified and included in diagnostic processes.

The diagnosis uses throat and nose swabs, bronchoalveolar lavage, tracheal aspirates, urine, feces and blood serum samples. Samples are usually taken from different sections of the respiratory system, taking into account different periods of the disease. In the case of the Wuhan virus, mainly molecular biology techniques are used.

It is worth emphasizing that coronaviruses have been circulating in the human environment for a long time, causing about 20-30% of respiratory tract infections annually, and in 3-15% of cases, patients require hospitalization. Most infections caused by these viruses are mild, but coronaviruses such as HCoV-SARS or 2019-nCoV also occur, causing serious infections, sometimes with death. It is also worth emphasizing that coronaviruses, which were considered animal pathogens, can also cause diseases in humans - animal-human transmission is very simple, and in addition, very high genetic variability and very fast virus replication should encourage high hygiene in contact with animals . Hence, the emergence of 2019-nCoV as the next animal coronavirus should not come as a big surprise.
Recall other dangerous viruses ...

- MERS-CoV (Middle Easet Respiratory Syndrome Coronavirus) virus, whose mortality is estimated at about 35% (the new virus causes a serious disease, which is fatal in about 35% of cases),
- 'Spanish', a type of H1N1 subtype of influenza A virus. About 500 million people fell ill with it, which at that time constituted 1/3 of the world's population,
- SARS-CoV - mortality at around 10%,
- avian influenza virus type A / H5N1, a highly pathogenic virus with a mortality rate of over 60%,
- Ebola virus (EVD), which is the etiological factor of Ebola hemorrhagic fever - mortality rate is 53%.

The strategy to fight the virus prevailing in Wuhan is very similar to the outbreak of the SARS epidemic at the turn of 2002 and 2003. Just like the borders of the city where sources of infection are seen as closed. Similarly to 2003, two new hospitals are being built in the city, where people infected with the new coronavirus are to be sent, and similarly as then, fatal cases occur mainly in Asia.

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