You must have seen the heartbreaking picture of a small-headed baby crying. This poor baby is ill with the Zika virus. Zika virus is universally known to cause microcephalia (소두증), causing an abnormally small head and underdeveloped brain. The main medium is known to be Egyptian mosquitoes, but sexual contact and transfusion also can cause Zika virus. Then what is this "virus" on earth?
Many people confuse viruses and bacteria. However, viruses are completely different from bacteria. Many bacteria attack our body cells, and viruses attack these bacteria or cells. So, we can describe that virus is a "bacteria of bacteria and cell." A virus is a small infectious agent – it is 1,000 times smaller than bacteria! – that replicates only inside the living cells of other organisms. It means, a virus can exist only in a living cell, but it is just a protein mass outside of a cell. Therefore, a virus has characteristics of not only an organism, but also an inanimate object. A virus has a protein shell, and lots of genetic materials, and DNA or RNA in it. Once it enters one certain cell, it spreads its gene all around said cell. As this cell becomes destructed, and baby viruses break it and go out to other cells. These horrible materials can cause terrible diseases in humans. Zika virus is only one example of them. Contagious viral diseases like Zika virus is NOT a suddenly found disease. Last year, MERS, struck Korea with terror and was also a kind of viral disease. Like those above, many diseases caused by viruses have stirred up the whole world since the Middle Ages. Let's find some viral diseases that have given menace to human beings.
1. Smallpox: Taking the queen's and king's lives
- Mary II, who was the queen of England and Louis XV, who was the king of France, both died from smallpox. Besides them, almost 100,000 people suffered from smallpox. Smallpox was a horrible disease in Korea, too. It was respected and was called 'Ma-ma' or 'Byeol-sang' during the Joseon Dynasty period because of fear. After 200 years, when an immune substance was found in a cow a vaccine for smallpox was found, so it disappeared completely.
- Caused by: Variola virus
- Symptoms: sudden fever, heavy stomachache, chills, blisters, pus
2. AIDS: Is it a distinct disease of homosexuals?
- People infected with HIV only are somewhat different from AIDS patients. The former are infected, but they have a good immunity, so they don't have distinct symptoms. However, as the immunity level of the latter gets weaker, they show signs of AIDS.
It's a fact that many homosexuals are suffering from AIDS. However, it's NOT because they are homosexual, but they come into contact many venereal diseases so their level of immunity becomes weaker. Also, heterosexuals are also capable of contracting AIDS.
- Caused by: HIV (Human Immunodeficiency Virus)
- Symptoms: headache, vomiting, fever, throat pain, rash, encephalitis (뇌염)
3. SARS (Severe Acute Respiratory Syndrome): Horror of 2011
- 'Corona' is named because the shape of virus resembles a corona, the atmosphere surrounding the sun. Corona virus is found in chickens first. A normal corona virus causes just a slight cold or diarrhea, but 'SARS corona virus' causing SARS is a mutant of a normal corona virus. SARS broke out from November 2011 to July 2013, and 8,069 people became infected, and 774 of them died.
- Caused by: SARS corona virus
- Symptoms: cough, dyspnea, diarrhea, fever, headache
4. Ebola Hemorrhagic Fever: Learning the immune system of bats
- 'Ebola' is named after the 'Ebola River' which the disease was found first near. The host is known to be fruit bats as they have an immune system that protects them from the Ebola virus. Therefore, scientists are studying their immune system to use for a good vaccine for humans.
- Caused by: Ebola virus
- Symptoms: heavy diarrhea, chest pain with cough, myalgia, fever, skin rash
5. MERS (Middle East Respiratory Syndrome): Striking South Korea in 2015
- MERS is caused by MERS Corona virus, similar to SARS virus. Its level of infection is lower than SARS, but the death rate is much higher. In 2015, the first MERS patient was found in South Korea. Until its end was announced, 38 Koreans died, and the death rate was 20.4%.
- Caused by: MERS Corona virus
- Symptoms: cough, dyspnea, fever, sputum, runny nose, headache, diarrhea
Like this, a virus causes lots of serious diseases. Although there are some viruses giving advantages to our body, most of them are harmful to living things including human beings.
Do you know that through a little cold you may have had recently is also a kind of viral disease? There are so many viral diseases we didn't refer to in this paper. A virus is so small as if it's just a material we don't have to care about. But, it has an enormous effect on our bodies, humanity, and this world. Still now, lots of researchers are investigating viruses in order to make our world safer.
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