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Persons using assistive technology might not be able to fully access information in this file. For assistance, please send e-mail to: mmwrq@cdc.gov. Type 508 Accommodation and the title of the report in the subject line of e-mail. Appendix B -- Guidelines for Confirmation for Foodborne-Disease OutbreaksAppendix B Guidelines for Confirmation of Foodborne-Disease Outbreaks A foodborne-disease outbreak (FBDO) is defined as an incident in which two or more persons experience a similar illness resulting from the ingestion of a common food. Before 1992, three exceptions existed to this definition: one case of botulism, chemical, or marine toxin poisoning constituted an FBDO if the etiology for that type of FBDO was confirmed. Since the beginning of 1992, two or more persons must become ill for the incident to be classified as an FBDO. The following table (Table_1) provides information concerning incubation periods, clinical syndromes, and criteria for confirming the etiology once an FBDO has been identified. The information on incubation periods and clinical syndromes is provided as a guideline and should not be included in the confirmation criteria. These guidelines may not include all etiologic agents and diagnostic tests. FBDOs should be reported to the Foodborne and Diarrheal Diseases Branch at CDC on form 52.13 (i.e., Investigation of a Foodborne Outbreak). Provision of other documents describing the outbreak investigation also is encouraged. For information regarding collection of laboratory specimens and for additional information on viral agents, refer to other CDC publications (i.e., "Recommendations for Collection of Laboratory Specimens Associated with Outbreaks of Gastroenteritis," MMWR 1990:39{No. RR-14} and "Viral Agents of Gastroenteritis: Public Health Importance and Outbreak Management," MMWR 1990;39{No. RR-5}). Table_1 Note: To print large tables and graphs users may have to change their printer settings to landscape and use a small font size.
Table B-1. Guidelines for confirmation of foodborne-disease outbreaks
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Etiologic agent Incubation Period Clinical Syndrome Confirmation
Bacterial
1. Bacillus
a. Vomiting toxin 1-6 hrs Vomiting, some patients with Isolation of organism from stool of
diarrhea; fever uncommon two or more ill persons and not
from stool of controls
OR
Isolation of >= 10^5 organisms/g from
epidemiologically implicated food,
provided specimen properly handled
b. Diarrheal toxin 6-24 hrs Diarrhea, abdonimal cramps, Isolation of organism from stool of
and vomiting in some patients; two or more ill persons and not
fever uncommon from stool of controls
OR
Isolation of >=10^5 organisms/g from
epidemiologically implicated food,
provided specimen properly handled
c. Brucella Several days to Weakness, fever, headache, Two or more ill persons and isolation
several mos, usually sweats, chills, arthralgia, of organism in culture of blood or bone
> 30 days weight loss, splenomegaly marrow, greater than fourfold increase
in standard agglutination titer (SAT)
over several wks, or single SAT titer
>=1:160 in person who has compatible
clinical symptoms and history of exposure
3. Campylobacter 2-10 days, usually Diarrhea (often bloody), Isolation of organism from clinical
2-5 days abdominal pain, fever specimens from two or more ill persons
OR
Isolation of organism from epidemiologically
implicated food
4. Clostridium botulinum 2 hrs-8 days, usually Illness of variable severity; Detection of botulinal toxin in serum,
12-48 hours common symptoms are diplopia, stool, gastric contents, or implicated food
blurred vision, and bulbar OR
weakness; paralysis, which is Isolation of organism from stool or intestine
usually descending and
bilateral, may progress
rapidly
5. Clostridium perfringens 6-24 hrs Diarrhea, abdominal cramps; Isolation of >=10^6 organisms/g in stool of
vomiting and fever are two or more ill persons, provided specimen
uncommon properly handled
OR
Demonstration of enterotoxin in the stool of
two or more ill persons
6. Escherichia coli
a. Enterohemorrhagic 1-10 days, usually Diarrhea (often bloody), Isolation of E. coli O157:H7 or other
(E. coli O157:H7 and 3-4 days abdominal cramps (often Shiga-like toxin-producing E. coli from clinical
others) severe), little or no fever specimen of two or more ill persons
OR
Isolation of E. coli O157 or other Shiga-like
toxin-producing E. coli from epidemiologically
implicated food
b. Enterotoxigenic (ETEC) 6-48 hrs Diarrhea, abdominal cramps, Isolation of organism of same serotype,
nausea; vomiting and fever which are demonstrated to produce heat-stable
are less common (ST) and/or heat-liable (LT) enterotoxin, from
stool of two or more ill persons
c. Enteropathogenic (EPEC) Variable Diarrhea, fever, abdominal Isolation of same enteropathogenic
cramps serotype from stool of two or more ill
persons
d. Enteroinvasive (EIEC) Variable Diarrhea (may be bloody), Isolation of same enteroinvasive
fever, abdominal cramps serotype from stool of two or more ill
persons
7. Listeria monocytogenes
a. Invasive disease 2-6 weeks Meningitis, neonatal sepsis, Isolation of organism from normally
fever sterile site
b. Diarrheal disease Unknown Diarrhea, abdominal cramps, Isolation of organism of same serotype
fever from stool of two or more ill persons
exposes to food that is epidemiologically
implicated or from which organism of same
serotype has been isolated
8. Nontyphoidal 6 hrs-10 days, Diarrhea, often with fever Isolation of organism of same serotype
Salmonella usually 6-48 hours and abdominal cramps from clinical specimens from two or more
ill persons
OR
Isolation of organism from epidemiologically
implicated food
9. Salmonella typhi 3-60 days, usually Fever, anorexia, malaise, Isolation of organism from clinical
7-14 days headache, and myalgia; specimens or two or more ill persons
sometimes diarrhea or OR
constipation Isolation of organism from epidemiologically
implicated food
10. Shigella 12 hrs-6 days, Diarrhea (often bloody), Isolation of organism of same serotype
usually 2-4 days frequently accompanied by from clinical specimens from two or more
fever and abdominal cramps ill persons
OR
Isolation of organism from epidemiologically
implicated food
11. Staphylococcus aureus 30 min-8 hours, Vomiting, diarrhea Isolation of organism of same phage type
usually 2-4 hours from stool or vomitus of two or more ill persons
OR
Detection of enterotoxin in epidemiologically
implicated food
OR
Isolation of >=10^5 organisms/g from
epidemiologically implicated food, provided
specimen properly handled
12. Streptoccus 1-4 days Fever, pharyngitis, scarlet Isolation of organism of same M- or T-type
Group A fever, upper respiratory from throats of two or more ill persons
infection OR
Isolation of organism of same M- or T-type
from epidemiologically implicated food
13. Vibrio cholerae 1-5 days Watery diarrhea, often Isolation of toxigenic organism from
a. O1 or O139 accompanied by vomiting stool or vomitus of two or more ill persons
OR
Significant rise in vibriocidal, bacterial-
agglutinating, or antitoxin antibodies in
acute- and early convalescent-phase sera among
persons not recently immunized
OR
Isolation of toxigenic organism from
epidemiologically implicated food
b. non-O1 and non-O139 1-5 days Watery diarrhea Isolation of organism of same serotype
from stool of two or more ill persons
14. Vibrio parahaemolyticus 4-30 hrs Diarrhea Isolation of Kanagawa-positive organism
from stool of two or more ill persons
OR
Isolation of >=10^5 Kanagawa-positive
organisms/g from epidemiologically
implicated food, provided specimen properly
handled
15. Yersinia enterocolitica 1-10 days, usually Diarrhea, abdominal pain Isolation of organism from clinical specimen
4-6 days (often severe) of two or more ill persons
OR
Isolation of pathogenic strain or organism
from epidemiologically implicated food
Chemical
1. Marine toxins
a. Ciguatoxin 1-48 hrs, usually Usually gastrointestinal Demonstration of ciguatoxin in epidemiologically
2-8 hrs symptoms followed by implicated fish
neurologic symptoms OR
(including paresthesia Clinical syndrome among persons who have eaten
of lips, tongue, throat, a type of fish previously associated with
or extremities) and ciguatera fish poisining (e.g., snapper, grouper,
reversal of hot and or barracuda)
cold sensation
b. Scombroid toxin 1 min-3 hrs, usually Flushing, dizziness, Demonstration of histamine in epidemiologically
(histamine) <1 hr burning of mouth and throat, implicated food
headache, gastrointestinal OR
symptoms, urticaria, and Clinical syndrome among persons who have eaten
generalized pruritus type of fish previously associated with
histamine fish poisoning (e.g., mahi-mahi or
or fish of order Scomboidei)
c. Paralytic or 30 min-3 hrs Parasthesia of lips, mouth, Detection of toxin in epidemiologically
neurotoxic shellfish or face, and extremities; implicated food
poison intestinal symptoms or OR
weakness, including Detection of large numbers of shellfish-
respiratory difficulty poisoning-associated species of dinoflagellates
in water from which epidemiologically implicated
mollusks are gathered
d. Puffer fish, 10 min-3 hrs, Parasthesia of lips, Demonstration of tetrodotoxin in
tetrodotoxin usually 10-45 mins tongue, face, or extremities, epidemiologically implicated fish
often following numbness; OR
loss of proprioception or Clinical syndrome among persons who have
"floating" sensations eaten puffer fish
2. Heavy metals 5 min-8 hrs, usually Vomiting, often metallic Demonstration of high concentration of
a. Antimony <1 hr taste metal in epidemiologically implicated food
b. Cadmium
c. Copper
d. Iron
e. Tin
f. Zinc
3. Monosodium 3 mins-2 hrs, usually Burning sensation in chest, Clinical syndrome among persons who
glutamate (MSG) <1 hr neck, abdomen, or have eaten food containing MSG (i.e.,
extremities; sensation of usually >= 1.5g MSG)
lightness and pressure over
face or heavy feeling in
chest
4. Mushroom toxins
a. Shorter-acting toxins: <=2 hrs Usually vomiting and Clinical syndrome among persons who
diarrhea, other symptoms have eaten mushroom identified as toxic
differ with toxin: type
OR
Muscimol Confusion, visual disturbance Demonstration of toxin in epidemiologically
Muscarine Salivation, diaphoresis implicated mushroom or mushroom-containing
Psilocybin Hallucinations food
Cobrinus artrementaris Disulfiram-like reaction
Ibotenic acid Confusion, visual disturbance
b. Longer-acting toxin 6-24 hrs Diarrhea and abdominal cramps Clinical syndrome among persons who
for 24 hrs followed by hepatic have eaten mushroom identified as toxic
and renal failure type
OR
Demonstration of toxin in epidemiologically
implicated mushroom or mushroom-containing
food
Parasitic
1. Cryptosporidium parvum 2-28 days, median: Diarrhea, nausea, vomiting, Demonstration of organism or antigen in
7 days fever stool or in small-bowel biopsy of two or more
ill persons
OR
Demonstration of organism in epidemiologically
implicated food
2. Cyclospora cayetanensus 1-11 days, median: Fatigue, protracted Demonstration of organism in stool of two
7 days diarrhea, often relapsing or more ill persons
3. Giardia lamblia 3-25 days, median: Diarrhea, gas, cramps, Two or more ill persons and detection of
7 days nausea, fatigue antigen in stool; or demonstration of
7 days fatigue organism in stool, duodenal contents, or
small-bowel biopsy specimen
4. Trichinella spp. 1-2 days for Fever, myalgia, Two or more ill persons and positive
intestinal phase; periorbital edema, serologic test or demonstration of larvae
2-4 wks for systemic high eosinophil count in muscle biopsy
phase OR
Demonstration of larvae in epidemiologically
implicated meat
Viral
1. Hepatitis A 15-50 days, median: 28 Jaundice, dark urine, Detection of lgM anti-hepatitis A virus in
days fatigue, anorexia, nausea serum from two or more persons who consumed
epidemiologically implicated food
2. Norwalk family of viruses, 15-77 hrs, usually Vomiting, cramps, diarrhea, More than fourfold rise in antibody titer to
small round-structured 24-48 hrs headache Norwalk-like virus in acute and convalescent
viruses (SRSV) sera in most serum pairs
OR
Visualization of small, round-structured viruses
that react with patient's convalescent sera but
not acute sera -- by immune-electron microscopy.
Assays based on molecular diagnostic (e.g.,
polymerase-chain reaction PCR|, probes, or
assays for antigen and antibodies from expressed
antigen) are available in reference
laboratories.
3. Astrovirus, calcivurus, 15-77 hrs, usually Vomiting, cramps, diarrhea, Visualization of small, round-structured
others 24-48 hrs headache viruses that react with patient's
convalescent sera but not acute sera -- by
immune-electron microscopy. Assays based on
molecular diagnostics (e.g., PCR, probes, or
assays for antigen and antibodies from expressed
antigen) are available in reference
laboratories.
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