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
Describe this Airborne Disease: Pertussis
(AKA/Causative Agent/Characteristic, Virulence Factors, Tissue/Organs Affected, Incubation Period, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: Whooping Cough
- CA: Bordetella pertussis
- Characteristic: Gram-negative, coccobacillus (oval)
Virulence Factors
- Tracheal cytotoxin
-> Damages ciliated cells = stop ciliary escalator = no mucus moves up and out - Capsule
-> Attach to ciliated cells in trachea
Tissue/Organ Affected
- Lower Respiratory Tract
Reservoir
- x
Mode of Transmission
- x
Predisposing Factors
- x
Incubation Period
- Days - Week (5-10d)
SXS
- Cold-like symptoms
- Violent, uncontrollable cough
- Gasping (for air)
Diagnosis
- Culture of throat mucus sample
Treatment
- ABX
Preventative Measures
- DTaP Vaccine
- TDaP Vaccine
MISC
- Highly Contagious
Describe this Airborne Disease: Pneumococcal Pneumonia
(AKA/Causative Agent/Characteristic, Virulence Factors, Tissue/Organs Affected, Predisposing Factors, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: Typical Pneumonia
- CA: Streptococcus pneumoniae (90 strains)
- Characteristic: Gram-positive, encapsulated diplococci
Virulence Factors
- Large Capsule
-> Attachment - α hemolysin
-> Partially lyses RBC’s = green zone
Tissue/Organ Affected
- Lower Respiratory Tract (Lungs)
Reservoir
- x
Mode of Transmission
- x
Predisposing Factors
- Age (very young/old)
Incubation Period
- x
SXS
Acute Symptoms:
- High fever
- Difficulty breathing
- Chest pain = fluid accumulation at level of alveoli = interferes with gas exchange
Diagnosis
- Serological (Blood) test = look for pathogen or Ab
- α hemolysis on blood agar
- Presence of capsular antigen in urine
Treatment
- ABX (Penicillin)
Preventative Measures
- Pneumococcal conjugate vaccine (protects against 13 strains based on capsule structure;PCV13 or Prevnar13R)
MISC
- Atypical Pneumonia: caused by non-bacterial microbes;
-> ex: viral Pneumonia (influenzavirus)/fungal pneumonia.
-> common in immunocompromised host
Describe this Airborne Disease: Tuberculosis
(Causative Agent/Characteristic, Virulence Factors, Tissue/Organs Affected, Mode of Transmission, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: x
- CA: Mycobacterium tuberculosis
-> MDR strain: resists 1st line drugs; use 2nd line drugs
-> XDR strains: resist 2nd line; PT isolate - Characteristic: Acid-fast bacterium, bacilli, obligate aerobe, Fungus-like growth, mycolic acid in the cell wall
Virulence Factors
- Mycolic Acid
-> Make bacteria resistant to drying; allow bacteria to multiply in macrophages (inhibit dig. enz. of lysosome)
Tissue/Organ Affected
- Lower Respiratory Tract (Lungs)
Reservoir
- x
Mode of Transmission
- Droplet Transmission
Predisposing Factors
- x
Incubation Period
- x
SXS
Chronic Symptoms (Sys Inf):
- Blood cough (alveolar dmg)
- Persistent Low-grade fever
- Night sweats
- Weight loss
- Weakness
Diagnosis
1) Tuberculin Skin Test:
- inj Tuberculin protein = check hardness days later
2) Chest X-ray (or CT scan):
- White spots = tubercle formation
3) Acid-fast staining
- Culture lung sputum sample = look for pink acid-fact bacilli
Treatment
- Multi-drug therapy (min. 6 months)
- First-line drugs: ABX
- Second-line drugs
-> used for treatment of drug-resistant Tuberculosis
Preventative Measures
- BCG vaccine (not used in US)
MISC
- Leading cause of death from infectious diseases worldwide
- 1/3 world’s pop. have latent TB
- Miliary Tuberculosis
-> (SYS TB inf; Bact spreads from primary lesion -alveolus- to other areas of lung, liver and NS, bone)
Describe this Airborne Disease: Influenza
(AKA/Causative Agent/Characteristic, Virulence Factors, Resevoir, Mode of Transmission, Predisposing Factors, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: Flu
- CA: Influenza Virus - RNA, (Some viral strains = Viral/Atypical Pneumonia)
- Characteristic: Enveloped, spikes (Influenza Types A, B, C, D; based on capsid protein)
Virulence Factors
- Protein Spikes:
-> HA (H) spikes
-> NA (N) spikes - Antigenic Variation of Spike:
-> genetic recombination & formation; mix human virus spikes and non-human virus spikes (HswNhk)
Tissue/Organ Affected
- X
Reservoir
- 1° = Humans
- 2° = Birds, farm animals
Mode of Transmission
- Zoonoses (animal -> human)
- Droplet Transmission
- Airborne Transmission
Predisposing Factors
- Age (Infants and Elderly)
Incubation Period
- x
SXS
Acute Symptoms:
- Fever
- Chills
- Headache & muscle ache
- No intestinal symptoms
Diagnosis
- Difficult to diagnose
-> Because of acute symptoms
Treatment
- Antivirals
-> (inhaled/oral; against Type A within 30 hours) - Supportive Treatment
Preventative Measures
- Multivalent vaccine: killed, multi-strains
-> Composition determined annually
-> No long-term immunity - Nasal spray flu vaccine
-> Live, weakened virus
MISC
- Type A - causes most Flu pandemics
- Low mortality; Thousands of deaths in the US annually
- Spanish Flu pandemic killed 20+ million people
Describe this Airborne Disease: Coronavirus Disease 2019 (Covid-19)
(AKA/Causative Agent/Characteristic, Virulence Factors, Resevoir, Mode of Transmission, Predisposing Factors, Incubation Period, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: 2019 Novel Coronavirus (Covid-19)
- CA: SARS-CoV-2; Coronaviridae Family
-> RNA - Characteristic: Enveloped, spikes, several human variants
Virulence Factors
- Multiply in ciliated epithelial cells of the respiratory tract
- Antigenic Variation of Spike
-> high mutation rates
Tissue/Organ Affected
- x
Reservoir
- 1° = Animals (bats, intermediate animal host; pangolin)
- 2° = Humans
Mode of Transmission
- Zoonoses (animal -> human)
- Fomites
- Droplet Transmission
- Airborne Transmission
Predisposing Factors
- Crowds
- Poor health
Incubation Period
- Days - Weeks (4 - 14d)
SXS
Range from mild -> severe:
- Shortness of breath -> respiratory failure
- Septic shock -> multiple organ failure
- Loss of taste/smell
- Dry cough
- Fever
- Headache
- Fatigue
Diagnosis
- PCR
- Antigen test (saliva, nasal/throat swab)
- Serology
Treatment
Treatment is not usually required:
- Antivirals
-> MIld-moderate: Antiviral tablets
-> Severe: Antiviral, steroids, Ab
Preventative Measures
- Frequently wash hands
- Social Distancing
- Respiratory hygiene
- Vaccine
-> Moderna: mRNA; 2 shots
-> Pfiezer: mRNA; 2 shots
-> J&J/ Janseen: viral vector; 1 shot
MISC
- First detected in open markets in China (2019)
- Coronaviridae family is responsible for several diseases:
-> SARS: (SARS-CoV-1; epidemic)
-> MERS: (MERS-CoV; epidemic)
-> Covid-19: (SARS-CoV-2; pandemic)
Describe this Airborne Disease: Smallpox
(AKA/Causative Agent/Characteristic, Virulence Factors, Mode of Transmission, SXS, Diagnosis, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: Variola
- CA: Variola Virus - DNA
-> Variola Major - Larger mortality
-> Variola Minor - Low mortality - Characteristic: Enveloped
Virulence Factors
- Proteins called SPICE (smallpox inhibitor of complement enzymes)
Tissue/Organ Affected
- x
Reservoir
- x
Mode of Transmission
- Airborne Transmission
Predisposing Factors
- x
Incubation Period
- x
SXS
Viremia (Sys Inf):
- Pus (WBC/dead tissue) - filled lesions = raised rash
Diagnosis
- Serology
Treatment
- x
Preventative Measures
- Vaccine
-> Live vaccinia (Cowpox) virus
-> Mild to severe side effects
MISC
- Highly contagious
- Completely eradicated (from human pop) by vaccination
- Potential for bioterrorism
Describe this Airborne Disease: Chickenpox
(AKA/Causative Agent/Characteristic, Virulence Factors, Tissue/Organ Affected, Reservoir, Mode of Transmission, Predisposing Factors, Incubation Period, SXS, Diagnosis, Treatment, Preventative Measures)
AKA/Causative Agent/Characteristic
- AKA: Varicella
- CA: Varicella-Zoster Virus, Herpesviridae family, HHV-3 - DNA Virus
- Characteristic: Enveloped
Virulence Factors
- Multiply in epithelial cells of URT -> Viremia
- Become latent in CNS
Tissue/Organ Affected
- Upper Respiratory Tract
Reservoir
- Humans
Mode of Transmission
- Droplet Transmission
Predisposing Factors
- Daycare
Incubation Period
- Weeks (10 - 21d)
-> Longer than Measles
SXS
Viremia (Sys Inf):
- Itchy rash
- Fluid-filled vesicles on face, chest & back = raised rash
- Fever
- Headache
Diagnosis
- Type (flat vs. raised/pus vs. fluid filled) & location of the rash
Treatment
- Calamine lotion
-> (relieves itching) - Non-aspirin medication in children
Preventative Measures
- Varicella Vaccine
-> Live, attenuated/weakened virus
MISC
- x
Describe this Airborne Disease: Shingles
(AKA/Causative Agent/Characteristic, Virulence Factors, Predisposing Factors, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: Herpes Zoster
- CA: Reactivation of latent Varicella-Zoster Virus - DNA
- CHRTX: (Enveloped)
Virulence Factors
- Reactivation: Travels along sensory nerves of skin
Tissue/Organ Affected
- x
Reservoir
- x
Mode of Transmission
- x
Predisposing Factors
- Age (elderly)
- Immunocompromised person
- Stress
Incubation Period
- x
SXS
- Fluid-filled, MERGING band-like rash = raised rash
- EXCRUCIATING nerve pain (post-herpetic neuralgia)
- Blisters scab (form in 7-10d)
Diagnosis
- Type (flat vs. raised/pus vs. fluid-filled) and location of rash
Treatment
- Antivirals
-> (management; relieve/suppress SXS)
Preventative Measures
- Shingles/Zoster Vaccine
-> (ex: Shingrix)
MISC
- Rash Limited to one side of the body (doesn’t cross midline)
Describe this Airborne Disease: Measles
(AKA/Causative Agent/Characteristic, Virulence Factors, Reservoir, Mode of Transmission, Incubation Period, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: Rubeola
- CA: Rubeola Virus - RNA
- Characteristic: Enveloped, spikes antigenically stable
Virulence Factors
- Attachment by H & F proteins
Tissue/Organ Affected
- x
Reservoir
- Humans
Mode of Transmission
- Droplet Transmission
Predisposing Factors
- x
Incubation Period
- Weeks (10 - 12d)
-> Shorter than Chickenpox
SXS
Viremia (Sys Inf):
- Merging macular (flat) rash
-> Face -> neck -> trunk -> extremities - Koplik spots - clustered, white lesions on the oral mucosa
- High fever
- Conjunctivitis (pink eye)
- Dry cough
- Runny nose
Diagnosis
- Based on SXS
- Serology
Treatment
- No treatment available
- Supportive care
Preventative Measures
- Monovalent measles vaccine (use single strain pathogen)
- MMR - prevents Measles, Mumps, Rubella
MISC
- Vaccine required once
- Complications
-> Encephalitis in 1 out of 1000 cases
-> Viral Pneumonia
Describe this Airborne Disease: Rubella
(AKA/Causative Agent/Characteristic, Reservoir, Mode of Transmission, Incubation Period, SXS, Diagnosis, Treatment, Preventative Measures, Misc.)
AKA/Causative Agent/Characteristic
- AKA: German Measles or 3-Day measles
- CA: Rubella Virus - RNA
- Characteristic: Non-enveloped
Virulence Factors
- x
Tissue/Organ Affected
- x
Reservoir
- Humans
Mode of Transmission
- Droplet Transmission
Predisposing Factors
- x
Incubation Period
- Weeks (14 - 21d)
SXS
- Discrete macular (flat) rash
-> last short days
-> Face -> neck -> trunk -> extremities - Mild/No fever
- Conjunctivitis (pink eye)
- Cough
- Runny Nose
Diagnosis
- Based on SXS
- Serology
Treatment
- No treatment available
- Supportive care
Preventative Measures
- MMR - prevents Measles, Mumps, Rubella
MISC
- Life-long immunity (after inf)
- Complications: Congenital Rubella Syndrome
-> Maternal inf during 1st trimester
-> Fetal damage
-> Cataracts, Cardiac abnormalities, deafness, intellectual disabilities
-> 15% mortality within 1st year of life
Describe the pathogenesis of Tuberculosis
- Mycobacterium tuberculosis is inhaled -> lung -> alveolus
- Monocyte from BV (around alveolus) travels into alveolus -> macrophage -> ingests pathogen -> bacteria multiply in macrophage -> inflamatory response
- Aggregation of activated macrophages with ingested pathogen = Tubercle Lesion
- Dying macrophages release bacteria (after bact multiplcation)
-> 4a. Bact. stop growing in tubercle lesion = dz process stops = lesions heal and calcify = bacteria dormant/no spread = Latent Tuberculosis (“local” inf)
-> 4b. Bact. multiply outside macrophage -> tubercle ruptures -> rel. bacteria lungs/CV system = Miliary Tuberculosis (sys inf)
CV = cardiovascular
In regards to the MMR vaccine, does one of the “M” protect against German Measles? Why or why not?
No, one of the M DOES NOT protect against German Measles. German measles is clinically known as Rubella. Therefore, the R protects against German Measles, while the first M protects against Rubeola (Measles)
MMR = Measles (Rubeola), Mumps, Rubella.(German Measles)
