General Concepts: Virus history
The history of virology goes back to the late 19th century, when German anatomist Dr Jacob Henle (discoverer of Henle's loop) hypothesized the existence of infectious agent that were too small to be observed under light microscope. This idea fails to be accepted by the present scientific community in the absence of any direct evidence. At the same time three landmark discoveries came together that formed the founding stone of what we call today as medical science . The first discovery came from Louis Pasture (1822-1895) who gave the spontaneous generation theory from his famous swan-neck flask experiment. The second discovery came from Robert Koch (1843-1910), a student of Jacob Henle, who showed for first time that the anthrax and tuberculosis is caused by a bacillus, and finally Joseph Lister (1827-1912) gave the concept of sterility during the surgery and isolation of new organism.
The history of viruses and the field of virology are broadly divided into three phases, namely discovery, early and modern.
The discovery phase (1886-1913)
In 1879, Adolf Mayer, a German scientist first observed the dark and light spot on infected leaves of tobacco plant and named it tobacco mosaic disease . Although he failed to describe the disease, he showed the infectious nature of the disease after inoculating the juice extract of diseased plant to a healthy one. The next step was taken by a Russian scientist Dimitri Ivanovsky in 1890, who demonstrated that sap of the leaves infected with tobacco mosaic disease retains its infectious property even after its filtration through a Chamberland filter. The third scientist who plays an important role in the development of the concept of viruses was Martinus Beijerinck (1851-1931), he extended the study done by Adolf Mayer and Dimitri Ivanofsky and showed that filterable agent form the infectious sap could be diluted and further regains its strength after replicating in the living host; he called it as “contagium vivum fluidum” . Loeffler and Frosch discovered the first animal virus, the foot and mouth disease virus in 1898 and subsequently Walter Reed and his team discovered the yellow fever virus, the first human virus from Cuba in1901. Poliovirus was discovered by Landsteiner and Popper in 1909 and two years later Rous discovered the solid tumor virus which he called Rous sarcoma virus.