Disease viruses in the modern world. What types of viruses are there? List of common viruses and infections

The computer virus was distributed via email in an attached file, and after the user opened this file, the virus sent itself to the first 50 addresses in the email program's address book Microsoft Outlook.

Today " Melissa“You can’t scare anyone anymore. But they will remember her for a long time. Basically, the same as about the next nine viruses. About the latter, by the way, in honor of “ Melissa“And we remember. Read.

Brain

This virus is the most harmless in this hit parade. All because he was one of the first. Distributed via floppy disks. The development lies with the brothers Amjat and Basit Alvi ( Amdjat and Basit Faroog Alvi). These guys started it in 1986. But discover “ something's wrong“The specialists succeeded only a year later in the summer.

They say that in the US alone the virus infected more than 18 thousand computers. Fun fact: the development was based entirely on good intentions. That is, the brothers wanted to punish local pirates who were stealing their company's software.

And also Brain took pride of place as the world's first stealth virus. When trying to read an infected sector, it “ substituted“ his uninfected original. It was very difficult to catch one.

Source: securelist.com

Jerusalem

The second name is “ Friday 13“. And the first arose thanks to the country of its origin - Israel ( in 1988). Why is this dangerous? Friday“? The one that was downloaded from a floppy disk. And as soon as the time came X ( Friday 13) - the virus immediately deleted absolutely all data from the hard drive. In those days, few people believed in the existence of computer viruses. There were almost no anti-virus programs at all. That's why Jerusalem terrified users.

Source: classifieds.okmalta.com

Morris worm

And this one “ worm“ went on a rampage in November 1988. It blocked the operation of computers with its chaotic and uncontrolled reproduction. Because of him, in fact, the whole ( not too global for those times) Net. Please note: the failure did not last long, but it managed to cause serious damage. Experts valued them at $96 million.

Source: intelfreepress.com

Michelangelo (“March6“)

“Michelangelo“ was rowdy in 1992. It penetrated the boot sector of the disk through floppy disks, and sat quietly there until March 6th arrived. As soon as the time came for X, “ Mark“I immediately formatted the hard drive. Its appearance was beneficial to all companies developing anti-virus software. They then fanned the hysteria to incredible proportions. Although, the virus mocked only 10 thousand machines.

Source: macacosabetudo.com

Chernobyl (CIH)

It was created by a Taiwanese student ( in 1998). This malicious software was named after the latter’s initials. The essence of the software: through the Internet, email and disks, the virus entered the computer and hid inside other programs. And on April 26 it was activated. And it not only erased all the information on the hard drive, but also damaged the computer hardware.

Peak “ Chernobyl“came in April 1999. More than 300 thousand cars were damaged then ( mostly East Asia). And even after everyone trumpeted the information about the presence of such a pest, it hid on computers for a long time and continued its dirty deeds.

Source: softpedia.com

Melissa

We return again to “ Melissa“. It was created by then 30-year-old David Smith. The amount of damage caused to the programmer's brainchild is more than $100 million. For this, the attacker was put behind bars for a term of 46 to 57 months.

Then Smith was released on bail of $100 thousand, and the case began to be put on hold. The hearings have been postponed several times, and the prosecutors who launched the case so loudly have now remained silent. Jim Smith himself and his lawyer are also silent.

Source: jrwhipple.com

ILOVEYOU (“Letter of happiness”)

Someone in 2000 thought of writing a pretty cute virus. It arrived in the mail in the form of a message “I LOVE YOU” with an attached file. Users downloaded it and... A script settled on the hard drive that:

• randomly sent letters in incredible quantities;
• deleted important files on PC.

The results are simply shocking: the damage caused by this “ by letter“, “slammed“ 10% of all computers that existed at that time. In monetary terms it is $5.5 billion.

Influenza is not such a serious disease, but many millions of people get sick with it every year, and periodically pandemics (widespread epidemics) occur and claim many lives.

In 1886 and 1887, influenza was registered in Russia; In the summer of 1889, pathogen activity increased in Bukhara, and later that year the infection spread to other regions of Russia and Western Europe. Thus began the influenza pandemic of 1889-1890. During the second and third epidemics, the number of deaths progressively increased. The most ominous feature of this epidemic was that it apparently gave impetus to some kind of process, and now the flu is with us, or, as the epidemiologist Greenwood wrote, “we are not able to regain lost ground.”

In 1918, after the end of the First World War, an unprecedented influenza pandemic, called the “Spanish flu,” broke out.

In a year and a half, the pandemic has spread to all countries, affecting more than a billion people. The disease was extremely difficult: about 25 million people died - more than from injuries on all fronts of the First World War in four years.

Never later did influenza cause such a high mortality rate: the mortality rate was low during all subsequent epidemics and pandemics, although the percentage of deaths from influenza is low, the mass nature of the disease leads to the fact that during each major influenza epidemic, thousands of patients die from it, especially the elderly and children. It has been noted that during epidemics the mortality rate from diseases of the lungs, heart and blood vessels increases sharply.

Influenza remains the “king” of epidemics. No disease can reach hundreds of millions of people in a short time, and more than a billion people get sick with the flu during a pandemic! This was the case not only during the memorable pandemic of 1918, but relatively recently - in 1957, when the “Asian” flu pandemic broke out, and in 1968, when the “Hong Kong” flu appeared. There are several types of influenza virus known - A, B, C, etc.; under the influence of environmental factors, their number may increase. Due to the fact that immunity to influenza is short-term and specific, repeated illness is possible in one season. According to statistics, an average of 20-35% of the population suffers from influenza every year.

The source of infection is a sick person; Patients with a mild form of the virus are the most dangerous as spreaders of the virus, since they do not isolate themselves in a timely manner - they go to work, use public transport, and visit places of entertainment.

The infection is transmitted from a sick person to a healthy person through airborne droplets when talking, sneezing, coughing or through household items.

Smallpox is one of the oldest diseases. A description of smallpox was found in the Egyptian papyrus of Amenophis I, compiled 4000 BC. Smallpox lesions were preserved on the skin of a mummy buried in Egypt 3000 BC. The mention of smallpox, which the Chinese called “poison from the mother’s breast,” is contained in the oldest Chinese source - the treatise “Cheu-Cheufa” (1120 BC). The first classical description of smallpox was given by the Arab physician Rhazes.

Smallpox was the most common and most dangerous disease in the past. Its destructive power was not inferior to the power of the plague.

The first mention of smallpox in Russia dates back to the 4th century. In 1610, the infection was brought to Siberia, where a third of the local population died out. People fled to the forests of the tundra and mountains, displayed idols, burned scars on their faces like pockmarks in order to deceive this evil spirit - everything was in vain, nothing could stop the ruthless killer.

However, attempts to protect against smallpox are as ancient as smallpox itself. They were based on the observation that people who once had smallpox did not get sick again.

The first vaccination against smallpox in Russia was carried out in a solemn ceremony by Moscow University professor Efrem Mukhin in 1801. A child from an orphanage in Moscow was vaccinated with smallpox using the Jenner method and in honor of this was given the surname Vaccinov.

April 10, 1919 V.I. Lenin signed a decree on compulsory smallpox vaccination, which marked the beginning of mass vaccinations.

Poliomyelitis is a viral disease that affects the gray matter of the central nervous system. The causative agent of polio is a small virus that does not have an outer shell and contains RNA. The polio virus affects the limbs, that is, it changes the shape of the bones. Characteristic bone changes were found during excavations in Greenland on skeletons dating back to 500-600 BC. The incidence of polio has a number of characteristic features. Poliomyelitis is spread by intestinal diseases. With high levels of sanitation, children do not become infected at an early age, but become infected later. Poliomyelitis seems to mature, and in adults the disease is much more severe. An effective method of combating this disease is the live polio vaccine. The use of a polyvaccine made it possible to effectively extinguish outbreaks of infection, and the incidence rate sharply decreased. However, vaccination with a live vaccine does not mean eliminating the killer virus, but only replacing it with an artificial laboratory strain that is safe for humans.

Rabies is an infectious disease transmitted to humans from a sick animal through a bite or contact with the saliva of a sick animal, most often a dog. One of the main signs of developing rabies is hydrophobia, when the patient has difficulty swallowing liquids and develops convulsions when trying to drink water. The rabies virus contains RNA, packaged in a nucleocapsid of helical symmetry, covered with a shell, and when multiplying in brain cells, it forms specific inclusions, according to some researchers, “viral graveyards” called Babes-Negri bodies. The disease is incurable.

Tumor viruses - Over the years since the fact of the occurrence of viral sarcomas in chickens was first established, numerous researchers have discovered oncogenic viruses belonging to two groups in different species of vertebrates: DNA-containing and retroviruses. Oncogenic DNA viruses include pacovaviruses, adecoviruses, and herpesviruses. Of the RNA viruses, only retroviruses cause tumors.

The range of tumors caused by oncogenic viruses is unusually wide. Although the polyoma virus primarily causes tumors of the salivary glands, its very name indicates that it can cause many other tumors. Retroviruses cause mainly leukemia and sarcomas, which often cause tumors of the breast and a number of other organs. Although cancer is a disease of the whole organism, an essentially similar phenomenon, called transformation, is also observed in cell cultures. Such systems are used as models for studying oncogenic viruses. The ability to transform cells in vitro underlies methods for the quantitative determination of many oncogenic viruses. The same systems are also used for comparative studies of the physiology of normal and tumor cells.

Viruses and human malignant tumors - One of the arguments against the role of viruses in the occurrence of most malignant tumors in humans is the fact that in the vast majority of cases, malignant tumors are not contagious, whereas with a viral etiology, transmission from person to person can be expected. If, however, we assume that activation of heritable viruses by exogenous factors plays a role in the occurrence of tumors, then we should expect that facts of hereditary predisposition to malignant tumors will be revealed. Such a predisposition to the development of some tumors has indeed been discovered, but various explanations can be found for this. Despite 10 years of intensive work directed by special government programs, the connection between human malignancies and viruses still remains problematic. It seems extremely strange that oncogenic viruses, which play such an obvious role in the occurrence of tumors in a wide variety of animals, should somehow “bypass” humans.

AIDS - Acquired Immune Deficiency Syndrome - is a new infectious disease that experts recognize as the first truly global epidemic in the known history of mankind. Neither the plague, nor smallpox, nor cholera are precedents, since AIDS is decidedly unlike any of these and other known human diseases. The plague claimed tens of thousands of lives in the regions where the epidemic broke out, but never covered the entire planet at once. In addition, some people, having been ill, survived, acquired immunity and took on the work of caring for the sick and restoring the damaged economy. AIDS is not a rare disease that affects a few people by chance. Leading experts currently define AIDS as a “global health crisis”, as the first truly global and unprecedented epidemic of an infectious disease, which still, after the first decade of the epidemic, is not controlled by medicine and every infected person dies from it.

AIDS by 1991 was registered in all countries of the world except Albania. In the most developed country in the world - the United States - already at that time one out of every 100-200 people was infected, every 13 seconds another US resident was infected, and by the end of 1991, AIDS in this country had become third in mortality, overtaking cancer. So far, AIDS forces one to recognize itself as a fatal disease in 100% of cases.

The first people with AIDS were identified in 1981. During the past first decade, the spread of the pathogen virus occurred mainly among certain groups of the population, which were called risk groups. These are drug addicts, prostitutes, homosexuals, patients with congenital hemophilia (since the life of the latter depends on the systematic administration of drugs and donor blood).

However, by the end of the first decade of the epidemic, WHO had accumulated material indicating that the AIDS virus had spread beyond the named risk groups. He entered the general population.

The second decade of the pandemic began in 1992. It is expected that it will be significantly heavier than the first one. In Africa, for example, in the next 7-10 years, 25% of agricultural farms will be left without labor due to extinction from AIDS alone.

AIDS is one of the most important and tragic problems that arose before humanity at the end of the 20th century. The causative agent of AIDS, the human immunodeficiency virus (HIV), is a retrovirus. Retroviruses owe their name to an unusual enzyme - reverse transcriptase (retrovertase), which is encoded in their genome and allows the synthesis of DNA on an RNA template. Thus, HIV is capable of producing DNA copies of its genome in host cells, such as “helper” T-4 lymphocytes. Viral DNA is included in the genome of lymphocytes, where its presence creates conditions for the development of chronic infection. Even theoretical approaches to solving such a problem as cleaning the genetic apparatus of human cells from foreign (in particular, viral) information are still unknown. Without solving this problem, there will be no complete victory over AIDS.

Although it is now clear that the human immunodeficiency virus (HIV) is the cause of acquired immunodeficiency syndrome (AIDS) and related diseases, the origin of the virus remains a mystery. There is strong serological evidence that the infection appeared on the west and east coasts of the United States in the mid-1970s. However, cases of AIDS-associated diseases known in central Africa indicate that the infection may have appeared there even earlier (50-70 years). Be that as it may, it has not yet been possible to satisfactorily explain where this infection came from. Several human and monkey retroviruses have been discovered using modern cell culture techniques. Like other RNA viruses, they are potentially variable; therefore, they are quite likely to have such changes in the host spectrum and virulence that could explain the emergence of a new pathogen (there are several hypotheses: 1) the impact of unfavorable environmental factors on a pre-existing virus; 2) bacteriological weapons; 3) mutation of the virus as a result of radiation exposure from uranium deposits in the supposed homeland of the infectious pathogen - Zambia and Zaire).

What types of viruses are there? - this is the question people ask when epidemics and viral diseases are raging around. With the arrival of cold weather, as well as with a lack of vitamins in the body, we increasingly have many anti-infective and antiviral drugs among our pharmacy purchases. The New Year's mood may worsen due to fever and cough. And it happens that the disease completely knocks us off our feet, and we cannot even get up from the couch. It is important for us to know which infections are the most common and what we have to fight against. Let's talk to you about the most common acute respiratory infections and influenza viruses.

Coxsackievirus (Rhinitis)

One of the most unpleasant diseases. A simple way to become infected is to overcool your body, and this is very difficult to notice. Bacteria form in the nasal cavity and begin to multiply and become inflamed. It is enough to breathe in cold air and long-term treatment is guaranteed.

The infectious agent can also be pollen, then the disease can be considered seasonal. Symptoms in this case are nasal discharge (dry, wet and purulent), headache, lacrimation.

In any case, it is important to know what treatment is needed. There is no need to self-medicate; an experienced doctor knows what viruses are, will find the cause of the disease and will prescribe you a specific list of medications. The main thing is not to hesitate with this issue.

Respiratory syncytial viruses (Viral bronchitis)

Every schoolchild will answer what viral bronchitis is. And the main symptoms may be cough, fever, and sputum production. In general terms, bronchitis is inflammation of the lung mucosa . And the disease can last a very long time. The temperature will be around 39, the sputum will acquire a greenish tint, and in difficult cases, with blood clots.

Reasons may vary, but it is generally accepted that the main reason is smoking. Many people are also sure that older people suffer from bronchitis more often. Unfortunately, children can also be affected by the disease, and the cause can be not only smoking, but also heredity, as well as the environment.

Respiratory viruses (laryngitis)

This disease is characterized as inflammation of the mucous membrane of the larynx. Pain and dry mouth, cough, fever appear, and can even lead to complete loss of voice. Like the above diseases, it can be acute or chronic.

Reason can be caused by external factors such as alcohol, smoking, ligament strain and much more. An experienced doctor will help you with treatment, because the disease cannot be neglected. Viruses can be very dangerous; a laryngeal abscess can form and be fatal.

Viral sore throat

Another name for sore throat is acute tonsillitis . In this case, the tonsils become inflamed. It is generally accepted that children suffer from sore throat more often, but this can also affect adults. Either one or two tonsils become inflamed.

Treatment is focused on relieving symptoms. But in acute forms it can even go so far as to remove these same tonsils. It also has a chronic form, and in all these cases there is no need to wait for the consequences and self-medicate.

Mycobacterium tuberculosis (TB)

This disease is not a cold, but it does occur. It is caused by the microbacterium tuberculosis. It most often affects the lungs, but can also spread to other tissues: bones, eyes, skin.

It is usually transmitted by airborne droplets, but do not forget that you can also become infected through contact with the patient’s belongings. You feel unwell, have a headache, and have a fever. The most important thing is that chest pain and cough may not appear at the initial stage. Sweating and loss of energy, and most importantly, weight loss.

Detected using a sputum smear, in some cases a negative result does not mean the absence of the disease. You definitely need to do fluorography.

Rhinoviruses (Pharingitis)

The main symptoms of pharyngitis, which is most often caused by rhinoviruses, are dry mouth and a cough with pus. Very often pharyngitis is confused with sore throat. The difference from a sore throat is a dry cough.

Also a very unpleasant symptom is a runny nose and nasal congestion. The consequence is difficulty breathing and lack of proper sleep. The cause of the disease is a variety of bacteria, such as streptococcus, adenoviruses,.

Influenza virus

Influenza is caused by viruses with complex names, such as H1N1, H1N2 and H3N2. It affects the upper respiratory tract of humans. As with tuberculosis, the source of influenza can be an infected person. Temperature, runny nose, chills, cough, aches in muscles and joints suddenly appear. In rare cases, abdominal pain and loose stools. It usually lasts 7-10 days, complications may become meningitis - inflammation of the lining of the brain.

The main fighter against the disease will be our immunity. But this cannot be done without support. The main thing is peace and abstinence from alcohol and smoking. Antiviral drugs will help. The most important thing is not to let the disease progress.

Prevention of viral infections and colds

To avoid viral diseases you need an integrated approach. Proper hardening will do. It is necessary to teach the body to react correctly to overheating and hypothermia.

///A healthy lifestyle also includes physical activity. If you cannot visit the gym, you should not forget about walks in the fresh air. A very important point - proper and nutritious nutrition . With a lack of vitamins in the body, the immune system is weakened. You need to include fresh vegetables and fruits in your diet. You can buy vitamin complexes at the pharmacy. The main thing is to remember what viruses there are, do not forget about your health, because the principle solve the problem as it arises in this case is not suitable.

Video about types of viruses

In this video, Alexander Pilyagin will talk about the TOP 10 killer viruses, what they are and how best to protect your body:

There is an opinion that animals, plants and humans predominate in numbers on planet Earth. But this is actually not the case. There are countless microorganisms (microbes) in the world. And viruses are among the most dangerous. They can cause various diseases in humans and animals. Below is a list of the ten most dangerous biological viruses for humans.

Hantaviruses are a genus of viruses transmitted to humans through contact with rodents or their waste products. Hantaviruses cause various diseases belonging to such groups of diseases as “hemorrhagic fever with renal syndrome” (mortality on average 12%) and “hantavirus cardiopulmonary syndrome” (mortality up to 36%). The first major outbreak of disease caused by hantaviruses, known as Korean hemorrhagic fever, occurred during the Korean War (1950–1953). Then more than 3,000 American and Korean soldiers felt the effects of a then unknown virus that caused internal bleeding and impaired kidney function. Interestingly, it is this virus that is considered the likely cause of the epidemic in the 16th century that exterminated the Aztec people.

Influenza virus is a virus that causes an acute infectious disease of the respiratory tract in humans. Currently, there are more than 2 thousand of its variants, classified into three serotypes A, B, C. The group of viruses from serotype A, divided into strains (H1N1, H2N2, H3N2, etc.) is the most dangerous for humans and can lead to epidemics and pandemics. Every year, between 250 and 500 thousand people worldwide die from seasonal influenza epidemics (most of them children under 2 years of age and elderly people over 65 years of age).

Marburg virus is a dangerous human virus first described in 1967 during small outbreaks in the German cities of Marburg and Frankfurt. In humans, it causes Marburg hemorrhagic fever (mortality rate 23-50%), which is transmitted through blood, feces, saliva and vomit. The natural reservoir for this virus is sick people, probably rodents and some species of monkeys. Symptoms in the early stages include fever, headache and muscle pain. In the later stages - jaundice, pancreatitis, weight loss, delirium and neuropsychiatric symptoms, bleeding, hypovolemic shock and multiple organ failure, most often the liver. Marburg fever is one of the top ten deadly diseases transmitted from animals.

Sixth on the list of the most dangerous human viruses is Rotavirus, a group of viruses that are the most common cause of acute diarrhea in infants and young children. Transmitted by the fecal-oral route. The disease is usually easy to treat, but kills more than 450,000 children under five worldwide each year, most of whom live in underdeveloped countries.

Ebola virus is a genus of virus that causes Ebola hemorrhagic fever. It was first discovered in 1976 during an outbreak of the disease in the Ebola River basin (hence the name of the virus) in Zaire, DR Congo. It is transmitted through direct contact with the blood, secretions, other fluids and organs of an infected person. Ebola fever is characterized by a sudden increase in body temperature, severe general weakness, muscle pain, headaches, and sore throat. Often accompanied by vomiting, diarrhea, rash, impaired renal and liver function, and in some cases internal and external bleeding. According to the US Centers for Disease Control, in 2015, 30,939 people were infected with Ebola, of whom 12,910 (42%) died.

Dengue virus is one of the most dangerous biological viruses for humans, causing dengue fever, in severe cases, which has a mortality rate of about 50%. The disease is characterized by fever, intoxication, myalgia, arthralgia, rash and swollen lymph nodes. It is found mainly in the countries of South and Southeast Asia, Africa, Oceania and the Caribbean, where about 50 million people are infected annually. The carriers of the virus are sick people, monkeys, mosquitoes and bats.

Smallpox virus is a complex virus, the causative agent of a highly contagious disease of the same name that affects only humans. This is one of the oldest diseases, the symptoms of which are chills, pain in the sacrum and lower back, rapid increase in body temperature, dizziness, headache, vomiting. On the second day, a rash appears, which eventually turns into purulent blisters. In the 20th century, this virus claimed the lives of 300–500 million people. About US$298 million was spent on the smallpox campaign from 1967 to 1979 (equivalent to US$1.2 billion in 2010). Fortunately, the last known case of infection was reported on October 26, 1977 in the Somali city of Marka.

The rabies virus is a dangerous virus that causes rabies in humans and warm-blooded animals, which causes specific damage to the central nervous system. This disease is transmitted through saliva from the bite of an infected animal. Accompanied by an increase in temperature to 37.2–37.3, poor sleep, patients become aggressive, violent, hallucinations, delirium, a feeling of fear appear, soon paralysis of the eye muscles, lower extremities, paralytic respiratory disorders and death occurs. The first signs of the disease appear late, when destructive processes have already occurred in the brain (swelling, hemorrhage, degradation of nerve cells), which makes treatment almost impossible. To date, only three cases of human recovery without vaccination have been recorded; all others ended in death.

Lassa virus is a deadly virus that is the causative agent of Lassa fever in humans and primates. The disease was first discovered in 1969 in the Nigerian city of Lassa. It is characterized by a severe course, damage to the respiratory system, kidneys, central nervous system, myocarditis and hemorrhagic syndrome. It is found mainly in West African countries, especially in Sierra Leone, the Republic of Guinea, Nigeria and Liberia, where the annual incidence ranges from 300,000 to 500,000 cases, of which 5 thousand lead to the death of the patient. The natural reservoir of Lassa fever is polymammated rats.

Human immunodeficiency virus (HIV) is the most dangerous human virus, the causative agent of HIV infection/AIDS, which is transmitted through direct contact of mucous membranes or blood with bodily fluid of the patient. During HIV infection, the same person develops new strains (varieties) of the virus, which are mutants, completely different in reproduction speed, capable of initiating and killing certain types of cells. Without medical intervention, the average life expectancy of a person infected with the immunodeficiency virus is 9–11 years. According to 2011 data, 60 million people worldwide have become infected with HIV, of which 25 million have died, and 35 million continue to live with the virus.

Share on social media networks

VKontakte Facebook Odnoklassniki

There are no safe diseases

You can die from a cold, a runny nose, or hiccups - the probability is a tiny fraction of a percent, but it exists. The mortality rate from common flu is up to 30% in children under one year of age and the elderly. And if you catch one of the nine most dangerous infections, your chance of recovery will be calculated in fractions of a percent.

1. Creutzfeldt-Jakob disease

1st place among fatal infections went to spongiform encephalopathy, also known as Creutzfeldt-Jakob disease. The infectious agent-pathogen was discovered relatively recently - humanity became acquainted with prion diseases in the mid-twentieth century. Prions are proteins that cause dysfunction and then cell death. Due to their special resistance, they can be transmitted from animal to person through the digestive tract - a person becomes ill by eating a piece of beef with the nervous tissue of an infected cow. The disease lies dormant for years. Then the patient begins to develop personality disorders - he becomes sloppy, grumpy, becomes depressed, his memory suffers, sometimes his vision suffers, even to the point of blindness. Within 8-24 months, dementia develops and the patient dies from impaired brain activity. The disease is very rare (only 100 people have fallen ill over the past 15 years), but absolutely incurable.

2. HIV

The human immunodeficiency virus has moved from 1st to 2nd place quite recently. It is also classified as a new disease - until the second half of the 20th century, doctors did not know about infectious lesions of the immune system. According to one version, HIV appeared in Africa, passing to humans from chimpanzees. According to another, he escaped from a secret laboratory. In 1983, scientists managed to isolate an infectious agent that causes immune damage. The virus was transmitted from person to person through blood and semen through contact with damaged skin or mucous membrane. At first, people from the “risk group” fell ill with HIV - homosexuals, drug addicts, prostitutes, but as the epidemic grew, cases of infection appeared through blood transfusions, instruments, during childbirth, etc. Over the 30 years of the epidemic, HIV has infected more than 40 million people, of whom about 4 million have already died, and the rest may die if HIV progresses to the AIDS stage - a defeat of the immune system that makes the body defenseless to any infections. The first documented case of recovery was recorded in Berlin - an AIDS patient received a successful bone marrow transplant from an HIV-resistant donor.

3. Rabies

Rabies virus, the causative agent of rabies, takes an honorable 3rd place. Infection occurs through saliva through a bite. The incubation period ranges from 10 days to 1 year. The disease begins with a depressed state, slightly elevated temperature, itching and pain at the bite site. After 1-3 days, an acute phase occurs - rabies, which frightens others. The patient cannot drink; any sudden noise, flash of light, or the sound of flowing water causes convulsions, hallucinations and violent attacks begin. After 1-4 days, the frightening symptoms weaken, but paralysis appears. The patient dies from respiratory failure. A full course of preventive vaccinations reduces the likelihood of disease to hundredths of a percent. However, once symptoms of the disease appear, recovery is almost impossible. With the help of the experimental “Milwaukee Protocol” (immersion in an artificial coma), four children have been saved since 2006.

4. Hemorrhagic fever

This term hides a whole group of tropical infections caused by filoviruses, arboviruses and arenaviruses. Some fevers are transmitted by airborne droplets, some through mosquito bites, some directly through blood, contaminated things, meat and milk of sick animals. All hemorrhagic fevers are characterized by highly resistant infectious carriers and are not destroyed in the external environment. The symptoms at the first stage are similar - high temperature, delirium, pain in muscles and bones, then bleeding from physiological orifices of the body, hemorrhages, and bleeding disorders occur. The liver, heart, and kidneys are often affected; necrosis of the fingers and toes may occur due to impaired blood supply. Mortality ranges from 10-20% for yellow fever (the safest, there is a vaccine, treatable) to 90% for Marburg fever and Ebola (vaccines and treatment do not exist).

5. Plague

Yersinia pestis, the plague bacterium, has long since fallen from its honorary pedestal as the deadliest. During the Great Plague of the 14th century, this infection managed to destroy about a third of the population of Europe; in the 17th century, it wiped out a fifth of London. However, already at the beginning of the 20th century, the Russian doctor Vladimir Khavkin developed the so-called Khavkin vaccine, which protects against the disease. The last large-scale plague epidemic occurred in 1910-11, affecting about 100,000 people in China. In the 21st century, the average number of cases is about 2,500 per year. Symptoms - the appearance of characteristic abscesses (buboes) in the area of ​​the axillary or inguinal lymph nodes, fever, fever, delirium. If modern antibiotics are used, the mortality rate for the uncomplicated form is low, but for the septic or pulmonary form (the latter is also dangerous because of the “plague cloud” around patients, consisting of bacteria released when coughing) is up to 90%.

6. Anthrax

The anthrax bacterium, Bacillus anthracis, was the first pathogenic microorganism to be captured by “germ hunter” Robert Koch in 1876 and identified as the causative agent of the disease. Anthrax is highly contagious, forms special spores that are unusually resistant to external influences - the carcass of a cow that died from the ulcer can poison the soil for several decades. Infection occurs through direct contact with pathogens, and occasionally through the gastrointestinal tract or air contaminated with spores. Up to 98% of the disease is cutaneous, with the appearance of necrotic ulcers. Further recovery or transition of the disease to the intestinal or especially dangerous pulmonary form of the disease is possible, with the occurrence of blood poisoning and pneumonia. The mortality rate for the cutaneous form without treatment is up to 20%, for the pulmonary form - up to 90%, even with treatment.

7. Cholera

The last of the “old guard” of especially dangerous infections, which still causes deadly epidemics - 200,000 patients, more than 3,000 deaths in 2010 in Haiti. The causative agent is Vibrio cholerae. Transmitted through feces, contaminated water and food. Up to 80% of people who have been in contact with the pathogen remain healthy or have a mild form of the disease. But 20% are faced with moderate, severe and fulminant forms of the disease. Symptoms of cholera are painless diarrhea up to 20 times a day, vomiting, convulsions and severe dehydration, leading to death. With full treatment (tetracycline antibiotics and fluoroquinolones, hydration, restoration of electrolyte and salt balance), the chance of death is low; without treatment, mortality reaches 85%.

8. Meningococcal infection

Meningococcus Neisseria meningitidis is the most insidious infectious agent among the especially dangerous ones. The body is affected not only by the pathogen itself, but also by toxins released during the decay of dead bacteria. The carrier is only a person, it is transmitted by airborne droplets, through close contact. Mostly children and people with weakened immune systems fall ill, about 15% of the total number of those in contact. An uncomplicated disease - nasopharyngitis, runny nose, sore throat and fever, without consequences. Meningococcemia is characterized by high fever, rash and hemorrhages, meningitis - septic brain damage, meningoencephalitis - paralysis. Mortality without treatment is up to 70%, with timely started therapy - 5%.

9. Tularemia

It is also known as mouse fever, deer disease, “lesser plague”, etc. Caused by the small gram-negative bacillus Francisella tularensis. Transmitted through the air, through ticks, mosquitoes, contact with patients, food, etc., virulence is close to 100%. The symptoms are similar in appearance to the plague - buboes, lymphadenitis, high fever, pulmonary forms. It is not lethal, but causes long-term impairment and, theoretically, is an ideal basis for the development of bacteriological weapons.