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![]() 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 ============================================================================================================================================== 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. ============================================================================================================================================== Return to top. Disclaimer All MMWR HTML versions of articles are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the electronic PDF version and/or the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices. **Questions or messages regarding errors in formatting should be addressed to mmwrq@cdc.gov.Page converted: 09/19/98 |
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