VBS 2032. Lectures 31-33 - Infectious
Diseases of the Upper Respiratory Tract,
Infectious Diseases of the Lower
Respiratory Tract pt. 1 & 2
What are some diseases of the upper respiratory tract? - answer*Sinusitis:*
inflammation of the sinuses
*Pharyngitis:* inflammation of the pharynx/throat
*Rhinitis:* inflammation of the nasal mucous membranes
*Tonsillitis:* inflammation of the tonsils
*Ottis media:* inflammation of the middle ear
What are the protective mechanisms of the upper respiratory tract? What happens
when parts of this system are compromised? - answerProtective mechanisms:
- nasal hairs
- lysozyme
- IgA
- saliva flushing
- coughing
- sneezing
- swallowing
- continuous sloughing of epithelium
- normal microbiota
- cilia
When these mechanisms are compromised, pathogens are able to evade our immune
system and infect our bodies
Describe the basic features of Streptococcus pyogenes. - answerGram-positive cocci
that grow in chains, encapsulated, non-motile, group A carbohydrate, beta hemolytic
How do virulence factors of Streptococcus pyogenes act to evade the immune system
and cause the spread of disease? - answerAttachment:
- *Specialized proteins* (M and F) aid in attachment
, Invasion or Spread:
- *Tissue degrading enzymes* break down extracellular matrix between cells and invade
deeper into tissue, helps with invasion and spread
Evasion of Host Defenses:
- *M protein:* prevent complement from attaching to cell
- *Streptolysin:* breaks down leukocytes
- *G protein:* binds to Fc region of antibodies to inactivate it
- *Capsule:* evade phagocytosis
- *C5a peptidase:* break down C5a to prevent complement pathway activation
What role do lysogenic phages play in S. pyogenes pathogenesis? - answer- Lysogenic
phages encode toxins in some strains
- Toxins are superantigens and cause massive activation of T cells e.g scarlet fever,
toxic shock, necrotizing fasciitis ("flesh-eating disease")
What are the clinical features of Strep throat and how is it diagnosed? - answer-
Naturally only infect human cells
- Spread by respiratory droplets or contaminated food
- Confirmation via diagnostic tests(rapid strep test/ELISA) and throat culture
Why is it important to treat Strep infections promptly with antibiotics? - answerUntreated
Strep infections can lead to Post streptococcal sequelae (complications)
- *Acute rheumatic fever:* lead to rheumatic heart disease, antibodies to M proteins
cross-react with proteins on the heart
- *Acute post-streptococcal glomerulonephritis:* antibody-antibody complexes activate
complement which can lead to kidney damage
What vaccine protects against Diptheria? What kind of vaccine is it? -
answer*Diptheria:* serious infection of the nose and throat
- Strains carrying lysogenic phage produce toxin that circulates in the blood and shuts
down protein synthesis in heart, kidneys and nerves
- DTaP is a toxoid vaccine that protects against Diptheria
What is the most common cause of the common cold? How can this be distinguished
from adenovirus infections? - answer*Common cold:*
- Mainly *rhinoviruses* (>100 types)
- Infect respiratory epithelial cells which stops ciliary motion
- has a short incubation time of 1-2 days
-usually no fever
*Viral pharyngitis:*
Diseases of the Upper Respiratory Tract,
Infectious Diseases of the Lower
Respiratory Tract pt. 1 & 2
What are some diseases of the upper respiratory tract? - answer*Sinusitis:*
inflammation of the sinuses
*Pharyngitis:* inflammation of the pharynx/throat
*Rhinitis:* inflammation of the nasal mucous membranes
*Tonsillitis:* inflammation of the tonsils
*Ottis media:* inflammation of the middle ear
What are the protective mechanisms of the upper respiratory tract? What happens
when parts of this system are compromised? - answerProtective mechanisms:
- nasal hairs
- lysozyme
- IgA
- saliva flushing
- coughing
- sneezing
- swallowing
- continuous sloughing of epithelium
- normal microbiota
- cilia
When these mechanisms are compromised, pathogens are able to evade our immune
system and infect our bodies
Describe the basic features of Streptococcus pyogenes. - answerGram-positive cocci
that grow in chains, encapsulated, non-motile, group A carbohydrate, beta hemolytic
How do virulence factors of Streptococcus pyogenes act to evade the immune system
and cause the spread of disease? - answerAttachment:
- *Specialized proteins* (M and F) aid in attachment
, Invasion or Spread:
- *Tissue degrading enzymes* break down extracellular matrix between cells and invade
deeper into tissue, helps with invasion and spread
Evasion of Host Defenses:
- *M protein:* prevent complement from attaching to cell
- *Streptolysin:* breaks down leukocytes
- *G protein:* binds to Fc region of antibodies to inactivate it
- *Capsule:* evade phagocytosis
- *C5a peptidase:* break down C5a to prevent complement pathway activation
What role do lysogenic phages play in S. pyogenes pathogenesis? - answer- Lysogenic
phages encode toxins in some strains
- Toxins are superantigens and cause massive activation of T cells e.g scarlet fever,
toxic shock, necrotizing fasciitis ("flesh-eating disease")
What are the clinical features of Strep throat and how is it diagnosed? - answer-
Naturally only infect human cells
- Spread by respiratory droplets or contaminated food
- Confirmation via diagnostic tests(rapid strep test/ELISA) and throat culture
Why is it important to treat Strep infections promptly with antibiotics? - answerUntreated
Strep infections can lead to Post streptococcal sequelae (complications)
- *Acute rheumatic fever:* lead to rheumatic heart disease, antibodies to M proteins
cross-react with proteins on the heart
- *Acute post-streptococcal glomerulonephritis:* antibody-antibody complexes activate
complement which can lead to kidney damage
What vaccine protects against Diptheria? What kind of vaccine is it? -
answer*Diptheria:* serious infection of the nose and throat
- Strains carrying lysogenic phage produce toxin that circulates in the blood and shuts
down protein synthesis in heart, kidneys and nerves
- DTaP is a toxoid vaccine that protects against Diptheria
What is the most common cause of the common cold? How can this be distinguished
from adenovirus infections? - answer*Common cold:*
- Mainly *rhinoviruses* (>100 types)
- Infect respiratory epithelial cells which stops ciliary motion
- has a short incubation time of 1-2 days
-usually no fever
*Viral pharyngitis:*
