For an explanation, see the main splats page
SPLATS about viral diseases
The principles of viral diseases
- Because viruses are too small to be filtered out of a solution, and too small to see, 19th centuries scientists called them by the Latin name for poison: virus.
- A virus is typically between 20 and 300 nanometres across, a protein coat surrounding nucleic acid. It needs to get into a cell to reproduce itself.
- Viruses are small packets of genetic material in a protein coat. They can only reproduce inside a living cell, which they destroy in the process.
- A virus can be called life because it can reproduce and mutate, or non-life because it needs to invade a cell to be able to reproduce. Take your choice.
- Because viruses can only reproduce inside a living cell, they are often classed as non-living, but on the other hand, they contain genetic material.
- Some viruses specialize in attacking bacteria. These are known as bacteriophages, and some bacteriophages have been used to treat bacterial infections.
- In 1915, Frederick Twort suggested that bacteriophages (as we now know them) were viruses which attack bacteria - these were later referred to as 'phages'.
- In 1917, Felix Hubert D'Herelle, independently of Frederick Twort, also discovered the same effect, and it was he who called it a bacteriophage.
- In 1945, Max Delbrück and Salvador Luria organized the first phage course at Cold Spring Harbor Laboratory which would be taught for 26 consecutive years.
- In 1953, André Lwoff, working with bacteriophage lambda, found that phage viruses are capable of inserting their genome into the host genome.
- In 1955, Seymour Benzer began fine-structure genetic mapping a phage, a process that would take five years. He concluded that a gene has many mutable sites.
- In 1981, the first reports of AIDS began to surface. Symptoms had been noted earlier, especially an increase in Kaposi's Sarcoma, but now AIDS was a condition.
- AIDS is caused by HIV, the human immunodeficiency virus. There are some people who argue that there are other causes, but the medical evidence points at HIV.
- HIV can be passed from mother to child, and in the absence of any of the alleged 'lifestyle causes' can develop into AIDS, and kill the child.
- AIDS and HIV do not kill people: the virus takes away the normal immune response, leaving people open to attack by diseases that would usually be controlled.
- AIDS is caused by HIV, but in a very real sense, AIDS can be said to be caused by poverty, because poor people are more likely to be infected by HIV.
- The Durban declaration of 2000 was drafted to counter a set of mischievous and ill-informed claims from 'AIDS sceptics' that HIV was unrelated to AIDS.
- In 1898, Martinus Beijerinck used filtering trials to show that tobacco mosaic disease is caused by something smaller than a bacteria and called it a virus.
- In 1910, Peyton Rous showed that viruses play a role in some cancers when he discovered the Rous Sarcoma Virus. He gained a Nobel Prize for this in 1966.
- In 1937, Sir Frederick Charles Bawden discovered that the tobacco mosaic virus contains RNA, the first virus found to contain RNA as the genetic material.
- In 1935, Wendell Meredith Stanley was the first researcher to purify and crystallize a virus, the tobacco mosaic virus, for which he gained a 1946 Nobel Prize.
- In 1955, Fraenkel-Conrat and Williams separated tobacco mosaic virus (TMV) nucleic acid from its protein coat and found that both were necessary for infection.
- In 1960 Heinz Fraenkel-Conrat announced the complete sequencing of the 158 amino acids which make up the protein coat of the tobacco mosaic virus.
- Smallpox is a viral disease, and like many viral diseases, it can be prevented with a suitable vaccine that prepares the immune system to attack the virus.
- In 1717 Lady Mary Wortley Montagu had two of her children variolated against smallpox. The practice continued until Edward Jenner developed vaccination.
- In 1776, George Washington had his troops inoculated against smallpox, using the pre-vaccination treatment called variolation, which was common in his time.
- Variolation was a procedure that usually gave people a mild dose of smallpox, but occasionally, it killed. In any case, it was a lesser risk than doing nothing.
- In 1796, Edward Jenner was ethical when he attempted to apply the standard inoculation with smallpox (variolation) on a boy who had previously been vaccinated.
- The point of was that variolation usually caused a mild form of smallpox, but was known to give immunity. Jenner's vaccination offered risk-free immunity.
- In 1977, there were no cases of smallpox known, anywhere in the world, as it had, by then, been wiped out in the wild. Laboratory stocks still exist.
- An arbovirus is a virus spread by blood-sucking arthropods: it is short for 'arthropod-borne virus'. A number of serious human diseases are from arboviruses.
- Rabies is a viral disease spread by animals. It attacks the nervous system producing the classic symptoms of 'madness' associated with the disease.
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