Сoronavirus

Сoronavirus

In December 2019, the world faced a new threat in China, the first cases of respiratory infection were recorded, which was characterized by an acute course of the disease with the transition to SARS. Soon, Chinese experts identified the pathogen. It turned out to be a virus from the coronavirus family, officially named 2019-nCoV.

What is it?

The coronavirus was first isolated from a sick person in 1965. It got its name because of its structural features: it has spine-like processes that look like a crown. Since then, scientists have already described 40 of its species, combined into two families. These agents have always existed next to humans, they are found in cats, dogs, pigs, cows, other mammals, and also in birds.

The coronaviruses discovered before the 2000s caused ARVI in humans. For the most part, the disease proceeded without serious complications, so its pathogens were not given as much attention as, for example, influenza viruses. However, the situation changed dramatically in 2002-2003, when an outbreak of SARS occurred in China. The patients were diagnosed with severe acute respiratory syndrome, which developed rapidly and was severe. It turned out that it was provoked by a coronavirus, later named SARS-CoV. China informed WHO too late about the new threat, so the pathogen managed to leave the country. Cases were recorded in 33 countries, 775 people died, and the overall death rate was 9.6%. In 2012, the coronavirus reminded of itself again, but this time in the Middle East. The patients also developed severe pneumonia, but this time the cause was the MERS-CoV coronavirus. Studies have shown that in all these cases, the pathogen overcame the species barrier, that is, animals became the source of human infection. For example, the Middle East virus was transmitted from camels, which in turn were infected from bats. And the source of SARS infection was civet animals living in Asia and Africa. Virologists have grouped these agents into a separate subgroup called beta-coronaviruses.

Studies have shown that 80% of people have specific antibodies to the strains of coronaviruses that cause ARVI. This confirms that the latter are very common in the environment and have long lived next to humans.

  • ways of their transmission:
  • airborne;
  • air-dust;
  • fecal-oral;
  • contact.

The proportion of infection with strains of coronavirus is estimated at 12% of the total number of all cases of acute respiratory viral infections, and after the disease, a short-term immunity is formed, that is, after a short period of time, a person can get sick again. In addition to respiratory diseases and pneumonia, pathogens can cause gastroenteritis, but this happens much less frequently. In aerosol, they retain their activity for 8-10 hours, in water – up to 9 days. They can withstand freezing to -70 ° C, but lose their disease-causing properties after 15 minutes of exposure to UV rays and several minutes of contact with organic compounds that dissolve fats and detergents. At a temperature of +56 ° C, viruses die in 10 minutes.

How did the outbreak start?

The outbreak of the new coronavirus 2019-nCoV began in the Chinese city of Wuhan. In December 2019, doctors first isolated it from a pneumonia patient who worked at a local fish market. All of the first cases of the disease were diagnosed in people associated with the fish market, which suggested that the virus has learned to bypass species barriers again. The new pathogen caused diseases of the respiratory system. Many patients developed an acute respiratory syndrome with a severe course (destruction of the pulmonary alveoli), which was fatal.

Unlike the situation in 2002, the Chinese authorities promptly reacted to the emergence of the problem and informed the world about the new threat in time. Local authorities imposed strict quarantine in Wuhan and adjacent cities, all public events were canceled, including the celebration of the Lunar New Year, transport links were stopped, and disinfection measures were carried out everywhere. Two hospitals were built especially for such patients as soon as possible. On January 30, WHO recognized the 2019-nCoV outbreak as an emergency of international concern.

Despite the fact that cases of coronavirus were detected in other countries, the large-scale spread of the pathogen was avoided. The infection was localized in China and nearby states. The world’s leading virologists quickly joined the work to combat the new threat, so its genome was quickly deciphered, markers for diagnostics were developed, and work began on the creation of a vaccine.

What is known about the pathogen?

Research has shown that the new 2019-nCoV coronavirus replicates the SARS virus by 80%. They use the same receptors to enter the human body. Initially, it was believed that the source of distribution were snakes –  the South Chinese multi-lane krait and the Chinese cobra, as well as the local population of bats, but later scientists blamed only the latter.

The incubation period for 2019-nCoV is 3 to 14 days. It is asymptomatic, but the carrier poses a danger to others: 3.3-5.47 people can become infected from one patient (an indicator above 1 is already considered epidemic, in influenza it is 2-3). Human-to-human transmission of SARS-CoV and MERS-CoV was not so intense, infection occurred mainly from animals or through very close contact with infected people. In the case of 2019-nCoV, the overall mortality rate was not very high, but the number of severely ill patients requiring hospitalization and expensive treatment is quite large.

Human coronavirus symptoms

The disease begins as a common cold, which complicates its early diagnosis. The patient develops a cough, headache, general weakness. Then the temperature rises sharply, the cough increases, shortness of breath appears. On the 8th-9th day, and in some earlier, acute respiratory syndrome develops, leading to lung damage. Attachment of a bacterial infection is possible. A serious condition developed in almost 25% of patients, but in some the process was mild, almost asymptomatic. A small number of patients with coronavirus also showed signs of an upper respiratory tract infection: runny nose, sneezing, sore throat.

Treatment and diagnostics

The exact diagnosis is determined by a PCR test. There is no specific cure for the new Chinese coronavirus, but doctors are testing the effectiveness of the latest broad-spectrum antiviral agents, as they have shown good results in animal experiments with MERS-CoV infection.

Patients are prescribed supportive therapy. For the treatment of pneumonia with respiratory failure, it is recommended to use the method of extracorporeal oxygenation, which allows the body to maintain its vital functions. It is not new, it was first used back in 1952. With the help of a special membrane oxygenator, blood is taken from the patient’s vein, which is purified, saturated with oxygen and returned back. Chinese doctors said this treatment was very effective, but it was expensive and not widely available due to the limited number of devices. In the case of a bacterial infection, antibiotics are additionally used.

Scientists from Hong Kong announced the creation of a prototype vaccine against 2019-nCoV, but its widespread use is still far away. The drug needs to be tested and checked for side effects. There are still no vaccines against SARS-CoV and MERS-CoV. In the first case, development has ceased due to suppression of the outbreak by preventive measures alone, and in the second, research is underway, but they are slowed down by a lack of funding.

Who can get sick

Anyone can get the disease caused by the Chinese coronavirus because our immune system is not yet familiar with it and cannot quickly identify it as a foreign object. However, the disease is not severe for everyone, this feature is still being studied, probably there are less virulent strains of 2019-nCoV. However, the following individuals are at risk:

  • people of retirement age;
  • children;
  • diabetics;
  • patients with chronic diseases and weakened immunity.

Preventive actions

Since the virus is localized in China, until the situation improves, it is not recommended to visit the Celestial Empire, or at least the Hubei province, in which the city of Wuhan is located. You should lead a healthy lifestyle, exercise and eat well. You should not take the popular antiviral drugs prophylactically, because they do not work, but you can buy pharmacy saline solutions to wash your nose and throat, and do it several times a day. The mucous membranes of the nasopharynx are the first immune barrier for all viruses and bacteria on their way into the human body. Normally, these membranes are cleaned on their own, neutralizing all pathogenic microflora that has settled on their surface. But due to a lack of fluid or other problems, the mechanism may malfunction, therefore, after visiting public places, washing the nasopharynx is very advisable.

A medical mask can be worn to prevent infection, but conventional products are ineffective. It is also useful to protect the mucous membrane of the eye, at least with ordinary glasses.

It is worth giving up culinary exoticism, and eating only well-boiled eggs, meat and fish. It is necessary to thoroughly wash fruits and vegetables, keep your hands clean.

If you have signs of a cold, you should see a doctor right away. When coughing, the mouth is not covered with hands, but with a napkin, which must be disposed of immediately. If drops of sputum or saliva get on your hands, they should be washed immediately with soap and water, because they can become a source of the spread of coronavirus.

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