Viruses

[kwicky]

When a vrus searches for its host what senses does it use before latching onto it.? The foot and mouth virus needed to travel miles before finding a cow. I find it hard to believe random movements of the virus took it to its destination.

[jake-the-peg]

A virus is little more than a chemical, it's not even really alive unless it gets into a host, where it gets itself into a hosts DNA or RNA and uses all the mechanisms and aparatus of the hosts cell to reproduce itself.

It spreads because when it gets out again it does so en-mass, and virus spores are about a thousanth of a mm in size.

Thousands could attach to a car or lorry or post van visiting a farm and spread to the next farm along.

[WaldoMcFroog]

Imagine a mobile phone in a car. The phone is continually searching for a network signal to connect to, but it is only the car's moving that will bring it in contact with one it can pick up.

It's not finding a network through any volition of its own, it's just that when it does come into contact with an available network, it will 'latch on', so to speak.

[dundurn]

What this also means is that millions of copies of the virus may be released and not find an acceptable host - a liitle bit like the millions of eggs/ larvae that some sea creatures release into the oceans of which the vast majority end up as food for other animals but if two survive to maturity the species can sustain itself.

Also remember that many viruses (and bacteria) co-exist perfectly happily, or at least don't threaten to kill their hosts. It's when the virus mutates or when it crosses over to an unfamiliar species that trouble starts.

[kwicky]

I sometimes look for analogies. The human influenza virus is caught either by touch or breathing in the expelled contents of a sneeze. But in this case the range of transmission is extremely low. I assume all viruses work this way including the blue tongued or foot and mouth varieties. If so they must be in close contact with the infected cow and therefore initially another species such as deer or boar which roam freely. If so this would eliminate transmission by vehicle or footwear.

I would think it highly unlikely anyone caught flue from footwear or vehicle tyres?

[jake-the-peg]

Maybe it would help if you thought of it more like pollen.

F&M virus spores have been found to travel large distance in the air.

Can you not imagine pollen on the wind attaching to a post van on one farm and then being blown off into a field where cattle are grazing at the next?.

And pollen is a lot bigger than a virus spore

[kwicky]

But a virus must be much lighter than air and to stay at ground level when a small gust of wind would blow it skywards?