The evolution of disease and the history of the human race against viruses

The history of mankind is the history of the battle against viruses, an arms race of evolution in which there is no room for peaceful compromise.

The fight against viruses and human illness

  • Familiarize yourself with the virus
  • The battle with poliovirus (polio)
  • Molecular history of the virus
  • It is not just about people

The world's leading epidemiologists have repeatedly stated that sooner or later a new infectious agent will be forced to fight. However, unlike the opponent who always has a significant advantage, humans can prepare for 'war' and the scientific method is our best weapon. Science has no borders and prejudices, over and over again making sure that humanity wins.

Viruses are tiny information systems encoded in DNA or RNA and their primary goal is survival. To survive, viruses need humans or, rather, our cells. Human survival depends on the knowledge of viruses and the more we know, the higher the chances of winning.

Picture 1 of The evolution of disease and the history of the human race against viruses
Viruses are tiny information systems encoded in DNA or RNA.

Familiarize yourself with the virus

In 1892, student Dmitry Ivanovsky had just graduated from St. Petersburg University. Petersburg has begun to pay attention to the pathology of tobacco leaves - they are wrinkled, full of rust and dry spots. Ivanovsky said that this pathology must have pathogens. To prove his theory, he crushed the leaves of infected plants, then the juice was filtered through a cloth.

No pathogenic bacteria were detected in the juice, but the trees that Ivanovsky watered the juice were sick in 80% of the cases. At that time, the young scientist thought that the bacteria causing the disease was very small, he continued to filter the juice with a ceramic filter to prevent bacteria from passing - but the results were the same.

The conclusions that Ivanovsky then made changed the world: the scientist proposed the existence of organisms so small they could not be seen by optical microscopes.

A few years later, Dutch microbiologist Martinus Beijerinck became interested in the causes of tobacco leaf disease. He came to the conclusion that the plant was infected by a toxic liquid that he called the virus (the Latin word for poison).

But it is a very strange poison: its concentration does not affect the results and it is always the same. The source of the poison remained a mystery until 1932, when Professor Windel Stanley received a crystal cup extracted from a ton of infected leaves. By rubbing the leaves of healthy plants with these crystals, he created their characteristic pathologies.

However, living creatures cannot be turned into crystals. This led Stanley to the conclusion that viruses are very small protein molecules, not living things. And for the first time people saw the virus only seven years later thanks to an electron microscope.

Picture 2 of The evolution of disease and the history of the human race against viruses
With the advent of micro-imaging, we were finally able to see what the various infectious disease agents look like.

In essence, a virus is an information system (encoded in DNA or RNA) surrounded by a protective shell and formed by evolution to ensure its own copying and survival. Every virus can be thought of as a genetic element, wearing a protective protein shell and being able to move from cell to cell.

Viruses only grow in living cells but they infect everything from simple unicellular organisms like amoeba to complex multicellular organisms like ours. And because bacteria are cells themselves and carry all the molecular mechanisms they need to reproduce. As a result, they have unique biochemical pathways that broad spectrum antibiotics can affect.

The battle with poliovirus (polio)

During the first half of the 20th century, viruses were the cause of serious illnesses, one of which was polio - polio in children, leading to central nervous system pathologies.

Although polio was once mentioned in ancient Greek and Egyptian history, the world only faced the first major pandemic until 1905 in Sweden, after which the virus began its journey across the planet. planet.

By 1916, 2,000 children died from polio alone in New York. In 1921, the disease attacked future US President, Franklin Roosevelt. In general, poliovirus disease in the 20th century became a real national disaster in many countries.

After Franklin Roosevelt became polio, in 1938 he founded a national organization to fight polio (National Foundation for Infantile Paralysis). The foundation has collected donations used to find vaccines and make beds.

Meanwhile, the virus has confidently walked around the planet. In 1952, 3,145 people died from polio in the United States and more than 20,000 were paralyzed. The Soviet Union suffered similar losses six years later.

During this time, 'iron breathing chambers' are the most effective way to fight polio - cells that help the paralyzed respiratory muscles to function by varying air pressure. Patients who remain infected with the disease for the rest of their life must remain 'in a box' and only have a small amount of head or limbs.

Picture 3 of The evolution of disease and the history of the human race against viruses
Perhaps everyone remembers these red drops - the vaccine against polio.

The invention of the vaccine did not begin until the mid-1950s, but by 1961 polio was virtually eradicated. The first vaccine was invented by Dr. Jonas Salk. By this time, when he had just worked at the Roosevelt Foundation, scientists had learned how to clone the virus on monkey kidney cells and ask antibiotics to clean the bacteria.

For his part, Salk decided to use formalin and test immunity in monkeys. In 1952, the scientist used a vaccine for himself and his wife and three sons. The vaccine has been shown to be safe and will not cause allergic reactions.

In 1954, Salk received an immunization license for 5,000 American students in Pittsburgh. Further analysis showed the presence of antibodies in the blood of the students and his vaccine was the first effective vaccine against polio.

News of the invention of the vaccine immediately spread around the world and scientists from all over flocked to the United States. A great contribution to the invention of the last vaccine made by Soviet scientists Mikhail Chumakov and Anatoly Smorodintsev. The collaboration of Soviet and American scientists took place despite the stress of the Cold War.

In 1958, Dr. Albert Sabin at Cincinnati City Children's Hospital concluded that when the virus was cultured at low temperatures, those non-pathogenic strains became a winner in natural selection. If such a virus enters the stomach, it will begin to replicate. This is a non-pathogenic 'live virus' , and our antibodies perceive it to be a common poliovirus.

However, the use of Sabin vaccine in the United States at that time was considered unnecessary because of the Salk vaccine. At that time, Sabin transferred the samples to Chumakov to test its effectiveness on Soviet territory.

In January 1959, mass vaccination began in which 15 million children in different republics received the vaccine. Soon, the incidence of polio has subsided. What about the Salk vaccine? It turned out that some people were vaccinated because it was polio again. In the end, Sabin's completed vaccine worked best and by 1960 was available in more than 100 countries around the world.

Picture 4 of The evolution of disease and the history of the human race against viruses
A bacterium looks like this under a microscope.

Thus, the first half of the 20th century - noting both the Spanish flu pandemic and the fight against the most dangerous virus in history - smallpox - passed under the banner of the battle against poliovirus. To this day, mankind has won almost completely against a large number of dangerous viral infections. But that does not mean there is nothing left to threaten us.

Molecular history of the virus

Did you know that each of us is a 'virus drive'? Numerous drug-resistant pathogens that we have been infected with since birth. For example, the herpes simplex virus type 1, the Epstein-Barr virus (causing salivary gland malaria or adolescent 'kissing pathology' ) and cytomegalovirus (also herpes) are always with us. lifetime.

Modern analysis of DNA sequences allows the conclusion that the link between Homo sapiens and certain viruses has spread throughout history. For example, data on human T-cell leukemia virus types 1 (HTLV1) - which causes leukemia and other diseases - have been with humans for thousands of years.

Tuberculosis and malaria - as elucidated by molecular analysis - have become more or less the cause of death in ancient Egypt and do not exclude traces of these viruses that will be found in DNA. Ancient Egyptian mummies. Studies also show that the ancient Egyptians also had smallpox and polio.

Chinese pediatrician Wang Quan (1495-1585) discovered smallpox, and at the same time the Chinese began the process of 'vaccinating' healthy people by blowing a powder into the nose. Known descriptions of an outbreak of influenza are from 1580 and in each of the 19th and 20th centuries there were three similar events.

Except for HIV / AIDS - which can be considered a "continuing" pandemic (since 1981) - the worst pandemic of our modern day, the Spanish flu in 1918, claimed the lives of around from 50 million to 100 million.

Picture 5 of The evolution of disease and the history of the human race against viruses
In ancient Egypt there was malaria, tuberculosis and possibly smallpox and polio.

For this reason, it is not surprising that new strains of virus are present. Like all living things on our planet, viruses are adapted to changing environmental conditions. Moreover, it is increasingly possible to observe cases when viruses are spread from animals to humans.

Like the H1N1 flu can 'jump' from poultry to humans, as well as the SARS and MERS viruses that caused outbreaks in the 2000s were bats. But while growing, we gave the virus an advantage - it's globalization.

Open borders, the ability to travel anywhere in the world, the delivery of goods and food to different parts of the planet - all of which have made the virus ' equipped to fight. '.

For example, the human immunodeficiency virus type 1 (HIV1) - the most pronounced form of human immunodeficiency syndrome (AIDS) - has 'jumped' to people in the first half of the century. XX. It is thought that it may have happened when a hunter cut his arm when slaughtering an infected chimpanzee.

Later, as is often the case, HIV-1 was spread among people until the first cases of AIDS in the United States were recorded in 1981. It is important to understand that many and many diverse Factors that influence similar penetration of diseases from other species into our lives.

Population growth, the appearance of cities of millions of people, high population densities and close contact with wildlife - are likely to lead to outbreaks of various infectious diseases. The combination of a large number of different factors eventually led to the arrival of Covid-19.

It is not just about people

Naturally, we are not the only ones that can suddenly be infected by other vertebrates. For example, dog plague (CDV) has been detected in the Serengeti hyena, and frequent lions in lions seem to have occurred directly from dogs or other wildlife, including spirits. crane.

Today, it is known that CDV is associated with both the plague virus virus currently being killed by large horned cattle, as well as with measles in humans, which are very close to each other. The genetic sequence allows for the assumption that the two pathogens separated from each other about 1,000 years ago, possibly from a "senior" virus unlike one or the other.

Picture 6 of The evolution of disease and the history of the human race against viruses
Vaccination has saved millions of lives.

Today, despite triumphs over a number of pathologies, the problem of vaccination still matters in areas predominantly war zones. Measles can be completely eliminated, but this is hampered by many parents in developed countries who say they do not need to vaccinate their children because the body is healthy. resistance against common diseases.

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