Virus: Microlife Virus: Microlife Infectious DiseasesInfectious Diseases

Objective: you will be able to Objective: you will be able to understand and explain how viruses understand and explain how viruses

attack and effect human cellsattack and effect human cells

Intro: Infectious Disease TermsIntro: Infectious Disease Terms

Disease which travels Disease which travels easily from one organism easily from one organism to another: Can also to another: Can also travel between species as travel between species as wellwell

Pandemic – fast Pandemic – fast spreading international spreading international outbreakoutbreak

Epidemic- wide spread Epidemic- wide spread out break of disease at a out break of disease at a specific locationspecific location

Asian Bird Flu 2007

PathogenPathogen

PathogenPathogen- Any organism that - Any organism that causes diseasescauses diseases

CarrierCarrier- any human giving a - any human giving a disease to another humandisease to another human

VectorVector- any NON-HUMAN - any NON-HUMAN source of a disease being source of a disease being passed on to a humanpassed on to a human

Diseases are primarily Diseases are primarily responsible for damaging responsible for damaging individual cells, which causes individual cells, which causes us “sickness” symptoms” as us “sickness” symptoms” as cells break downcells break down

Ex: sore throatEx: sore throat

4 Forms of Pathogens4 Forms of Pathogens

VirusVirus

BacteriaBacteria

FungiFungi

ProtistsProtists

Bacteria

What are Viruses?What are Viruses?

VirusesViruses

Non- Living: Do not Non- Living: Do not require any energy to require any energy to survive; No food/gas survive; No food/gas needsneeds

Extremely Small Extremely Small Organism made up of Organism made up of DNA or RNA and a DNA or RNA and a Protein Coat : Protein Coat : CAPSIDCAPSID

Only capable of Only capable of reproducing itself by “hi-reproducing itself by “hi-jacking” another celljacking” another cell

HIV Virus

3 Main forms of Viruses3 Main forms of Viruses

(Norovirus) /Polyhedral(Norovirus) /Polyhedral

BacteriophageBacteriophage

(Filovirus)/ Rod Shaped ) (Filovirus)/ Rod Shaped )

All viruses have two types of All viruses have two types of infection cyclesinfection cycles

Lytic Cycle (Active) Lytic Cycle (Active) show signs of show signs of sickness immediatelysickness immediately

Lysogenic Cycle (Non Lysogenic Cycle (Non Active) no illness Active) no illness creates “provirus creates “provirus cells” within body then cells” within body then becomes active becomes active

Lysogenic CycleLysogenic CycleShows no disease Shows no disease symptoms, may carry symptoms, may carry virus for yearsvirus for yearsFACT: HIV can stay like FACT: HIV can stay like this for over 10 YEARS!!this for over 10 YEARS!!1. Virus attaches to host1. Virus attaches to host2. Viral DNA integrates 2. Viral DNA integrates or combines with cells or combines with cells DNA; becomes a DNA; becomes a “provirus” cell“provirus” cell3. As cell splits and 3. As cell splits and divides virus replicates divides virus replicates with cell creating more with cell creating more “provirus” cells“provirus” cells4. Some trigger activates 4. Some trigger activates virus: become illvirus: become ill

Lytic CycleLytic Cycle

Show disease symptomsShow disease symptoms

Virus actively attacking cellsVirus actively attacking cells

1. Virus attaches to host cell1. Virus attaches to host cell

2. Virus enters host cell2. Virus enters host cell

3. Virus destroys host cell’s 3. Virus destroys host cell’s DNA, replaces DNA with its DNA, replaces DNA with its own VIRAL DNAown VIRAL DNA

4. “Hijacked” cell creates more 4. “Hijacked” cell creates more Viral DNA and protein coatingViral DNA and protein coating

5. Lysis-host cell ruptures and 5. Lysis-host cell ruptures and releases hundreds of new releases hundreds of new virus to attack more cellsvirus to attack more cells

Common VirusesCommon Viruses

Chicken poxChicken poxHerpesHerpesHIVHIVEbolaEbolaEpstein Bar (mono)Epstein Bar (mono)MumpsMumpsWartsWartsInfluenzaInfluenzaHepatitisHepatitisCommon ColdCommon Cold

How we fight back: VaccinesHow we fight back: Vaccines