The deadliest viruses in history.

The tiny monster that has been poisoning human life since ancient times is called a virus. The Latin word ‘virus’ means ‘poison’. Again, people are using this 'poison' for human welfare lately. Tiny viruses have terrible killing power. In the twentieth century, smallpox has claimed the lives of about 300 million people. It is now possible to eradicate this monster. Another nightmare is the Spanish flu. Between 1918 and 1919, the virus killed between five and ten million people, about three percent of the world's population. There are many unknown viruses in the world. Six of these viruses can be identified as the most dangerous. Coronavirus has recently been added to those six viruses.

1. Ebola virus:

Never before in the history of the world has there been such an epidemic as the Black Death. Outbreaks appear to be exacerbated during the 14th century. The disease is called Black Death because it spreads from the coastal areas of the Black Sea. At that time trade between Europe and Asia was done through this Black Sea. According to some experts, the disease was a kind of adrenal plague. The other part claims that this terrible epidemic was caused by the Ebola virus. Rats were the main carriers of this disease.

The Ebola virus is a member of the Filovirus family. These are single-stranded RNA viruses. Filoviruses are the longest at about 1000 nanometers. Ebola is a single-stranded RNA virus with 19,000 nucleotides. It encodes seven structural proteins: nucleoprotein (NP), polymerase cofactor (VP35), (VP40), GP, transcription activator (VP30), (VP24), and RNA dependent RNA polymerase (L).

So far the Ebola virus is at the top of the deadly virus. The first outbreak of the Ebola virus was reported in 1986 near the Ebola River in the Congo. It can spread from wildlife to humans. Bats are thought to be carriers of the virus. Again it can spread from person to person. The disease is spread through body fluids or tissues, including the blood of infected people or animals. The Ebola virus has several strains (microorganisms). The severity or risk of death from the Ebola infection may vary from strain to strain. According to the WHO, there is a strain called Ebola Reston, which does not make people sick. But the risk of death from Bundibagyo strain infection is 50 percent. In the case of the Sudanese strain, the risk rises to 71 percent. The mortality rate of patients infected with this virus is 83-90%. However, experts said that if the affected person can be brought under treatment quickly, it is possible to save him.

The first outbreak of this deadly virus was reported in 1976. Simultaneously in Niger, Sudan, Yambuku, and Republican Congo. The Ebola epidemic from 2014 to 2015 affected about 28,616 people in West African countries and killed 11,310 people. In the Democratic Republic of Congo, 2,909 people were infected with the Ebola virus in 2019, and 1,953 of them died. To date, no effective antidote to the virus has been developed. The Ebola virus is transmitted to infected people through blood, saliva, or any secretions, or through wounds. If a person survives being infected with the virus, they can continue to spread the virus through sexual intercourse for about two months. This is because the virus stays in the semen for a long time.

2. Rabies virus:

Rabies virus is a single-stranded negative polarity RNA virus with a bullet-shaped capsid and lipoprotein envelope belonging to the rhabdovirus family. Because the genome is RNA negative polarity, its variants contain RNA dependent RNA polymerase. The rabies virus is a single antigenic type. The antigenicity of this virus exists in the envelope of glycoprotein spikes. The rabies virus is neurotropic, meaning it spreads from animals to humans. The rabies virus spreads to infected animal bites. They start breeding at the bite site.

Rabies virus, like other rabid viruses, has many host animals. The disease caused by this virus is called rabies. It is usually spread by dogs, cats, bats, otters, raccoons, etc. The virus is not usually spread by rabbits or rodents such as rats, mice, squirrels, etc. According to the Pasteur Institute in Paris, 59,000 people die of rabies every year around the world.

The rabies virus spreads in the saliva of infected animals. People get infected when those animals bite people. The virus directly attacks the human nervous system and disrupts its normal functioning. Once the virus reaches the central nervous system, it continues to reproduce and re-accumulate in other organs, including the salivary glands, through the peripheral nervous system. The virus enters the salivary glands from the salivary glands so that it can be transmitted to other people through the bite of a rabies patient. In the nervous system, it destroys neurons and can cause encephalitis. At first, there are some indeterminate symptoms such as fever, loss of appetite, changes in the feeling of the bite site. Symptoms such as drowsiness, confusion, increased secretion of saliva, etc. appear after a few days. The most notable thing is that there is a sharp painful contraction during swallowing, especially when drinking water, there is a sharp pain in the throat, which leads to hydrophobia in the patient.

Despite having an effective vaccine, it is not yet possible to get rid of the panic of rabies due to not giving the vaccine to the infected person in time. If the vaccine is not given in time, the death of the infected person is inevitable. When the rabies virus spreads to the brain, the symptoms of rabies begin to appear. Within three to five days of the onset of symptoms, the patient dies of severe convulsions and paralysis.

3. H5N1 mutated and seasonal influenza virus:

Orthomyxoviridae is a virus in the family that is responsible for influenza. This virus is a mutant. Dutch virologist Ron Fuchs converted the bird flu virus to the laboratory. In 2011, the American Biosafety Agency (NSABB) imposed strict restrictions on research and publication of the virus, as it is highly contagious and extremely dangerous. Researchers have confirmed that the monster virus has been housed in a highly secure cell in the laboratory. There is no way to escape from there. The lethality of the common bird flu virus is over eighty percent. Even then, the highly lethal virus can transform itself. That is why the experts are especially unaware of it.

According to the World Health Organization, seasonal influenza is responsible for the deaths of 290,000 to 650,000 people worldwide each year. The worst epidemic was in 1918-1919. This global epidemic was then called the Spanish flu. At that time, 40 percent of the world's population was affected and at least 18,000 people died. The virus killed 8,100 people in France in the 2018-2019 season.

4. Marburg virus:

The most dangerous virus in the world is the Marburg virus. The first virus was detected here in 1967. It later spread to Frankfurt and Belgrade, the capital of Serbia. Although it is less deadly than the Ebola virus. However, these two viruses have a lot in common. About 80 percent of infected people die from the virus. Infection with the Marburg virus can cause high fever in the infected person on the fifth or seventh day, as well as hemorrhage, blood in the stool, severe bleeding in the nose, gums, and vagina. It can be transmitted from an infected person to someone else.

Like Ebola, bats are thought to be the source. It can kill anyone within eight to nine days. The risk of death is 90 percent. Hopefully, this virus is not transmitted very easily. Excessive contact with an infected person can cause the Marburg virus to be transmitted through feces, urine, saliva, or vomit.

5. Dengue:

Dengue fever is a disease caused by the Aedes mosquito-borne dengue virus. Outbreaks of dengue fever occurred in the Philippines and Thailand in 1950. Currently, 40 percent of the world's population lives in dengue-affected countries. Aedes mosquito is the carrier of the dengue virus. Symptoms of dengue fever usually occur within 3 to 15 days of being infected by Aedes mosquito bites. Symptoms include fever, headache, vomiting, muscle and joint pain, and rash on the skin. Dengue patients usually recover within two to seven days.

Several species of Aedes mosquitoes (female mosquitoes) are the main carriers of the dengue virus. Aedes aegypti mosquito is the main one. Five serotypes of the virus are found. When infected with a serotype of the virus, the patient gains immunity against that serotype for life. But acquires temporary resistance against different serotypes. If the dengue virus of a different serotype is infected later, the patient may have serious complications. Dengue fever can also be diagnosed through a variety of tests, such as the presence of the virus or its RNA-resistant antibodies.

Vaccines against dengue fever have been approved in several countries. However, this vaccine is only effective in people who have been infected once. Avoiding Aedes mosquito bites is the main way to prevent dengue. Therefore, mosquito breeding must be prevented by destroying mosquito habitats. For this, water trapped in various containers suitable for the breeding of Aedes mosquitoes, such as cups, tubs, tires, coconut shells, holes, roofs, etc., needs to be removed. Clothing that covers most of the body should be worn.

Dengue has become a global scourge since World War II. Hemorrhagic fever can also occur in dengue. Dengue has another name, 'Tropical Flu'. If not treated, the risk of death is 20 percent. Dengue is endemic in more than 141 countries in Asia, South America, and other continents. The dengue virus has recently hit Europe as well. The first mention of dengue was made in 1779. An estimated 390 million dengue cases occur in more than 141 countries worldwide each year. Worldwide, about 500,000 people are infected with dengue fever each year, and about 25,000 of them die. It is possible to get rid of dengue virus infection by following Aedes mosquito control and some hygiene rules.

6. HIV (AIDS):

HIV( Human Immunodeficiency Virus) is a virus belonging to the genus Lentivirus, which causes AIDS in humans. Basically, AIDS is not a disease, it is a combination of various diseases caused by a lack of immunity.

The most dangerous virus in the modern world is HIV. The World Health Organization has identified the HIV virus infection in the human body as Pandemic. The virus was discovered in 1981. The virus can lurk in host cells for eight to ten years. When activated, the host defects the body's natural defenses and pushes it to the brink of death. According to the World Health Organization, 75 million people have been infected with the HIV virus since the beginning of the AIDS epidemic, which is about 0.6 percent of the world's population. About 32 million people have died of HIV. In 2005, AIDS claimed the lives of 22 to 33 million people, including more than 560,000 children. One-third of these deaths occurred in sub-Saharan Africa.

7. Novel Corona (Covid-19):

Coronavirus (Covid-19) is a variant of the coronavirus that has been causing panic around the world lately. According to the information we have so far, less than 4 out of 100 people infected with the virus have died and more than half have already recovered. The new version of the coronavirus has not yet been fully unveiled. Scientists are trying to understand its speed and have come up with an antidote to it. Researchers at the Pasteur Institute in Paris hope to bring good news to the world soon.

 The first coronavirus was discovered in the 1960s. It was first seen as an infectious bronchitis virus in chickens. Later, two types of the virus were found in patients suffering from the common cold, sneezing, and coughing. The coronavirus is not a single virus. It is a large family of several virus species. Deadly viruses like SARS and Mars also belong to this family. Viruses in this family are zoonotic, meaning they can be transmitted from animals to humans and from humans to animals. The newest member of this family is the Novel Coronavirus or Uhan virus. The disease was first identified in Wuhan, Hubei Province, China. Common symptoms of infection are fever, cough, and shortness of breath. The most devastating areas can be pneumonia, kidney failure, and even death. So far 215 countries around the world have been attacked, 18,509,934 people have been infected and 698,897 people have died. Of the 100 people infected with the virus, less than four have died, or 3.78% and more than half have already recovered. Doctors and scientists have not yet fully uncovered the new form of the coronavirus. They are trying to understand its speed and have come up with an antidote. The only prayer of the terrifying world is that God will save millions of lives on earth from the epidemic called Kovid-19 very soon.