What are viruses and how are they dangerous? The most dangerous viruses for humans. Deadly rabies virus
The human species constantly interacts with living nature. Today, the opinions of world scientists are unanimous - viruses appeared long before the formation of the DNA molecule. There is a hypothesis that bacteria are the evolutionary result of degenerative unicellular organisms, a kind of descendant of an ancient precellular life form. The annual struggle of humanity with unknown types of viruses leads to reasonable conclusions - they mutate, develop and adapt to the conditions we create, while actively participating in the evolutionary formation of the genetic material of all living organisms. Each year, widespread pandemics claim hundreds of lives.
We present to you the top 10 most dangerous viruses known to man not only since ancient times.
Human immunodeficiency virus (AIDS)
The deadly virus rightfully ranks first in the world rankings. To date, there is no medicine that can cure AIDS. It is possible to protect yourself from infection only through effective prevention.
The first cases of AIDS were recorded in the 1930s in a West African country. It was then believed that monkeys carried the virus. The official isolation and laboratory testing of the pathogen was carried out in 1980 with the identification of 440 carriers-residents of the United States.
The causative agent, the human immunodeficiency virus, destroys the defense system by damaging CD4 lymphocytes (cells responsible for destroying pathogenic infections), a decrease in the number of which leads to a decrease in the body's resistance to the surrounding pathogenic microflora.
The source of infection is a latent carrier or a sick person. Infection occurs through blood and biological secretions - sexual contact of all types, blood transfusions, childbirth, breastfeeding, injections, organ transplantation, household microtraumas.
The incubation period is long; from the moment the pathogen enters the body until the symptoms appear, quite a lot of time passes - from a year or more.
The average life expectancy of an HIV-infected person is no more than 11-15 years.
Known stages of HIV
Fever - appears in 50% of infected people, characterized by minor intestinal or cold symptoms (body aches, diarrhea, nausea, rarely rash and sore throat);
asymptomatic – duration up to 10 years. The virus destroys the immune defense. Very rarely, small swellings appear in the area of the lymph nodes;
development of AIDS. Activation of latent pathogenic organisms living in the human body. The appearance of a white coating on the tongue, hemorrhagic rashes of the extremities, sweating, decreased vision, sudden weight loss of up to 10% of the total weight. The condition is then aggravated by hyperthermia, diarrhea, lymphoma, tuberculosis and Kaposi's sarcoma.
The life expectancy of an HIV patient with progressive symptoms is no more than two years.
HIV treatment is carried out with immunostimulating, antiviral and antibacterial drugs in a hospital setting. The main goal of drug therapy is to prolong the life of the infected person.
Fundamental methods for effective HIV prevention
1. Use a condom, one sexual partner.
2. Do not use other people's hygiene items.
3. During medical manipulations, use a disposable instrument.
Rabies virus
A very dangerous virus in the world for humans. The disease has been known since ancient times. An effective method of combating the disease is timely and urgent revaccination immediately after infection. The countries most vulnerable to infection are Asia, Africa, Canada, and the USA (the first cases of human infection since 1880).
The causative agent is the Rabies virus, transmitted through a bite or the ingress of saliva into the bloodstream of a domestic or wild animal. Having penetrated the body, the virus destroys the central nervous system, causing meningoencephalitis, asphyxia and cardiac arrest due to paralysis of the respiratory tract.
The source is an infected animal - dog, cat, fox, raccoon, rodents. Infection of a human pet is possible even during the incubation period.
The process of disease development lasts from 10 days to a year in humans (usually 1-4 months), in animals – up to 2-3 weeks. If you do not get vaccinated within the first 10 days after the bite, the probability of death for a person is 99% (only 3 cases of recovery after the active phase are known worldwide).
Symptoms of rabies
Symptoms of disease progression are characterized by periods:
1. Early – subfebrile body temperature, anxiety (1-3 days).
2. High point – aggression, hallucinations, delirium, fear of water (up to 4 days).
3. Paralyzed – the state of a living corpse, indifference, lack of reactions, paralysis of the limbs, suffocation (up to 8 days).
Treatment of a patient during the period of active symptoms is not effective - medical supervision is limited to symptomatic measures to alleviate the condition of the infected person.
Rabies preventative measures taken
Timely vaccination of pets;
immediately seek medical help if bitten by stray dogs, cats or wild animals;
completing a full course of conservative therapy immediately after the bite.
Ebola virus (hemorrhagic fever)
This is the name of a dangerous, highly infectious virus for humans, the causative agent of which is the filovirus Zaire ebolavirus. First identified in 1976, during an epidemic in Zaire that covered most of the Ebola River basin (almost 90% fatal).
It has been established that the carriers of the virus are rodents, bats and monkeys.
Subsequent epidemics are caused by mutational types of the virion:
town of Nzara and Uganda (Sudan). In 1976, the mortality rate from this virus was 54%, in 1979 - 53%, in 2000 - 53% of cases. The source of infection has not been identified;
Philippines, then USA. 1989 - outbreak of hemorrhagic fever among monkeys;
Tai forest (Africa). 1994 – human infection through laboratory studies of monkey corpses;
Bundibugyo (Uganda). 2007 - the epidemic claimed 40 lives out of 140 registered cases of the disease;
Congo. 2012 – 37% mortality rate.
Currently, the vaccine against the Ebola virus is being tested on monkeys, so there is no information about the imminent arrival of the antiserum on the consumer market. The Ministry of Health has officially confirmed the approval of the experimental serum to prevent the popularization of epidemics.
The disease is characterized by seasonal outbreaks and is recognized as a worldwide threat to humanity.
Localization of the pathogen is mainly in the blood, saliva, other secretions and fluids of the infected person (sperm, urine, mucus). Transmitted by contact, injection, or sexual contact. Infection cannot be ruled out by shaking hands and using common household items.
The period of development of the disease covers 2-3 weeks. Once in the body, the virus blocks the complement blood group (inactive proenzymes that bind to antigenic bodies to destroy and agglutinate the latter).
The main signs of Ebola fever are hemorrhagic rashes, fatigue, apathy, pain in the spine and limbs, pharyngitis, and a sharp increase in temperature. Then diarrhea, abdominal pain, and disorientation appear. After a week, the active phase gives way to increased pain, nosebleeds, bloody diarrhea, dry cough and acute pancreatitis. On the 14th day of illness - infectious intoxication, hemorrhagic shock, massive blood loss.
Convalescent plasma (carriers who acquire immunity after illness) has positive dynamics in the treatment of Ebola patients. However, the method does not guarantee complete recovery. The overall mortality rate from the Ebola virus is about 50%.
Marburg virus (hemorrhagic fever)
A close relative of Ebola hemorrhagic fever. 1967 is the date of the first human infection with this virus, recorded in Marburg (Germany). The source of infection was monkeys from Uganda brought for experiments.
The causative agent of the disease is the Filoviridae virus of zoonotic origin (transmitted to humans from animals). It is assumed that infection occurs through contact with biological fluid (saliva, vomit, blood, secretions).
Risk group for potential Marburg virus infection
veterinarians exposed to monkeys from Africa;
scientists researching the virus;
healthcare workers in contact with a patient with Marburg virus;
laboratory staff involved in biomaterial research.
The period of fever development (incubation) lasts no more than 10 days. Then the patient feels fever and muscle pain. Gradually, the symptoms worsen - rashes appear all over the body, diarrhea, abdominal pain, jaundice, pancreatitis, organic dysfunction, weight loss. Further development of liver failure, internal blood loss, delusions and hallucinations cannot be ruled out. The mortality rate ranges from 25 to 85%.
There is no vaccine against Marburg virus.
Contagiousness research and serum development began in 2014. Today, the world knows of nanoparticles that have the ability to virally dereplicate and have been tested on monkeys.
According to scientists, the only way to protect against the virus is to use maximum precautions when in contact with African animals.
Smallpox virus (natural)
The smallpox virus, which is dangerous to humans, is divided into two types: Variola Minor (chickenpox) and Magor (black pox). Black smallpox epidemics claim from 40% to 90% of human lives, and survivors become visually impaired.
The first mention of a deadly disease in the 4th century was the smallpox epidemic in China (95% mortality). 6th century - the disease affects densely populated areas of Korea (88% fatality rate). 737 - Japanese population decreases by 35% (black smallpox pandemic). Since 1500, smallpox has claimed millions of European lives. Between 1700 and 1800, the first smallpox serum was produced and tested. Variolation (vaccination) had the effect of reducing mortality by up to 10%.
Infection occurs through airborne droplets, through contact with a carrier or patient. The incubation period does not exceed two weeks. Entering the lymph, the virus spreads throughout the epithelium and forms purulent pustules. Severe forms of the disease develop hemorrhagic syndrome, encephalitis, infectious-toxic shock and death. The cured person receives ugly scars from pustules all over his body. As a consequence of extensive hemorrhoidal hemorrhages, survivors experience blindness.
A person is infectious to others from the last five days of incubation until the crusts of the pustules fall off.
The body of a person who died from smallpox is contagious for up to four months.
Treatment of smallpox is carried out with antiseptic and bacterial drugs, broad-spectrum antibiotics.
The blackpox virus has been repeatedly used by humanity as a biological weapon. To date, there is no data on the presence of the virus in the natural climate; samples are preserved in the laboratory.
Spanish flu virus (Spanish flu) or influenza
The most dangerous virus in the world. During the First World War, more than 35% of the world's population became infected with the Spanish flu, of which the mortality rate was about 5% of the total population (150 million people).
The causative agent is the H1N1 virus, isolated during the study of a mummy in Alaska (XVIII-XIX centuries). Transmitted by airborne droplets. After a certain incubation time (up to 4 days), the patient develops cyanosis of the skin, a sharp increase in body temperature to 40 degrees, and coughing up blood. Then lightning development of pulmonary hemorrhage. Death occurs from choking on one's own blood.
The development of severe complications with a fatal outcome in the first days of the disease was observed mainly in patients with reduced immunity, during pregnancy, in children under 14 years of age, and in the elderly.
Signs of infection
Characteristic signs of infection for patients at risk
1. Rapid development of hemorrhagic pneumonia (in a few hours).
2. The disease affects only adults (from 25 to 45 years old).
3. The probability of death is 95% on the first day of the disease.
The massive Spanish flu pandemic during the First World War is recognized as a global catastrophe of a large-scale nature.
In subsequent years, active vaccination of the population was carried out, and infected patients were treated with antiviral drugs.
Today, the H1N1 virus has been modified and has a milder course. When outbreaks of Spanish flu are detected, the fatal outcome is no more than 2% (mainly among patients who sought medical help late).
Dengue virus (bone fever or date disease)
A dangerous virus transmitted transmissibly (through the bites of blood-sucking insects). Localization locations - in the countries of South and East Asia, Africa, the Caribbean. The annual incidence is about 50 million people; with the hemorrhagic form, the mortality rate is up to 50%. Secondary infection with the Dengue virus is more dangerous for humans than the primary one, since the body’s production of antibodies and the acquisition of immunity only aggravates the course of the recurrent disease.
In the mid-20th century, the causative agent of the Dengue virus was the Flavivirus virion (family of abroviruses Flaviviridae - antigenic group B).
The source of infection is monkeys, sick patients, and rarely bats. The disease is believed to be transmitted by mosquitoes. The insect is contagious for the first three months after the bite of an infected individual and can be a carrier of several serotypes of the virus at once. The period of development of the virus in the human body is up to seven days.
The main symptoms of the mild stage (primary infection - classic)
muscle and bone pain;
temperature rise up to 40 degrees;
heartbeat;
hyperemia of the eyeballs, throat;
rashes on the body, itching;
anxiety.
A more severe form of the disease develops in the local population, and occurs during simultaneous infection with several varieties of abrovirus.
Symptoms of the hemorrhagic form of the disease
increased lymph, nausea, vomiting;
cough, weakness, abdominal pain;
development of pancreatitis, gastric bleeding;
cyanosis;
rapid heartbeat, vomiting blood.
Dengue fever is treated with painkillers and vitamins. In severe forms, plasma therapy, coagulants, and glucocorticoids are used.
Zika virus (Zika fever)
One of a variety of dangerous viruses transmitted transmissibly. Isolated in laboratory from monkeys of the Zik forest (Uganda) in 1947. The first human infection was recorded in 1968 (Nigeria). From 1951 to 1982, serological cultures of the virus were detected in India and Egypt. Since 2007, there has been an eastern popularization of the virus - New Caledonia, Easter and Cook Islands, South and Central America, Africa. In 2007, the disease was given pandemic status.
The causative agent is the Flavivirus virus, which causes the same type of disease. The source of infection is monkeys. The infection is transmitted by blood-sucking insects, and transmission through blood, natural secretions, and sexual contact cannot be ruled out.
The incubation period lasts no more than two weeks. The first signs of the disease are rashes on the body, fever, aches, joint pain, swelling of the limbs. There are no indicators of severe intoxication.
In the modern world, there are still no specific drugs to treat viral infections. The disease is not fatal, but has a pronounced degree of neurotropism (affects nerve and neural stem cells). As a complication, it causes microcephaly.
Lassa virus (Lassa fever)
The infection is characterized by a severe course, damage to the respiratory organs, hemorrhagic consequences, and a high percentage of deaths.
The causative agent is the Lassa mammarenavirus virus, officially recognized as one of the most dangerous to humans. The source of infection is rats. The main localization is Western and Central Africa. The mechanism of transmission of the virus to humans is predominantly fecal-oral (through food, water), aerosol and direct contact.
A patient with Lassa fever is very contagious to others. Infection from humans occurs through blood, natural secretions, and contact. There are known cases of viral infection of medical staff through the instruments they use.
The period of development of the disease lasts from six days to two to three weeks. The patient feels general malaise, fever, and muscle pain. Gradually, lesions of the mucous membranes of the eyes appear (conjunctivitis), an increase in lymph. In 80% of patients, manifestations of ulcerative necrotic pharyngitis of the pharynx are observed; An increase in temperature is accompanied by diarrhea and vomiting. The second week of the disease is characterized by a rash, hemorrhagic bleeding (nasal, uterine, subcutaneous, pulmonary). A severe course is marked by swelling of the face and rapid development of blood loss, general intoxication. Death is highly likely within 10-12 days of illness.
Treatment of patients with Lassa fever is carried out using antiviral drugs, antibiotics, and plasma injection is practiced in the early stages. In severe stages of the disease, mortality reaches 55%.
Protective preventive measures against infection with the Lassa virus include disinfection of premises and quarantine measures for those arriving from localized countries.
Rotavirus (stomach flu)
Due to the presence of 40% of the fatal outcome, the disease caused by is considered dangerous to human life. Children under five years of age are at particular risk of infection.
The causative agent of the disease is the Reoviridae virus, isolated in 1943. Once in the body, it causes severe dehydration followed by intoxication. The occurrence and development of the disease is seasonal – the virus becomes active in the winter.
Focal cases of the disease are most often recorded in nursing homes and preschool institutions. The most famous outbreak of rotavirus infection was recorded in 2005 (Nicaragua - 30% mortality). According to research, it is assumed that the outbreak of rotavirus arose due to a mutation of the virus. Another outbreak of focal infection was previously known in Brazil (1977).
The origins of the virus are unknown. A person can become infected by drinking dirty water, through household appliances, or through close contact with an infected person. The period of development of symptoms of malaise is up to five days.
Symptoms of rotavirus infection
1. Primary – against the background of weakness and loss of strength, an increase in temperature to 40 degrees, vomiting, and the appearance of light yellow clay-like stools.
2. Secondary – signs of dehydration (loss of fluid) worsen; against the background of vomiting and frequent loose bowel movements, there is no appetite, a runny nose and sore throat, dark urine.
Treatment is carried out comprehensively - simultaneous relief of dehydration symptoms, reduction of body intoxication, intravenous fluid administration.
It is used as a prophylactic against rotavirus infection in countries with an insufficient level of medical care and severe signs of unsanitary conditions.
The ranking of the top 10 dangerous viruses on the planet is not final. Which of them is the most dangerous is also impossible to predict. Every day, scientists discover new types of viruses, study their origin and nature, and try to understand how safe they are for human existence.
However, despite high scientific achievements, the problem of human resistance to viruses remains relevant to this day. To preserve our population, constant active opposition to destructive viral diseases is necessary. Therefore, it is very important to know the etiology of the most aggressive, but already familiar to humanity, biological microorganisms.
There is an opinion that previously people got sick much less often, but the truth is that without the necessary level of technological progress, it was impossible to identify some viruses and provide treatment for them. Why, even today, having the opportunity to grow artificial organs and having mastered neurosurgery, humanity has not been able to significantly reduce the list of incurable diseases; moreover, it is increasing due to exposure to radiation, environmental pollution, poor-quality food, as well as the adaptation of viruses and bacteria to antibiotics.
We have collected the deadliest and most persistent pathogens and ranked them the most dangerous viruses in the world for humans, describing the main symptoms, origin and distribution area of each of them. Some have already been almost eradicated through vaccination, and some were the main topic of the evening news just a week ago.
10. Influenza virus A subtype H5N1 (bird flu)
It got its name due to the killing of huge populations of poultry in Southeast Asia, from where it spread throughout the planet. The greatest damage was caused to countries with poorly developed medicine or suffering from an influx of migrants. Initially it affected all types of animals besides humans, but soon reached us. It began as a regular flu, with a cough and fever, and was able to take the lives of about half of those infected only because, due to symptoms typical of a cold, they avoided going to the hospital and tried to solve the problem on their own. The spread was stopped by vaccination, because if the immunity copes with the first hit of the strain, then subsequently you lose the chance of becoming infected, with the exception of rare mutations.
9. Luho fever
On the ninth line of the ranking of the most dangerous viruses for humans in the world is a fever that is not inferior in aggressiveness even to Ebola. The only thing that has prevented the epidemic is the complex method of transmission - exclusively tactile contact. The first victim was a travel agent, followed by her four doctors. The main symptoms are heavy bleeding, coma and failure of internal organs, but it has not yet been possible to establish either the causes of its occurrence or ways to combat the disease, because it is relatively young - less than six months have passed since its discovery.
8. Cercopithecus (simian) herpes virus B
About 70 percent of macaques are considered carriers of this disease. It is extremely easy to become infected; all you need to do is get a scratch, or get a primate’s saliva on your skin, after which you will develop symptoms of ordinary herpes. After a few days, the rash will go away, but there is no way back - herpes B has already settled in the nerve cells, first a cough and runny nose will appear, which will be replaced by tremors and loss of consciousness. A total of 17 human cases of infection were reported, 15 of which were fatal. The only saving grace is that it is transmitted by airborne droplets only in monkeys; people need closer contact, which is quite easy to avoid.
7. Dengue fever
Every year, about 50 million people in Central Africa are infected, which makes dengue fever one of the most dangerous viruses in the world for humans. There are two types: classic and hemorrhagic, and if the first can be treated extremely effectively, then the second will give you a 50% chance of survival. Carriers are mosquitoes and bats, as well as primates. The good news is that only areas near the equator are favorable conditions for spread, meaning it is extremely difficult to get sick as a European.
6. Rabies virus
In the Middle Ages, when diagnostics in medicine was just emerging, it was assumed that a person was possessed by demons, hence the name, although in practice this is an extremely aggressive form of inflammation of the brain, which first disrupts the functioning of the nervous system, clouding the mind, and then finishes off through the failure of internal organs. Everyone, without exception, is vaccinated against rabies at an early age, which significantly increases the effectiveness of treatment after bites of infected animals, but you should still go to the nearest hospital immediately. In general, the prognosis is positive, but if you delay it, then after 8 days you can already find yourself on your deathbed.
5. H1N1 virus (Spanish flu)
The number of victims of this disease, which originated in Spain and immediately affected about half of its population, not even passing through the royal family, was twice as large as the bloodiest war in human history. The worst thing is that there was no treatment for the disease as such; recovery depended on the strength of the immune system of each individual person, his diet and compliance with hygiene standards. The name originated during the First World War, where the leading bloody battles of the country decided to avoid news of the epidemic, and neutral Spain decided to take this desperate step, thereby allowing its citizens to take the necessary precautions, but still lost one and a half percent of the total population. In some cities, gravediggers died so often that people organized mass graves on their own.
4. Ebola
West Africa in 2014 attracted the attention of the world community, because an extremely rare, but almost always lethal virus was raging there. After an outbreak that killed about 15 thousand people, the World Health Organization recognized it as a global threat and began searching for a vaccine, which to this day has not been successful, which is extremely unfortunate, because in the case of a response to treatment with antiviral drugs within 7 days after infection , the chances of survival are only 4%. In Europe, Ebola fever has not become widespread due to the high level of medical care, water filtration and significant distance from natural sources of spread. This virus was first discovered in the Ebola River area (Democratic Republic of Congo) 12 years ago, where the first victims of the disease were registered.
3. Smallpox virus
Fortunately, the third of the most dangerous viruses for humans in the world was completely eradicated three decades ago, although its manifestations have been recorded in literature since the time of Alexander the Great. But in 1964, a worldwide smallpox vaccination campaign was launched, and by the end of the eighties, the disease was completely defeated. The last victim was one of the laboratory assistants in the United States in May 1978. The fact is that someone did not pay enough attention to ventilation, and the room in which she worked was not properly ventilated. Let us remember that there is no cure for this virus today, and death from smallpox occurs just a few days after infection. Smallpox spread throughout the world during the era of the slave trade, when it was brought from Africa.
2. Marburg hemorrhagic fever
Very similar to Ebola, but much more treatable. The gateways to the body are the mucous membranes of the nose and eyes, as well as small wounds. It all starts with a sharp increase in temperature, then cirrhotic liver damage and disruption of the nervous system occur. It is when neuralgic symptoms appear that the greatest mortality rate is observed; people lose consciousness and never come to their senses. Mortality rates range from 50 to 90 percent. The body of a person who died of Marburg fever poses a biological hazard even three months after burial. Another problem is the possibility of asymptomatic fever during the first few days, which significantly reduces the chances of a positive treatment outcome.
1. HIV virus (AIDS)
The most dangerous virus in the world continues to claim millions of lives every year. The first victims among the population of civilized countries were homosexuals and drug addicts, which for a long time distracted attention from his research, spreading the erroneous assumption that it was lifestyle that led to such a significant deterioration in the functioning of the immune system. In 2008, French scientists received a Nobel Prize for the discovery of the human immunodeficiency virus, and in 2015, for the first time, they succeeded in completely curing a child born from an HIV-positive mother from AIDS. Unfortunately for our country, the epidemic of this virus is gaining momentum in the Yekaterinburg region, and the total number of infected people in the country is about 1 million 100 thousand people. Therefore, try to avoid questionable sexual relations, drug use, and trust only those beauty salons that comply with the standards of sterilization of instruments.
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.
10 Hantaviruses
Hantaviruses are a genus of viruses that are 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 probable cause of the epidemic in the 16th century that exterminated the Aztec people.
9 Influenza virus
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).
8 Marburg virus
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.
7 Rotavirus
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.
6 Ebola virus
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.
5 Dengue virus
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.
4 Smallpox virus
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.
3 Rabies virus
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.
2 Lassa Virus
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.
1 Human immunodeficiency virus
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 have become infected with HIV throughout the world, of which 25 million have died, and 35 million continue to live with the virus.
How are representatives of the microcosm related to each other - viruses and bacteria? Can they be considered enemies, friends, blood relatives or partners? Let's understand their interaction and role in the human body.
Most often, a person becomes acquainted with viruses and bacteria during the cold season. Acute respiratory infections are one of the most common diseases in the world. Most of these diseases occur due to viruses and bacteria that enter the human body along with inhaled air and settle on the mucous membranes of the nose or mouth 1 .
To understand the infection process, we can give an analogy with any public institution, which in our case is the human body. Through open doors, various guests - viruses and bacteria - enter the establishment. Some bacteria are intelligent people and do no harm, while some are strictly prohibited from entering: they can provoke a real conflict. As for viruses, these are, for the most part, bandits. You shouldn't expect anything good from them.
There is a security system against undesirable persons outside and inside the establishment - human immunity. Sometimes the immune system does not cope with its tasks, gets tired or is “distracted” by bacteria, allowing dangerous viruses to enter, which immediately begin a raider takeover.
So what is the main difference between them? First, you need to clearly understand what they are, and based on this, determine the difference and the principle of their effect on the body.
What are viruses
A virus is a tiny organism that can exist and reproduce only inside living cells. In the external environment, the virus is found in microparticles of biological material, but multiplies exclusively in the cells of living beings. In other words, the virus is not active until it is inside a person 2 .
And he gets there like this:
- Airborne, like most respiratory infections
- When drinking dirty water, with food, or not following hygiene rules
- From mother to unborn child
- Contact – in close contact through the skin or mucous membranes
- Parenterally - bypassing the gastrointestinal tract, by injection
After entering the body, the virus first attaches to the cell, then delivers its biological genome into it, loses its envelope, and only then multiplies. After reproduction, the virus leaves the cell, and the infectious agent spreads along with the blood, continuing total infection. Viruses can suppress the immune system 2.
What are bacteria
A bacterium is a complete, albeit single-celled, organism. It can reproduce through division, which is what it actively does in nature or within humans 3 .
Not all bacteria cause infectious diseases. Some are beneficial and live in the organs of the body. For example, lactic acid or bifidobacteria, which live in the intestines and gastric tract, are actively involved in human life and actually form part of his immune defense 3 .
The entry of bacteria into the body follows the path of viruses. But bacteria multiply more often outside the cell than inside it. The list of diseases that develop as a result of their penetration into the human body is extremely long. Bacteria can cause 3:
- Respiratory diseases (most often caused by staphylococci and streptococci)
- Gastrointestinal infections (caused by Escherichia coli and enterococci)
- Damage to the nervous system (sometimes caused by meningococci)
- A number of diseases of the reproductive system, etc.
By multiplying, they spread through the bloodstream, which leads to generalization of the infection and clinical worsening of the patient’s condition. Bacteria can also suppress the immune system, making it harder for the body to resist viruses 3 .
How does a virus differ from a bacterium?
Thus, both viruses and bacteria are capable of infecting the body, causing infection. The key difference between them is in the reproduction mechanism. Viruses cannot reproduce in the external environment, so they need to invade the cell. Bacteria reproduce by division and can live in the external environment for a long time, waiting to enter the human body. Accordingly, the mechanisms for antibacterial and antiviral protection should also differ 4 .
Let's summarize briefly. The differences between a virus and a bacteria are as follows:
- Size and form of existence. A virus is the simplest life form, a bacterium is a single-celled living creature.
- Life activity. The virus exists only inside the cell and infects it, after which reproduction (cloning) occurs. The bacterium lives a full life, reproducing by division, and the body for it is only a favorable place of existence.
- Form of manifestation. Viruses tend to manifest themselves by increased body temperature, general weakness, muscle and joint pain. Bacteria manifest themselves as unhealthy discharge (purulent or as a specific plaque).
Typical viral diseases: ARVI, influenza, herpes, measles and rubella. These also include encephalitis, hepatitis, smallpox, HIV, etc.
Typical bacterial diseases: syphilis, whooping cough, cholera, tuberculosis, diphtheria, typhoid and intestinal infections, STIs.
It happens that both of them cause one disease together. Such a symbiosis requires special treatment. Examples include: sinusitis, tonsillitis, meningitis, pneumonia and other diseases 5.
Fighting viruses and bacteria
It is impossible to completely protect yourself from viruses and bacteria. A person is constantly attacked by a huge number of microorganisms and the main barrier to their path is immunity. Therefore, it is important to strengthen and keep the immune system in a “fighting” state, especially during the cold season and during periods of seasonal diseases.
The immunomodulator IRS®19 will become an assistant on the path to a healthy and strong immune system. It contains a mixture of bacterial lysates, which are specially isolated parts of pest bacteria. Lysates activate the immune system and direct it to fight bacteria and viruses. The drug has a high level of safety and can be prescribed to prevent infections in adults and children over 3 months of age. It has been tested many times and has shown excellent results in the fight against infections, including ARVI 6.
There are a myriad of microorganisms in the world, viruses predominate among them. They can survive in the harshest conditions. Viruses have been found in the eternal ice of Antarctica, in the hot sands of the Sahara, and even in the cold vacuum of space. Although not all of them pose a danger, more than 80% of all human diseases are caused by viruses.
Back in the 40s of the last century, humanity knew about 40 diseases provoked by them. Today this figure is more than 500, not counting the fact that new species are discovered every year. People have learned to fight viruses, but knowledge is not always enough - more than 10 of their types remain the most dangerous for humanity. Viruses are causative agents of dangerous human diseases. Let's look at the main ones.
Hantaviruses
The most dangerous type of virus is hantavirus. When contacting small rodents or their waste products, there is a possibility of becoming infected. They can cause many diseases, the most dangerous of which are hemorrhagic fever and hantavirus syndrome. The first disease kills every tenth person, the probability of death after the second is 36%. The largest outbreak occurred during the Korean War. Then more than 3,000 soldiers from different sides of the confrontation felt its effect. There is a strong possibility that the hantavirus caused the extinction of the Aztec civilization 600 years ago.
Ebola virus
What other dangerous viruses exist on Earth? The epidemic created panic in the world community just a year ago. The virus was discovered in 1976, during an epidemic in the Congo. It got its name in honor of the pool in which the outbreak occurred. Ebola disease has many symptoms, making it difficult to diagnose. The most common of them include: increased body temperature, general weakness, vomiting, impaired liver and kidney function, sore throat. In some cases, internal and external bleeding is observed. In 2015, this virus took the lives of more than 12 thousand people.
How dangerous is the influenza virus?
Of course, no one would argue that the dangerous virus is an ordinary flu. More than 10% of the world's population suffers from it every year, making it one of the most common and unexpected.
The main danger to people is not the virus itself, but the complications it can cause (kidney disease, pulmonary and cerebral edema, heart failure). Of the 600 thousand people who died from the flu last year, only 30% of deaths were caused by the virus itself; the rest were the result of complications.
Mutations are another danger of the influenza virus. Due to the constant use of antibiotics, the disease becomes stronger every year. Chicken and swine flu, epidemics of which have broken out over the past 10 years, are yet another confirmation of this. In the worst-case scenario, in a few decades, drugs that can fight influenza will pose an extreme danger to humans.
Rotavirus
The most dangerous type of virus for children is rotavirus. Although the medicine for it is quite effective, about half a million babies die from this disease every year. This disease causes acute diarrhea, the body quickly becomes dehydrated and death occurs. Most of those affected live in underdeveloped countries where it is difficult to obtain a vaccine against this virus.
Deadly Marburg
The Marburg virus was first discovered in the city of the same name in Germany in the late 60s of the last century. It is one of the top ten deadly viruses that can be contracted from animals.
About 30% of diseases with this virus are fatal. In the early stages of this disease, a person suffers from fever, nausea, and muscle pain. In more severe cases - jaundice, pancreatitis, liver failure. The disease is transmitted not only by humans, but also by rodents, as well as some species of monkeys.
Hepatitis in action
What other dangerous viruses are known? There are more than 100 types of them that affect the human liver. The most dangerous of them are hepatitis B and C. It is not for nothing that this virus is nicknamed the “gentle killer”, because it can remain in the human body for many years without causing noticeable symptoms.
Hepatitis most often leads to the death of liver cells, that is, cirrhosis. It is almost impossible to cure the pathology caused by strains B and C of this virus. By the time hepatitis is detected in the human body, the disease, as a rule, is already in a chronic form.
The discoverer of this disease was the Russian biologist Botkin. The strain of hepatitis he found is now called “A”, and the disease itself is treatable.
Smallpox virus
Smallpox is one of the oldest diseases known to mankind. It only affects humans, causing chills, dizziness, headaches and lower back pain. A characteristic sign of smallpox is the appearance of a purulent rash on the body. Over the past century alone, smallpox has killed nearly half a billion people. Enormous amounts of material resources (about $300 million) were used to combat this disease. Yet virologists have achieved success: the last known case of smallpox was recorded forty years ago.
Deadly rabies virus
The rabies virus is the first of this rating, leading to death in 100% of cases. You can become infected with rabies after being bitten by a sick animal. The disease is asymptomatic until the time when it is no longer possible to save the person.
The rabies virus causes severe damage to the nervous system. In the last stages of the disease, a person becomes violent, experiences a constant feeling of fear, and suffers from insomnia. A few days before death, blindness and paralysis occur.
In the entire history of medicine, only 3 people have been saved from rabies.
Lassa virus
What other dangerous diseases are known? The virus caused by this virus is one of the most dangerous diseases in West Africa. It affects the human nervous system, kidneys, lungs, and can cause myocarditis. During the entire period of illness, body temperature does not fall below 39-40 degrees. Many painful purulent ulcers appear on the body.
Lassa virus is transmitted by small rodents. The disease is transmitted by contact. Every year, about 500 thousand people become infected, of which 5-10 thousand die. In severe forms of Lassa fever, the mortality rate can reach 50%.
Human acquired immunodeficiency syndrome
The most dangerous type of virus is HIV. It is considered the most dangerous of those known to man at this time.
Experts have found that the first case of transmission of this virus from a primate to a human occurred in 1926. The first death was recorded in 1959. In the 60s of the last century, symptoms of AIDS were discovered in American prostitutes, but then they did not attach much importance to this. HIV was considered simply a complex form of pneumonia.
HIV was recognized as a separate disease only in 1981, after the outbreak of an epidemic among homosexuals. Just 4 years later, scientists figured out how this disease is transmitted: blood and seminal fluid. The real AIDS epidemic in the world began 20 years ago. HIV is rightly called the plague of the 20th century.
This disease primarily affects the immune system. As a result, AIDS itself does not lead to death. But an HIV-infected person who simply lacks immunity can die from a simple runny nose.
All attempts to invent it to date have failed.
How dangerous is the papilloma virus?
About 70% of people are carriers of the papilloma virus, most of them are women. Papilloma is transmitted sexually. Of the more than 100 types of papilloma virus, about 40 lead to various diseases. As a rule, the virus affects the human genitals. Its external manifestation is the appearance of growths (papillomas) on the skin.
The incubation period of the virus after entering the body can last from several weeks to several years. In 90% of cases, the human body itself will get rid of foreign microbodies. The virus is dangerous only for weakened immune systems. Therefore, papilloma often appears during other illnesses, such as influenza.
The most serious consequence of papilloma can be cervical cancer in women. 14 known strains of this virus are highly oncogenic.
Is bovine leukemia virus dangerous for humans?
Viruses can infect not only people, but also animals. Since humans eat animal products, the question of the danger of such pathogens to humans is increasingly being raised.
The leukemia virus is in first place in terms of damage. It infects the blood of cows, sheep, goats and provokes serious illnesses, and in some cases, death.
Research shows that more than 70% of people have antibodies in their blood that can fight the bovine leukemia virus. However, this does not exclude the possibility of human infection with this virus. The likelihood that bovine leukemia can lead to blood cancer in humans is very low, but there is the possibility of other negative consequences. The leukemia virus can attach to human cells, causing mutations. In the future, this may create a new strain of it, which will be equally dangerous for both animals and humans.
Although viruses can benefit people, this does not outweigh their harm. More people have died from them than have died in all the world's wars throughout time. This article listed the most dangerous viruses in the world. We hope you find this information useful. Be healthy!