Discovery of virus

Spread the love

Introduction

The word virus is derived from latin word venome meaning poisonous fluid.

Definition

IT can be defined as non cellular infectious entities which contain either RNA or DNA , normally encased in proteinaceous coat , and reproduce only in living cells viruses utilize the biosynthetic machinery of the host for its own synthesis and then transfer themselves efficiently to other cells.

The branch which deals with the study of viruses is known as virology.

Early Period

ABout a century ago the time of Louis Pasteur(1822-1895) and Robert Koch (1843-1910), the word virus was generally referred to a poison associated with disease and death.

Present Concept OF Virus

The present notion of virus is entirely different.Now viruses are recognized as particles of nucleic acid often with a protein coat.

They replicate in living cells and cause many disease such as influenza,hepatitis, small pox and AIDS.

Work of Edward Jenner

Some viral disease have been known for centuries.

in fact, the first infections disease against which effective method of prevention was developed was a viral disease.

in 1796, Edward jenner first vaccinated an 8 years old boy with material removed from cowpox lesion on the hand of milkmaid.

After six weeks the boy was inoculated with pis from a small pox victim, but he did not develop the disease.

Later Jenner used material for vaccination from cowpox lesion and successfully vaccinated 23 persons.

As The material he used was obtained from cow (latin vacca), later the term vaccination was used by Louis Pasteur for inoculation against disease.

Work of CHarles Chamberland

IN 1884, one of pasteur associates , Charles Chamberland, found that;

  • Bacteria cannot pass Through porcelain filters.
  • While agent responsible for rabies ( adisease which is transferred to human by bites of rabid dogs, foxes cats , bats and other animals) can pass through these filters.
  • As in those days the word virus was loosely used a describe any toxic substance that caused disease, those unseen filterable agents of disease were describe as filterable viruses.

Work of ivanowski

in 1892 , Ivanowski discovered that the agent which caused tobacco mosaic disease was filterable.

  • He obtained bacteria free filtrate from ground up infected plants and placed it on healthy leaves of tobacco.
  • He observed that filtrate produce that disease in healthy plants
  • After that, presence of similar filter passing ultra microscopic agents was seen in the victims of many disease,, including foot and mouth disease (1898) and yellow fever (1901).

Work of Stanley
The filterable agents were first purified in 1935, when Stanley was successful in crystallizing the tobacco mosaic virus.

Chemical Composition

Chemical analysis of these particle showed that they contained only nucleic acid and protein,This suggested that, unlike other forms, viruses are of simple chemical composition.

9 thoughts on “Discovery of virus

  1. Pingback: kardinal stick
  2. Pingback: Online Dispensary
  3. Pingback: relx
  4. Pingback: sbo

Leave a Reply

Your email address will not be published. Required fields are marked *