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Things you should know about coronaviruses and COVID-19

Nowadays, everybody talks about 'the coronavirus'. We can find an enormous amount of information about it, including frightening claims and news about the increasing number of new infections. So, what is that we should all know?

This lesson aims to answer these questions.

What is the difference between viral and bacterial infections?

Certain viral infections can make us feel very sick in the first few days. The symptoms include:

  1. headache;
  1. feeling unwell
  2. sweating, chills, muscle pain and loss of appetite and a general feeling of being unwell;
  1. mild or severe fever;
  1. sore throat, pain in the arms and legs, or in the stomach;
  1. runny nose with thin, mostly clear discharge;
  1. nausea or diarrhea.

However, our body fights viruses, so in a few days, we usually feel better. At this time, doctors do not prescribe antibiotics, only medication to relieve symptoms, such as pain and fever.

Staying in bed, drinking plenty of liquids and taking vitamins help our immune system quickly fight off the intruders. But we must be aware that we can infect others too.

If the symptoms persists for more than 10–14 days, we may have a secondary, bacterial infection besides the primary, viral one.

Common bacterial infections last for 5–14 days and rarely go away without medication. The symptoms of these include

  1. general weakness;
  2. pain, fever and inflammation;
  3. cough, stuffy nose, runny nose with dense, yellow, greenish or rust-coloured discharge.

Antibiotics are useful against bacterial infections, but they are completely inefficient against viral infections.

Viruses consist of genetic material embedded into proteins. They do not have their own metabolism, so we do not consider them living organisms. In order to reproduce, they need a host organism, that is, all viruses can be considered parasites. Without a host, viruses lose their ability to cause infection and 'die' within a certain period of time.

Bacteria, however, are real living organisms with life processes. There are useful and harmful bacteria. Bacteria useful for humans include lactic acid bacteria. Certain bacteria are parasites, similarly to viruses. These bacteria, however, do not die without a host. They surround themselves with an envelope in which they can survive unfavourable conditions.

Open the following 3D scenes to learn more about viruses and bacteria. Collect information about diseases caused by viruses and bacteria (symptoms, treatment, possible complications etc.).

What is a coronavirus and COVID-19, a disease caused by a coronavirus?

In December 2019, a patient was registered in Wuhan, China, with symptoms so far unknown to science. Later it turned out that the patient's infection was caused by a coronavirus strain, so the illness was named COVID-19, that is, COronaVIrus Disease 2019.




Coronaviruses are a group of viruses with several members. Their name refers to their appearance in electron microscopic images, similar to the solar corona, which is due to the bulbous protein projections found on their surface.

Most coronaviruses infect animals, few of them can infect humans too. They are present in only about 2% of humans and cause only the 5–10% of respiratory illnesses.

The virus causing the epidemic in 2019 and 2020 is officially called SARS-CoV-2, referring to the fact that it is very similar to the coronavirus that caused the SARS outbreak in 2002.

What is the course of the COVID-19 infection like?

At first, the infection is not obvious because of the lack of symptoms. This is called the incubation period. An infected person can infect others during this period.

According to current knowledge, the infection is transmitted by droplets, that is, by sneezing or coughing via air, or by touching objects where droplets or saliva fell. This is why it is recommended that we wear a mask when we have a cough or a cold.

Most of the time (in about 80% of the cases) the infection causes mild symptoms or no symptoms at all.

The mild form of infection is accompanied by low-grade fever, upper respiratory symptoms, dry cough, sore throat, runny nose, weakness, muscle pain and headache. Diarrhea is rare.

In a minority of cases, breathing difficulties and pneumonia occur and, in the most severe cases, patients need artificial assistance to support breathing.

According to current knowledge, the mortality rate of the disease is 2–3%, that is, 2–3 out of 100 patients die. People with a weakened immune system and the elderly are the most vulnerable groups.

What is an epidemic?

An epidemic is a rapid spread of a known disease to a large number of people in a given population within a relatively short period of time.

The COVID-19 epidemic affected so many people and countries that the WHO has declared it a pandemic.

Find information about the countries where there are registered patients of COVID-19. Mark these countries on the world map.

Search the Internet for simulator programs that show how infections spread. Why do you think isolation may help contain epidemics?

Quarantine helps to slow the spread of the virus and to protect those who are the most vulnerable (the elderly).

Which fields of science do you think can help to model epidemics and their effects?

Biology and medicine: information about viruses, infections and the immune system
Medicine, pharmacology: ways to strengthen the immune system, producing vaccines.
Mathematics, physics: studying networks, mathematical modelling of the spread of diseases and making estimations about the geographical extent and the number of infections.

Should we be scared?

"Better safe than sorry" – as the saying goes.

We should be very careful, because the numbers show that the infection is spreading day by day.

We should not panic, however, as it just makes the situation worse.

Instead of panicking, we should understand and follow the rules regarding the epidemic.

How can we slow down the coronavirus epidemic?

The COVID-19 is highly contagious, 1 infected person will infect 2.2 individuals on average. We must pay special attention to avoid contact with infected people or those who are suspected to be infected.

Infected patients are placed in quarantine, that is, isolated from healthy people. At the early stage of the infection, people may not have any symptoms, it is difficult to detect the presence of the virus. It is possible only using medical tests.

To slow down or stop the epidemic, it is important to minimise contact between people and thereby reduce the possibility of spreading the infection.

This will help lower the pace of the spread of the disease and keep the number of people simultaneously infected at a low enough level to be manageable for the healthcare system ('flatten the curve').

In numerous countries around the world, public institutions, schools and universities were closed so that employees and students have less contact with other people and thereby minimise the chance for a rapid spread of the disease.

However, it would be wrong to think that staying away from school means simply taking a break and having a party. It is important to avoid contact with others as much as possible. People with weakened immune systems should especially avoid social gatherings.

We should wash our hands often and thoroughly. It is important that we have hand sanitiser gel on us and that we avoid touching our face and mouth, as well as greeting each other with handshakes, kisses or hugs.

When we sneeze or cough, we must use a tissue then wash our hands right away. If we do not have a tissue, we can also cough or sneeze into our elbow or sleeve.

If we experience symptoms typical of the disease, we must not leave our homes to go to our doctor's surgery or to an emergency unit, as we may infect people waiting there. Instead, we should call our doctor to ask what we have to do.

What can we do at home?

Many people think that while educational institutions are closed and they are quarantined at home, they can do whatever they want. This is wrong, however.

Precautions are extremely important at home too.

It is important to wash our hands regularly, to rest and to avoid contact with others.

A healthy diet is also important. We should also do some exercise every day (not in groups, of course).

We must pay attention to one another. If there are elderly people or families who need help, we can help them do the shopping or pay their bills, while strictly keeping hygiene rules.

Observe the picture and formulate statements. What should we do and what should we avoid during an epidemic?

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