A person is most susceptible to various colds in the autumn and spring. Viral infectious diseases are a type of disease that is caused by an infection that has penetrated into a weakened body. They can wilt in an acute form or sluggish, but treatment must be carried out in both cases, so as not to aggravate the situation, to avoid dangerous complications. On average, a person suffers from 2 to 3 times a year with colds, but the development of the disease always gets due to viral DNA.
Types of viruses
Symptoms of pathology can cause different types bacteria that differ in the place of localization, rate of development, signs. Human viruses have a special classification, conventionally they are divided into rapid and slow. The second option is very dangerous in that the symptoms are very weak and it is not possible to immediately detect the problem. This gives her time to multiply, to strengthen. Among the main types of viruses, the following groups are distinguished:
- Orthomyxoviruses- all influenza viruses.
- Adenoviruses and Rhinoviruses. They provoke ARVI - an acute respiratory viral infection that affects the respiratory system. Symptoms are very similar to those of the flu, can cause complications (bronchitis, pneumonia)
- Herpesviruses- herpes viruses that can long time live in the body asymptomatically, they are activated immediately after weakening of the immune system.
- Meningitis. It is provoked by a meningococcal infection, the mucous membrane of the brain is damaged, the virus feeds on cerebrospinal fluid (cerebrospinal fluid).
- Encephalitis- affects the lining of the brain, provokes irreversible disturbances in the work of the central nervous system.
- Parvovirus, which is the causative agent of poliomyelitis. A very dangerous disease that can cause convulsions, spinal cord inflammation, paralysis.
- Picornaviruses- causative agents of viral hepatitis.
- Orthomyxoviruses- cause mumps, measles, parainfluenza.
- Rotavirus- cause enteritis, intestinal flu, gastroenteritis.
- Rhabdoviruses- pathogens of rabies.
- Papoviruses- the cause of human papillomatosis.
- Retroviruses- AIDS pathogens, first HIV develops, and then AIDS.
List of human viral diseases
Medicine knows a huge number of infectious viruses and infections that can provoke various diseases in the human body. Below are only the main groups of diseases that are likely to be encountered:
- One of the most voluminous groups of viral diseases - flu (A, B, C), different types of colds that cause inflammation in the body, high fever, general weakness and sore throat. Therapy is carried out with the help of fortifying agents, antiviral drugs, if necessary, antibacterial medicines are prescribed.
Complex remedies help to eliminate unpleasant symptoms of influenza and SARS, to maintain efficiency, but often contain phenylephrine, a substance that increases blood pressure, which gives a feeling of vigor, but can cause side effects from the cardiovascular system. Therefore, in some cases it is better to choose a drug without components of this kind, for example, AntiGrippin from Natur Product, which helps to alleviate the unpleasant symptoms of influenza and SARS without provoking an increase in pressure.
There are contraindications. It is necessary to consult a specialist.
- Rubella. A common childhood pathology, less common in adults. Symptoms include damage to the membranes of the respiratory tract, skin. eyes, lymph nodes. The virus is transmitted by droplets, always accompanied by high fever, skin rashes.
- Piggy. A dangerous viral disease affecting the respiratory tract, the salivary glands are severely affected. Rarely in adult males, testes have been affected by this virus.
- Measles- often found in children, the disease affects the skin, respiratory tract, intestines. It is transmitted by airborne droplets, the causative agent is paramyxovirus.
- Poliomyelitis (infantile paralysis). Pathology affects the respiratory tract, intestines, then enters the bloodstream. Further, motor neurons are damaged, which leads to paralysis. The virus is transmitted by droplets, sometimes a child can become infected through stool. In some cases, insects are the vectors.
- Syphilis. This disease is sexually transmitted, it affects the genitals. Then it affects the eyes, internal organs and joints, heart, liver. Antibacterial agents are used for treatment, but it is very important to determine the presence of pathology immediately, because it may not cause symptoms for a long time.
- Typhus. It is rare, characterized by a rash on the skin, damage to the blood vessels, which leads to the formation of blood clots.
- Pharyngitis. The disease provokes a virus that enters the human body along with dust. Cold air, streptococci, staphylococci can also provoke the development of pathology. A viral illness is accompanied by fever, cough, sore throat.
- Angina- a common viral pathology, which has several subspecies: catarrhal, follicular, lacunar, phlegmonous.
- Whooping cough... This viral disease is characterized by damage to the upper respiratory tract, laryngeal edema is formed, and severe coughing fits are observed.
The rarest human viral diseases
Most viral pathologies are infectious diseases that are sexually transmitted, airborne. There are a number of diseases that are extremely rare:
- Tularemia. Pathology in its symptoms strongly resembles the plague. Infection occurs after penetration into the body Francisella tularensis is an infectious bacillus. As a rule, it gets in with the air or when bitten by a mosquito. The disease is transmitted from a sick person.
- Cholera. This disease is very rare in modern medical practice. Vibrio cholerae virus, which enters the body through dirty water, contaminated food, causes symptoms of pathology. The last outbreak of pathology was recorded in 2010 in Haiti, the disease claimed the lives of more than 4500 people.
- Creutzfeldt-Jakob disease. A very dangerous pathology that is transmitted through the meat of infected animals. The causative agent is prion - a special protein that begins to actively destroy the cells of the body after penetration. The insidiousness of pathology lies in the absence of symptoms, a person begins to have a personality disorder, severe irritation, dementia appears. It is impossible to cure the disease and the person dies within a year.
Symptoms of the virus
Symptoms do not always appear immediately, some types of viral diseases can proceed for a long time without obvious signs, which becomes a problem with further treatment. Each infectious disease goes through the following stages:
- incubation period;
- premonitory;
- the height of pathology;
- recovery.
The duration of the first stage always depends on the specific type of virus and can last from 2-3 hours to six months. Symptoms will differ depending on the developing disease, but, as a rule, the following manifestations are attributed to the general symptoms of viral pathologies:
- soreness, muscle weakness;
- slight chills;
- persistent body temperature;
- sensitivity of the skin to touch;
- cough, sore throat, watery eyes;
- dysfunction of some organs;
- swollen lymph nodes.
Temperature with a viral infection
This is one of the main reactions of the body to the penetration of any pathogen. Temperature is a defense mechanism that activates all other immune functions to fight viruses. Most of the diseases occur with a high body temperature. The viral pathologies that provoke this symptom include:
- flu;
- ARVI;
- tick-borne encephalitis;
- childhood diseases: chickenpox, mumps, rubella, measles;
- polio;
- Infectious mononucleosis.
Often there are cases of development of diseases for which the temperature does not rise. The main symptoms are watery compartments with a runny nose, sore throat. The lack of temperature is explained by the insufficient activity of the virus or the immune system is strong, therefore, it does not fully use all possible methods of fighting the infection. If the growth has begun, then high rates are maintained, as a rule, for about 5 days.
Signs
Most viruses provoke the development of acute respiratory pathologies. There are some difficulties in identifying diseases that were caused by bacteria, because the treatment regimen in this case will be very different. There are more than 20 types of viruses that cause SARS, but their main symptoms are similar. The primary signs include the following manifestations:
- rhinitis (runny nose), cough with clear mucus;
- low temperature (up to 37.5 degrees) or fever;
- general weakness, headaches, poor appetite.
How to tell a cold from a virus
There is a difference between the two. A cold occurs during prolonged exposure to the cold, severe hypothermia of the body, which leads to a weakening of immunity and the appearance of an inflammatory process. This is not the name of the disease, but only the reason for the development of other pathologies. Viral pathology often becomes a consequence of a cold, because the body does not have enough defenses to resist the pathogen.
Virus diagnostics
When contacting a doctor, he should conduct a visual examination and take an anamnesis. Usually. viral diseases are accompanied by fever, cough, runny nose, but after 3-4 days a person feels an improvement. Specialists can determine the type of disease based on general symptoms or based on seasonal outbreaks of diseases, for example, flu epidemics often begin in winter, and SARS in autumn. Determining the exact type of virus will be required for specific treatment (HIV, syphilis, etc.). For this, virological research is used.
This method in medicine is the "gold standard", which is carried out in a special laboratory. As a rule, such methods are used during epidemic outbreaks of viral infectious diseases. Methods of immunodiagnostics (immunoindication, serodiagnostics) are widely used for diagnosing pathogens. They are realized through a variety of immune responses:
- enzyme immunoassay (ELISA);
- radioisotope immune analysis (RIA);
- hemagglutination inhibition reaction;
- complement fixation reaction;
- immunofluorescence reaction.
Treatment of viral diseases
The course of therapy is, depending on the type of pathogens. For example, if it is necessary to treat ARVI, childhood viral pathologies (mumps, rubella, measles, etc.), then all medications are used to eliminate symptoms. Subject to bed rest, the diet, the body itself copes with the disease. Treatment of viruses is carried out in cases where they cause significant discomfort to a person. Apply for example:
- antipyretics, if the temperature is above 37.5 degrees;
- vasoconstrictor drops are used to relieve nasal edema;
- in rare cases, antibiotics (if a bacterial infection has joined);
- NSAIDs that relieve pain and lower fever, such as aspirin, paracetamol, ibuprofen.
During treatment, doctors recommend drinking more fluids in order to fight intoxication of the body, moderate nutrition, bed rest and humidity in the room of at least 50% where the patient is. Therapy for influenza is no different, but the doctor must be sure to monitor the patient, because this disease can cause serious consequences. One of them is pneumonia, which can lead to pulmonary edema and death.
If such complications have begun, then treatment must necessarily be carried out in a hospital with the use of special medications (Zanamivir, Oseltamivir). When the human papillomavirus is digested, the therapy consists in maintaining immunity in good shape, surgical removal of warts, and genital warts. In cases of severe viral pathologies. For example, HIV, a course of antiretroviral drugs is needed. It cannot be completely eliminated, but you can keep it under control and prevent the spread of the disease.
In case of infection with herpes of the genitals, it is necessary to take special drugs, their maximum effectiveness is confirmed in the first 48 hours. If you use the funds later, their medicinal effect is significantly reduced and the course of treatment can last from several weeks to several months. Herpes on the lips should be treated with local remedies (ointments, gels), but even without them, the wound heals within a week.
Antiviral drugs
In medicine, there is a certain number of medicines of this group, which have proven their effectiveness and are used constantly. The entire list of drugs is conventionally divided into two types:
- Medicines that stimulate human immunity.
- The drugs that attack the detected virus are direct-acting drugs.
The first group refers to broad-spectrum drugs, but their use leads to serious complications. One example of such drugs is interferons, and the most popular of them is interferon alpha-2b. It is prescribed for the treatment of chronic forms of Hepatitis B, previously it was prescribed for hepatitis C. Patients could hardly tolerate such therapy, which led to side effects from the central nervous system, cardiovascular system. In some cases, pyrogenic properties are manifested - they cause fever.
The second type of drugs PPD is more effective, easier to tolerate by patients. Among the drugs in demand, the following treatment options are distinguished:
- Herpes- acyclovir. It helps to overcome the symptoms of the disease, but does not completely kill it.
- Flu- influenza neuraminidase inhibitors (Zanamivir, Oseltamivir). To the previous drugs (adamantanes), modern strains of influenza have developed resistance, and they are not effective. Name of drugs: Relenza, Ingavirin, Tamiflu.
- Hepatitis... For the treatment of group B viruses, interferons are used together with Ribavirin. For hepatitis C, a new generation of drugs is used - Simeprevir. Its effectiveness reaches 80-91% of a persistent virological response.
- HIV... It cannot be completely cured, antiretroviral drugs provide a lasting effect, cause remission, and a person cannot infect others. The therapy is lifelong.
Prophylaxis
Preventive measures may differ slightly depending on the type of virus. For example, to prevent infection with hepatitis or HIV, you need to protect yourself during sexual intercourse. There are two main areas of prevention of viral diseases:
- Specific... It is carried out to develop specific immunity in humans through vaccination. A person is injected with a weakened strain of the virus so that the body develops antibodies to it. This will help protect you from people with measles, flu, polio, hepatitis (liver disease). Most life-threatening diseases can be prevented with vaccines.
- Nonspecific... Strengthening human immune defenses, healthy lifestyle, physical activity and normal nutrition. A person must follow the rules of hygiene, which will protect him from intestinal infections, protect himself during sexual intercourse in order to prevent HIV infection.
Video
They have existed since the dawn of life on Earth. Millions of years ago there were no multicellular organisms, no plants, no animals, but viruses were already flourishing. If there is an apocalypse on our planet, they will still survive. Over the years of evolution, they have been able to adapt to all conditions. They go through mutations over and over again to outsmart their victims.
They developed the ability to pass from species to species and mutated by altering their genetic material. Viruses today are so complex that they cannot be controlled. Over millions of years, they have developed the survival rate so that they are now beginning to win the battle with antibiotics. Today we will touch on the topic of the most deadly strains.
Rotavirus infection
According to the WHO, this merciless virus kills more than half a million children every year. It is believed that by the age of five, almost every child on the planet has had a rotavirus infection at least once. Fortunately, our bodies have learned to develop immunity to this type of strain. Therefore, each subsequent disease proceeds with milder symptoms.
However, in countries with poorly developed medicine, the first encounter with a rotavirus can be fatal for a baby. Its strains are capable of living outside the host for a long time. The transmission of bacteria itself can occur through food, water, or through dirty hands that come into contact with an infected surface. Once the rotavirus enters the body, it infects the cells lining the small intestine. Further, inflammatory processes become the cause of gastroenteritis.
Ebola fever
Ebola is a rare disease and usually does not claim more than 100 lives a year. This virus rarely spreads outside Africa, but it is dangerous because there is no vaccine and no effective treatment against it. In addition, an Ebola outbreak was reported in West Africa in March 2014, killing nearly 2,000 people. This number exceeded all previous lethal cases of the virus, which caused a great resonance in the scientific world.
After a person becomes infected through fluids or body fluids, an incubation period of 2 to 21 days begins. The danger of this virus lies in the fact that often its initial stage is asymptomatic. Later, general malaise, headache, muscle spasms, high fever, vomiting, hemorrhage in the eyes and on the oral mucosa are observed. According to statistics, in 50-90% of patients, death occurs within a few days. The likelihood of death is determined by the virulence of a particular Ebola strain.
HIV
The human immunodeficiency virus kills more than 3 million lives every year. In total, from 1981 to the present day, more than 25 million people have died from HIV. The disease is relatively new and enters the immune system through mucous membranes and blood. Important cells of the immune system, including macrophages and dendritic cells, are soon attacked. This leads to a complete weakening of the immune system, and most people with HIV develop AIDS. In the latter stages of the disease, patients are more likely to die from pneumonia and different types herpes.
Smallpox
Medicine officially defeated smallpox, but we could not ignore the terrible disease that killed 300-500 million people in the 20th century alone. An acute infectious disease is localized in the small capillaries of the skin, in the mouth and throat. This leads to the appearance of the characteristic rash, and later to purulent blisters. Smallpox is believed to have developed in humans around 10,000 BC. NS.
This disease did not spare even the monarchs and was responsible for a third of cases of blindness. The survival rate was only 20 percent, and the survivors had ugly scars on their body and face for life. After a series of large-scale vaccinations around the world during the 19th and 20th centuries, WHO certified smallpox eradication in December 1979. Note that by this time, mankind has managed to completely defeat only two infectious diseases.
Hepatitis B
Hepatitis B causes more than half a million deaths every year. A third of the world's population has come into contact with this virus, including 350 million chronic carriers. In China and other parts of Southeast Asia, up to 10% of the adult population is carriers. Symptoms of the disease include yellowness of the skin and eyes, dark urine, nausea, vomiting, chronic fatigue, and abdominal pain. Scientists estimate that 95% of those infected develop immunity. This disease would not be so harmless if it did not provoke chronic liver failure, cirrhosis and liver cancer.
Flu
It seems to us that the flu is harmless, but it is not. Its constantly mutating strains claim the lives of half a million people every year. Now we have effective vaccines and new generation antiviral drugs. But in the history of mankind, the flu is known as a very effective killer. The symptoms of this disease were first described by Hippocrates over 2,400 years ago. Pandemics were recorded approximately three times during each century, resulting in millions of deaths.
The pandemic of the Spanish flu in 1918 is considered a record outbreak, which, according to various expert estimates, killed 20 to 100 million people. Influenza strains can easily enter the host's body through airborne droplets or through dirty hands. As soon as the protein membranes of the virus cling to cells in the respiratory tract, they immediately kill them. This leads to symptoms of cough, runny nose and sore throat. Too many damaged cells in the lungs are fatal.
Rabies
Rabies could be the deadliest condition on this list if it weren't for successful PEP. Medicine has invented an effective injection against the zoonotic virus transmitted through the bite of an animal. The incubation phase of rabies can take several months before microorganisms reach the central nervous system. Symptoms of rabies include acute pain, depression, uncontrollable agitation, and inability to drink water.
Hepatitis C
Experts estimate that approximately 300 million people worldwide are infected with the hepatitis C virus. Most of those infected do not show any symptoms for several years. Over time, however, liver damage begins to manifest itself. Modern medicine practices organ transplants so that patients with chronic liver disease do not die of cirrhosis or cancer.
Measles
Despite the invented vaccine, measles still takes the lives of people (about 200 thousand a year). This sad statistic continues thanks to Third World countries whose citizens are malnourished, have weak immunities and do not receive adequate medical care. Over its long history, the disease has killed more than 200 million unfortunate people. To date, 21 strains of measles virus have been identified.
Hantavirus infection
Hantavirus infection, transmitted by infected rodents, accounts for about 70,000 deaths a year. This virus is considered dangerous, albeit rare. Its symptoms include tachycardia and tachypnea, which lead to cardiovascular shock.
Yellow fever
This acute viral disease is transmitted through the bite of infected female mosquitoes and occurs only in the subtropics. Yellow fever is native to Africa, from where it spread to South America through the slave trade in the late 16th century. In the 19th century, this virus was considered one of the most dangerous, but now medicine has effective vaccines and means of protection against mosquitoes.
Light cough - often it is with him that diseases begin, outbreaks of epidemics and even pandemics, which can spread across entire continents. However, modern medicine and hygiene practices have enabled us to fight back the most destructive infections.
Today it seems that we are in control of the epidemic situation. Indeed, mankind has coped, for example, with smallpox, poisoned the plague and other deadly dangers. However, most infections are still with us, periodically manifesting themselves in the poorest (and therefore vulnerable) countries.
What infectious diseases have claimed the greatest number of lives on our planet? What kind of infections has humanity suffered more than from all the wars that have ever been on Earth?
And another, most important question: what infections can become potential killers of humanity? What infectious diseases now claim millions of lives every year? We offer you a list of 27 of the most famous and terrible infectious diseases.
Smallpox
From three hundred to five hundred million lives - approximately this number of people was taken with smallpox (also called natural smallpox) in only one of the 20th century. One of the last most severe outbreaks of this terrible disease was recorded in Bangladesh in 1973. In a hospital in Dhaka, the capital of Bangladesh, the death rate was 46 percent. In 1959, there was a small outbreak of smallpox in Moscow, where the infection got from India (it was "brought" by a citizen of the USSR who visited India). Thanks to the efforts of Soviet doctors, the disease was stopped, although three people still died.
Some scientists believe that smallpox, which leaves characteristic scars on human skin, began its destructive journey from Egypt three thousand years ago. The smallpox virus, which actually causes smallpox, killed at least a third of all those who were infected. The rest were left disfigured.
The World Health Organization (WHO) announced in 1980 that the disease had been completely eradicated thanks to an unprecedented vaccination campaign that took decades. The latest strains of the virus are stored in special centers under certain conditions in Russia and the United States of America.
Plague
Unlike smallpox, this ancient deadly infection is still with us. The flea-borne plague mowed down entire cities in Europe, Asia and North Africa in the 14th century during a pandemic called the Black Pestilence. Plague is of three types, but the most famous form is bubonic plague, which causes painful inflammation of the lymph nodes called buboes. Plague is still found in representatives of the animal world all over the planet, but especially in the west of the United States and in Africa.
In September 2016, WHO reported 783 cases of plague worldwide, 126 of which were fatal. In Russia, the bubonic plague manifested itself quite recently, in Altai, where a 10-year-old boy contracted it through contact with a sick animal. In total, according to historians, in our era, the plague took the lives of about 150 million people (mainly during major epidemics).
Malaria
Despite the fact that malaria is highly preventable and treatable, the infectious disease continues to wreak havoc in Africa. On the mainland, about 20 percent of child mortality is due to this disease. Rabies used to be called fear of hydration since the sound of pouring water causes a spasm, it is impossible to take a sip. To date, medicine knows less than ten cases of survival after a person infected with rabies showed the above symptoms.
Regardless, there is a rabies vaccine that has been shown to be most effective as a preventive measure, and also as a method of treating an infected person before he or she has the symptoms mentioned above.
Rabies has been known to mankind since time immemorial. The specificity of infection (through the saliva of an animal) saved our species from massive pandemics of this infection. However, in our time there are reports of outbreaks of this infection in a number of backward countries or even tribes. Usually the cause is contact with an infected animal.
Pneumonia
usually not as awesome as rabies or bubonic plague, but this lung infection is fatal. Pneumonia is especially dangerous for children under five years old and elderly people over 65 years old. Many people underestimate the danger of pneumonia. If powerful outbreaks of plague have sunk into oblivion, then from lung disease, according to the WHO, in 2015, almost a million children died around the world. In general, this disease claims seven million lives a year, with the number of cases of almost half a billion people.
Rotavirus infection
Rotavirus infection, caused by rotaviruses, is the most common cause of acute gastroenteritis in children with acute diarrhea. This disease, which leads to inflammation of the intestines and stomach, is also fatal. According to the WHO, in 2013, rotavirus killed 215,000 children under the age of five around the world. About 22 percent of deaths occurred in India. This viral infection leads to dehydration of the body as a result of severe diarrhea and vomiting. In total, there are up to 25 million cases of this infection a year in the world; dies from 660 to 900 thousand.
Causative agents of infectious diseases in humans
Ebola
Ebola haemorrhagic fever is a rare but often fatal infection caused by one of five types of Ebolavirus. The virus spreads at a very high rate, overcoming the resistance of the body's immune system and causing fever, muscle pain, headache, weakness, diarrhea, vomiting and abdominal pain. Some people with Ebola have had bleeding from the mouth and nose during advanced stages of the disease, a condition known as hemorrhagic syndrome. The most recent Ebola outbreak occurred in South Africa in 2014; this is the largest outbreak in history to date.
By April 2016, 28,652 cases were known. Of these, almost 11,300 people died. Ebola is spread from person to person through body fluids. There is also a risk of catching the virus through contact with the blood of an infected person, saliva, sweat (or by touching, for example, clothing or bedding that has absorbed an infected substance).
Creutzfeldt-Jakob disease
The name of this disease is not well known to the common man in the street. However, this infection is more familiar as a human variant. mad cow disease... It is a rare but fatal disease and belongs to the group of so-called transmissible spongiform encephalopathies. These infections tend to be transmitted from animals (cattle) to people. The word "spongy" in the name appeared for the reason that infections lead to the degradation of brain tissue and the appearance of characteristic holes in the cerebral cortex, with an increase resembling a sponge.
A person can contract this infection, for example, by eating beef that is infected with bovine spongiform encephalopathy. In fact, this is the same disease, only in animals.
As discussed above, this is a rare infection. Its geography is not particularly tied to backward countries, as is the case, say, with malaria. For example, between 1996 and March 2011, 225 cases of the disease were recorded in the UK. There have been cases of infection in France.
It is noteworthy that until 1996, scientists had no idea that a person could acquire spongiform encephalopathy by eating meat infected with spongiform encephalopathy. Before that, it was only known about the hereditary nature of the disease, as well as that the disease can be introduced into the body of the operated person during brain surgery, in front of the eyes.
For all its non-prevalence, this infection is extremely merciless. It is known that in the case of mild forms of mad cow disease, the patient survival rate is 85 percent. If we are talking about a severe form of this disease, then the death of the sick person is inevitable.
Marburg hemorrhagic fever
Marburg hemorrhagic fever, also known as Marburg disease or green monkey disease, causes a family of so-called filoviruses. They are characterized by the filamentous form of viral particles. The fever itself is transmitted from person to person through body fluids (like Ebola). In general, the Marburg virus has a lot in common with Ebolavirus, which is not surprising, since the latter also belongs to the filovirus family.
A person can contract this disease from bats of the fruit bats. Some of those infected show acute hemorrhagic fever. According to various sources, the mortality rate for this disease ranges from 60 to 90 percent.
This virus was first identified in Germany in 1967. Then the employees of the scientific laboratory, who conducted experiments with monkeys from Uganda, contracted the Marburg disease. As it turned out, monkeys, just like humans, are susceptible to this infection.
But in bats, which are carriers of the virus, it does not cause the corresponding disease (as in the case of Ebola). Despite appropriate treatment, fever leads to serious complications, among which there may be long-term mental disorders.
Middle East respiratory syndrome
Another very "fresh" disease, which has a high mortality rate. For this inflammatory disease of the respiratory tract, humanity should also be "grateful" to bats. In addition, camels are carriers of this virus (also called the Middle East respiratory syndrome coronavirus). For the first time, this disease became known in 2012, after cases of infection in Saudi Arabia. Three years later, WHO published information on 1154 cases of infection in 23 countries of the world, of which 431 cases were fatal.
Some people who become infected with this infection may not show any symptoms. But most often, the infected have a fever, cough, shortness of breath. In more severe cases, there is a failure of the functioning of organs (for example, the kidneys), and respiratory arrest occurs.
An infectious disease that threatens billions of people
Dengue fever
This disease has many names. We may know it by tropical fever... Every year, the virus that causes this disease kills around the world, according to the WHO, about 50 thousand people. It is noteworthy that without the complicity of these two species, a healthy person cannot catch dengue fever from an infected person. Symptoms are initially almost the same as with the flu: the patient has a fever, he coughs, the temperature rises, and chills appear.
In more serious stages, the symptoms become significantly greater. Sometimes the virus leads to a potentially fatal condition known as severe dengue... Dengue haemorrhagic fever causes stomach pain, vomiting, bleeding and shortness of breath.
According to the WHO, an average of 400 million people suffer from dengue fever a year. Some scientists, who are seriously studying the ways of spreading dengue, argue that almost 4 billion people in 128 countries of the world are at risk of spreading this fever.
Yellow fever
Like dengue and other diseases, yellow fever, or amaryllosis, is caused by a virus from the Flaviviridae family - a flavivirus (as in the case of dengue fever). The virus is transmitted from an infected person to a healthy person through the bites of mosquitoes of the genus biters (Aedes) and Haemagogus. This fever got its name due to one of the symptoms (registered, by the way, in a small percentage of people from among the sick) - the appearance of yellowness of the skin and eyes. At the same time, the overwhelming majority of those who have encountered this disease have never encountered such a symptom.
The color of the skin and the white of the eyes changed in those people who had a second, more severe phase of fever, which has a devastating effect on human organs, including the liver and kidneys. According to the WHO, half of the patients in the second phase of yellow fever (hemorrhagic fever) died within seven to ten days.
The mortality rate is quite high with this disease: for two hundred thousand infected, there are 30 thousand deaths. Almost 90% are in Africa. Fortunately, for many people in 47 at-risk countries (including Central and South America), there is a highly effective vaccine against the disease.
This was not the case in the 17th century, when the yellow fever virus, which first appeared in North America and then in Europe, caused severe epidemic outbreaks of the disease, which sent many thousands of people to the next world.
Hantavirus Pulmonary Syndrome
Hantaviruses are spread among humans by rodents (mainly rats and mice). Humans can become infected with Hantavirus Pulmonary Syndrome if they have had direct contact with body fluids from these animals; or if you inhale virus-containing microparticles from rodent droppings that may have entered the air (for example, in a barn or basement). For the first time, the world learned about one of these viruses, most often causing hantavirus pulmonary syndrome (Sin Nombre virus), after it was discovered in the United States in 1993. Then several young people mysteriously died in the southwestern region of the country, called the "four corners".
24 people were hospitalized, of which half later died. Then the world first learned about a new virus, which was later dubbed the Sin Nombre virus (actually, "an unnamed virus" in Spanish), leading to a severe respiratory infection.
Outside the United States — in Asia, Europe, and parts of Central and South America — hantaviruses also cause a serious illness known as hemorrhagic fever with renal syndrome.
The initial symptoms of this disease are similar to those of hantavirus pulmonary syndrome (fever, vomiting, nausea), but it can cause bleeding and kidney failure. The disease is extremely dangerous, since diseases from hantaviruses are ten times more common than rabies, for example.
Spread of infectious diseases
anthrax
(anthrax) belongs to the category of especially dangerous infectious diseases. This infection is caused by the anthrax pathogen, a species of bacteria Bacillus anthracis that lives in the soil. Initially, wild and domestic animals (cattle, sheep, goats, etc.) are infected. A person usually becomes infected in the process of caring for animals, or from animal products. Bacterial spores can penetrate human skin, but sometimes they can breathe them in (for example, when working with animal skins or their fur). The pulmonary form of the disease is much more deadly - death occurs in 92 percent of cases of infection.
Anthrax has been known for a long time. A similar disease was mentioned in Chinese manuscripts about five thousand years ago. The bacterium Bacillus anthracis is believed to have wiped out entire species of animals. It is no coincidence that anthrax spores are considered a bacteriological weapon intended for the mass destruction of the enemy.
Whooping cough
This acute airborne infection of a bacterial nature of spread is caused by the pertussis bacillus (Bordetella pertussis bacterium). The main symptom that signals the presence of this disease is a severe cough, often spasmodic. However, the fungal type of meningitis is not contagious, although it can cause an outbreak of this disease, as happened, for example, in the United States in 2012, when hundreds of patients were infected through injections of the drug, where there were fungal spores. Several dozen people have died.
Meningococcal meningitis is caused by the bacteria Neisseria meningitidis, which causes flu-like symptoms such as nasal discharge, nausea, sensitivity to light, and confusion. The lethal outcome remains possible, although the situation has changed dramatically over a hundred years: then the mortality rate could exceed 90 percent.
Syphilis
Is an infectious disease of a chronic nature. This is a sexually transmitted disease, that is, the main route of infection is sexual contact with an infected person. However, there are many cases of infection through the blood (in drug addicts; through the use of the same toothbrush, where microscopic particles of blood from the patient's gums remain, and so on). Syphilis is now quite simple to cure, but it is a very insidious disease. If the infection is started, it leads to severe complications. At the first stage of the disease, syphilitic ulcers appear on the patient's genitals and in the anus.
They are usually very small, although painful, and go away on their own. A sick person can immediately forget about temporary inconveniences, attributing them to temporary pimples that popped up for some reason not worthy of attention.
In the second stage of this disease, syphilis begins to express itself clearly - a rash begins to appear in one or different parts of the body. However, in this case, the rash may not be very bright and not be accompanied by itching. The patient may not even pay attention to these redness.
In other cases, the rash may be accompanied by fever, swollen lymph nodes, and muscle pain. And if syphilis was not treated during the development of the first and second stages, the subsequent problems for the patient will be simply catastrophic.
It also happens that syphilis does not go into the late stage for a very long time. According to some reports, this can last from 10 to 30 years. However, at a later stage, the patient loses the ability to coordinate muscle contractions, paralysis, rigidity, bleeding occurs, and dementia is noted. If the internal organs are damaged, the patient may die.
According to data for 2016, up to three hundred thousand patients with syphilis are annually registered in Russia. Now the disease ends in death only if it is not treated (in about a third of patients with a late stage of the disease). During the Renaissance, syphilis killed tens of millions of people, being almost the main cause of death in some periods of history.
Infectious diseases causing deformities
Leprosy
As soon as this disease was called - and the disease of St. Lazarus, and the sorrowful illness, and the Crimea. However, we know it better as "leprosy". This contagious chronic infectious disease is caused by the bacterium Mycobacterium leprae (also called Hansen's bacillus). Leprosy affects the skin of a sick person, peripheral nerves, upper respiratory tract and eyes. If left untreated, it leads to muscle atrophy, physical deformities and permanent damage to the nervous system.
Although people at one time tried to protect themselves from contact with patients with leprosy, this infectious disease is not so contagious. The infection is spread by airborne droplets when an infectious person sneezes or coughs.
If you just touch a leprosy patient, there is no particular risk of infection. Moreover, according to the WHO, the immune system of a healthy person is usually able to resist this infection if bacteria get inside. However, the most vulnerable category is children.
According to the WHO, in 2017, more than two hundred thousand new cases of leprosy were registered in the world. In about 40 percent of cases, patients are at risk of disability. If there is no proper treatment, the person is doomed within 5-10 years.
Measles
What a disease could also compete for the title of "plague of our time" is measles. This acute viral infection is highly infectious. Moreover, she has a fairly high mortality rate. The infection leads to the appearance of a characteristic rash on the skin, which is accompanied by a general intoxication of the body. Other symptoms of this dangerous disease are not much different from the symptoms of a common cold.
Measles is so contagious that even just being in a room next to an infected person can already be dangerous. According to WHO, 134,200 people died from measles in 2016. Before the spread of vaccination (that is, in 1980), this disease claimed the lives of 2.6 million people.
Fortunately, vaccination has proven to be extremely successful in the fight against this viral infection. It is known that out of every thousand people vaccinated against measles, 997 have never encountered the disease.
SARS
Viral atypical pneumonia proved to be a serious illness quite recently - in 2002, when it killed 813 people with 8437 cases. This is one of the most dangerous types of SARS - Severe Acute Respiratory Syndrome (SARS). Bats help spread the disease (as is the case with the Ebola virus, Marburg fever and Middle East respiratory syndrome). In this case, the so-called horseshoe bats are the distributors.
The virus began its movement from China, but quickly spread to other countries and continents due to the fact that the PRC authorities initially tried to hide information about the outbreak of this disease. The SARS case has demonstrated to humankind how important it is to act together when it comes to such formidable adversaries as viral and bacterial infections.
Staphylococcal infection
Methicillin-resistant Staphylococcus aureus - such a complex (and sometimes beautiful) name is used for a bacterium that causes very serious, life-threatening infectious diseases of the skin and human blood. The main problem is that this Staphylococcus aureus (as it is called for simplicity) is able to resist most antibiotics. The history of the "fight" of staphylococcus with antibiotics began in 1940, when doctors began to treat staphylococcal infections with penicillin.
A drug overdose (or misuse) caused microbes to develop resistance to penicillin for ten years, prompting scientists to try a new way to fight staphylococci - with an antibiotic called methicillin.
However, staphylococci have also demonstrated the ability to develop resistance to this drug. Today, this microbe is able to resist the effects of many antibiotics of the penicillin group, such as amoxicillin, oxacillin, dicloxacillin and all other beta-lactam antibiotics.
As a result, humanity has received a powerful enemy in the person of a kind of super microbe that causes infections that are difficult to diagnose and disguise themselves as other diseases. They reduce the body's defenses, promoting the penetration of toxins into the blood and tissues, causing many dangerous pathologies.
Staphylococcal cutaneous infections usually begin as small, red rashes that can turn into purulent sores that require surgery. These infections can cause even more serious consequences by affecting the blood, heart, bones and other internal organs of a person. Sometimes they lead to the death of the patient.
Zika virus
The Zika virus is probably one of the most "non-lethal" on this list of killer viruses, which, however, does not make it completely safe. For the first time, mankind identified this virus in 1947 in Africa. It belongs to the genus of flaviviruses, carried by the already known genus of biting mosquitoes (Aedes). The disease caused by this virus (called Zika disease) is not particularly dangerous for most people. But today the disease has the status of a pandemic.
According to research, one in five people infected with the Zika virus eventually contract the disease of the same name. However, the virus threatens with serious complications for the developing human body in the womb and for newborn babies.
In the infected, an increase in temperature is recorded, a rash, joint pain appears, conjunctivitis develops, but these symptoms are mild and last only a few days. However, the virus causes miscarriages in pregnant women and leads to congenital malformations (for example, microcephaly).
There is an opinion that animals, plants and humans prevail in numbers on the planet Earth. But this is actually not the case. There are countless microorganisms (germs) 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 viruses for humans.
10. Hantaviruses
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 rate on average 12%) and “hantavirus cardiopulmonary syndrome” (mortality rate up to 36%). The first major outbreak of the 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 impact of a virus unknown at the time, which caused internal bleeding and impaired kidney function. Interestingly, this particular virus is considered the likely cause of the outbreak in the 16th century, which exterminated the Aztec people.
9. Influenza virus
Influenza virus is a virus that causes acute respiratory infections in humans. Currently, there are more than 2 thousand variants of it, classified into three serotypes A, B, C. A group of the virus 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 in the world from 250 to 500 thousand people die from seasonal flu epidemics (most of them are children under 2 years old and elderly people over 65 years old).
8. Marburg virus
The 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 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. Early symptoms include fever, headache, and muscle pain. In the later, jaundice, pancreatitis, weight loss, delirium and neuropsychiatric symptoms, bleeding, hypovolemic shock, and multiple organ failure, most commonly the liver. Marburg fever is one of the ten deadly animal-borne diseases.
7. Rotavirus
The sixth most dangerous human virus is Rotavirus, a group of viruses that are the most common cause of acute diarrhea in infants and young children. It is transmitted by the fecal-oral route. The disease is usually easy to treat, but more than 450,000 children under the age of five die each year worldwide, most of whom live in underdeveloped countries.
6. Ebola virus
The Ebola virus is a genus of viruses that causes Ebola haemorrhagic fever. It was first discovered in 1976 during an outbreak in the Ebola River Basin (hence the name of the virus) in Zaire, DR Congo. It is transmitted by direct contact with blood, secretions, other fluids and organs of an infected person. Ebola is characterized by a sudden increase in body temperature, severe general weakness, muscle and 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, as of 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 viruses for humans, causing dengue fever in severe cases, with 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
The smallpox virus is a complex virus, the causative agent of the 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, a 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. Around $ 298 million was spent on the smallpox campaign from 1967 to 1979 (equivalent to $ 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, in which a specific damage to the central nervous system occurs. This disease is transmitted through saliva when bitten by an infected animal. It is accompanied by an increase in temperature to 37.2-37.3, poor sleep, patients become aggressive, violent, hallucinations, delirium, a feeling of fear appear, paralysis of the eye muscles, lower extremities, paralytic respiratory disorders and death soon occur. The first signs of the disease appear late, when destructive processes have already occurred in the brain (edema, hemorrhage, degradation of nerve cells), which makes treatment almost impossible. To date, only three cases of human recovery have been recorded without the use of vaccination, all the rest ended in death.
2. Lassa virus
Lassa virus is a deadly virus that causes 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 occurs 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 5,000 lead to the death of the patient. The natural reservoir of Lassa fever is the multi-nipple rat.
1. AIDS virus
Human immunodeficiency virus (HIV) is the most dangerous human virus, the causative agent of HIV / AIDS, which is transmitted through direct contact of mucous membranes or blood with bodily fluid of the patient. In the course of HIV infection, all new strains (varieties) of the virus are formed in the same person, 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 data for 2011, 60 million people in the world fell ill with HIV infection, of which 25 million died, and 35 million continue to live with the virus.
So what's the deadliest virus on Earth? You might think that this is a fairly simple question that can be answered, but it turns out that there is more than one way to determine the lethality of viruses. For example, is it the virus that kills the most people (overall mortality rate) or is it a disease that has a high mortality rate, i.e. kills most of the infected people. For most of us, this will be the disease with the highest mortality rate, it is definitely a death sentence if you ever get it.
Ironically, it is a series of diseases that have a reassuringly low death rate that actually kill millions of people. There is a reason for this - these are viruses that cause the most dangerous diseases, usually killing themselves by killing their hosts faster than they can spread. Two especially good examples These phenomena are: the Ebola virus, with a 90% fatality rate from which to date about 30,000 people have died and the Spanish flu pandemic, which has killed approximately 100 million people, despite the fact that it has a fatality rate of less than 3%.
Besides the two metrics like the crude death rate and the death rate mentioned above, there is also a historical dimension: which virus has killed the most people in history?
Given these various criteria, in order to determine which virus is the most deadly, we will take all these indicators into account in order not only to compose the TOP 10 viruses, but also to provide some individual statistics at the end of the article.
10. Dengue fever
Photo. Mosquito
Dengue fever is a mosquito infection that was first described nearly 2,000 years ago in China. After the gradual spread to other countries with yellow fever mosquitoes (lat.Aedes aegypti), the spectrum of diseases in the 18th century expanded significantly. This was due to the slave trade, as well as human activities during World War II, when the spread accelerated, especially of more dangerous forms of disease.
In recent years, globalization has had an impact on dengue rates, which have increased 30 times since the 1960s.
As with many of these diseases, the vast majority of people either had no symptoms or rather mild symptoms not characteristic of fever. Dengue fever is sometimes referred to as "breakbone fever", which refers to severe pain that can be felt in the muscles and joints.
For those unlucky, the disease can develop into "severe dengue" with the risk of potential death from dengue haemorrhagic fever and dengue shock syndrome. This occurs in less than 5% of cases, the main reason for this is an increase in the permeability of the blood vessels. This can lead to vomiting of blood, organ damage, and shock.
Today, up to 500 million people are infected each year in 110 countries with endemic dengue, resulting in an estimated 20,000 deaths. The grim reality is that these numbers will continue to rise.
9. Smallpox
Photo. Smallpox patient
Smallpox has been eradicated, hasn't it? The WHO assures that it has not been there since 1979, however, the United States and the former USSR conducted scientific research on the samples of the virus. According to some rumors after the collapse of the Soviet Union, some of these samples went missing. Even if the variola virus became extinct, presumably it could have been re-engineered from the digital viral genome and inserted into the envelope of the poxvirus.
The good news is that all smallpox targets are now extinct in the wild. Although historically this has led to a devastating impact. Smallpox appeared around 10,000 BC, in those days it led to massive loss of life. Smallpox is contagious and, of course, in those early days, the mortality rate reached 90%.
The most terrible period for people was when smallpox was introduced to the New World by European researchers in the 18th century. Whether this was done by accident or not, it is estimated that about half of Australia's Aboriginal population was killed by smallpox in the early years of British colonization. The disease also took a toll on the indigenous population of the Americas.
Despite the fact that Edward Jenner developed the smallpox vaccine in 1796, it killed an estimated 300-500 million people in the 1800s.
In terms of the appearance of smallpox, it is especially shocking that the body becomes covered with blisters filled with fluid. It can occur in the mouth and throat and, in some cases, smallpox has led to complications such as blindness. Mortality from this disease largely depends on the course in which the disease will develop, if it is malignant and hemorrhagic smallpox, it will invariably lead to death.
8. Measles
Photo. Child with measles
Most people in developed countries do not even remotely consider measles dangerous. We are used to the fact that about 90% of all children will have had measles by the time they reach the age of 12. Nowadays, with routine vaccinations being carried out in many countries, the incidence rates have dropped significantly.
But what may shock you is that between 1855 and 2005, measles claimed 200 million lives worldwide. Even in the 1990s, measles killed over 500,000 people. Even today, with the advent of cheap and affordable vaccines, measles is one of the leading causes of death in young children, claiming more than 100,000 lives each year.
Measles has caused the greatest devastation in communities that were not previously exposed to it. In the 16th century, Europeans brought measles to Central America. In particular, Honduras lost half of its population during the measles epidemic in 1531.
In common cases, measles leads to fever, cough, and rash. However, complications are fairly common and this is where the danger lies. In about 30% of cases, symptoms range from relatively mild, such as diarrhea, to pneumonia and brain inflammation, all of which can be fatal. Other complications include blindness.
7. Yellow fever
Photo. Memorial in Savannah, Georgia
Yellow fever is another massive killer in history. Also known as the yellow plague and vomito negro (black vomit), this acute hemorrhagic disease has led to a number of serious outbreaks over the centuries.
Most people have completely recovered from yellow fever, but about 15% of cases show a second, more serious stage of the disease. In these cases, there may be bleeding from the mouth, nose, eyes, or stomach. About 50% of patients who enter this toxic phase die within 7-10 days. Although the overall mortality rate reaches 3%, during epidemics it reached 50%.
Like most of these viral infections, yellow fever originated somewhere in Africa. In the early colonial years, it was noted that outbreaks in the village among the natives did not lead to serious complications, it looked more like flu-like symptoms, while most of the European colonists died. This difference in disease severity is thought to be due to prolonged exposure to low doses during childhood, leading to some degree of immunity.
It can be argued that there is a certain malevolence in the fact that the slavery and exploitation of Africa led to epidemics in Europe and North America in the 18th and 19th centuries. Probably the most famous of these was the 1792 outbreak in Philadelphia, then the capital of the United States. It was reported that President George Washington fled the city while 10% of those who remained died.
Yellow fever swept across America, claiming between 100,000 and 150,000 lives in the 18th and 19th centuries.
Today, despite the existence of an effective vaccine, there are regions where 200,000 people worldwide contract yellow fever every year, killing 30,000 each year.
6. Lassa Fever
Photo. Electron micrograph of the Lassa virus
You may have thought of Lassa fever as a “mild variant of Ebola,” but again it kills as many people in West Africa every year as Ebola did during the 2013-15 epidemic. In addition, the symptoms are easily confused with Ebola; they are both classified as acute viral hemorrhagic fevers. Lassa fever infects virtually every tissue in the human body and outbreaks are usually triggered by local Mastomys rats.
If you are in doubt about the dangers of Lassa fever, then its Biosafety Level 4 (BSL-4) should convince most of you. This is the most high level biosafety, designed to work with pathogens that can cause death and for which there is no vaccine or cure. To have general idea, MRSA, HIV and hepatitis viruses are classified as Biosafety Level 2.
Lassa fever kills an average of 5,000 people annually. It is estimated that more than 300,000 people are infected every year endemic throughout West Africa. Although most do not have any symptoms, those who do have a mortality rate of 15-20%. During epidemics, the mortality rate for Lassa fever reaches 50%. It's not quite like the Ebola virus or the Marburg virus, but the numbers are still dangerous.
5. Hepatitis
Photo. Hepatitis C virus
Hepatitis is the name given to a series of viral diseases that attack the liver. There are 5 types of infectious hepatitis, which are designated by letters from A to E (A, B, C, D, E). Of these, the most serious are hepatitis B and hepatitis C, which together kill nearly a million lives per year. They are often passed from mother to child, but can also be transmitted through blood transfusions, tattoos, dirty syringes, and sexual activity.
Hepatitis B reaps the most deaths in a year (about 700,000). This is a rather inconspicuous disease that is asymptomatic. Most deaths are the result of a disease that slowly attacks a person's liver over several years, eventually leading to liver cancer or cirrhosis. Although infection with hepatitis B in an adult usually results in an acute episode of the disease, it ends with full recovery. Children are usually infected, who are more prone to developing the disease in the long term.
Although the overall death rate from hepatitis C is lower than that of hepatitis B, it still kills an estimated 350,000 people annually, mostly in developing countries. Figures show that about 200 million people (or 3% of the total population) are living with hepatitis C.
4. Rabies
Photo. Patient in the last stage of rabies
Rabies is one of the deadly diseases belonging to the genus Lyssavirus. This name is derived from Lyssa, the Greek goddess of rage, madness and anger, the word itself comes from the Latin "madness". This is one of the most terrible diseases of mankind, which has been known since ancient times and there is every reason for this.
The most common form of rabies is referred to as “furious rabies” and affects 80% of those infected. This stage includes the classic symptoms of confusion, agitation, paranoia, and terror. An infected person may also exhibit anxiety (fear of water). In this seemingly strange state, the patient panics when given a drink. Rabies infects the salivary glands at the back of the mouth, so it can be transmitted by a simple bite. This infection also causes the muscles in the throat to go into excruciating spasms, leading to increased salivation.
Infection with rabies occurs when an infected animal, usually dogs or bats, attacks a person by biting or scratching. Although some flu-like symptoms may appear after the bite, the illness is usually asymptomatic during the incubation period. This usually lasts 1-3 months, but it can take years for the infection to travel through the nervous system to the brain.
Rabies is difficult to diagnose and neurological symptoms may develop if a suspicious bite is left unnoticed. At this stage, it is definitely too late for the patient, rabies has an almost 100% mortality rate within a few days. In fact, only 6 people survived the rabies, and the first was Jeanna Giese in 2005. She was a new approach (Milwaukee Protocol) in the fight against this disease, she was introduced into an artificial coma and she survived, almost completely recovered. Despite success in this case, this method still has an approximately 8% chance of success.
Fortunately, the bite of an animal infected with rabies is no longer a death sentence. If you receive post-exposure prophylaxis (PEP) treatment within 10 days, you have an almost 100% chance of survival. There is also an equally effective vaccine.
However, almost 60,000 people die from rabies every year, mostly in Africa and South Asia. More than one third of these deaths occur in India, where dogs are still the main culprit. More details about this disease and, can be found in our other article.
3. Viral hemorrhagic fevers (Filoviruses)
Photo. Ebola outbreak in 2015
If any disease can cause fear in the 21st century, it is viral hemorrhagic fevers from the filovirus family. These include the Ebola virus and the Marburg virus, for both there is no effective treatment, there is no vaccine and the mortality rate reaches 90%. Having very unpleasant symptoms - these are potentially deadly viruses on Earth.
From a diagnostic point of view, Marburg and Ebola are clinically indistinguishable. The name of this group of viruses serves as a clue to some of the symptoms; it is obvious that these fevers are accompanied by pain throughout the body, joints, muscles, abdominal pain, and headaches. The hemorrhagic aspect is associated with the fact that filoviruses interfere with the mechanism of blood coagulation, thereby causing bleeding from any hole in the human body. More than likely, death, as a rule, is explained by multiple organ failure, necrosis of internal tissues.
Ebola and Marburg usually appeared in isolated villages in Central Africa as a result of small outbreaks that quickly destroyed themselves. However, in 2013, the Ebola virus arrived in the West African country of Guinea, where it was not recognized as such until it began to spread rapidly. Over the next 2 years, the Ebola epidemic raged in six countries, infecting 25,000 people, of whom about half died.
The largest outbreak of the Marburg virus was in 2004 in Angola. Of the 252 infected, 227 died, i.e. 90%. During the early epidemics, Congo had a death rate of 83%.
It is believed that the Marburg and Ebola viruses were transmitted to humans from wild animals. Although the first cases of Marburg virus infection occurred with researchers working with African green monkeys, bats are believed to be the natural host of the virus. This also applies to the Ebola virus, which is why bats are considered the main vectors of some of the most terrible diseases on the ground.
2. HIV / AIDS
Photo. HIV virions infect cells
Over the past three decades, AIDS has become major news and is a devastating disease. The tremendous progress in antiretroviral drugs means that taking the right drugs for HIV infection is not a death sentence as it used to be.
This disease is another that originated in Central Africa, where it hid in monkey populations for millions of years until it crossed with humans in the middle of the 20th century. It is not known exactly how this happened, but it is believed that the monkey SIV (Monkey Immunodeficiency Virus) transmitted the virus to humans through eating meat, later the virus mutated and now we know it as HIV.
It is suspected that HIV existed for a while before it became headline news, with the first reported case in the Congo in 1959.
The main reason for not finding direct treatment for HIV is the fact that it is constantly and rapidly changing. It reproduces quickly (about 10 billion new individual virions per day) and the mutation rate is very high. Even in one person, the genetic diversity of the virus can resemble a phylogenetic tree with different organs infected with practically different species.
Today, about 40 million people are living with HIV, mainly in sub-Saharan Africa. Unfortunately, only half of the infected people have access to the medicines they need, which is why the global AIDS death rate is so high. It is estimated that AIDS takes about 2 million lives annually, and over the past 30 years, the virus has killed more than 25 million people.
1. Influenza
Photo. Spanish flu patients
Influenza is the most widely known virus and hardly the most exciting on our list of deadly viruses. Everyone had the flu and for most it didn't end well. However, every year the flu leads to a large number of deaths and the most vulnerable group of the population is the elderly, the very young and the sick. Despite the fact that a safe and effective vaccine was obtained more than 60 years ago, the flu still kills up to half a million people every year.
But this is only a basic indicator, in addition to this, occasional devastating epidemics occur when virulent strains of the virus develop. The 1918 Spanish Flu is a prime example of this. It is believed to have infected nearly a third of the world's population and claimed up to 100 million lives. During the epidemic, the mortality rate was 20% compared to the usual seasonal flu of 0.1%. One of the reasons the Spanish flu was so deadly was because it killed healthy people, a particular strain causing an overreaction of the immune system known as a cytokine storm. Therefore, people with strong immune systems were at the greatest risk.
Other illnesses have not even come close to these rates, which is what makes the flu so dangerous. The influenza virus has the ability to often combine and mutate to form new strains. Fortunately, the most deadly strains currently differ from the most infectious strains. One fear is that a potentially deadly H5N1 avian influenza strain that cannot be transmitted from person to person, for example, will need a small genetic "event" to create a possible epidemic. Although there have been just over 600 cases of avian influenza to date, nearly 60% of them have been fatal, making it one of the most dangerous diseases to humans.
