Incubation Periods and Symptoms

      

Common   Pathogens

Incubation PeriodS

Common                          Symptoms

◙   Bacillus Cereus

 

1-6 hrs (vomiting)               6-24 hrs (diarrhea)

Nausea and diarrhea. Typically resolves within 24 to 48 hours

◙   Campylobacter

 

     

2 to 7 days               (usually 3 to 5 days)

Diarrhea (often bloody), abdominal cramps, nausea and headaches. Typically resolves within 1 to 10 days

◙   C. Botulinum

 

 

12 to 72 hrs                 (usually 18 to 36 hrs)

Nausea, vomiting, diarrhea, fatigue, headache, dry mouth, double vision, muscle paralysis, respiratory failure. Duration is variable (days to months).

◙   C. Perfringins

 

 

8 to 22 hrs            (average is 12 hrs)

Diarrhea, abdominal cramps and vomiting; usually no fever. Typically resolves within 1 to 2 days.

◙   E. coli O157:H7

 

 

24+ hrs to 10 days (usually 3 to 4 days)

Diarrhea (often bloody), abdominal cramps and vomiting; usually no fever. HUS may develop in rare cases. Typically resolves within 1 to 8 days (in non-complicated cases)

◙   Hepatitis A

 

15 to 50 days        (average is 28 days)

Diarrhea, dark urine, jaundice and flu-like symptoms, including headaches, fever, nausea and abdominal pain. Duration is variable (ranging a few weeks to 3 months).

◙   Listeria

 

9-48 hrs                         (for GI symptoms)

2 to 6 weeks                 (for invasive disease)

 

Fever, muscle aches, nausea, diarrhea; pregnant women may suffer flu-like symptoms and stillbirth; elderly, immune-compromised and infants can develop sepsis and meningitis. Duration is variable.

◙   Norovirus

 

 

12 to 72 hrs            (usually 24 to 48 hrs)

Diarrhea, abdominal cramps, vomiting, headaches and fever. Typically resolves within 1 to 3 days.

◙   Salmonella

 

6 to 72 hrs              (usually 12-36 hrs)

Diarrhea, abdominal cramps, nausea, vomiting and fever. Typically resolves within 4 to 7 days.

◙   Shigella

 

 

24 to 72 hrs             (usually 36 to 48 hrs)

Watery diarrhea, nausea, vomiting, abdominal cramps, chills and fever. Stool may contain blood and mucus. Typically resolves within 4 to 7days.

◙  Staphylococcus

 

30 minutes to 8 hrs (usually 2 to 4 hrs)

Diarrhea, abdominal cramps, nausea and vomiting. Typically resolves in 24 to 48 hrs.
 

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Bacillus Cereus Fact Sheet

Bacillus cereus, a commonly occurring pathogen which can survive in remarkably hostile conditions, is typically found in soil. Illness associated with B. cereus can occur when heat-resistant B. cereus endospores survive cooking. If the food is then inadequately refrigerated or held for extended periods at improper temperatures the endospores can germinate and multiply. Once the spores germinate, the vegetative cells can multiply and produce illness causing enterotoxins. B. cereus is known to cause two distinctly different types of food-borne illness.

  • The first type of illness, referred to as the Rapid-onset (Emetic) Vomiting-type, is characterized by nausea and vomiting. The incubation period ranges from 1 to 6 hours. Both the symptomology and incubation period mirror those of Staphylococcus aureus.
  • The second type of illness, generally referred to as the Slow-onset Diarrheal-type, is characterized by diarrhea and abdominal pain. The diarrheal-type illness has an incubation period ranging from 6 to 24 hours. The symptoms include watery diarrhea, abdominal cramps and pain. This type generally mimics the symptoms of Clostridium perfringens.

Regardless of type, symptoms typically persist for less than 24 hours. Generally, gastroenteritis symptoms from B. cereus resolve by themselves. In very rare cases, however, some degree of medical intervention may be required.

The diarrheal-type food poisoning has been associated with a wide variety of foods, including meat and vegetable dishes, sauces, pastas, desserts and dairy products. In turn, the vomiting-type outbreaks have typically been associated with rice products. Other starchy foods such as potato, pasta and cheese have also been implicated. Some outbreaks may ultimately go unreported because of the similarities between B. cereus, Staphylococcus aureus intoxication (B. cereus vomiting-type) and C. perfringens food poisoning (B. cereus diarrheal-type).

B. cereus and B. anthracis may pose a higher risk to those working in food preparation areas and slaughterhouses. While intact tissues and meat from animals are sterile, once slaughtered, the potential for contamination emerges.

The presence of large numbers of B. cereus (greater than 10^6 organisms /g) in a food can be indicative of active growth and proliferation of the organism. Confirmation of B. cereus as the etiologic agent in a food-borne illness outbreak requires, at the very least: (1) isolation of strains of the same serotype from the suspect food and patient; (2) isolation of large numbers of a B. cereus serotype known to cause food-borne illness from the suspect food and patient, and (3) isolation of B. cereus from suspect foods and determining their enterotoxigenicity by serological (diarrheal toxin) or biological (diarrheal and emetic) tests. According to the FDA, the rapid onset time from consumption to symptoms in the emetic form of the disease, coupled with microbiological evidence, is often sufficient to diagnose this type of food poisoning.

References:

www.cfsan.fda.gov/~mow/chap12.html

Schneider et al., "Preventing Foodborne Illness: Bacillus cereus and Bacillus anthracis ". Florida Cooperative Extension Service, University of Florida. November, 2004.

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Bacillus Cereus Images

 

 

 

 

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