Question

What is the first virus in the world?

Answer 1

Viruses are submicroscopic and non cellular organisms generally smaller than 200mu/200 nm. They are obligate intracellular parasites. They have either RNA or DNA, no virus contains both DNA AND RNA. They are inserted outside their specific host cell in crystalline form, they contain nucleic acid so they are capable of protein synthesis by the help of ribosomes of the host cell.

Complete answer:

'Virus' is a Latin word which means poisonous fluid.
Ivanowsky first separated a microorganism from the sap of an infected plant and its TMV(Tobacco mosaic virus). In 1892 he reported that extracts from infected leaves were still infectious after filtration through a chamberland filter candle. Bacteria are retained by such filters.

In 1898, Bejrink first called this fluid as virus, the incitant of the tobacco mosaic, so he called them Contagium vivum fluidum or living infectious fluid.

In 1881, Carlos Finlay identified the first human virus which was the yellow fever virus. He first conducted and published research that indicated that mosquitoes were carrying the causative agent of yellow fever, a theory proved in 1900 by a commission headed by Walter Reed (1851–1902).

The DNA and RNA sequences of viruses may change over time. Scientists can look at these genetic sequences to estimate how different viruses are related and how they may have evolved.

These studies have shown us that viruses do not have a single origin, i.e. they did not all arise from one single virus that changed and evolved into all the viruses we know today. Viruses probably have a number of independent origins.

One assumption scientists make is that viruses are co-evolved with its host, for example, the herpes virus that infects humans evolves over time, adapting so that it will continue to retain the ability to infect human cells.

Origin stories of viruses:

1. One theory suggests that viruses arose from plasmid (single circular DNA) that can replicate independently and move between cells, transferring genetic information from one organism to another.

2. Another theory suggests that viruses could have evolved from more complex free-living organisms, such as cells or bacteria.

Both the theories above assume that viruses evolved from preexisting cells or bacteria.

But there is yet another hypothesis which proposes that viruses existed even before cells. Viruses might have existed as self-sustaining entities, a sort of ancient machine that could probably reproduce its genetic material.

Note:
There are only theories about the origin of viruses as the technology and resources we have today cannot confidently test these theories and identify the most possible explanation for the origin of viruses. So at this point it is difficult to find the first virus in the world, we can only assume their existence.