Viral Inf of Upper Respiratory Tract Flashcards
1
Q
the common col symptoms and incidence:
A
- Rhinitis – inflammation of the nasal mucosa
- Pharyngitis – sore throat
- *-No high fever, LRT involvement , or respiratory distress –> DISTINGUISHING FROM OTHER RESPIRATORY INF
- 2-3/yr Adults, 6-8/yr Children
- Spring and Fall peak.
2
Q
the common cold complications:
A
- Otitis media
- Sinus Infections
- Exacerbation of asthma (especially rhinovirus C)
3
Q
if someone comes in with constant upper respiratory issues may be?
A
the common cold or allergies
4
Q
major viruses contributing to common cold:
A
- rhinovirus (MAIN)
- coronavirus (SECOND)
- adenoviruses
- Coxsackieviruses
5
Q
Rhinoviruses: Virology
A
-the common cold virus
-Picornavirus family member (SMALL RNA)
-Non-enveloped
+ ssRNA genomes
-Three viral species :
1)Human Rhinovirus A; 2) Human Rhinovirus B; 3) Human Rhinovirus C (MOST RECENT IDENTIFIED)
-Over 100 different serotypes of rhinovirus circulate in the human population.
6
Q
Rhinoviruses: Clinical
A
- the common cold virus
- Shed in respiratory secretions.
- Transmission through direct contact with nasal secretions, large droplets, and contaminated fomites.
- Extremely low inoculum needed for infection.
- Incubation period 1-3 days.
- Exacerbates asthma in school-aged children and COPD in adults.
7
Q
Rhinoviruses: Pathology
A
- the common cold virus
- Virus binds to ciliated epithelium of lungs
- replicates in epithelial cells
- kills those cells
- immune system attachs = some damage but recovery
8
Q
Rhinoviruses: Treatment & Prevention
A
- the common cold virus
- Treatment regimens aimed to alleviate symptoms, e.g, antihistamines, decongestants.
- Antibiotics only given in the case of bacterial superinfections.
- Immune response to rhinovirus infection can be long lasting in a serotype specific manner. But, 100 + serotypes!
- No vaccine available.
9
Q
Non-SARS coronaviruses: Virology
A
-the common cold virus
-Enveloped
+ ssRNA genome
10
Q
Non-SARS coronaviruses: Clinical
A
- the common cold virus
- Replicate in the epithelial cells of the respiratory tract.
- Optimal temperature for replication is 33- 35 degrees C (upper respiratory tract.)
- Transmission occurs through large droplets.
- Incubation period approximately 3 days.
- Outbreaks common in the spring and winter months.
- Infections are most common in infants and children.
11
Q
Non-SARS CoV: Treatment & Prevention
A
- the common cold virus
- Like rhinoviruses, the treatment for Non-SARS coronavirus infections is aimed to alleviate symptoms.
- No vaccine available.
- Reinfection can occur despite circulating antibodies.
12
Q
Adenoviruses: Virology
A
-the common cold
-Adenovirus Family
-Non-Enveloped
dsDNA genome (ONLY DNA COMMON COLD VIRUS)
-The adenoviral fiber proteins protrude from the 12 vertices of the icosohedral capsid. These are used for attachment and are toxic to cells
13
Q
Adenoviruses: Clinical
A
- the common cold
- No seasonal pattern of disease***
- Over 50 different serotypes of adenovirus.
- Most common respiratory disease causing serotypes are 1, 2, and 5.
- Infections most prevalent in children under 5 yrs
- Transmission: Oral, droplet inhalation, conjunctiva.
- Replicates in respiratory epithelial cells causing tissue damage.
- May enter lymphoid tissues following acute infection.
- Individuals can shed virus for up to 18 months following infection.
- No seasonal pattern of disease
14
Q
Other illnesses of Adenoviruses
A
- Pharyngoconjunctival fever. Conjunctivitis; Pharyngitis; Fever
- More severe respiratory infections, such as croup, bronchiolitis, and pneumonia.
- Serotypes 40 and 41 are associated with gastrointenstinal disease.
15
Q
Adenoviruses: Prevention & Treatment
A
- the common cold
- Treatment are aimed at reducing symptoms.
- Immunity is long-lived, but serotype specific.
- Live oral vaccine to serotypes 4 and 7 for military recruits.
16
Q
Coxsackieviruses: Virology
A
-cause colds
-Enterovirus subfamily of picornaviruses
-Nonenveloped
+ ssRNA genome
-Replication is fast and occurs in the cytoplasm.
-Able to survive low pH conditions found in the GI tract.
17
Q
Coxsackievirus: Clinical
A
- Transmitted through the fecal-oral route.
- No vaccine available.
- Recovery generally occurs in a couple of weeks without treatment.
18
Q
Coxsackievirus: Herpangina
A
- Symptoms: Abrupt onset of fever; Small vesicles on the soft palate. When they rupture, they form small white ulcers.
- Incidence: Highest in children 1- 7 years
- Complications: In rare instances causative agent (Coxsackievirus) can cause meningitis or encephalitis.
19
Q
Coxsackievirus: Hand-Foot-&-Mouth Disease
A
- Symptoms: Fever; Vesicular lesions on the soles of hand and feet and on oral areas.
- Incidence: Most frequent in children.
20
Q
Other common cold viruses:
A
- Influenza viruses: especially B and C
- Respiratory Syncytial Virus: Adults and school-aged children
- Parainfluenza virus: Adults and school-aged children
21
Q
Rhinovirus: genome; transmission; other diseases; special notes-
A
+ssRNA
transmitted by contact, large droplet
note:exacerbates asthma in children and COPD in adults
22
Q
Non-SARS CoV: genome; transmission; other diseases; special notes-
A
+ssRNA
transmitted by contact, large droplet
Other family members cause SARS
note: corona = thick glycoprotein coat
23
Q
adenovirus: genome; transmission; other diseases; special notes-
A
dsDNA
transmitted by contact, large droplet
conjunctivitis, gastrointestinal, LRT infections
note: non-enveloped, stable in environment
24
Q
coxackie-virus: genome; transmission; other diseases; special notes-
A
+ssRNA
fecal-oral transmission
herpangina, hand-foot, and mouth disease
note: often spread in childcare centers, schools…
25
Parainfluenza virus: genome; transmission; other diseases; special notes-
-ssRNA
transmitted by contact, large droplet
crop, LRT infections
note: colds in older children and adults
26
Respiratory syncytial virus: genome; transmission; other diseases; special notes-
-ssRNA
transmitted by contact, large droplet
LRT infections
note: life threatening infections can occur in premature infants, colds in older children and adults
27
influenza: genome; transmission; other diseases; special notes-
-ssRNA Segmented
transmitted by contact, large droplet
LRT infections; influenza
note: B and C more commonly associated with colds
28
Croup
- Croup: laryngotracheobronchitis. Symptoms from swelling in the subglottic region of the larynx.
- Symptoms: Fever and a distinct brassy cough compared to a “seal’s bark”.; Inspiratory stridor
- Radiograph: narrowing of air shadow of trachea in the subglottic area. “steeple sign"
- Prodrome : nasal discharge, mild cough, pharyngitis.
- Incidence - highest in children less than 6 yrs
- Complication - Hypoxia bc of swelling in throat
- Differential Diagnosis - noninfectious causes of airway obstruction and bacterial epiglottis.
29
croup treatment
-goal = alleviate symptoms
-Is there stridor at rest?
iF yes- oxygen, epinephrine, glucocorticoids
IF no= MILD form- humidified air hydration
30
Croup etiology
- Parainfluenzavirus-Parainfluenza type 1 is the most common cause of acute croup.
- Parainfluenza type 2-3 can also cause croup
- (Parainfluenza type 3 also causes LRT infection.)
- Others – respiratory syncytial virus and measles virus.
31
Parainfluenza viruses: Virology
- Paramyxovirus family
- Helical nucleocapsid
- Envelope contains hemagglutinin and neuraminidase.
- ssRNA Genome
- RNA synthesis occurs in the cytoplasm.
32
Parainfluenza viruses: Clinical
- Transmission: Large droplets and direct contact.
- Incubation period:2-10 days
- Pathogenesis: Infect and replicate in the ciliated epithelium of the respiratory tract.
- Short lived immunity occurs following infection.
- Reinfection usually results in less severe illness (Colds in adults).
33
Influenza symptoms, incidence, incubation
- Symptoms: Myalgia; Headache; Fever; Shaking chills; Cough peaking between 3 & 5 days of illness; Cough, fatigue, and generalized weakness may last 2-6 weeks; Increased severity of symptoms and incidence of complication usually seen in pandemic outbreaks.
- Incidence: In temperate climates, the infections peak during the winter months.
- Incubation period 2 days
34
Risk for complication due to Influenza
- Children younger than 2 years old
- Adults 65 years of age or older
- Pregnant women and women up to 2 weeks postpartum
- Persons with certain medical conditions: Asthma; Neurological and neuro-developmental conditions; Chronic lung disease; Heart disease; Blood disorders; Endocrine disorders; Kidney disorders; Liver disorders; Metabolic disorders; Weakened immune system; People younger than 19 years of age who are receiving long-term aspirin therapy
35
Pneumonia definition:
Inflammation of the lung parenchyma leading to abnormal gas exchange.
36
pneumonia symptoms
- Fever
- Chills
- Cough
- Pleuritic chest pain
- Increased respiratory rate
- Wheezes and crackles
- Hypoxia and cyanosis (severe cases)
37
consolidated pneumonia is most likely
bacterial?
38
Primary Influenza virus pneumonia
- Usually Influenza A
- Higher in children and 40 + population
- Symptoms:
a) 1-4 days following influenza virus symptoms.
b) Increased cough, tachypnea, dyspnea, acute respiratory distress
c) Sputum Gram Stain – abundant PMN cells, w/o significant # bacteria.
d) Chest radiograph bilateral, midlung, lower lung infiltration.
e) Fatality rate ~50%.
39
Bacterial influenza-associated pneumonia
- influenza has predisposed you to dev bacterial infection
- Usually onset a week after influenza symptoms began.
- Symptoms
a) Influenza symptoms, which lessen, then followed by increased cough, return of fever, and respiratory distress.
b) Gram stain may contain bacterial cause.
- Etiology:
1. S. pneumoniae
2. S. aureus & H. influenzae
3. Others: N. meningitidis, other Streptococcus, and Gram negative Bacillus.
40
Cause of Influenza : Influenza virus
- Orthomyxovirus
- Segmented, -ssRNA virus genome
- Enveloped
- Hemagglutanin (H): Attachment; Agglutinates RBC
- Neuraminidase (N): Cleaves sialic acid; Virion Release; Virion Spread
41
Antigenic Drift
- regarding influenza virus pattern of change
- Small changes in H and N
- Driven by point mutations made by the polymerase during replication**
- Epidemiological significant changes every 2-3 years
42
Antigenic Shift
- regarding influenza virus pattern of change
- Large changes in H and N
- Driven by reassortment of two viruses**
- Co-infection of the same cell
- Risk for pandemics
43
where does reassortment occur?
- regarding influenza viruses
| - mixing vessel - intermediate species - usually a pig
44
Influenza virus A - # segments, host range, disease severity, epidemic potential, antigenic change?
-8 segments
-humans, swine, avians, equines, marine mammals
-often severe disease
-often epidemics and pandemics
antigenic drift and shift
45
Influenza virus B - # segments, host range, disease severity, epidemic potential, antigenic change?
- 8 segments
- humans
- occasionally severe
- outbreaks, occasional epidemics
- antigenic drift
46
Influenza virus C - # segments, host range, disease severity, epidemic potential, antigenic change?
- 7 segements
- humans, swine
- usually minld
- limited outbreaks
- antigenic drift
47
Hemagglutanin
ttachment; Agglutinates RBC
48
Neuraminidase
Cleaves sialic acid; Virion Release; Virion Spread
49
treating influenza illness?
- Mild or uncomplicated illness:
- -->WITHOUT risk factors = if within 48 hours of onset may consider antiviral, symptomatic care, infection control,
- --> WITH risk factors= treat with antiviral, close follow up, symptomatic care and infection control.
50
Amantadine
- influenza anti-viral drug
- ion channel blockers
- blocks replication prior to genome release (M2)
- effective against only influenza A
- many current influenza viruses are resistant to this drug
51
Rimantidine
- influenza anti-viral drug
- ion channel blockers
- blocks replication prior to genome release (M2)
- effective against only influenza A
- many current influenza viruses are resistant to this drug
52
Zanamivir
- influenza anti-viral drug
- neuraminidase inh
- intranasal or inhalation administration.
- Inhibit virion release and spread.
- Active against influenza A and B viruses.
- Must be given early (first 48 h) to reduce disease symptoms.
53
Oseltamivir
- influenza anti-viral drug
- neuraminidase inh
- oral administration.
- Inhibit virion release and spread.
- Active against influenza A and B viruses.
- Must be given early (first 48 h) to reduce disease symptoms.
54
best way to fight against influenza?
VACCINATE
55
Inactivated Influenza Vaccines (IIV)
- formaldehyde-inactivated influenza virus
- INTRAMUSCULAR--> for older than 6mo and even those with chronic medical conditions ---> trivalent or quadrivalent
- INTRADERMAL ---> for 18yr-64yr ---> trivalent
56
Live attenuated influenza vaccines (LAIV)
- attenuated influenza viruses
| - INTRANASAL INHALATION ---> for healthy, non pregnant, 2yr-49yr --> quadrivalent
57
Recombinant Influenza vaccine (RIV)
- hemagglutinin protein
| - INTRAMUSCULAR ---> for 18yrs-49yrs ---> trivalent
58
production of influenza virus vaccine - CLASSIC METHOD
- produced in embryonated chicken egg cells
- need lots of eggs and time to grow
- may have allergy reactions
59
production of influenza virus vaccine - NOVEL METHOD
- production in mammalian cells
- rapid scale up of vaccine production
- reduced likelihood of egg protein carryover
60
Baculovirus Expression vector System technology for vaccine production
- use engineered baculovirus to express recombinant protein under powerful promoter
- infect cells in fementer with low cost serum free media
- purify the protein and formulate into vaccine
- rapid scale up of vaccine production
- egg-free system
61
trivalent vaccines protect against
2 influenza A and 1 influenza B
62
quadrivalent vaccines protect against
2 influenza A and 2 influenza B
63
chemoprophylaxis
- protection method against influenza virus
- Daily dose of anti-viral for duration of flu season in the community.
- Those at high risk for complications, which are vaccinated after the flu season has begun.
- Non immune health care workers and family members who care for those at high risk for influenza complications.
- Poor match between vaccine and currently circulating strains.
64
SARS Coronavirus details
Coronavirus Family
Enveloped
+ ssRNA genome
More resistant to environmental conditions than non-SARS CoV
65
SARS Coronavirus: Clinical
- Course of disease
1. Fever, malaise, and mylagia
2. Dry cough & shortness of breath.
3. Most severe cases - adult respiratory distress syndrome (ARDS) & death within weeks.
4. Other - diarrhea, abnormal liver function, and lymphopenia.
- Transmission- Fecal-oral, close contact, and aerosol routes
- Incubation is 2-10 days
66
SARS Coronavirus Control
isolation and infection control measures
67
Bronchiolitis defineition
Inflammation of the bronchioles
68
bronchiolitis symptoms/incidence/differnetial diagnosis:
- Symptoms: Expiratory Wheezing; Nasal flaring; Air Trapping; Subcostal Retractions; Variable fever
- Incidence - Can be a severe disease in infants due to the small size of these tissues.
- Differential Diagnosis should include allergic asthma and foreign body inhalation.
69
most common cause of bronchiolitis in children less than 1 yr old?
Respiratory Syncytial Virus (RSV)
70
Respiratory Syncytial Virus (RSV)
```
Most common cause of bronchiolitis and pneumonia in children less than 1 year old.
Paramyxovirus family
Enveloped
- ssRNA genome
Highly infectious
```
71
Respiratory Syncytial Virus (RSV) transmission/ incubation/incidence
Transmission
Inhalation of large droplets
Direct contact with respiratory secretion.
Incubation Period between 4-5 days.
Incidence
Nearly all children have been infected by age 4.
Between 25-40% of primary infections result in pneumonia or bronchiolitis.
Reinfection leads to less severe disease (colds in adults).
Can also be a serious infection in the elderly and immunocompromised populations.
72
treatment for Respiratory Syncytial Virus (RSV)
Aerosolized Ribavirin Treatment
73
Aerosolized Ribavirin Treatment
- Mechanism of action: Guanosine analogue; Inhibits nucleotide biosynthesis and mRNA capping and promotes hypermutation of the genome.
- Indicated for severe LRT RSV infection in special populations: Premature infants; Patients with chronic lung disease; Patients with congenital heart disease; Immunocompromised patients
74
Does RSV vary?
VARIES BY REGION
75
RSV: Prevention
RSV Passive Immunoprophylaxis
76
RSV Passive Immunoprophylaxis
- not an active immunization = giving antibodies to tag virus
77
RSV Passive Immunoprophylaxis
Indications
Birth ≤32 weeks gestation
Age ≤ 2 years and therapy for chronic lung disease within 5 months preceding RSV season.
(Considered for infant born between 32 and 35 weeks gestation.)
Agents
Palivizumab (pah lih VIH zyou mab): chimeric human-mouse monoclonal anti-RSV antibody.
RSIG: Pooled human immunoglobin, enriched for anti-RSV antibodies.
78
Rhinovirus
Frequent: Common cold
Occasional: Exacerbation of chronic bronchitis and asthma
Infrequent: Pneumonia in children
79
Coronavirus
Frequent: Common cold
Occasional: Exacerbation of chronic bronchitis and asthma
Infrequent: Pneumonia and bronchiolitis
80
Human respiratory syncytial virus
Frequent: Pneumonia and bronchiolitis in young children
Occasional: Common cold in adults
Infrequent: Pneumonia in elderly and immunosuppressed patients
81
Parainfluenza virus
Frequent: Croup and lower respiratory tract disease in young children
Occasional: Pharyngitis and common cold
Infrequent: Tracheobronchitis in adults; lower respiratory tract disease in immunosuppressed patients
82
Adenovirus
Frequent: Common cold and pharyngitis in children
Occasional: Outbreaks of acute respiratory disease in military recruits
Infrequent: Pneumonia in children; lower respiratory tract and disseminated disease in immunosuppressed patients
83
Influenza A virus
Frequent: Influenza
Occasional: Pneumonia and excess mortality in high-risk patients
Infrequent: Pneumonia in healthy individuals
84
Influenza B virus
Frequent: Influenza
Occasional: Rhinitis or pharyngitis alone
Infrequent: Pneumonia
85
Human metapneumovirus
Frequent: Lower respiratory tract disease in children
Occasional: Upper respiratory tract illness in adults
Infrequent: Pneumonia in elderly and immunosuppressed patients
