Microbio 2: Viral Pathogenesis

Front 1

Virulence

Back 1

The capacity of a virus to cause disease

Front 2

Viral pathogenesis

Back 2

the process by which a viral infection leads to disease. The sum of the effects of virus replication and the immune response on the host.

Front 3

3 patterns of viral infection

Back 3

1. Acute
2. Chronic
3. Latent, Relapsing

Front 4

Acute Infection

Back 4

-Self limited
-Often asymptomatic
-Often RNA viruses
-Interact with innate immune system
-Often shut of host cell protein synthesis
-Cytopathic in vitro (inclusions, syncytia, cell swelling, apoptosis)
-Replicate quickly and kill the cell
-ex: influenza, rhinovirus

Front 5

Syncytia

Back 5

Cell fusion that can be caused by viral infection. Viral fusion proteins delivered to surface and the infected cells fuse together

Front 6

Viral infections triggers production of...

Back 6

Cytokines, interferon, TNF

Front 7

What induces the anti-viral state in neighboring cells

Back 7

INF (alpha and beta) released by infected cell

Front 8

Chronic Infections

Back 8

-Prolonged period of time, continuously or intermittently
-Often DNA virus
-May or may not be cleared
-Non-cytopathic
-Evasion of host immune defenses
-Do not kill cell
-Symptoms often from immune response that kills infected cells
-Encounter Adaptive immune system (and innate too)

Front 9

3 mechanisms chronic infections use to evade adaptive immunity

Back 9

1. Mutate and evolve
2. Modify immune response
3. Establish a latent infection and wait for immune response to wane

Front 10

Latent Infections are usually DNA or RNA viruses

Back 10

dna

Front 11

Main Routes of Transmission

Back 11

1. Respiratory (aerosolized droplets, saliva)
2. Ailementary tract (fecal/oral, non-enveloped)
3. Urogenital (sexually transmitted)
4. Skin, mucous membranes

Front 12

Passive Viral Dissemination (types)

Back 12

1. Hematogenous spread
2. Lymphatic Spread

Front 13

Viremia

Back 13

Presence of infectious virus particles in the blood

Front 14

Hematogenous spread

Back 14

virus enters the blood streams

Front 15

Active Viral Dissemination (types)

Back 15

1. Hitch ride on migratory cells (DC and HIV)
2. Viral Surfing- Attach to cell surface and induce cell to move virus to where it can enter
3. Trigger own internalization into the cell
4. Move within a cell via microtubules (retrograde/anterograde spread)
5. Movement from cell to cell via filopods, budding, and actin rockets

Front 16

3 major ways that viruses cause disease

Back 16

1. Direct cytopathic effects
2. Immunopathology
3. Viral oncogenesis

Front 17

Diseases of immuno pathology
4 classes

Back 17

1. cell mediated
2. antibody mediated
3. autoimmunity
4. immunosuppression

Front 18

What % of human cancers arise from viruses. What % are liver and cervical

Back 18

20% and 70%

Front 19

Mechanisms for Virus Induced Tumorigenesis

Back 19

1. Targeting tumor supressors
2. Inappropriate expression of growth factors
3. Induction of chronic injury/inflammation (hep B)
4. Retroviruses can encode oncogenes
5. Inderectly by prolonged immunosupression

Front 20

Which 2 HPV viral proteins are highly expressed in cervical cancer tissue

Back 20

E6- Degrades p53
E7- Inactivates pRB

Front 21

Function of HPV E2 protein

Back 21

E2 inhibits the production of E6 and E7 proteins, which are related to cancer formation. E2 is often removed when the HPV genome is incorporated into the cellular genome

Front 22

Gardasil

Back 22

protects against type 16 and 18 (70% of cancer) and types 6 and 11 (90% of warts)