Viral gastroenteritis includes Norovirus, Calcivirus, and Rotaviral enteritis. Risk for norovirus contamination is high in food prepared in unsanitary conditions (especially sandwiches and salads), water or ice inadequately treated, and raw shellfish (especially oysters).
CASES/YEAR
30,800,000 (US); 1,360,000,000 (Global)
OTHER NAMES
Norovirus (formerly Norwalk-like virus) or Calcivirus gastroenteritis; Epidemic viral gastroenteritis; Rotaviral enteritis;
INCUBATION
10-50 hours (Norovirus); 1-3 days (Rotavirus); [CCDM]
INITIAL SYMPTOMS
Case definition of gastroenteritis caused by norovirus (the most common cause): 1.) Vomiting in more than 1/2 of cases; 2.) Incubation period of 24-48 hours; 3.) Illness duration of 12 to 60 hours; 4.) No bacterial pathogens in stool cultures; [Cecil]
PRECAUTIONS
ROTAVIRUS: Contact; "Ensure consistent environmental cleaning and disinfection and frequent removal of soiled diapers. Prolonged shedding may occur in both immunocompetent and immunocompromised children and the elderly." NOROVIRUSES: Standard; Use Contact Precautions for diapered or incontinent persons for the duration of illness or to control institutional outbreaks. Persons who clean areas heavily contaminated with feces or vomitus may benefit from wearing masks since virus can be aerosolized from these body substances; ensure consistent environmental cleaning and disinfection with focus on restrooms even when apparently unsoiled. Hypochlorite solutions may be required when there is continued transmission. Alcohol is less active, but there is no evidence that alcohol antiseptic handrubs are not effective for hand decontamination. Cohorting of affected patients to separate airspaces and toilet facilities may help interrupt transmission during outbreaks." [CDC 2007 Guideline for Isolation Precautions]
COMMENTS
FINDINGS:
Rotavirus causes gastroenteritis in infants and young children. Findings include the sudden onset of vomiting and low-grade fever followed by diarrhea. Most cases resolve spontaneously within 3 to 9 days. Rotavirus usually causes a mild illness, but can cause dehydration and shock. Rotavirus causes chronic diarrhea in children with AIDS. [ID, p. 677-81, 2161; PPID, p. 1987, 2122-7, 1255; Cohen, p. 1391t] Seizures may occur in cases of rotavirus infection. [Guerrant, p. 408] Patients with norovirus infection have vomiting and non-bloody diarrhea. Resolution usually occurs within 1-3 days. Low grade fever may occur. [CDC Travel, p. 302] See "Gastroenteritis."
EPIDEMIOLOGY:
In children <5 years old hospitalized for gastroenteritis, rotavirus causes about 1/3 to 1/2 of cases. Outbreaks occur in daycare centers (fecal-oral route). Most adults have asymptomatic infections. Norovirus gastroenteritis is transmitted by the fecal-oral route with secondary contamination of water, produce, and shellfish. Outbreaks of Norovirus occur in cruise ships, restaurants, day care centers, hotels, and nursing homes. Most susceptible are children <5 years, adults >65 years, and immunocompromised patients. [CCDM, p. 437, 525] When vomiting is the primary symptom, acute gastroenteritis is usually caused by preformed toxins from Staphylococcus aureus or Bacillus cereus or by viruses, most commonly rotavirus in infants and Norwalk-like virus in children or adults. [Foodborne Illnesses. MMWR. 4/16/04] "In the United States, ~50% of outbreaks of nonbacterial gastroenteritis are caused by noroviruses." [Harrisons, p. 407] Immunity to rotavirus is obtained in virtually all children by the age of 5. [Cecil, p. 2212]
PREVENTION:
Rotavirus is a common cause of gastroenteritis in infants and young children in developing countries. [CDC Travel, p. 13] Risk for norovirus contamination is high in food prepared in unsanitary conditions (especially sandwiches and salads), water or ice inadequately treated, and raw shellfish (especially oysters). "Washing hands with soap and water for at least 20 seconds is considered the most effective way to reduce norovirus contamination;" [CDC Travel, p. 301]
DIAGNOSTIC
Rotavirus: commercially available ELISA test kits widely used to detect viral antigen in rectal swab; [PPID, p. 1991] Norovirus: RT-PCR effectively identifies norovirus in stool specimens; Commercially available EIAs have poor sens/spec; [CDC Travel]
SIGNS & SYMPTOMS
-
>fatigue, weakness
-
>fever
-
>myalgia
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G abdominal pain
-
G diarrhea
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G nausea, vomiting
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N headache
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N seizure
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*shock
ENTRY
Ingestion, Swimming
SOURCE
Person-to-Person, Human Fecal-Oral, Eating Contaminated Food, Eating Contaminated Mollusks or Crustacean, Waterborne (Ingesting, Inhaling, or Swimming)
RISK FACTORS
- AIDS patients
- Care for patients (fecal-oral pathogens)
- Eat undercooked meat or fish
- Ingest infectious agents in food/water
- Live together in close quarters
- Swim in contaminated water (ingestion or inhalation)
TREATMENT
No specific antimicrobial treatment; [CCDM, p. 437, 526]
REFERENCES FOR CASES/YEAR
1. (US) Estimated total cases/year in 1997 = 30.8 million (23 million Norovirus, 3.9 million Rotavirus, and 3.9 million Astrovirus); [Mead1999: PMID 10511517]
2. (Global) No agent found in 25-50% of patients with acute gastroenteritis; Norovirus causes 200,000 deaths/year in children <5 years in developing countries; [Cecil, p. 2210] 1.7 billion cases of diarrheal illnesses/year; [Fact sheets from WHO] Estimate: In the US, 38.6 million illnesses/year (13% bacteria, 7% parasites, and 80% viruses); [Mead1999: PMID 10511517] 80% X 1.7 billion = 1.36 billion;