L24 evolution Flashcards
name the two systems of virus clarification
ICTV system
Baltimore
which is the preferred and followed system
ICTV
hierarchal levels of ICTV system
order> family> subfamily> genus> species
virus properties ICTV system is based on?
nucleic acid symmetry of capsid dimension of virion and capsid envelope presence host range
how many groups are in the Baltimore system
7
what is Baltimore system based on
viral genome replication
mRNA synthesis
what are the 7 groups
dsDNA ssDNA dsRNA \+veSS RNA -ve SS RNA retroviruses reverse transcribing viruses
two steps of virus introduction into the human population
introduction to a new host population (if no further interactions occur, virus dies)
dissemination of the virus within the new host population (further interaction between healthy and infected people can result in establishment)
factors that drive virus emergence (4)
ecological changes
human demographics and behaviour
international trade and travel
virus adaptation and evolution
Examples of ecological changes
agriculture: puts us in contact with the natural host
changes In water system: puts us in contact with vectors (mosquitos)
flood: dissemination of viruses like polio and hep A/E
examples of human demographics and behaviour
pop. density & lack of herd immunity
urbanisation
IV drugs
multiple sex partners
examples of international trade and travel
globalisation
reducing dead-end host/virus interactions
global trade
