Adenovirus Infections

Description

• Acute, typically self-limited, febrile illnesses characterized by inflammation of mucous membranes including the conjunctivae, respiratory, and GI tracts
• Adenovirus infections can occur as epidemic or endemic outbreaks.
  • Common types:
    • Acute febrile respiratory illness—affects primarily children
    • Acute respiratory disease—affects adults
    • Viral pneumonia—affects children and adults
    • Acute pharyngoconjunctival fever—affects children, particularly after summer swimming
    • Acute follicular conjunctivitis—affects all ages
    • Epidemic keratoconjunctivitis—affects adults
    • Intestinal infections leading to enteritis, mesenteric adenitis, and intussusception
  • Conjunctivitis
• System(s) affected: cardiovascular; GI; hematologic/lymphatic/immunologic; musculoskeletal; nervous; pulmonary; renal/urologic; ophthalmologic

Geriatric Considerations
Complications more likely in elderly populations
Pediatric Considerations
Viral pneumonia in infants and neonates (may be fatal)

Epidemiology

• Predominant age: <10 years but epidemics in all ages
• Predominant sex: male = female
• Occurs worldwide and throughout the year but more frequently in warmer months

Incidence

• Common infection: 2–5% of all upper respiratory infections (URIs) and >10% of URIs in children
• Most individuals show evidence of prior adenovirus infection by age 10 years.
• Many adenovirus infections are subclinical or asymptomatic.
• 15–70% of conjunctivitis worldwide

Etiology and Pathophysiology

• DNA virus 60 to 90 nm in size, 6 species (A through F) with >50 known serotypes
• Adenovirus can remain dormant in lymphoreticular tissue (adenoids and tonsils) after exposure, and viral shedding may persist for months (1).
• Transmission
  • Aerosol droplets, fomites, fecal–oral
  • Virus survives on skin and environmental surfaces.
  • Incubation period is 5 to 9 days (2).
• Most common known pathogens:
  • Types 1 to 5, 7, 14, and 21 cause upper respiratory illness and pneumonia.
  • Types 3, 7, and 21 cause pharyngoconjunctival fever.
  • Types 31, 40, and 41 cause gastroenteritis.
  • Types 8, 19, 37, 53, and 54 cause epidemic keratoconjunctivitis.
  • Types 5, 7, 14, and 21 cause more severe illness.

Risk Factors

• Large number of people gathered in a confined area (e.g., military recruits, college students, daycare centers, summer camps, community swimming pools)
• Immunocompromised are at risk for severe disease.

General Prevention

• Live, enteric-coated oral type 4 and type 7 adenovirus vaccine available for military recruits (or other personnel at high risk ages 17 to 50 years); reduces incidence of acute respiratory disease (3)
• Frequent hand washing
• Decontamination of environmental surfaces using chlorine, bleach, formaldehyde, or heat
• Universal precautions, particularly when examining patients with epidemic keratoconjunctivitis; droplet precautions if suspected respiratory infection
• Health care providers with suspected bilateral adenoviral conjunctivitis should avoid direct patient contact for 2 weeks after onset of symptoms in the second eye.

Commonly Associated Conditions

• Otitis media
• Conjunctivitis
• Bronchiolitis
• Viral enteritis
• Less frequent syndromes (seen primarily in immunocompromised individuals): meningoencephalitis, hepatitis, myocarditis, pancreatitis, genital infections, intussusception and mesenteric adenitis hemorrhagic cystitis, and interstitial nephritis