Gastroenteritis, Viral

Key Features

• Viruses are responsible for at least 30–40% of cases of infectious diarrhea in the United States

• Agents include rotaviruses; caliciviruses, including noroviruses such as Norwalk virus; astroviruses; enteric adenoviruses; and, less often, toroviruses, coronaviruses, picornaviruses (including the Aichi virus), and pestiviruses

Clinical Findings

• Rotaviruses

  • Leading cause of dehydrating gastroenteritis in young children

  • Usually mild and self-limiting

  • A 2- to 3-day prodrome of fever and vomiting is followed by nonbloody diarrhea (up to 10–20 bowel movements per day) lasting for 1–4 days

• Noroviruses, such as Norwalk virus, are the major causes of severe diarrhea and recognized as the major cause of epidemic gastroenteritis

  • A short incubation period (24–48 hours)

  • Short symptomatic illness (12–60 hours)

  • High frequency (> 50%) of vomiting

  • Absence of bacterial pathogens in stool samples

  • Presence of antibodies is not associated with protection against reinfection

Diagnosis

• Rotaviruses: PCR of the stool is method of choice

• Noroviruses: RT-PCR of stool samples is used for diagnostic and epidemiologic purposes

Treatment

• Rotaviruses

  • Treatment is symptomatic, with fluid and electrolyte replacement

  • Local intestinal immunity gives protection against successive infection

  • Adjunctive therapies such as oral odansetron shorten the median duration of diarrhea and hospitalization

  • Two oral rotavirus vaccines are available in the United States: a live, oral pentavalent human-bovine reassortment rotavirus vaccine (PRV, RotaTeq; to be given at 2, 4, and 6 months of age) and live, oral attenuated human rotavirus vaccine (HRV, Rotarix; to be given at 2 and 4 months of age)

  • A trial with nitazoxanide was attendant with moderate success among a small cohort of patients with gastroenteritis from Egypt with efficacy in both the rotavirus and norovirus subgroups

  • The enkephalinase inhibitor racecadotril (also known as acetorphan, given 1.5 mg/kg every 8 hours orally)

    • Available in many countries but not the United States

    • Appears to be clinically effective in reducing diarrheal symptoms

• Noroviruses: Treatment is largely symptomatic

• Prevention

  • Strict adherence to general hygienic measures

  • Cohorting of sick patients

  • Contact precautions for symptomatic hospitalized patients

  • Exclusion from work of symptomatic staff until symptom resolution (or 48–72 h after this for norovirus disease)

  • Proper decontamination procedures

  • An intranasally delivered norovirus particle vaccine has showed protection against infection with a homologous virus strain