Airborne Infectious Diseases Flashcards
In regards to airborne diseases, what is the major portal of entry?
Respiratory tract (nose, mouth) involving mucous membranes
Describe this Airborne Disease: Streptococcal Pharyngitis
(AKA/Causative Agent/Characteristic, Virulence Factors, Tissue/Organs Affected, SXS, Diagnosis, Treatment, Preventative Measures)
AKA/Causative Agent/Characteristc
- AKA: Strep Throat
- CA: Streptococcus pyogenes
- Characteristic: Gram-positive, chains;
group A streptococci (GAS) - inv Lancefield classification based on CW structure for Streptococci
Virulence Factors
Produces:
- β hemolysin [Super Ag; exotoxin]
-> (completely lyse RBC = clear zone) - Streptokinase
-> (dissolve/pvt blood clot form.) - Hyaluronidase
-> (dissolve CT) - Capsules and M proteins
-> (adherence)
Tissue/Organ Affected
- Upper Respiratory Tract (Lungs)
Reservoir
- x
Mode of Transmission
- x
Predisposing Factors
- x
Incubation Period
- x
SXS
- Inflammation/Erythema: throat, tonsils, otitis media/middle ear
- Fever (bc type 1 exotoxin/SuperAg)
Diagnosis
- Serological test = rapid antigen detection (look antigen)
- β hemolysis on blood agar (look clear zone)
Treatment
- ABX (Penicillin)
Preventative Measures
Good Respiratory Hygiene:
- Cover mouth/nose
- Wear mask
MISC
- x
Describe this Airborne Disease: Scarlet Fever
(AKA/Causative Agent/Characteristic, Virulence Factors, Tissue/Organs Affected, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: Scarlatina
- CA: Streptococcus pyogenes
- Characteristic: Gram-positive, chains;
group A streptococci (GAS) - inv Lancefield classification based on CW structure for Streptococci
Virulence Factors
Produces:
- Erythrogenic toxin
-> prod. by lysogeny = phage conversion
-> toxin gene from bacteriophage → integrates into the chromosome of S. pyogenes → becomes a prophage → S. pyogenes erythrogenic toxin. - β hemolysin [Super Ag; exotoxin]
-> (completely lyse RBC = clear zone) - Streptokinase
-> (dissolve/pvt blood clot form.) - Hyaluronidase
-> (dissolve CT) - Capsules and M proteins
-> (adherence)
Tissue/Organ Affected
- Upper Respiratory Tract (Lungs)
Reservoir
- x
Mode of Transmission
- x
Predisposing Factors
- x
Incubation Period
- x
SXS
Toxemia (Sys Inf):
- Flat, bright red, sandpaper rash on UB
- Strawberry tongue
-> Inflammed/red bumpy tongue with white coating - High fever
- Sore Throat
Diagnosis
- Serological test = rapid antigen detection (look antigen)
- β hemolysis on blood agar (look clear zone)
Treatment
- ABX (Penicillin)
Preventative Measures
Good Respiratory Hygiene:
- Cover mouth/nose
- Wear mask
MISC
- Common in children
- Rare today
- Most common cause of death in children in 1800s
Describe this Airborne Disease: Diphtheria (Toxigenic Strain)
(Causative Agent/Characteristic, Virulence Factors, Tissue/Organs Affected, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: X
- CA: Corynebacterium diphtheria
-> 2 strains - Characteristic: Gram-positive, Bacilli; pleomorphic (irreg cube shape); Very resistant to drying = stays on surfaces
Virulence Factors
Produces:
- Potent, Diphtheria exotoxin
-> Low LD50
-> Prod by lysogeny = phage conversion via virus
Tissue/Organ Affected
- Upper Respiratory Tract (Lungs)
Reservoir
- x
Mode of Transmission
- x
Predisposing Factors
- x
Incubation Period
- x
SXS
Toxemia (Sys Inf):
- Partial Paralysis of the soft palate and pharynx
-> Difficulty breathing = death - Heart and Kidney damage
Diagnosis
- Throat Swab = culture sample
Treatment
MUST START IMMEDIATELY:
- ABX (Penicillin)
- Diphtheria Antitoxin
Preventative Measures
- Diphtheria Vaccine
-> DTaP: Diphtheria, Tetanus, acellular Pertussis; children less 6yr
->TDaP: Tetanus, Diphtheria, acellular Pertussis; less conc than DTaP; teens/young adult
->Td: Tetanus, Diphtheria toxoid; booster vaccine
MISC
- Vaccine ≠ lifelong immunity (bc requires multiple vaccine)
Describe this Airborne Disease: Diphtheria (Nontoxigenic Strain)
(Causative Agent/Characteristic, Tissue/Organs Affected, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: X
- CA: Corynebacterium diphtheria
-> 2 strains - Characteristic: Gram-positive, Bacilli; pleomorphic (irreg cube shape); Very resistant to drying = stays on surfaces
Virulence Factors
- x
Tissue/Organ Affected
- Upper Respiratory Tract (Lungs)
Reservoir
- x
Mode of Transmission
- x
Predisposing Factors
- x
Incubation Period
- x
SXS
- Early SXS: Sore throat, fever
- Later SXS: Formation of tough, greyish pseudomembrane on throat
-> Blocks air passage to lung = death
Diagnosis
- Throat Swab = culture sample
Treatment
MUST START IMMEDIATELY:
- ABX (Penicillin)
Preventative Measures
- Diphtheria Vaccine
-> DTaP: Diphtheria, Tetanus, acellular Pertussis; children less 6yr
->TDaP: Tetanus, Diphtheria, acellular Pertussis; less conc than DTaP; teens/young adult
->Td: Tetanus, Diphtheria toxoid; booster vaccine
MISC
- No toxin produced
- Vaccine ≠ lifelong immunity (bc requires multiple vaccine)
Is contact or vehicle transmission more contagious and why?
Vechile transmission is more dangerous because its airborne transmission MORE than 1 meter away
Contact transmission = less than 1 meter away
What are the most comon type of infectious diseases world-wide?
Respiratory tract infectious diseases
In regards to airborne diseases, what is a common predisposing factor?
crowds
In regards to airborne diases, what are the most effective preventative measures?
Good respiratory hygeine (cover nose/mouth; mask)
Name structures of the respiratory system in the upper respiratory tract and lower respiratory tract
URT: Nose, Oral Cavity, pharynx (throat), middle ear, auditory tube
LRT: larynx (voicebox), trachea, bronchial tubes, alveoli; ciliary escalatory, respiratory mucus
Name host defenses against airbone pathogens
- Normal Microbiota: compete against invading pathogens
- Mucus: traps pathogens
- Lysozyme: enzyme that destorys pathogens
- Ciliary escalatory: moves mucus up and out the body
Bacterial growth on blood agar helps to differentiate between what?
Provide examples
Helps differentiate between different streptococcal species that cause airborne diseases
Ex: Streptococcus pyogenes vs. Streptococcus pneumoniae
RBC serve as a ___________ _________
nutrient source
RBC are lysed by toxins called ________ (__________) in the process called __________
hemolysins (type 1 exotoxin; Super Ag)
hemolysis
Compare β hemolysis vs α hemolysis
β hemolysis:
- Completley destory RBC = clear zone
- Ex: Streptococcus pyogenes
α hemolysis:
- Partially destroy RBC = green zone
- Ex: Streptococcus pneumoniae