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Foodborne Disease: Frequently Asked Questions

What are the signs and symptoms associated with foodborne disease?

Foodborne diseases usually cause gastrointestinal illness, meaning they affect your stomach or bowel.  Signs and symptoms associated with gastrointestinal illness vary, depending upon several factors including the disease, the age and health status of the patient and how much of the particular pathogen was ingested (eaten).  Typical signs and symptoms include nausea, vomiting, diarrheal illness and abdominal pain.  Additional signs and symptoms may include fever, headache, malaise, a general feeling of being unwell, myalgia (muscle ache), loss of appetite, loss of weight, chills and dehydration.  Certain signs and symptoms are usually associated with particular diseases, such as jaundice with hepatitis A.  In addition, sometimes serious illness can follow a gastrointestinal illness.  Examples of this include HUS, a severe kidney condition that can occur after illness caused by E. coli infections or Guillain-Barre syndrome, a nerve condition that occasionally follows illness with campylobacteriosis.

What are some of the leading causes of foodborne disease in Virginia?

The most frequently reported gastrointestinal diseases in Virginia include bacterial infections, such as salmonellosis and campylobacteriosis, and giardiasis, a parasitic disease.  In addition, norovirus is one of the most frequently reported causes of gastrointestinal outbreaks.  Additional information regarding foodborne disease may be found by referring to factsheets on the Foodborne Disease Data page.

When may my bout of gastrointestinal illness be investigated by the Virginia Department of Health?

There are currently more than seventy-five reportable diseases and conditions in Virginia as required by state law.  Doctors, hospitals and laboratories report these diseases and conditions to the health departmnet when a reportable disease diagnosis is suspected or confirmed.  The health department usually calls patients to collect information about the illness and certain exposures.  Health department interviews usually include questions about certain exposures the patient had before the start of the illness (i.e. food history, water exposure, travel history, contact with animals) as well as a review of information contained in the initial report.  Confidentiality of information collected from patients by communicable disease staff at the local  or state health department is maintained according to state and federal law, including the provisions of §§ 32.1-38, 32.1-41 and 32.1-74 of the Code of Virginia.

In situations in which a suspected foodborne outbreak is discovered, all persons identified as being part of the investigation (includes people who were at the same event or the same restaurant) may be contacted by local health department staff to collect additional information.  This may include individuals that became ill, but did not seek medical attention or individuals that did not become ill.  The health department will record all illness complaints called in to them, however, not all complaints will result in an investigation being started.

What should be done if I suspect that I may be infected with a foodborne disease?

If you develop gastrointestinal illness (i.e. diarrhea, nausea, vomiting, abdominal cramps, etc...) and believe your symptoms may have been caused by food, you may need to visit your medical provider or a hospital, depending upon the severity of your symptoms.  Upon a visit to a healthcare professional/facility, a stool specimen may be collected to test at a laboratory to help determine if you have been infected with a particular foodborne disease.  Another consideration would be to report your concern to the Virginia Department of Health or Virginia Department of Agriculture, depending upon the source of the food product you suspect may have caused your illness.  The health department is responsible for inspecting restaurants and licensed caterers.  The Virginia Department of Agriculture and Consumer Services is responsible for inspecting other types of food retail establishments, such as grocery stores and delicatessens with limited seating capacity.  When contacting the health department to report a complaint, call the local health district (environmental health services) in which the restaurant or caterer is located.  An inspection of the retail food establishment may result from your call.

What is an incubation period and how does this relate to my bout of gastrointestinal illness/foodborne disease?

An incubation period is the amount of time it takes for signs and symptoms to appear.  It is measured as the length of time between exposure to and the appearance of the first symptoms of illness.  For example, a person eats a piece of undercooked chicken that is contaminated with Salmonella bacteria on Monday at 12pm.  The person starts to feel sick on Tuesday at 2pm with diarrhea and stomach cramps.  The incubation period is measured from Monday at 12pm, when the bacteria first entered the body, until Tuesday at 2pm, when they first started to feel sick.  This person’s incubation period was 26 hours.  The incubation period is important because it gives a specific timeframe in which an exposure most likely caused a disease.  When the person ill with salmonellosis is interviewed by the health department, questions about foods eaten will focus on the three days before their illness started (Saturday at 2pm until Tuesday at 2pm) because the incubation period ranges up to 72 hours for salmonellosis.  Each foodborne disease has a different incubation period.

A common misconception is that gastrointestinal illness was caused by the last food item that was eaten before symptoms started.  While there are a few instances in which gastrointestinal illness may result within a few hours of exposure to a particular pathogen, in fact, many of the foodborne diseases have incubation periods that are longer than a day.  Some foodborne diseases, such as hepatitis A and listeriosis, may cause illness one to two months following exposure to the pathogen.  Below is a listing of several foodborne diseases with their incubation period averages and ranges:


Bacterial Diseases:




E. coli infection (Shiga toxin-producing):


Usual Incubation Period

12- 36 hours

1-3 days

2-5 days

3-4 days

3 weeks

Range of incubation period

6-72 hours

12-96 hours

1-10 days

2-10 days

3-70 days

Viral Diseases:


Hepatitis A:

Usual Incubation Period

24-48 hours

28-30 days

Range of incubation period

10-50 hours

15-50 days

Parasitic Diseases:



Usual Incubation Period

7-10 days

7 days

Range of incubation period

3-25 days

1-12 days

Foodborne Intoxication:

Staphylococcus aureus:

Bacillus cereus:

Clostridium perfringens:

Usual Incubation Period

2-4 hours

range is .5-6 hours (emetic type)

10-12 hours

Range of incubation period

30 minutes - 8 hours

6-24 hours (diarrheal type)

6-24 hours

Last Updated: 10-28-2011

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