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51 Cards in this Set
- Front
- Back
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Colonization |
A pathogen is living within the host but does not mean infection exists |
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Infection |
Invasion, colonization, and multiplication of pathogens within the host - diagnosed when there is isolation of a pathogen - evidence of its presence and pathogen-related host symptoms |
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Virulence |
Disease-producing potential of an organism |
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Virulence Factors |
Enhance the pathogen's ability to infect the host - pathogenic toxins that destroy host cells - adhesion factors that enhance attachment of the pathogen to the host cells |
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Severity of infection depends on: |
- virulence of the pathogen - strength of the host defenses at the time of infection |
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Reservoir |
Any organism or substance with the disease caused by the pathogen if reservoir is alive Ex: - a child with chickenpox because they harbor the transmissible microorganism - Fomites |
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Vector |
A living organism that can carry the pathogenic organism from the reservoir to the host - commonly an insect - not infected but can transmit to host |
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Epidemiology |
- The study of disease distributions in human population |
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Incidence |
Number of new cases of infection within a population |
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Prevalence |
Number of active ongoing cases of infection at any given time |
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Endemic Disease |
The incidence and prevalence are relatively stable |
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Epidemic Disease |
An abrupt increase in the incidence of disease within a geographic region is observed |
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Pandemic Disease |
Global spread of a specific disease is observed - high virulence, cause disease so fast, immune system doesn't have a chance |
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Normal Flora |
Do not cause infection when they remain within the strict boundaries of their anatomic niche in the body - if they invade non-colonized areas of the body, they can cause infection |
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Carriers |
Individuals who can carry certain bacteria and transmit infection to susceptible individuals - Mary Mallon |
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Immunocompetence |
An individual's ability to protect oneself from infectious agents because of a strong immune system |
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#1 cause of nosocomial infection |
Healthcare workers not washing their hands between patients |
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Gram Positive |
Turns purple, thick peptidoglycan cell wall - staph - pneumonia strep |
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Gram Negative |
Thin cell wall with outer membrane - pink-colored stain - E.coli |
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Spirochetes |
Corkscrew shape - syphilis |
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Bacteria that can't be classified by shape |
- chlamydia - rickettsia - mycoplasma |
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Rickettsia |
"in between" viruses and bacteria - grouped with bacteria usually - typhus, rocky mountain, spotted fever - spread by arthropods usually |
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Mycoplasma |
- tiny - commonly found in genitourinary tracts - urethritis |
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A virus enters a human cell and... |
reprograms the infected cell to synthesize viral particles |
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HIV so virulent because it is a... |
retrovirus - mutate exceptionally fast and doesn't lose virulence |
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Flu virus not endemic because |
it mutates slowly and loses virulence |
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Fungi |
- moldlike organisms also called mycoses - candida (thrush, yeast infection) - cause disease on mucus membrane - trichophyton (ringworm, dermatophyte) |
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Thrush |
Candida of the mouth |
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Parasites |
Protozoa, helminths, and insects - entamoeba histolytica - giardia lamblia - toxoplasma gondii - plasmodium - taenia saginata (tapeworm) - trichinella spiralis (trichinosis) - enterbius vermicularis (pinworm) |
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Prions are resistant to human... |
proteases and have the ability to confer this resistance to other proteins in human cells |
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Prions enter brain neurons and... |
convert existing proteins - proteins clump together, giving spongy appearance to brain tissue under microscope - creutzfeldt-jakob, spongiform encephalopathy |
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Adaptive immunity begins |
>3 days to 2 weeks |
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Five Distinct Stages of Infection |
1 - incubation period 2 - prodromal stage 3 - acute stage 4 - convalescent stage 5 - resolution stage |
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Incubation Period |
- active replication of pathogen without symptoms in the host - takes time to grow large/big enough int # |
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Prodromal Stage |
Initial appearance of symptoms in host - duplicated itself enough to evoke inflammation |
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Acute Stage |
Host experiences full infectious disease with rapid replication of pathogen |
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Convalescent Stage |
Host's body attempts to contain and eliminate the pathogen - T-lymph/B-lymph active = exudate changes |
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Resolution Stage: |
Host eliminates pathogen without residual signs or symptoms - can mean death |
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Mucus color indicator of stage of infection |
Clear = still infected Green/Gunky = fighting it/getting over, T-lymph/B-lymp active |
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Weapons used in innate response to injury |
- WBCs - Complement System - Coagulation System - Cytokines |
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Weapons used in adaptive response to injury and infection: |
- needs more time than innate - specific white blood cells |
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Antibodies |
Proteins secreted by B plasma cells that recognize antigen and leads to pathogen destruction - keep blueprint, not full-fledged antibodies |
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Basic Structure of Antibodies |
- 2 heavy chains + 2 Light Chains create Y-shape - Constant vs Variable regions - antigen binding site |
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Constant Region |
- millions in lymph nodes - precursor |
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Variable Regions |
- part that gets tailor-made - premade blueprints for variable synthesis |
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5 Categories of Antibodies |
- IgG - IgM - IgA - IgD - IgE |
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Antigen causes proliferation of... |
clone effector cells |
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T cells create receptors to... |
bind to and neutralize epitopes |
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T cells mature in thymus but most are destroyed before successful cells enter circulation. Why? |
- self vs. non-self discrimination - fail to develop appropriate T-cel receptor (TcR) |
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B cells most are destroyed. Why? |
- Fail to develop appropriate Ig - Self vs. non-self discrimination |
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B cells lifespan |
4 weeks |
