Viruses

“They Are Not Alive!”

Viruses

Non-Living?

Viruses DO NOT: Metabolize on their own Reproduce Move Take in food Grow Consist of cells

What they can do is take a host cell “Hostage”

Bacteriophage

Consist of a protein coat called a Capsid Contain Viral DNA Special Ligands allow the virus to attach

to the cell receptors of a host cell.

Viral Infection

A virus can reproduce in two ways:

1.The Lytic Cycle: infects and affects the host cell very quickly. Flu, Ebola, Cold

2. The Lysogenic Cycle: infects but does not affect immediately HIV, Herpes

The Lytic Cycle

The Lysogenic Cycle

INCUBATION PERIOD

Lytic Cycle Animation

Lytic Cycle #2 Virus Attack H1N1 Lytic Infection PH

Viral Infections Encephalitis Influenza Meningitis Ebola HIV Lassa Fever Mononucleosis Rabies Dengue Fever Yellow Fever H1N1 (Swine Flu)

Small Pox Chicken Pox Herpes Hanta Mumps Measles Polio Hepatitis West Nile Corona

Vaccines

Vaccines are used to establish immunity. They can be made of weakened viruses or

“dead” viruses. The body recognizes and

destroys the viruses. It will“remember” them so that the next time they are in the body, they will be destroyed.

Ex. The H1N1 Shot

More Human Viral Diseases

Chicken Pox Mumps Herpes Hepatitis Warts

How big are Viruses?

Viroids and Prions

Viroids

• Infections agents composed of a single, circular strand of RNA. They are not protected with a protein coat.

• Viroid RNA does not code for any known protein.

• Mostly affect plants but recently have been found to affect humans.

Viroids and Prions

Prions

• An infectious particle made of protein

• Affect the brain or neural tissue.

• All are untreatable and fatal

• Ex. Mad Cow Disease