COVID-19

On December 31, 2019, the Wuhan Municipal Health and Sanitation Commission (China) reported a group of 27 cases of pneumonia of unknown cause, with a common exposure to a wholesale market of marine products, in addition to 7 serious cases. Chinese authorities identified it as an agent causing a new type of virus of the Coronaviridae family. On March 11, the WHO (World Health Organization) declared the global pandemic.

So far (April 2021), there have been 131 million positive COVID cases, 74 million cured, and 2.84 million deaths, and, despite everything, to date, the origin and transmitter of the virus to humans are still unknown.

Coronaviruses are a subfamily of positive (+) single-stranded RNA viruses belonging to the Coronaviridae family. Its genetic material is the largest in RNA viruses, they are called coronaviruses because of the crown of spikes that you see around the surface of the virus. It was first described in 1965.

They are capable of infecting birds and mammals, causing a series of digestive and respiratory diseases, many of them lethal. The human infection causes a mild cold to more serious diseases such as bronchitis or pneumonia. Thirty-nine species of coronavirus have been recorded to date.

There is little information on transmission, severity, and clinical impact, and therefore there are no approved treatments to date, however, several of the symptoms can be treated. It is a zoonotic disease, which means that it can be transmitted from animals to humans, which probably explains the origin of the pandemic.

Coronaviruses have four genera depending on their genetic structure: Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Deltacoronavirus. Structurally they have a spherical shape, lipid bilayer, and single-stranded RNA (ssRNA). The SARS-CoV-2 virus genome encodes 4 structural proteins: protein S (spike protein), protein E (envelope), protein M (membrane), and protein N (nucleocapsid).

Nucleocapsid protein encapsulates viral genome and can be used as diagnostic antigen.

It produces flu-like symptoms, including fever, cough, dyspnea, myalgia, and fatigue. It also causes the sudden loss of smell and taste. In severe cases, it is characterized by pneumonia, acute respiratory distress syndrome, sepsis, and septic shock, leading to death in about 3% of those infected.

Mainly because the ACE 2 protein, to which COVID-19 binds, has an activity in the body that with the union of these stops taking place. In this case, ACE 2 acts on the regulation of blood pressure, and most of the damage it does to the body is due to the immune system (inhibiting the production of interferon, one of the body's defense response mechanisms), since SARS-CoV-2 grows in lung cells.

It also has a high level of contagion since it is transmitted by air and saliva.