Introduction to viruses
A virus is a tiny infectious agent that reproduces inside the cells of living hosts. When infected, the host cell is forced to produce thousands of identical copies of the original virus. Unlike simpler infectious agents like prions, they contain genes, which allow them to mutate and evolve. Viral infections can cause disease in humans, animals and plants. In healthy humans and animals, infections are usually eliminated by the immune system.
About Introduction to viruses in brief
A virus is a tiny infectious agent that reproduces inside the cells of living hosts. When infected, the host cell is forced to produce thousands of identical copies of the original virus. Unlike simpler infectious agents like prions, they contain genes, which allow them to mutate and evolve. Viruses range in size from 20 to 300 nanometres; it would take 33,000 to 500,000 of them, side by side, to stretch to 1 centimetre. Viral infections can cause disease in humans, animals and plants. In healthy humans and animals, infections are usually eliminated by the immune system, which can provide lifetime immunity to the host for that virus. Antibiotics, which work against bacteria, have no impact, but antiviral drugs can treat life-threatening infections. Those vaccines that produce lifelong immunity can prevent some infections, and can prevent pandemics, as in the 2009 swine influenza that spread to most countries. The invention of the electron microscope in 1931 brought the first images of viruses of the world to the public. A short time later scientists found it to be mainly made from protein and RNA. A problem for early scientists was not to know how viruses live without using animals without living cells. In 1935, American biochemist and virologist Wendell Stanley examined the tobacco mosaic virus and found it was mainly made of protein, RNA and DNA. He called it a “contagious living fluid” —or a ‘soluble living germ’. In the early 20th century, English microbiologist Frederick Twix discovered viruses that infect bacteria, and added them to the areas of dead bacteria growing on agar.
This lead to the formation of whole viruses that, when added to dead bacteria, would lead to their formation in the suspension in the dead areas of Agar. The discovery of the germ-like particles in bacteria led to the development of the ‘gland-like’ virus. The first virus was found to be made from mainly protein andRNA, and this lead to its formation in dead animals. The ‘garlic’ or ‘coconut’ species of virus was discovered in the 1950s. It is made of either two or three parts. All include genes. All viruses are also covered with a protein coat to protect the genes. Some viruses may also have an envelope of fat-like substance that covers the protein coat, and makes them vulnerable to soap, and make them vulnerable. A virus with this envelope uses it, along with specific receptors, to enter a new host cell. Viruses vary in shape from the simple helical and icosahedral to more complex structures. Some viruses of humans and other animals are spread by exposure to infected bodily fluids. Others, such as the dengue virus, are spread through the air by droplets of moisture when people cough or sneeze. Rotavirus is often spread by direct contact with infected children. The human immunodeficiency virus, HIV, is transmitted by bodily fluids transferred during sex.
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This page is based on the article Introduction to viruses published in Wikipedia (as of Nov. 05, 2020) and was automatically summarized using artificial intelligence.
