17 Infectious Diseases Flashcards
What percentage of deaths worldwide are associate with infectious disease?
25%
What are viruses comprised of?
A nucleic acid genome (DNA/RNA) packaged in a protein coat (envelope, or capsid)
How can viruses be neutralized by antibodie?
- binding to cell surface receptor
- block viral penetration
- facilitate opsonization
How do viruses evade host defense mechanisms?
- can inhibit type I interferon expression
- can inhibit MHC I presentation
- escape complement-mediated destruction
- mutate to change their antigens
True or false: Genetic variability generates new virus strains that can cause pandemics
TRUE
In what two ways can antigenic change in viruses occur?
Antigenic drift: slowly but continuously
Antigenic shift: suddenly but episodically
How does antigenic drift occur?
The accumulation of point mutations within regions of the envelope glycoprotein genes – RNA Pol. don’t have proofreading mechanisms
How does antigenic shift occur?
Reassortment of influenza virus genes during mixed infections when there are two or more virus subtypes
What are the four primary steps in bacterial infection?
- Attachment to host cells
- Proliferation
- Invasion of host tissue
- Toxin-induced damage
What is the main protective response against extracellular bacteria?
humoral immune response
What is the main protective response against intracellular bacteria?
cell-mediated immune response
The majority of parasitic infection result in _______ rather than acute diseases
chronic
Who cause parasitic diseases?
Protozoans and helminths (worms)
What controls most of fungal infections?
Innate immunity
Protective immunity can be achieved by active immunization as well as _______ immunization
passive
What are the different vaccine development strategies? How?
Live, attenuated vaccines: weakened pathogens (often do not need boosters, but may have more side-effects)
Inactivated/killed vaccines: heated or chemically treated to inactivate (NO reversion to pathogenic form, but often require booster shots)
Subunit vaccines: use purified macromolecules derived from pathogen, similar to pros/cons of killed vaccines
Recombinant vector vaccines: Use an attenuated pathogen (all benefits of attenuated vaccines, stability issues)
What are DNA vaccines?
Plasmids carrying pathogen genes injected into muscle tissue, host cells take up DNA, and express it internally. Too new to know cons, but very stable and customizable!
What are mRNA vaccines?
Pathogen gene mRNA coated with lipid nanoparticles injected into muscle tissue
Conjugate or ___________ vaccines can improve immunogenicity and outcome because some molecules aren’t strong enough Ag on their own to stimulate a good response.
multivalent
What do you do if you want to induce CTL responses?
Deliver Ag into cells for presentation in MHC class I molecules which creates lipid carriers for delivery
Adjuvants are included to _______ the immune response to a vaccine
enhance ; by promoting inflammation, more immune cells are recruited to the area to enhance effectiveness
