VIRUSES Nature’s Robots

General Characteristics Non-Living Contain strand of genetic material: DNA/RNA Encased in a Protein Coat: Capsid Have structures for attachment to a host cell CAROUSEL

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Cannot make proteins Require a vector; can’t move by themselves: air, water, blood, body fluids, other organisms Smallest disease causing pathogen Cannot replicate themselves, so are called: obligate intracellular parasites Are a mechanism for transferring DNA/RNA to cells: Good for genetic treatments, bad can cause some cancers Many shapes: spheres, hexagons, spirals, etc.

Viral Replication COLDS FLU HPV: WARTS MEASLES GENITAL HERPES ASSEMBLY TRIGGERED BY TRAUMA, OR IMMUME DECLINE ATTACHMENT RELEASE ENTRY AS CELL REPLICATES SO IS THE VIRAL DNA, RESULTS IN MILLIONS OF CELLS WITH ‘HIDDEN’ VIRAL DNA ASSEMBLY COLDS FLU MEASLES CHICKEN POX HPV: WARTS GENITAL HERPES SHINGLES COLD SORES REPLICATION VIRAL DNA INCORPORATES GOES DORMANT

IMMUNITY SHORT TERM LONG TERM

IMMUNITY NATURAL ACTIVE IMMUNITY ARTIFICIAL ACTIVE IMMUNITY Person is exposed to live pathogen Develops the disease Immune system produces antibodies to fight infection Antibodies remain after viruses are destroyed Immune response is induced by introduction of a vaccine Vaccine contains viral genetic signature Antibodies produced without infection