The virus dropped in unnanounced to the swimming pool.  Everyone ran screaming out of the pool immediately.  The owner called the pool guy for treatment.  The pool guy said "My tests found dirt particles that may contain the virus.  I will treat the pool for $5,000.  It will need to be treated regularly for this unique virus that could kill your pool water."  The owner was perplexed at the cost.  The owner wondered how a virus that was so infinitessimally small could possibly ruin the whole pool.  The pool guy said "Well, it replicates itself and eventually takes over".  The owner was scared so he called in another pool guy who said, "Viruses are dead, let the filter clean them out" and didn't charge him a dime.  The owner of the pool decided to play it safe.  He signed a contract with the first pool guy who said he was an expert.  The contract was for treatments at a cost of $10,000 a year.  At a pool party he told his story about treatment and this new pool virus.  Some in the group said their pool never got tested for NPV, that "new pool virus", and that they only have to spend $75 a year on chlorine to kill living organisms that get into the pool which actually have the ability to replicate.  They were baffled as to why he would spend so much money trying to kill something that was already dead.