AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Food-borne illnesses are diverse in etiology, and they can follow ingestion of infectious organisms or noninfectious substances. The Centers for Disease Control and Prevention (CDC) emphasized that food-borne diseases (FBDs) constitute a serious public health problem in the United States. FBDs encompass classic toxin-mediated food poisoning, such as botulism, gastroenteritis that follows ingestion of preformed Staphylococcus aureus toxin, ingestion of chemicals in foods, and bacterial, parasitic, and viral infections. Many FBDs are zoonoses, which implies that the infectious agent has a primary animal reservoir and humans are affected incidentally. This chapter discusses FBDs in a broad sense, in that it includes discussion of water and fomite-borne pathogens.

Pathophysiology

Although the gastrointestinal tract is the primary target, autonomic nervous system disturbances and CNS impairment are prominent manifestations in chemical-, plant-, and seafood-related poisonings and in botulism. The severity of dehydration can vary depending on the pathogen. Typically, FBDs in which severe vomiting (eg, staphylococcal-toxin gastroenteritis) and small bowel diarrhea occur, typified by Vibrio cholerae infection, can cause life-threatening dehydration. Other organs involved include the liver in hepatitis A, muscles in trichinosis, lymph nodes in toxoplasmosis, and, importantly, the kidneys in hemolytic-uremic syndrome (HUS), which follows enterohemorrhagic Escherichia coli-induced diarrhea.

Frequency

United States

Current US Public Health Service estimates are that 76 million people acquire FBDs annually, with 325,000 hospitalizations and 5,200 deaths. Most deaths occur in elderly persons or individuals who are immunocompromised or pregnant.

International

International statistics are probably impossible to compute, but the obvious relevance of worldwide FBDs is the risk to travelers in the very mobile American and world population and the estimated 2 million deaths in children alone.

Mortality/Morbidity

The epidemiologic relevance of FBD is that outbreaks can involve an immense number of individuals and have the potential to overwhelm local health care services. Death can occur in a small proportion of affected patients; therefore, practitioners must take responsibility for reporting suspected FBDs and participate in investigations by the agency (eg, by saving food or vomitus samples).

Race

No specific racial predilection exists, except that invasive Salmonella infections are more prevalent in individuals with hemoglobinopathies, which in turn are more common among people of African and Mediterranean descent.

Sex

No sex predilection is known for any food-borne illness; however, Listeria infection often is severe and life threatening in pregnant women.

Age

No age predilection is known for the acquisition of food-borne illnesses, but patients at the extremes of ages experience higher morbidity and mortality.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

Because few food-borne illnesses present with their own pathognomonic clinical picture, and because laboratory tests are of limited value in acute situations, a systematic interrogation of patients and their families is the best way to deduce the etiology. Immediately following initiation of supportive treatment, the practitioner should obtain a history in the areas described below. This allows the list of possible agents to be narrowed, which helps dictate treatment and laboratory investigation.

A statement of the etiology and a brief description of the illness are included with each of the 4 incubation periods (ie, intervals between suspected food and onset of illness) to help relate this important historical clue to the specific infective agent.

• Short incubation (ie, within 1 d, usually <16 h)
• • Chemical causes (ultrashort incubation): The onset of nausea, vomiting, and cramps within 1-2 hours is observed in poisonings involving metal, fish-associated toxins (eg, scombroid, ciguatera), shellfish-associated toxins, monosodium glutamate, or mushrooms. The toxic agent in shellfish- and ciguatera-related disease is derived from dinoflagellate organisms present in the fish or shellfish. Note that neurologic symptoms can present weeks later. Amanita mushrooms can lead to hepatorenal failure.
  • Bacterial causes - Emetic syndrome (1-6 h)
  • • S aureus: Nausea and vomiting are caused by the action of preformed enterotoxins A-E.
    • Bacillus cereus (emetic syndrome, indistinguishable from staphylococcal food poisoning): This spore-forming rod is present in raw rice grains. The emetic toxin is a preformed heat-stable toxin produced upon germination of the spores.
  • Bacterial causes - Diarrheal syndrome (8-16 h)
  • • B cereus (diarrheal syndrome): The diarrheal toxin is a heat-labile toxin formed after sporulation.
    • Clostridium perfringens type A: Diarrhea and abdominal cramps occur within 1 day of ingestion of cooked meat stored at 15-60°C. Slow cooling allows heat-activated spores to germinate and to elaborate the enterotoxin.
• Intermediate incubation (1-3 d)
• • Diarrheal disease: This category comprises bacterial and viral infectious pathogens. The clinical presentation depends upon the target organ (ie, small bowel or large bowel), which varies depending on the pathogen.
  • Diarrheal disease, large bowel enteritis: Fever and constitutional symptoms usually accompany the diarrhea caused by invasive pathogens in the large bowel. Dysentery, bloody stools with mucous, and cramps or tenesmus are typical.
  • • Campylobacter jejuni: This is a leading cause of bacterial food-borne illness in the United States. Vomiting is uncommon, and the illness is short and self-limiting.
    • Shigella species: Shigellae cause the prototypical diarrheal syndrome with blood, mucous, and pain that is termed bacillary dysentery. Tenesmus and small-volume stools are typical. Toxemia may be severe, occasionally causing seizures in children.
    • Enteroinvasive E coli (EIEC): Several serotypes of diarrheagenic E coli possess Shigella-like invasiveness factors that allow mucosal invasion. The disease is a febrile dysentery that mimics shigellosis.
    • Salmonella species, nontyphoidal salmonellosis: This is a zoonotic infection acquired from bovine or poultry reservoirs and is very common in the United States. The illness can range from mild nonbloody diarrhea to a severe dysenteric illness.
    • Salmonella species, enteric (typhoid) fever: In the United States, enteric fever occurs in travelers or recent immigrants and is a systemic toxic illness. Salmonella typhi has an exclusively human reservoir and is acquired either via ingestion of a large inoculum in food or contaminated water or from personal contact with a carrier.
    • Vibrio parahaemolyticus: Although it is a common worldwide pathogen, in the United States, V parahaemolyticus infection is restricted geographically to the Atlantic and Gulf coasts. The diarrhea is profuse and watery, and blood is not commonly present in the stool.
  • Diarrheal disease, small bowel enteritis
  • • Enterotoxigenic E coli (ETEC): Enterotoxin-producing strains of E coli are the most common cause of traveler's diarrhea. The diagnosis is clinical; fever and bloody stools typically are absent.
    • Vibrio cholerae (01 and non-01 strains): Cholera is likely only in endemic areas and during epidemics. The profuse diarrhea and vomiting can lead to dehydration and prostration.
    • Viral agents (Norwalklike viruses, rotavirus, adenoviruses, astroviruses, caliciviruses): Vomiting and headache accompany the diarrhea and fever more commonly with viral than with bacterial infections.
    • All the large bowel pathogens also secrete enterotoxins that induce profuse watery small bowel diarrhea in some patients.
  • Botulism: Nausea, vomiting, skeletal muscle paralysis, and autonomic symptoms occur within 18-36 hours of ingestion of food containing Clostridium botulinum. The disease is mediated by preformed toxin in older children and adults, but it may follow ingestion of spores in infants. Diarrhea occurs only in approximately 5% of patients; instead, constipation may be noted. Infants with botulism present with muscular weakness that manifests as weak cry, difficulty sucking and swallowing, or respiratory failure. Upon examination, the baby has profound hypotonia but may be alert.
• Long incubation (3-5 d)
• • Enterohemorrhagic E coli (EHEC): These strains of E coli cause hemorrhagic colitis with a 15% risk of progression to HUS in children, which is the result of cytotoxins termed verotoxins or Shigalike toxins. E coli O157:H7 is one of many such cytotoxin-producing E coli strains that reside in the gut of cattle. Although these organisms can cause mild nonbloody diarrhea, hemorrhagic colitis is the usual symptom. Mild abdominal pain, malaise, and transient fever are followed by watery diarrhea. Bloody stools and more severe abdominal pain ensue several days later. Paucity of fever is a diagnostic clue. When HUS occurs, its onset is 5-13 days after the onset of diarrhea.
  • Yersinia species
  • • Yersinia enterocolitica most often causes a febrile illness with abdominal pain due to mesenteric lymphadenitis in which diarrhea is not prominent. The illness can mimic appendicitis. The illness may be prolonged, lasting 2-3 weeks. In infants, a diarrheal illness is common, with occasional septicemia. The diagnosis is made with blood and stool cultures. Treatment is indicated only for infants with septicemia.
    • Yersinia pseudotuberculosis: The symptom complex for this uncommon infection includes fever, rash (scarlatiniform or erythema nodosum), and abdominal pain.
• Very long incubation (1-4 wk)
• • This category comprises parasitic FBDs, but shorter incubation periods can occur, especially in Entamoeba histolytica infection.
  • Parasitic
  • • Giardiasis: The spectrum of illness ranges from asymptomatic carriage to acute watery diarrhea, but a subacute intermittent diarrheal illness also is common.
    • Amebiasis: E histolytica is a protozoan that causes dysentery and extraintestinal, most commonly hepatic, abscesses.
    • Cryptosporidiosis: The organism Cryptosporidium parvum causes a diarrheal illness with fever and abdominal pain.
    • Cyclosporiasis: Frequent watery stools, which can be accompanied by fever and a relapsing course, characterize this FBD caused by Cyclospora cayetanensis.
    • Trichinosis is a rare illness, caused by Trichinella spiralis, that is acquired by ingestion of contaminated or raw pork, bear, or moose meat. Gastrointestinal tract symptoms are followed by muscle inflammation and periorbital edema.
    • Cysticercosis: This infection is caused by the larval stage of pork tapeworm and most often is acquired by ingestion of food or water contaminated with the ova of the tapeworm rather than from eating raw pork.
    • Anisakiasis, fish tapeworm, and flatworm infections: These uncommon worm infestations occur after consumption of certain types of raw fish (see Type of food consumed).
  • Bacterial
  • • Listeriosis: Diarrhea in Listeria monocytogenes infection may be mild, but systemic symptoms are prominent. The diarrhea has a short incubation period (<48 h), but symptoms of systemic spread could appear weeks later. The major risk is that of maternal infection during pregnancy. Neonatal sepsis and meningitis follow amniotic fluid infection. Older children and adults can develop meningitis. The infection is a particular hazard to individuals who are immunocompromised.
    • Brucellosis: This is a febrile illness now only rarely acquired in the United States. The food source is raw or unpasteurized milk or cheese, most commonly from goats (Brucella melitensis).
  • Viral: The incubation period of hepatitis A is 15-50 days for this viral hepatitis transmitted via the fecal-oral route.
  • Protozoal, toxoplasmosis: A febrile and subacute lymphadenitis results from ingestion of undercooked meat. A nonspecific illness with systemic symptoms and generalized lymphadenopathy can occur in healthy individuals, or an asymptomatic infection can result. Persons who are immunocompromised can develop CNS infection.
• Type of food consumed: The following is a checklist of commonly implicated food items that may suggest the etiology of a FBD:
• • Tap water when traveling abroad
  • Undercooked eggs, egg salad, or egg-containing salad dressings
  • Shellfish, including mussels, oysters, or scallops
  • Wild mushrooms
  • Fish
  • • Ciguatera - Grouper, red snapper, barracuda, or amberjack
    • Scombroid - Tuna, bluefin tuna, skipjack, mackerel, marlin, mahi mahi, or puffer fish
  • Raw fish prepared at home (sashimi or sushi, especially Alaskan salmon, rockfish)
  • Chinese food
  • Meat (specify if undercooked or wild game)
  • Unpasteurized milk, cheese, eggnog, ice cream, or juices
  • Cream pastries or cookie and cake batters
  • Home-canned goods
  • Food in corroded metal containers
  • Fresh produce, including fruit
  • Hot dogs, deli meats, or chitterlings (ie, pork innards)
  • Soft cheeses or cheese sauces
  • Tofu
  • Rewarmed rice
• Travel or activity
• • Farming
  • Pet contact
  • Daycare
  • Foreign travel, especially coastal
  • Gulf coast of the United States
  • Camping
  • Group picnic or family reunion

Physical

Symptoms and signs of food poisoning include the following:

• Nausea and vomiting
• Diarrhea
• • Bloody diarrhea
  • Profuse watery diarrhea with consequent risk of dehydration
• Severe abdominal pain and cramps
• Fever
• Neurologic involvement such as paresthesias, motor weakness, visual disturbances, and cranial nerve palsies
• • Autonomic symptoms such as flushing, hypotension, and anaphylaxis
  • Headache, dizziness, respiratory failure, and urticaria
• Myalgias
• Lymphadenopathy
• Appendicitislike presentation
• Oliguria
• Neck stiffness and meningeal signs

Causes

See History.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

In most FBDs, the differential diagnosis includes infection by various toxins or pathogens that can cause the same presentation (eg, diarrhea vs bloody diarrhea).

Large bowel enteritis (ie, dysentery) can mimic inflammatory bowel disease and intussusception.

A noteworthy diagnostic dilemma is botulism, in which the differential diagnosis includes Guillain-Barré syndrome, organophosphate ingestion, tick paralysis, brainstem tumor, poliomyelitis, and myasthenia gravis. In infant botulism, an additional possibility is Werdnig-Hoffman disease.

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Stool culture is an expensive test with a very low yield and is indicated particularly if patients have bloody diarrhea, severe abdominal pain, or are immunocompromised. When the likely pathogen is a Campylobacter, Yersinia, or Vibrio species, or if Shigalike toxin-producing E coli (eg, E coli O157:H7) is suspected, the laboratory should be notified because special media or incubation conditions (high or low temperature) are required.
• Stool examination for parasites is indicated for gastrointestinal tract illnesses that appear to have occurred after a long incubation period. Certain travel history, such as travel to tropical countries, camping, and drinking well or stream water should prompt consideration of parasitic food-borne illness.
• Blood cultures are performed for bacteremic FBDs.
• Serum electrolytes, blood urea nitrogen, creatinine levels, complete blood count, and urinalysis are performed to assess hydration, renal function, and presence of HUS. Evidence of hemolysis and thrombocytopenia are present in patients with HUS.
• Toxin testing, serotyping, and molecular techniques are available only from large commercial and public health laboratories. They are generally ordered only as part of an epidemiologic investigation.
• Testing of food or vomitus for toxins may be offered by a poison control center or the local health authorities.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

The mainstay of medical treatment is fluid and electrolyte replenishment. Most FBDs are not amenable to specific antidotes or antimicrobial therapy, but the few exceptions are mentioned below.

• Short incubation
  • Chemical/mushroom: Treatment varies depending on the chemical or toxin. Consult with staff at a poison control center or an emergency manual. For most agents, the care is supportive only. Exceptions include intravenous mannitol for ciguatera toxin, antihistamines for scombroid poisoning, and atropine or physostigmine for poisoning with certain mushrooms.
  • Bacterial: No specific therapy is indicated. Institute rehydration.
• Intermediate incubation
• • Campylobacter Infections: Azithromycin, a quinolone, or a parenteral aminoglycoside, such as gentamicin, is indicated; however, symptoms often resolve by the time culture results are received.
  • Shigella Infection: Antibiotic choices are becoming limited, especially because resistance to trimethoprim-sulfamethoxazole (TMP-SMZ) is now highly prevalent. Local profiles of susceptibility should be used a guide to therapy, but quinolones are still effective in most strains in developed countries. Two doses of parenteral ceftriaxone or oral azithromycin are among the current drugs of choice (Ashkenazi, 2004). Treatment is important to prevent transmission.
  • Salmonella Infection: Institute rehydration. Administer parenteral extended-spectrum cephalosporin if bacteremia occurs.
  • Salmonella enteric fever: A typical regimen is a parenteral cephalosporin followed by oral amoxicillin or quinolone.
  • V cholerae, V parahaemolyticus, Vibrio vulnificus: Institute rehydration; a tetracycline can be administered to children older than 8 years.
  • ETEC (see Escherichia Coli Infections): For rapid resolution of illness, a short course of a quinolone, TMP-SMZ, or rifaximin can be administered on an outpatient basis.
  • Norwalklike virus, rotavirus, or other viruses acquired via the fecal-oral route: Supportive care is indicated. Rehydration is especially important for infants with rotavirus infection.
  • Botulism: Treatment is chiefly supportive, with the notable exception of infant botulism, for which an antitoxin (BabyBIG) is available from the California Department of Health Services. Contact them at (510) 231-7600 to review the indications for such treatment. Rarely, use of a botulinum antitoxin can be considered in older children by contacting the CDC at (404) 639-2206 during business hours and (404) 639-2888 after hours.
• Long incubation
  • EHEC (see Escherichia Coli Infections): Most studies suggest that antibiotics are likely to increase the risk of developing HUS. Treatment, including treatment of HUS, is supportive.
  • Yersinia Enterocolitica Infection: Treatment is supportive. Parenteral aminoglycosides or third-generation cephalosporins are indicated if bacteremia is present.
• Very long incubation
• • Giardiasis: Metronidazole is the drug of choice.
  • Amebiasis: Metronidazole followed by an antiluminal agent, usually paromomycin or iodoquinol, is indicated.
  • Cryptosporidiosis: The illness is brief and self-limiting. Paromomycin is considered in severe cases.
  • Cyclosporiasis: TMP-SMZ may be an effective treatment for the immunocompromised host.
  • Listeria Infection: Intravenous ampicillin or TMP-SMZ is administered to treat systemic Listeria infection.
  • Brucellosis: A tetracycline and rifampin are used to treat Brucella infections.

Consultations

• Consultation with an infectious disease specialist may be beneficial in complicated or unusual cases.
• For chemical or mushroom poisonings, consult with a poison control center for advice on specific antidotes and for help with identifying the implicated mushrooms.
• For suspected point-source outbreaks of staphylococcal toxins or infective pathogens, call the local health department. Staff members usually have information regarding the species or strain involved and its antibiotic susceptibility.

Diet

As with other pediatric gastroenteritides, dietary restrictions no longer are the standard of care, and the child is allowed solid foods as desired to maintain the nutritional status.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

See Medical Care.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

In/Out Patient Meds

• See Medical Care.

Deterrence/Prevention

• Prevention of FBDs occurs on 2 levels.
• • Level 1: The CDC has initiated a major educational initiative for practitioners and the lay public to recognize, report, and prevent FBDs. Part of this effort is "Fight BAC!".
  • Level 2: The second level of prevention is at the individual level.
  • • Care with food preparation, good hand-washing technique, and refrigeration are essential to prevention of FBDs. Particular care should be taken with foods offered to persons who are pregnant or who are immunocompromised. A good axiom is never to serve reheated leftovers to these individuals.
    • Unfortunately, many diseases are difficult to prevent, and following a vegetarian diet does not guarantee that organisms customarily associated with meat (eg, Shiga toxin-producing E coli, Listeria species, cysticerci) will not be a hazard. The seafood that causes chemical food poisoning is not obviously spoiled; therefore, the occurrence is unpredictable.
    • Most mushroom toxins are not destroyed by heating.

Patient Education

• For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center and Poisoning Center. Also, see eMedicine's patient education articles Food Poisoning, Gastroenteritis, Vomiting and Nausea, and Diarrhea.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• The treating physician should be careful not to assign blame for the cause of food poisoning, for example, a particular restaurant or gathering, since the information available is almost always circumstantial until health or law enforcement officials have completed an investigation.
• Bioterrorism or negligence of hygiene may be suspected but difficult to prove by the physician.
• Immediate specific antibiotic therapy is not indicated in most food-borne illnesses; therefore, the physician should not be concerned about medicolegal pitfalls regarding failure to prescribe an antibiotic. In fact, in enterohemorrhagic E coli infection that may lead to HUS, antibiotics are contraindicated.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• Ashkenazi S. Shigella infections in children: new insights. Semin Pediatr Infect Dis. Oct 2004;15(4):246-52. [Medline].
• Batz MB, Doyle MP, Morris G, et al. Attributing illness to food. Emerg Infect Dis. Jul 2005;11(7):993-9. [Medline].
• Friedman CR, Hoekstra RM, Samuel M, et al. Risk factors for sporadic Campylobacter infection in the United States: A case-control study in FoodNet sites. Clin Infect Dis. Apr 15 2004;38 Suppl 3:S285-96. [Medline].
• Hennessy TW, Marcus R, Deneen V, et al. Survey of physician diagnostic practices for patients with acute diarrhea: clinical and public health implications. Clin Infect Dis. Apr 15 2004;38 Suppl 3:S203-11. [Medline].
• Herwaldt BL, Beach MJ. The return of Cyclospora in 1997: another outbreak of cyclosporiasis in North America associated with imported raspberries. Cyclospora Working Group. Ann Intern Med. Feb 2 1999;130(3):210-20. [Medline]. [Full Text].
• Karch H, Tarr PI, Bielaszewska M. Enterohaemorrhagic Escherichia coli in human medicine. Int J Med Microbiol. Oct 2005;295(6-7):405-18. [Medline].
• Kassenborg HD, Hedberg CW, Hoekstra M, et al. Farm visits and undercooked hamburgers as major risk factors for sporadic Escherichia coli O157:H7 infection: data from a case-control study in 5 FoodNet sites. Clin Infect Dis. Apr 15 2004;38 Suppl 3:S271-8. [Medline].
• Mead PS, Griffin PM. Escherichia coli O157:H7. Lancet. Oct 10 1998;352(9135):1207-12. [Medline].
• Mermin JH, Townes JM, Gerber M, et al. Typhoid fever in the United States, 1985-1994: changing risks of international travel and increasing antimicrobial resistance. Arch Intern Med. Mar 23 1998;158(6):633-8. [Medline].
• Morgan MR, Fenwick GR. Natural foodborne toxicants. Lancet. Dec 15 1990;336(8729):1492-5. [Medline].
• Schantz PM. The dangers of eating raw fish. N Engl J Med. Apr 27 1989;320(17):1143-5. [Medline].
• Schlech WF 3rd. Listeria gastroenteritis--old syndrome, new pathogen. N Engl J Med. Jan 9 1997;336(2):130-2. [Medline].
• Shapiro RL, Hatheway C, Swerdlow DL. Botulism in the United States: a clinical and epidemiologic review. Ann Intern Med. Aug 1 1998;129(3):221-8. [Medline]. [Full Text].
• Voetsch AC, Van Gilder TJ, Angulo FJ, et al. FoodNet estimate of the burden of illness caused by nontyphoidal Salmonella infections in the United States. Clin Infect Dis. Apr 15 2004;38 Suppl 3:S127-34. [Medline].
• Wong CS, Jelacic S, Habeeb RL, et al. The risk of the hemolytic-uremic syndrome after antibiotic treatment of Escherichia coli O157:H7 infections. N Engl J Med. Jun 29 2000;342(26):1930-6. [Medline].

Article Last Updated: Jun 20, 2006