When you hear a word “virus”, what do you imagine?

“A pathogen”?

“An epidemic”?

Or its “shape” such as a sea urchin, a scourer or spaghetti?

I just speculate what you have imagined would be different each other. That means, it is not as easy as we expect to grasp the identity and “raison d’etre” of viruses.

So, what is the identity of viruses?

I think, the word “virus” would be a sort of generic term for expressing itself, or just a sort of a virtual.

Let me take “the influenza virus prevalent this year” as an example. Its shape would be similar to “the influenza virus that was prevalent last year”, which is a typical shape of influenza virus. But the pathogenicity and infectivity of “this year’s virus” would be definitely different from those of the “last year’s”. Also, the influenza virus that I infected is not identical to yours. Moreover, the viruses replicated in me yesterday would be neither identical to those are replicating in me today, nor will those be replicating in me tomorrow.

This example illustrates the difficulty to define and express “the real of virus” through the single word “virus”. Let me introduce my personal image - “virus” is like birds flying in swirling masses in the evening sky, or a flock of young fish migrating in the sea. Each individual can be recognized in detail as an entity. However, at the same time, when we try to grasp themselves as “the whole entity”, it is vague and variable, but it can be grasped as “an entity” and behaves in an integrated manner.

Then, what is the identity that makes a virus “a virus”? To answer this question, its shape, infectivity, pathogenicity, and even certain specialized classifications such as genotypes and serotypes would be just sufficient conditions (e.g., apples, watermelons, cherries), however, none of them are necessary conditions (e.g., fruit). So, what are the necessary condition(s) for expressing a virus “the virus”, namely, what is “the real” or “the entity” of the virus?

“Systems Virology” is a coined word made by myself, and hopefully, is a science to give an optimal answer to this question. We aim to pioneer a scientific field to understand “the entity” and/or “the real” of viruses. We aim to pioneer an interdisciplinary research field, that is not made of the common divisor of the virology nowadays but is made of the common multiple of the advanced virology and other sciences. And I hope the people in my lab think of this question and learn how to reach to the answer of this question together.

Kei Sato

October 2019, in Tokyo.