survey of viruses 2

where does DNA replication typically occur in

the nucleus

in DNA replication what might they use

replication may or may not use host machinery depending wheather the virus carries a DNA polymerase

• bigger because carrying something in the genome

when is virus DNA synthesis most efficient

during host cell dna synthesis (mitotically active cells )

• when it has something to highjack

where does RNA viruses replication typically occur in

the cytoplasm

what is replication of progeny genomic RNA molecules mediated by

viral specific RNA polymerases

for RNA replication viruses must carry

RNA dependent RNA polymerase

what does RNA repliaction require 

synthesis of anti- genome 

what does RNA replication typically occur with

simultaneously with the sythesis of viral proteins

what does protein poduction rely on

host machinery

what is influenza structure

negative sense single stranded RNA virus

• enveloped virus

influenza genome

has 8 segments

does influenza have glycoprotein spikes

yes 2

influential:Neuraminidase spike (NA)

enzyme breaks down respiratory mucus and assists in budding

influential:hemagglutinin spike (HA)

binds receptors and induces entry

clinical features of influenza

• spread by respiratory droplets (about 6 ft radius)

• 1-3 day incubation period 

• complications in immunocompromised 

• pneumonia (caused by influenza virus) and bacterial pneumonia 

• fever, myalgia, headache, pharyngitis 

antigenic drift

slower because is drifitng, like drifting out to sea

• has mutations on spikes

• seasonal epidemics ( like flu: can predict how viruses are going to react/ mutate)

antigenic shift 

faster

• creates new HA gene, sometimes new NA gene

• rearrangement of subgenomic viral RNA

• pandemics (spanish flu)

laboratory diagnosis 

• virus isolation from respiratory secretions 

• serology (serum antibodies to HA)

• sometimes needs no further testing

treatment for influenza

tamiflue and relenza

• however by the time most of these medicines are given it is to late and they dont have to much help because of how far the sickness has been

• antibiotics for secondary bacterial infections

what should you not give to people for influenza

asprin because it increases the likelyhood of reyes syndrome

influenza prevention

annual immunization(only 40-60 percent effective because of how often it mutates)