Gastroenteritis, Viral

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

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

Rotaviruses: PCR of the stool is method of choice

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

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