ETIOLOGY INCUBATION SIGNS/SYMPTOMS DURATION ILLNESS ASSOCIATED FOODS LAB TESTS TREATMENT
Hepatitis A

 

28 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, contaminated drinking water, 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.

 

Noroviruses (and other caliciviruses)

 

12-48 hrs

 

Nausea, vomiting, abdominal

cramping, diarrhea,

fever, myalgia, and some

headache. Diarrhea is

more prevalent in adults

and vomiting is more

prevalent in children.

 

12-60 hrs

 

Shellfish, fecally contaminated

foods, ready-to-eat

foods touched by infected

food workers (salads,

sandwiches, ice, cookies,

fruit).

 

Routine RT-PCR and EM on fresh

unpreserved stool samples.

Clinical diagnosis, negative

bacterial cultures. Stool is

negative for WBCs.

 

Supportive care such as

rehydration. Good hygiene

 

Rotavirus

 

1-3 days

 

Vomiting, watery diarrhea,

low-grade fever. Temporary

lactose intolerance may

occur. Infants and

children, elderly, and

immunocompromised 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, 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.

Commercial ELISA kits are now

available for adenoviruses and

astroviruses.

 

Supportive care, usually mild,

self-limiting. Good hygiene.