Viruses exist in a variety of shapes and sizes.

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Viruses exist in a variety of shapes and sizes.
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• Simple and small pathogen
• Made of Capsid and RNA or DNA
• Non living (must infect living cells)

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• Shapes

(foot-and-mouth disease)
(influenza)
1. Enveloped
3. Polyhedral
(rabies)
2. Helical
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• 4. Bacteriophages- viruses that infect bacteria.

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• Viruses enter cells in various ways.

• bacteriophages pierce host cells

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• - viruses of eukaryotes enter by endocytosis and
  also fuse with membrane

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Viruses cause two types of infections.

• A lytic infection causes the host cell to burst.

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• A lysogenic infection does no immediate harm.

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Viral Diseases

• Common Cold contaminated objects
• Influenza respiratory droplets (sneeze)
• HIV/AIDS body fluids
• Chicken Pox respiratory droplets (sneeze)
• Hepatitis B contaminated blood/ body fluids
• West Nile Virus - mosquitoes
• HPV sexual contact (causes cancer)
• Small Pox respiratory droplets
• Mumps respiratory droplets
• Measles respiratory droplets
• Food Poisoning eating bad food

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• Virus Prevention
• Vaccines
• Wash hands/ Good hygiene
• Cough/ Sneeze in tissue/ sleeve
• Disinfectants (breaks apart capsid/RNA)