The Brief History of Virology

It all started in the late 1800’s with the works of Breijerinck, Mayer and Ivanovski on contagium vivum fluidum, the pathogen that ravaged tobacco crops around the globe. Now known as tobacco mosaic virus (TMV), this microscopic pathogen was the first identified virus, and its discovery marks the birth of virology.

Through the past 120 years virology has evolved and viruses have been at the center of scientist’s interests at multiple different occasions like the 1918 Spanish flu pandemic or the more recent SARS-CoV2 pandemic. In addition, even though virology is only officially 124 years old, scientists have been studying viruses long before they even knew what they were. Variola virus, responsible for smallpox, is the first known pathogen against which a vaccine has been developed, and this was done by Edward Jenner in 1780, over 100 years before the discovery of TMV. The development of the variola virus vaccine also marked the birth of immunology as a discipline and opened the doors for the development of multiple other preventive or curative vaccines.

But what is a virus?

Scientists define viruses as obligate intracellular parasites, incapable of multiplying outside of a living host. In other words, this implies that when a virus enters a cell it hijacks the cell machinery and basically reprograms it to favor its own replication instead of ensuring the multiple processes necessary to keep the host cell alive. We could compare these pathogens to plane hijackers, who knock-out the pilot, lock themselves in the cockpit and then do as they please with the plane and all its passengers. Just like the hijackers, viruses do their best to pass unnoticed by the organism’s defenses by either hiding when circulating inside and outside cells, or by implying a more aggressive tactic where they deactivate the host’s defense mechanisms. Successful immune evasion is at the heart of a productive infection and helps to tilt the scales to the virus’ side, but we’ll talk about this at another time.

Since Brejerinck published his work on TMV in 1898, laying the first stones in the history of virology, the world has seen dozens of generations of virologists who have helped build this rich and diverse discipline. Nowadays, modern virologists focus on all possible aspects of virology. Whether they work on host-pathogen interactions, virus immune-evasion, epidemiology or emerging viruses they all work towards the same end goal, which is characterizing and understanding the dynamics of transmission and multiplication of these curious and diverse pathogens.