The seven most dangerous viruses in the world

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Since the outbreak of the epidemic in the early 80s, the human immunodeficiency virus (HIV) has killed approximately 40 million people worldwide. However, it is not the only organic molecule that threatens us. There are many more deadly viruses.

Ebola

It belongs to the Filoviridae family and causes a particularly dangerous hemorrhagic fever with a mortality rate of 70-80%. The first cases of the disease were recorded in 1976 in the Democratic Republic of Congo. Fruit bats or some monkeys are likely to be the reservoirs for the virus, from which the infection is transmitted to humans. The sick person is very dangerous to the environment because of the disease’s high contagiousness. Nosocomial infections, blood-borne infections caused by needle stick injuries and sexual infections during convalescence are possible.

Once inside the body, the Ebola virus multiplies enormously and spreads through the lymphatic system, liver and spleen, and attacks white blood cells, haematopoietic and reticuloendothelial cells. The clinical course of Ebola hemorrhagic fever is characterized by an acute onset with a rapid rise in body temperature to over 40 ° C, headaches, muscle and joint pain, pharyngitis, and oesophagitis accompanied by ulcerations. Symptomatic treatment is of paramount importance, consisting in the correction of water and electrolyte disturbances, substitution of coagulation factors, anti-shock management and treatment of complications such as renal failure or respiratory failure.

So far, there are no registered antiviral drugs with documented effect.

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HIV

HIV belongs to the retrovirus family and primarily attacks cells of the immune system – white blood cells located in the blood, bone marrow, gastrointestinal tract and central nervous system. The infection occurs most often through blood, sexual contact or vertically from mother to child during pregnancy or breastfeeding. The progression of the disease leads to a steady decrease in the number of white blood cells and an intensification of the multiplication of the virus. Acquired immunodeficiency syndrome (AIDS) usually develops 8-10 years after infection, but this time can vary from one to many years. The hallmark of AIDS diagnosis in Europe is the occurrence of a specific opportunistic disease in an infected person. It is a state of increased susceptibility of the body to all pathogens and an increased risk of developing cancer.

Currently available antiviral drugs do not completely cure HIV infection. The main goal of the therapy is to inhibit the multiplication of the virus and slow down the progression of the disease. The most important form of prevention is to avoid risky sexual behavior. In the case of exposure to infection, usually up to 48 hours (or 72 hours in high-risk exposure), there is a possibility of introducing post-exposure prophylaxis.

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Marburg

It belongs to the filovirus family, is closely related to the Ebola virus and is responsible for the emergence of the Marburg disease, also known as Marburg hemorrhagic fever. The infection occurs through droplets, direct and indirect contact. The first documented cases of disease took place in 1967 in Marburg, Frankfurt am Main and Belgrade. The source of the virus was green monkeys imported from Uganda, and the infection occurred in people who took care of monkeys or prepared their tissue.

The disease manifests itself initially: high fever, progressive weakness, muscle pain, chills, headache. Over the next few days, symptoms include vomiting, cramping abdominal pain, nausea, and watery diarrhea. Then, on the 5-7 day of the disease, multifocal haemorrhagic symptoms develop: bloody stool and vomiting, difficult-to-control bleeding from the injection sites, bleeding from the gums, nose and genital organs, ecchymosis on the palate, skin of the face and trunk, and subconjunctival hemorrhages. So far, no vaccine against the virus has been developed.

SARS

The SARS coronavirus infections were the cause of the acute severe respiratory distress syndrome epidemic at the turn of 2002–2003. Within a few months, over 8 cases were reported worldwide, and the mortality rate was almost 10%. Initially, it was assumed that the natural reservoir of the SARS virus was the Chinese paguma (Chinese gourd), but research conducted in recent years has shown that bats were the most likely natural host.

The SARS virus is transmitted through direct contact with sick people, mainly by airborne and droplets. Infection is also possible through indirect contact with objects contaminated with the secretions of the respiratory tract or the patient’s body fluids. In the course of the disease, there are fever above 38 degrees C and problems with the respiratory system, such as sore throat, dry cough and shortness of breath. A drug has not been developed to fight the SARS virus, so symptomatic treatment is similar to that for severe pneumonia.

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MERS-CoV

Like SARS, it belongs to the coronavirus family, but is more aggressive – it replicates faster than SARS and is able to penetrate the barrier created by the immune system as easily as the virus that causes the common cold. In addition, the MERS-CoV virus is much more deadly than SARS – every second infected person dies. The first confirmed human infection with MERS-CoV was found in 2012 in the Middle East. The sick – a 49-year-old citizen of Qatar – was transported to a hospital in Great Britain, but died of acute respiratory disease and kidney failure.

According to the results of recent studies, the most likely source of the virus is camels, where the virus is found in the secretions of the respiratory tract, faeces, urine and milk. Acute respiratory diseases with fever, cough and shortness of breath appear most often. Most of the infected patients developed severe pneumonia and required hospital care. In addition, patients developed gastrointestinal symptoms such as abdominal pain, vomiting and diarrhea. To date, no vaccine against the MERS-CoV virus has been developed.

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Yellow fever

Yellow fever, historically also known as yellow fever, is a dangerous tropical infectious disease caused by the yellow fever virus of the Flaviviridae family. The disease can take various clinical forms – from mild, nonspecific flu-like symptoms to severe hemorrhagic fever, resulting in death of 50%. sick. The name “yellow fever” comes from jaundice, a symptom that occurs in some patients. Yellow fever is spread by stinging by infected Aedes, Haemagogus and Sabethes mosquitoes. Disease reservoirs are humans and monkeys. The disease is also spread through breastfeeding.

Blood-borne infections (stings) and infections caused by blood transfusion are possible, although rare. After entering the body, yellow fever viruses spread through the lymphatic system, liver and spleen and attack white blood cells, cells of the hematopoietic and reticuloendothelial systems, mainly monocytes and macrophages. The virus damages the liver, kidneys and heart the most. Hepatitis can result in intrahepatic cholestasis and coagulation disorders. Yellow fever prophylaxis consists of immunization and preventing bites by mosquitoes that transmit the disease.

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Dengue

Dengue is a viral disease that is transmitted by mosquitoes in tropical parts of the world. It is caused by four types of dengue virus: DENV 1–4. Infection with dengue virus may be imperceptible to the traveler or lead to acute disease symptoms, including severe coagulation disorders and haemorrhages. The dengue virus is transmitted by Aedes mosquitoes called tiger mosquitoes. Dengue symptoms usually appear 3–14 days after an infected mosquito bites. The most common complaints are fever, headache, severe weakness and severe muscle or joint pain.

Sometimes there are also conjunctivitis or pharyngitis and gastrointestinal complaints. Some patients develop a hemorrhagic form or shock in the further course of the disease. No antiviral drugs effective against dengue-causing pathogens have been developed, so treatment is symptomatic therapy, primarily rehydration with oral preparations or drips, combating fever and pain, and correcting blood clotting disorders. Mortality due to the haemorrhagic form of dengue in developing countries reaches 10-20%, but in facilities with good conditions for caring for patients, as well as appropriate equipment and trained personnel, it is much lower and does not exceed 0,5%.

We encourage you to listen to the latest episode of the RESET podcast. This time we devote it to the problems of the perineum – a part of the body just like any other. And although it concerns all of us, it is still a taboo subject that we are often ashamed to talk about. What do hormonal changes and natural births change? How not to harm the pelvic floor muscles and how to care for them? How do we talk about perineal problems with our daughters? About this and many other aspects of the problem in a new episode of the podcast.

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