Viral Propagation


Evolution is a necessary accumulation of mutation and selection.  RNA viruses can participate in evolution in a day.  After 25 to 30 plaque to plaque assays, a scientist gets a sick population of viruses.  A genetic bottleneck occurs.  The diversity of the virus is causing fewer viruses to be selected for in a particular plaque assay.  This is known as Muller’s ratchet.  So far 18 different Hemagglutinins have been  discovered, along with 11 Neurominidases.

Ebola is an acute infection.  Ebola comes, it’s infective for a particular time, and then it’s over.  In a massive Ebola outbreak in Africa, it was found that the virus can persist.  It persists in at least two sites in the body.  One of them is in the ocular fluid.  The Ebola virus is contained within the eye ball and it’s not shed in tears.  Another site where Ebola virus is found a long time after infection is in the semen.

Zika was identified in 1947 in Uganda, isolated from Aedes africanus.  It was isolated from humans in Nigeria in 1954.  Zika was serologically detected throughout Africa and Asia; but there were no outbreaks.  There were  less than twenty cases in people over the next fifty years, going into the late 1990’s.  The first cases of Zika were in the Americas in Brazil.  The misquitoe transmits the Zika virus.  Zika may also access the Central Nervous System and cause complications.