RS11 - Adenoviruses

What family do adenoviruses belong to?

Family: Adenoviridae

What type of genome do adenoviruses have?

dsDNA

Are adenoviruses enveloped or non-enveloped?

Non-enveloped

How many adenovirus serotypes infect humans?

More than 50 serotypes infect humans

Why are adenoviruses resistant to environmental conditions?

Capsid is resistant to inactivation by GI tract, drying and detergents

What are the major routes of adenovirus transmission?

Aerosols, respiratory secretions, fecal-oral route

What environmental source is associated with adenovirus outbreaks?

Inadequately chlorinated swimming pools and ponds

What types of cells do adenoviruses infect?

Virus infects mucoepithelial cells in respiratory tract, GI tract, conjunctiva, cornea

How long can adenovirus be shed after infection?

Adenovirus shed for long periods of time after infection (pharynx and feces)

Why do adenoviruses spread easily in crowded conditions?

Close human-to-human interaction promotes spread (classrooms, military barracks)

Why do asymptomatic infections facilitate adenovirus spread?

Most infections are asymptomatic, which facilitates spread

How does adenovirus attach to host cells?

Attachment using unique "spike" or fiber to host cell receptor (CD46 or Coxsackie adenovirus receptor)

What allows adenovirus entry into host cells?

Secondary interaction with integrin, results in endocytosis

What type of cells does adenovirus infect?

Mucoepithelial cells in respiratory tract, GI tract, conjunctiva, cornea

How does adenovirus cause direct cell damage?

Infected cells accumulate virions and virus parts causing lysis ("Death protein" causes cell lysis)

What determines the clinical disease caused by adenovirus?

Disease is determined by tissue tropism of adenovirus serotype

Where can adenovirus become latent?

Lymphoid tissue (tonsils, adenoids, Peyer's patches)

When does adenovirus viremia occur?

Viremia may occur after local infection

spread to visceral organs

more likely in immunocompromised

What percentage of pediatric respiratory disease is caused by adenovirus?

Causes ~10% of respiratory diseases in children

What are common symptoms of adenoviral pharyngitis?

Cough, fever, sore throat, rhinorrhea, lymphadenopathy

How long does adenoviral pharyngitis typically last?

Usually lasts 3-5 days (main complaint is sore throat)

How does adenoviral pharyngitis resemble bacterial infection?

Mimics strep throat

What severe respiratory disease can adenovirus cause?

Acute respiratory disease and viral pneumonia

What population is commonly affected by acute respiratory disease due to adenovirus?

Military recruits

Which serotypes cause acute respiratory disease in military recruits?

Serotypes 4 and 7

What is pharyngoconjunctival fever?

Pharyngitis, conjunctivitis (pinkeye), rhinitis, cervical adenitis, fever

How long do symptoms of pharyngoconjunctival fever last?

Fever and other symptoms last 3-5 days

Is pharyngoconjunctival fever usually unilateral or bilateral?

Almost always unilateral

When are outbreaks of pharyngoconjunctival fever common?

Summer

associated with inadequate chlorination of pools

What tissues are infected in epidemic keratoconjunctivitis?

Conjunctiva and cornea

How infectious is epidemic keratoconjunctivitis?

Extremely infectious

What is the incubation period of epidemic keratoconjunctivitis?

~14 days

How long may conjunctivitis last in EKC?

1 to 4 weeks

How long are patients contagious with EKC?

At least 2 weeks after onset

What severe ocular complication can EKC cause?

Visual impairment (months)

What are key signs of epidemic keratoconjunctivitis?

Conjunctival hyperemia (bulbar and palpebral), follicular reaction, chemosis, epithelial keratitis, subepithelial infiltrates, membranes or pseudomembranes

What symptoms may patients with EKC experience?

Clear or yellow discharge, ocular itchiness, irritation, photophobia, epiphora, foreign body sensation, blurred vision/loss of visual acuity

What severe complication may occur in 25% of EKC cases?

Membranous or pseudomembranous conjunctivitis causing scarring and symblepharon formation

What causes infantile diarrhea due to adenovirus?

Serotypes 40 and 42

How long does adenoviral infantile diarrhea last?

1-2 weeks

What is hemorrhagic cystitis?

4-5 day acute illness, blood in urine, frequent urination, dysuria

What life-threatening GI complication is associated with adenovirus?

Intussusception (blockage of GI tract, can be fatal)

What severe neurologic complication can adenovirus cause?

Meningoencephalitis

Who is at risk for persistent or systemic adenovirus infections?

Immunocompromised patients

How is adenovirus infection typically diagnosed?

Frequently made on clinical criteria

What confirms adenovirus infection definitively?

Viral antigens or nucleic acid in tissue/infected cells

How can adenovirus be typed?

Hemagglutination-inhibition or neutralization assay

What is the usual course of most adenovirus infections?

Most infections are self-limited

Is there an efficacious antiviral therapy for adenovirus?

No efficacious antiviral therapy available

What may be used in severe adenovirus cases?

Interferon therapy in early stages

What vaccine is available for adenovirus?

Live, oral vaccine available for types 4 and 7 (new in 2011)

Who is recommended to receive the adenovirus vaccine?

Military recruits aged 17-50

What infection control measures prevent adenovirus spread?

Personal hygiene, infection control, adequate chlorination of swimming pools