For all the time of its existence, humanityconstantly struggling with epidemics and diseases, outbreaks of which periodically wipe out part of the population from the face of the Earth. Often pathogens are bacteria, however viruses also do not disappear. The most tenacious part of them remains undefeated, many of them continue to take human lives. You don’t have to go far for an example; in just a few months the coronavirus was able to paralyze almost the whole world and caused the death of hundreds of thousands of people. So what viruses still scare people from all over the world, and how do they manifest themselves?
- 1 What is a virus?
- 2 The most dangerous viruses
- 2.1 smallpox virus
- 2.2 Swine flu - H1N1 virus
- 2.3 Ebola virus
- 2.4 Human Immunodeficiency Virus (HIV)
- 2.5 Coronavirus
What is a virus?
Virus - A non-cellular infectious organism that can only live inside living cells.
Not just because everyone is afraid of viruses. After all, they can infect the most complex living organisms (including humans), even kill some dangerous bacteria that themselves are pathogens. Despite the fact that viruses are parasites, that is, they cannot survive on their own, unlike bacteria, they are still very dangerous.
Any contact with a living cell canactivate the virus and give it food. Very quickly, the virus enters the cell and releases its genetic material. And there it’s the small business - to create your own copies and populate new cells in the same way. So the virus spreads throughout the body, whether it be a plant, animal or human.
The most dangerous viruses
In the history of mankind, several especially dangerous viruses. Some of them pose a threat due to fatal effects on the body; others are distinguished by an increased degree of survival and resistance even to modern medications.
One of the most dangerous infectious diseases in the world - smallpox, caused by a virus. variola (Variola). The virus may not manifest itself until 17 days inthe average incubation period for smallpox virus is 13 days. Sick smallpox begins to first feel a headache and fever, often all accompanied by nausea and vomiting.
The temperature drops in a couple of days, however itdoes not mean that the virus is defeated. Instead, a nodular rash appears on the skin and mucous membranes, which leaves scars. Due to the fact that the smallpox virus is able to mutate, in some cases the mortality rate from it is 30%, and sometimes all 70%. The virus is transmitted by airborne droplets, as well as through objects with which the infected person came into contact.
Smallpox could continue to destroy hundreds of thousands of lives - earlier, more than 1.5 million people died every year from this disease. However, in the 1960s, a global vaccination program was launched.
The last human case of smallpox was recorded October 26, 1977 in Somalia.
Now the smallpox virus is finally defeated, but its samples are still stored - however, in only two places on the planet. At research centers in Russia and the United States that research viruses.
And it would be better for them to guard him well.
Swine Flu - H1N1 Virus
This virus is much younger than smallpox - first outbreak of swine flu was registered in 2009 among domestic pigs in Mexico and the United States. The virus is transmitted both by airborne droplets and by domestic means (through objects or through the consumption of infected meat).
"Swine flu" is typical of influenza andSARS symptoms: cough, runny nose, fever, vomiting, diarrhea. The virus itself is not as dangerous as the complications it causes. The virus combines the subtypes H1N1 (the most common), H1N2, H3N1, H2N2 and H2N3. Vaccination is used to prevent infection.
Although "modern swine flu" was not detectedso long ago, its subtypes (types of “swine flu”) did bad things in the 50s of the 20th century. Then, according to various estimates, up to 50% of the world's population suffered from H2N2, which led to the death of 4 million people. The last epidemic of the virus occurred in 2009-2010; for the year, "swine flu" spread to 214 countries, killing more than 18 thousand people. Nevertheless, the risk of a new epidemic always remains.
It is believed that one of the types of "swine flu" was the so-called "Spaniard" - the epidemic of 1918-1919, spread throughout the world from Spain. Then half a billion people fell ill, 10% of them died.
For the first time Ebola virus was recorded in 1976 in Zaire (now itDemocratic Republic of the Congo), in one of the villages on the banks of the Ebola River, from where it got its name. Presumably, at first the virus was in bats (something reminds, isn't it?), And then, after eating them, it appeared in humans.
The incubation period of the Ebola virus varies from2 to 21 days, however, it is not transmitted easily - either through close contact between people through the mucous membrane, or through damage to the skin. Therefore, the outbreak of the Ebola epidemic is usually suppressed. The greatest number of lives was claimed by the epidemic in 2013-2016, which swept Guinea, Sierra Leone and Liberia. Then, according to official figures, 11 thousand people died. How many actually is unknown, in African countries, as a rule, statistics are not very good.
Ebola virus is dangerous not by the degree of spread, but by the consequences of ingestion. Mortality from it reaches 90%. During an illness, a person develops fever, jaundice, renal failure, and all this together. Without medical intervention, he dies.
A vaccine capable of curing such a dangerous infectious disease is already under development. You can read about its creation directly in this article.
Human Immunodeficiency Virus (HIV)
One of the most dangerous viruses in history.humanity affects the immune system and weakens the body's defense against infections and diseases. HIV is transmitted through sexual contact and through the blood through the use of infected instruments, needles, and so on. It can also be passed from mother to child. Virus causes disease AIDS - Acquired Immunodeficiency Syndrome. First of all, its danger lies in the fact that it can develop even 2-15 years after infection!
In addition, so far mankind has failedinvent drugs that could completely eradicate HIV infection. Nevertheless, scientists have learned to treat it with antiretroviral drugs - this way it is possible to suppress the activity of the virus and prevent its transmission to other people.
It is believed that HIV appeared back in the 1920s, transmitted frommonkeys. The first virus infected allegedly died in Congo in 1959. However, HIV received its full description only by 1983, when researchers from the USA and France studied it.
In 2018, there were about 37.9 million in the worldHIV infected. This is the longest “pandemic” in the history of mankind, as scientists sometimes call it. The most dangerous regions are the countries of Africa, where the virus infection rate is high. In Russia, the first case of AIDS was officially recorded in 1987. Over 30 years, almost 1.4 million people have become infected among citizens of the Russian Federation, more than 300 thousand have died.
A type of virus called coronavirusfirst discovered in the 1960s. Then they were described as the cause of gastrointestinal and respiratory infections in both humans and animals. Currently, there are 39 types of coronavirus infection, among which SARS with a mortality rate of about 10% and the Middle East respiratory syndrome with a mortality rate of up to 40%. The latter, as a rule, is treated using the blood plasma of patients who have successfully suffered a coronavirus infection.
At the end of 2019, a new epidemic erupted in the worldcoronavirus caused by SARS-CoV-2 virus, which soon developed into a pandemic. In just six months, almost 12 million cases of infection were recorded in different countries of the world, more than half a million people died. SARS-CoV-2, also known as COVID-19, causes similar symptoms with flu and SARS, but there are those that secrete it.
Symptoms of Coronavirus
- Dry cough
- Runny nose
- Muscle pain
- Sore throat
- Loss of taste or smell
After fixing of SARS-CoV-2 coronavirus inthe body, the disease can proceed severely until the development of SARS or not manifest at all. This greatly complicates the identification and quarantine of infected people. According to researchers, the number of asymptomatic carriers ranges from 25 to 50%, which probably explains the rapid spread of the disease on the planet.
Now accurately evaluate coronavirus mortality almost impossible - for this you need to do tests for all dead people. Most countries do not see this as necessary.
Obviously, the coronavirus will not end -humanity will face dangerous viruses more than once; history only confirms this. The problem is that once a deadly virus can appear, which will destroy most of the world's populationbecause, as shown by coronavirus COVID-19, humanity is not ready for such a pandemic. Therefore, it is very important to develop medicine and observe basic hygiene methods - take a shower every day, wash your hands with soap and try not to contact people who have severe symptoms of the disease.