Cell, organs, system, body. From the smallest to the most complex, the Wisdom of Nature came up with a brilliantly choreographed dance to keep everything balanced, with one purpose: homeostasis. Defense mechanisms are naturally in place to block and eliminate  intruders that could jeopardize the beautiful intersect balance.

Yes, it is all about balance!

Balance,

balance

and balance

Infections are also part of this balance. In the case of viral infection, one has to be mindful of its contribution to the evolution of mankind. Viruses are the most abundant biological entities on Earth. They are present everywhere, in our surrounding, the oceans, the soil and in every living being. They are all part the life cycle. We understand the viruses are obligatory parasite ; they absolutely need the host to survive. Being lethal for a virus is not a good survival strategy. Mutations are part of viral life cycle, mainly to lose some of its initial lethality and gain transmissibility.

As new virus came into contact with humans throughout our time on hearth, a kind of symbiotic relationship was established where the virus adapted overtime trough mutations, to lose a bit of its initial lethality in order to cohabit and maintain a living host (a dead host is useless). On the other hand, the host surviving the initial infection, reinforced its innate immunity trough those diverse viral encounters triggering adaptive immune responses. The immune memory is passed on from a generation to the next by the mother breastfeeding her baby. From time to time, the symbiotic relationship was also instrumental to the evolution of the host when retroviral genetic material is reversed transcribed into the host genetic material. Through these new integrated external genes, the host sometimes gained beneficial new functions. Ref: RNase H As Gene Modifier, Driver of Evolution and Antiviral Defense

Yes, Man evolved partly due to viral infections. It was somehow integrated in the universal balance, where every living organism is doing what it can to survive. Yes, even viruses are part of the universal balance…