Enterovirus

 

Clinical Background

Enteroviral disease is a common, under-recognized childhood illness.

Epidemiology

  • Prevalence – Non-polio enteroviruses cause about 10-15 million symptomatic cases annually in the U.S.
  • Age – affects all ages; most severe in infants and older adults
  • Occurrence
    • Infections occur throughout the year but peak during July-October
  • Transmission – fecal-oral
  • Wild type poliovirus 1-3 no longer in Western hemisphere due to effective vaccine strategies

Organism

  • Enteroviruses (EV) are single-stranded RNA viruses in the Picornaviridae family
  • >70 recognized  serotypes
  • Non-polio enteroviruses
    • Coxsackieviruses A 1-22 and 24
    • Coxsackieviruses B 1-6
    • Echoviruses 1-9, 11-27 and 29-31
    • Enteroviruses 68-71

Clinical Presentation

  • Nonspecific febrile illness with or without rash
  • Acute hemorrhagic conjunctivitis (coxsackie A24 & echovirus 70)
  • Hand-foot-mouth disease (coxsackievirus A16)
  • Sepsis syndrome in neonates
  • Myocarditis (coxsackievirus B)
  • Hepatitis
  • Central nervous system (CNS) infections
    • Aseptic meningitis (meningeal inflammation in absence of bacterial pathogen)
      • Enteroviruses are the most common cause (80-92% of all cases)
      • Serotype of enterovirus varies
      • Clinical manifestations depend upon host
    • Enteroviral encephalitis is less common, but more severe, than aseptic meningitis
      • Global neurologic depression
      • Evidence of focal encephalitis, similar to herpes simplex encephalitis (enterovirus found on brain biopsy)
      • Immunocompromised adults and children with agammaglobulinemia are susceptible to chronic meningitis or meningoencephalitis
    • Paralytic syndrome
      • Classically associated with poliovirus
      • Enterovirus 70/71 and coxsackievirus A7 can cause similar syndrome
  • In the neonate, enterovirus may cause severe morbidity and mortality
    • Related to sepsis, meningoencephalitis, myocarditis or hepatitis
    • Complications associated with poor outcome generally occur 1-2 days after birth
      • Suggests prenatal origin of infection
    • Sudden onset of fever, irritability and poor feeding characterize infection
    • One-fourth of children have diarrhea, vomiting and rash (macular or maculopapular)
    • Meningeal involvement in febrile disease 70% of time
  • Meningitis beyond neonatal period characterized by sudden onset of fever (38°-40°C)
    • Meningeal irritation (>6 weeks) occurs in >50% of patients
    • Headache and photophobia are almost universally reported
    • Neurologic abnormalities rare
    • Both short and long term outcomes generally good for immunocompetent hosts

    • Manifestations Commonly Associated with Enterovirus Serotypes

      Serotype(s) of Indicated Virus

      Manifestation

      Coxsackievirus

      Echovirus (E) and Enterovirus (Ent)

      Acute hemorrhagic conjunctivitis

      A24

      E70

      Aseptic meningitis

      A2, 4, 7, 9, 10; B1-5

      E4, 6, 7, 9, 11, 13, 16, 18, 19, 30, 33; Ent70, 71

      Encephalitis

      A9; B1-5

      E3, 4, 6, 9, 11, 25, 30; Ent71

      Exanthem

      A4, 5, 9, 10, 16; B1, 3-5

      E4-7, 9, 11, 16-19, 25, 30; Ent71

      Generalized disease of the newborn

      B2-5

      E4-6, 9, 11, 14, 16, 19

      Hand-foot-and-mouth disease

      A5, 7, 9, 10, 16; B2-5

      Ent71

      Herpangina

      A1-10, 16, 22; B1-5

      E6, 9, 11, 16, 17, 25; Ent71

      Myocarditis, pericarditis

      A4, 9, 16; B1-5

      E6, 9, 11, 22

      Paralysis

      A4, 7, 9; B1-5

      E2, 4, 6, 9, 11, 30; Ent70, 71

      Pleurodynia

      A1, 2, 4, 6, 9, 10, 16; B1-6

      E1-3, 6, 7, 9, 11, 12, 14, 16, 19, 24, 25, 30

      Pneumonia

      A9, 16; B1-5

      E6, 7, 9, 11, 12, 19, 20, 30; Ent68, 71

      Reproduced with permission from McGraw-Hill Material.  Cohen JI. Enteroviruses and Reoviruses. In Kasper D et al. eds. Harrison's Principles of Internal Medicine, 16th ed. New York: McGraw-Hill, 2005;1145.

Treatment

  • Supportive