1. Biology 331 Virology II

2. Class IV and V Viruses RNA/RNA Pol (1 error/50,000 bases)

3. Class IV Poliovirus GI mucosa/diarrhea 99%, neuron/paralysis 1% Unenveloped capsid, NO enzymes in virion ss(+) RNA - 3 proteins from ONE reading frame Host ribosomes translate into POLYPROTEIN Protease autocleavage - coat, RNA/RNA Pol

8. Special Issue - Polio History in the US Pre-1900, polio/fecal water everywhere… Infants exposed while still passive IgA-protected Post-1900, sanitation delayed exposure So - US epidemics 10 3-4 /year, 1910-55 Now, polio vaccines - close to eradication

12. Class V Influenza Mammalian lower respiratory, pneumonia Envelope with H and N proteins - bind, virulence 8 helical gene segments, RNA/RNA Pol in virion (+) copies - host translates; (-) copies - genomes Ag shift (coinfection/reassort) vs. drift (mutations) “Shift” and “Drift” coined to describe influenza but relate to ANY virus.

22. Class VI and VII Viruses Use RT RT Pol (1 error/12,000 bases)

23. Class VI Retroviruses Tumors/HTLV, immunodeficiency/HIV Envelope/surface protein around capsid with… Reverse Transcriptase (RT), Integrase (IN)… Diploid/2 ss(+) RNAs genomes - to DNA (RT) INT inserts DNA into genome, host expresses

26. Retrovirus Genes LTR - long terminal repeat promoter, CIS! GAG (capsid/protease) and POL (RT/INT) ENV - surface protein and tat (TRANS activator)

28. HIV/AIDS STD, blood, perinatal (in utero and breastmilk) Phagocytes - spreads inside, “Trojan Horse” T cells - kills, decline = AIDS, opportunists MALT - kills, GI wasting, opportunists Brain Phagocytes/Microglia - dementia

32. AIDS Cases - US Distribution What most of the world looks like

33. Class VII Hepatitis B STD/blood/perinatal - chronic liver, cancer Envelope/surface protein around capsid… Partial dsDNA, encodes BOTH DNA Pol and RT DNA Pol finishes DNA, host - RNA/proteins RNA partly copied to DNA by RT - packaged Contrast with A - acute, no envelope, food-water acquired (Section 34.12)