Food-borne Illnesses Table: Viral Agents

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Etiology

Incubation Period

Signs and Symptoms

Duration of Illness

Associated Foods

Laboratory Testing

Treatment

Hepatitis A

30 days average
(15-50 days)

Diarrhea; dark urine; jaundice; and flu-like symptoms, (i.e., fever, headache, nausea, and abdominal pain.)

Variable,
2 weeks -
3 months

Shellfish harvested from contaminated waters, raw produce, uncooked foods and cooked foods that are not reheated after contact with infected food handler.

Increase in ALT, bilirubin. Positive IgM and anti-hepatitis A antibodies.

Supportive care. Prevention with immunization.

Norwalk-like viruses

24-48 hrs

Nausea; vomiting; watery, large-volume diarrhea; fever rare.

24-60 hrs

Poorly cooked shellfish; ready-to-eat foods touched by infected food workers; salads, sandwiches, ice, cookies, fruit.

Clinical diagnosis, negative bacterial cultures, >fourfold increase in antibody titers of Norwalk antibodies, acute and convalescent, special viral assays in reference lab. Stool is negative for WBCs.

Supportive care. Bismuth sulfate.

Rotavirus

1-3 days

Vomiting; watery diarrhea; low-grade fever. Temporary lactose intolerance may occur. Infants and children, elderly, and immunocompro-mized are especially vulnerable.

4-8 days

Fecally contaminated foods. Ready-to-eat foods touched by infected food workers (salads, fruits).

Identification of virus in stool via immunoassay.

Supportive care. Severe diarrhea may require fluid and electrolyte replacement.

Other viral agents (astroviruses, calciviruses, adenoviruses, parvoviruses)

10-70 hrs

Nausea; vomiting; diarrhea; malaise; abdominal pain; headache; fever.

2-9 days

Fecally contaminated foods. Ready-to-eat foods touched by infected food workers. Some shellfish.

Identification of the virus in early acute stool samples. Serology.

Supportive care, usually mild, self-limiting.

Etiology

Incubation Period

Signs and Symptoms

Duration of Illness

Associated Foods

Laboratory Testing

Treatment