Download Viruses HIV

Basics of HIV Virus
Vijay Kandula, MD MPH AAHIVS
Adjunct Assistant Professor
Division of Public Health, Department of Family and Preventive Medicine
University of Utah, Salt Lake City
2013
Viruses are not living organisms
Viruses do not
– Grow
– Metabolize
Viruses do
– Infect cells and use the host cell to make
more copies of themselves
– Cause disease in many organisms
Parts of a Virion (a virus particle)
Nucleic Acid – RNA or DNA
Capsid – protein coat that surrounds the DNA
or RNA in a virus
Lipid Membrane – a membrane around the
capsid in many kinds of viruses; helps the
virus enter cells (“enveloped” viruses;
without the membrane, the virus is “naked”)
– Made of proteins, lipids, and glycoproteins
Mutating viruses
Viruses can mutate when they copy the
genetic material
– For e.g., a photocopy of document with stains;
they show up in subsequent copies
– Mistake proves useful
– Can lead to stronger virus (more infectious)
Viruses don’t mutate often, except…
– Influenza
– HIV
HIV Replication
• RNA Virus
•Produces 1010-1012 new virions each day
Basic Structure
• Viral envelope: lipid layer; glycoproteins protrude from
surface
– Glycoproteins enable virus to recognize surface proteins of
special CD4 or T Helper Cells (a special type of immune cells)
– This allow entry into these cells (like a key to the cell’s door)
• 2 strands/copes of RNA
– only 9 genes; 3 are found in many viruses (structural proteins)
• Reverse Transcriptase enzyme
– converts RNA into DNA (this makes HIV a RETROvirus);
– This DNA instructs cell to make more viruses
HIV Replication 3D
Medical Animation
• http://www.youtube.com/watch?v=9leO28y
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Introduction Continued
Introduction Continued
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HIV Types, Groups, and Subtypes
Geographic Distribution of HIV-1 Subtypes and HIV-2
A,B,A/B
BF
B
HIV-2 C,E
HIV-2
BFC
A,G,A/ C
A,D
G
C
C EB
B
Subtypes A, B, C, D, “E”, F, G, H, “I”, J, K, CRFs, and untypable