Adenovirus Flashcards
Respiratory infections
What type of virus is adenovirus?
Nonenveloped, lytic DNA virus
Which type of DNA does this virus has?
Linear, souble-stranded
Whic are the three major proteins in the virus capsid?
- Hexon
- Penton
- Fiber
T/F. The virual fiber protrudes from a pentone protein.
True
What are the three fiber regions?
- Distal globular knob
- Central shaft
- Tail
Minor capsid proteins are IIIA, VI, VIII, and IX. THeir functions is…
Stabilize the capsid structure
Neutralizing antibodies tend to bind to this protein.
Hexon
Determinants in this protein are responsible for hemagglutination properties.
Fiber
How many adenovirus species are there?
7: A-G
This is caused by infected respiratory droplets in the host.
Acute respiratory disease
Adenovirus species with tropism for the respiratory tract.
C, E, and B
What is the primary cellular receptor for adenovirus sepecies A, C, E, and F?
Coxsackie B virus-adenovirus receptor (CAR)
Where is CAR found in the lung?
Epithelial cell tight junctions
Adenovirus receptor used by species B and D.
CD46
Mention the rest of receptors used by adenovirus (3).
- CD80 and CD86
- Sialic acid
- Heparan sulfate proteglycans
T/F. Adenovirus uses microtubules to reach the endoplasmic reticulum.
False; it uses them to reach the nuclear pore
This is a key regulatory gene that controls the expression of other early genes (E1B, E2, E3, and E4).
E1A
Mention the E3 gene function related to antigen presentation.
It inhibits the expression of MHC-I
Mention the E3 gene function related to apoptosis inhibition.
Downregulation of Fas, TNF, and TRAIL receptors
In which way is adenovirus released from the cell?
Cell lysis
T/F. Adenovirus can persist in a latent state for years.
True
T/F. Adenovirus infections are dangerous and can be fatal.
False; 50% of infections are subclinical, and most symptomatic cases are mild and self-resolving.
Most individuals show serologic evidence of prior adenovirus infection by age…
10
Transmission of adenovirus can occur via…
- Aerosolized droplets
- Fecal-oral route
Outbreak settings for adenovirus.
- Daycare centers
- Summers camps
- Public swimming pools
Acute adenovirus infections are uncommon in immunocompetent adults, but in which group are they more frequent?
Military recruits
Military personnel experience epidemics of acute respiratory disease (ARD) caused by adenovirus types…
4 and 7
In which groups can fatal adenovirus infections occur?
- Immunocompromised host
- Neonates
- Occasionally healthy children and adults
Percentage of URIs caused by adenovirus.
5%
Percentage of pneumonias caused by adenovirus.
10%
What are the common presentations of adenoviral URIs?
- Mild pharyngitis or tracheitis with coryza
- Fever, malaise, headache, myalgia, and abdominal pain
- Exudative tonsilitis and cervical adenopathy
- Otitis media
- Pertussis-like syndrome
How does adenoviral pharyngitis mimic group A streptococcal infection?
Both present exudative tonsilitis and cervical adenopathy
What upper respiratory symptoms are commonly associated with adenovirus?
Mild pharyngitis or tracheitis with coryza (nasal congestion, rhinorrhea, sneezing)
What systemic symptoms often accompany adenoviral upper respiratory infections?
Fever, malaise, headache, myalgia, and abdominal pain
In which age group is otitis media due to adenovirus most common?
Children under 1 year old
A patient presenting with a prolonged cough similar to pertussis but with a negative Bordetella pertussis culture. This is a…
Pertussis-like syndrome
Which adenovirus types are known to cause pneumonia?
1-5, 7, 14, and 21
What long-term complication can adenoviral pneumonia lead to?
Bronchioectasis
Which adenovirus subgroup is associated with severe pneumonia, especially in infants?
Subgroup B (3, 7, 14, 21)
What are the common clinical features of adenoviral acute respiratory disease (ARD)?
Fever, sore throat, cough, hoarseness, rhinorrhea
What are the key physical exam findings in adenoviral ARD?
- Pharyngitis
- Rales and rhonchi
What chest radiograph findings are typical in adenoviral pneumonia?
Bilateral patchy ground-glass opacities
Why is diagnosis of adenovirus infections not always pursued in immunocompetent patients?
Most are mild and self-limited
How long does it take for adenoviruses to produce a cytopathic effect in viral culture?
Most of them 2-7 days
What types of clinical samples can be used for adenovirus viral culture? (In RIs)
- Nasopharyngeal swabs
- Throat swabs
How long is viral shedding detectable in pharyngitis?
1-3 days
Which antigen detection method is used for respiratory samples and tissue?
Immunofluorescence assay (IFA)
What is the preferred method for diagnosing, typing, and quantifying adenovirus?
PCR
What are the key histopathological findings in adenoviral lung infections?
- Diffuse interstitial pneumonitis
- Necrotizing bronchitis
- Bronchiolitis
- Pneumonia with mononuclear cell infiltration
- Hyaline membrane formation
What histological changes are seen in the early stage of adenovirus infection?
Small eosinophilic inclusions
What characteristic nuclear inclusions are seen in the late stage of adenoviral infection?
Basophilic intranuclear inclusions surrounded by a clear halo (smudge cells)
How do adenovirus-infected cells differ from cytomegalovirus-infected cells histologically?
Adenovirus does not produce intracytoplasmic inclusions or multinucleated giant cells
T/F. There are no approved antiviral agents for adenovirus infections.
True
What is the in vitro activity of cidofovir against adenovirus?
Good activity
What adverse effect is significantly associated with cidofovir?
Nephrotoxicity
Which two antiviral agents show in vitro activity against adenovirus but have scant clinical data?
Vidarabine and ganciclovir
What methods are useful for adenovirus infection prevention?
- Handwashing
- Social distance
- Chlorination of water
For which group are adenovirus oral vaccines available in the US?
The military
