I, Virus

"Unimpeded by friction with the surface of the Earth, you can travel great distances, and so intercontinental travel is quite easy [for viruses]."
"It wouldn't be unusual to find things swept up in Africa being deposited in North America."
"If you could weigh all the living material in the oceans, 95 percent of it is stuff you can't see, and they are responsible for supplying half the oxygen on the planet."
"Viruses aren't our enemies. Certain nasty viruses can make you sick, but it's important to recognize that viruses and other microbes out there are absolutely integral for the eco-system."
Curtis Suttle, marine virologist, University of British Columbia

"Viruses modulate the function and evolution of all living things."
"But to what extent remains a mystery."
Matthew B. Sullivan, Ohio State
Joshua Weitz, Georgia Tech
Steven W. Wilhelm, University of Tennessee

Viruses and bacteria fall back to Earth via dust storms and precipitation. Saharan dust intrusions from North Africa and rains from the Atlantic.  Credit: NASA Visible Earth

More commonly the general layperson knows viruses as an inimical presence to human health. Scientists, however, are learning more about them all the time. Three of whom last year recommended a vigorous new initiative be undertaken to focus on their presence, to enable a greater understanding of viral ecology. Recognized as the elite predators of the world of microbes they cannot reproduce and are co-dependent on a host. When they attach to a host they take over cells and this process is called 'infection'.

This enables the virus to replicate, injecting its own DNA into the host and in the process those alien virus genes become useful to the host, resulting in their becoming an integral part of the host's genome. Research has progressed; recent research identified an ancient virus that at one time inserted its DNA into the genomes of four-limbed animals, the ancestors of homo sapiens. That minuscule part of the genetic code, the ARC, forms part of the nervous system of modern humans playing a vital role in human consciousness; nerve communication, memory formation and higher-order cognition.

Scientists estimate that between 40 to 80 percent of the human genome may have graduated from primitive viral invasions. Understanding the function and ecology of viruses and their prey will eventually enable better understanding of the role they play in the world's ecosystems, so research is geared at factoring their presence into an understanding of a formidable connection in how the world works.

In Spain's Sierra Nevada mountains, a team of international researchers set out to retrieve viruses falling from the sky, placing four buckets in position to gather any possible samples, the thought being that a stream of viruses circle the planet above our weather systems, below the level of height achieved by airplanes. This is an entirely new realm of scientific study. The team of scientists was amazed to collect around 800 million viruses falling on each square metre of Earth, surpassing expectations entirely in a magnitude never imagined.

It has been hypothesized that most of the viruses cascading down onto the Globe, are swept into the air by sea spray, with some of their numbers scattering in dust storms. Dr. Suttle and his team's findings were published in the International Society of Microbial Ecology Journal, the first to actually count the numbers falling to Earth, representing the virosphere. These viruses are held to originate on the planet but become upwardly swept. On the other hand, some researchers hold to the theory they may originate in the atmosphere.

And though viruses equate in most peoples' minds with illnesses like influenza-onset, as infectious agents inimical to people's health, as the most abundant organisms on the planet alongside bacteria, they are essential to existence in countless measure, from our immune system to our gut microbiome, to land and sea ecosystems, climate regulation and species' evolution, all aided by the vast array of unknown genes contained in viruses, spreading and inserting them in other species.

Dr. Suttle's laboratory experiments included filtering viruses out of seawater, leaving behind bacteria. With the viruses absent, plankton present in the water failed to grow, since microbes were not present to liberate nutrients in the organisms they infect. By altering the composition of microbial communities, viruses assist in the balance of ecosystems. A virus attacks algae as it spreads in toxic blooms in the ocean, causing it to explode and die, effectively putting an end to the outbreak.

Credit: CC0 Public Domain     Viruses are the most abundant and the least understood entities on Earth. They might also exist in space, but as of yet scientists have done almost no research into this possibility.

Viruses are the most abundant and one of the least understood biological entities on Earth. They might also exist in space, but as of yet scientists have done almost no research into this possibility.

Read more at: https://phys.org/news/2018-01-viruses-space.html#jCp

But while viruses have an undeniably positive impact, they can also become invasively injurious to species, causing changes and leading to extinction. When West Nile virus altered the composition of bird communities, crows died while ravens thrived. Mosquito-borne avipoxvirus spreads into the mountains of Hawaiian forests, once too cold for mosquitoes to thrive.

An example of species' extinction occurred when a viral disease called rinderpest arose when the Italian army brought along a few head of cattle to North Africa in 1887 and the virus spread across the Continent, killing cloven-hoofed animals from Eritrea to South Africa, wiping out 95 percent of herds in some instances. "It infected antelope, it infected wildebeest and other large grazers across the whole ecosystem", explained Peter Daszak, president of Ecohealth Alliance.

Drought exacerbated the situation, the result being that large numbers of people died of starvation in lock-step with the spread of rinderpest killing the animals they depended upon as a food source. Two thirds of the Masai people who depended on cattle, died in 1891. An intensive round of vaccinations helped to completely wipe out rinderpest, in Africa and globally by 2011.

Berliner et al review current virology research pertinent to astrobiology and propose ideas for future astrovirology research foci. Image credit: Arek Socha / FL.