Last December, a new virus emerged in China that has health authorities around the world on alert. How should we protect ourselves if it occurs in our country?
In December 2019, Dr. Li Wenliang, from the Central Hospital of Wuhan City, Hubei Province, China, warned his colleagues on social media about seven patients who had atypical pneumonia similar to severe acute respiratory syndrome (SARS). , for its acronym in English). This syndrome caused the death of almost 800 people worldwide in 2003, in an epidemic outbreak that emerged in China. The police forced Dr. Wenliang to silence us and with this we lost the opportunity to end the epidemic that now concerns us in its infancy.
The situation soon worsened and on December 12, the municipal health commission of the city of Wuhan reported 27 cases of a rare viral pneumonia; seven of them were from seriously ill patients. What caught the attention of the authorities was that most of the patients had been in the same Wuhan fish and seafood market, where you can also buy all kinds of live creatures that are an essential part of the various cooking recipes of that region: insects, bats, hedgehogs, snakes, marmots, field rats and other animals that are poached and sold illegally.
At first it was thought that the epidemic had its origin in said market, since many viral diseases arise from contact between animals and humans (zoonoses). However, since not all infected patients had been there, it is possible that the epidemic emerged elsewhere. It is now thought that it is most likely that an infected person visited the market and infected several of the customers. In any case, the market was closed on January 1st.
Sensing that things would become more serious, the Chinese government reported the situation to the local office of the World Health Organization (WHO) on December 31. And he was right: by January 3 of this year, 17 new cases had already accumulated, two days later there were 59 patients and by February 16, 51,857 patients and 1,669 deaths had been confirmed. Of them, only 683 cases and three deaths are not from China. Very soon it was discovered that the new virus is capable of being transmitted from person to person, but it does so less quickly than SARS and despite the enormous number of infected people, the disease is not as lethal. Although the figures are not clear yet, it is estimated that around 2% of those who become infected die. On January 31, the WHO declared this epidemic an international emergency.
Virus unmasked
Given the seriousness of the situation, Chinese researchers did everything in their power to identify the pathogen. In the first days of January they were not only able to isolate, culture and identify it, they also managed to decipher its genome. The evidence left no doubt that a new coronavirus is responsible for the epidemic; According to the WHO, coronaviruses are a large family of viruses that cause diseases ranging from the common cold to more serious diseases such as SARS. They are zoonotic viruses, that is, they are transmitted between animals and humans. The new coronavirus is called 2019-nCoV and the disease it causes is called COVID-2019 (acronym for Coronavirus Disease and year in which it arose).
On January 5, some researchers from the Shanghai Public Health Clinical Center and the School of Public Health of Fudan University deposited the genomic sequences of the new pathogen in an international database, GenBank, so that scientists from other parts of the world can contribute to understanding and solving the problem. With the analysis of this data, it was determined that the pathogen was closely related to two other coronaviruses that have caused serious problems in the recent past: one of them, responsible for the SARS epidemic that emerged in China in 2002 and that killed 10%. of the people who were infected and the other, the cause of Middle East respiratory syndrome (MERS) that emerged in the Arabian Peninsula in 2012 and killed 30% of those infected. Coronaviruses are so called because when observed under an electron microscope they look like little crowns seen from above. By the way, its “spikes” are essential for the virus to initiate infection.
At this time, there are already many genomic sequences of 2019-nCoV from different patients. With them, researchers have designed molecular diagnostic methods, based on the amplification of specific regions of the coronavirus genome. These methods are a key tool to control the epidemic.
What is a coronavirus?
Coronaviruses are a group of pathogenic viruses that usually affect birds, mammals and other vertebrates. They usually cause infections in the respiratory tract, although they can affect the gastrointestinal system and sometimes also the nervous system. Coronaviruses belong to the Coronavirinae subfamily that includes four genera: alphacoronaviruses, betacoronaviruses, gammacoronaviruses, and deltacoronaviruses. The virus 2019-nCoV belongs, along with the viruses that cause SARS and MERS, to the betacoronaviruses. Many of the colds that we suffer year after year are caused by some alphacoronaviruses, but the infections they induce are usually mild and recover quickly.
The genome of coronaviruses is made up of a single, long RNA molecule. In fact, these viruses have one of the largest RNA genomes known. The fact that the genome of these viruses is made of RNA is relevant since it makes them more prone to mutate and therefore to evolve rapidly. Coronaviruses have 4 important structural proteins, but the protein that forms the spikes (protein S) determines which host and which organism it can infect.
The origin of the epidemic
Coronaviruses usually infect a wide range of animals. In some, the infection occurs without causing major damage, probably because they have evolved together for thousands of years and over time they have managed to smooth out their rough edges. These animals that allow limited reproduction of the virus without making them sick are called reservoirs. In the case of the coronavirus responsible for SARS, the reservoir was civets and in the case of the MERS coronavirus, camels and dromedaries. With this data in mind, it is certain that the first victim of this new epidemic was infected by being in close contact with a wild animal and not necessarily inside the Wuhan market. For this reason, the Chinese authorities have prohibited the trafficking and sale of wild animals.
For an animal virus to infect us, it has to go through a series of mutations that allow it to infect human cells and replicate in them. Initially, these mutations allow the virus to “jump” from animals to humans. However, infection is poor and human-to-human infections are rare. For the pathogen to be easily transmitted from human to human, the virus needs to acquire new modifications in its genome. When this happens, an epidemic can arise. On some occasions, viruses acquire other mutations that further increase their ability to infect. The problem is that our immune system is not prepared to fight the new pathogen; That is, we do not have specific defenses against the disease it produces.
Genome analysis of 2019-nCoV also suggests that this new virus is a “hybrid.” On the one hand, it is clear that it is related to coronaviruses that live in bats, like the virus that causes SARS. On the other hand, it was found that a fraction of its genome arises from another coronavirus present in an animal species yet to be identified. The fraction involved is precisely the one that has to do with the elements that form the spikes of the virus and that, as I already mentioned, play a crucial role in the first steps of infection.
A multidisciplinary group of Chinese researchers suggested that snakes could be that reservoir, but their conclusions were soon shown to be premature. Recently, doctors Liu-Chen and Chen published an analysis of pangolin viruses in the journal Viruses and found coronaviruses very similar to 2019-nCoV, which suggests that perhaps the reservoir is this small mammal that is illegally trafficked in China. to use it in the traditional medicine of that country. Pangolins were not on the lists of animals sold at the Wuhan seafood market, perhaps because trafficking them is punishable by 10 years in prison.
Transmission
Human coronaviruses are spread from an infected person to others through the air by coughing or sneezing, touching or shaking hands with an infected person, or touching an object or surface with the virus on it and then touching your mouth, nose, or hands. eyes.
Symptoms
- Fever
- Headache and general malaise
- Coughing and/or sneezing
- Difficulty breathing
Preventive measures
- Wash your hands frequently with soap and water for at least 20 seconds or use an alcohol-based hand sanitizer.
- Avoid touching your eyes, nose and mouth with unwashed hands.
- Avoid close contact with people with cold or flu symptoms.
- When coughing or sneezing, cover your nose and mouth with a disposable tissue and then throw it in the trash or use the inner corner of your arm.
The correct use of face masks
If you are healthy, you only need to wear a mask if you are caring for someone who is suspected of being infected with the new coronavirus.
- Avoid touching the mask when you are wearing it; If you do, wash your hands again.
- Face masks are only effective if used in combination with frequent hand cleaning with alcohol-based gel or soap and water.
- Remove your mask, touching only the back straps or the straps that attach to your ears, and wash your hands.
- Cover your mouth, nose and chin well with the mask.
- Change the mask as soon as it becomes wet and immediately throw it into a trash can that has a lid. Never reuse a mask.
- Before putting on a mask, wash your hands with soap and water or an alcohol-based gel.
- Wear a mask if you are coughing and sneezing.
Treatment
There is no specific antiviral treatment against 2019-nCoV. People infected with the virus only receive medication to relieve symptoms.
How dangerous is the new coronavirus?
One of the problems with this new epidemic is not only that the symptoms of the disease vary greatly, but also the time in which they appear changes: in some of the infected the symptoms occur after two days and in others up to 14 To make things difficult, patients initially have symptoms that can be easily confused with the flu: fever and cough, frequently…