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Center for Food Safety & Applied Nutrition Foodborne Pathogenic Microorganisms and Natural Toxins Handbook |
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1. Name of the Organism: Vibrio cholerae Serogroup O1 |
This bacterium is responsible for Asiatic or epidemic cholera. No major outbreaks of this disease have occurred in the United States since 1911. However, sporadic cases occurred between 1973 and 1991, suggesting the possible reintroduction of the organism into the U.S. marine and estuarine environment. The cases between 1973 and 1991 were associated with the consumption of raw shellfish or of shellfish either improperly cooked or recontaminated after proper cooking. Environmental studies have demonstrated that strains of this organism may be found in the temperate estuarine and marine coastal areas surrounding the United States.
In 1991 outbreaks of cholera in Peru quickly grew to epidemic proportions and spread to other South American and Central American countries, including Mexico. Over 340,000 cases and 3,600 deaths have been reported in the Western Hemisphere since January 1991. However, only 24 cases of cholera have been reported in the United States. The U.S. cases were brought into the country by travelers returning from South America, or were associated with illegally smuggled, temperature-abused crustaceans. |
| 2. Name of the Acute Disease: | Cholera is the name of the infection caused by V. cholerae. |
| 3. Nature of the Disease: | Symptoms of Asiatic cholera may vary from a mild, watery diarrhea to an acute diarrhea, with characteristic rice water stools. Onset of the illness is generally sudden, with incubation periods varying from 6 hours to 5 days. Abdominal cramps, nausea, vomiting, dehydration, and shock; after severe fluid and electrolyte loss, death may occur. Illness is caused by the ingestion of viable bacteria, which attach to the small intestine and produce cholera toxin. The production of cholera toxin by the attached bacteria results in the watery diarrhea associated with this illness.
Infective dose -- Human volunteer feeding studies utilizing healthy individuals have demonstrated that approximately one million organisms must be ingested to cause illness. Antacid consumption markedly lowers the infective dose. |
| 4. Diagnosis of Human Illness: | Cholera can be confirmed only by the isolation of the causative organism from the diarrheic stools of infected individuals. |
| 5. Foods in which it Occurs: | Cholera is generally a disease spread by poor sanitation, resulting in contaminated water supplies. This is clearly the main mechanism for the spread of cholera in poor communities in South America. The excellent sanitation facilities in the U.S. are responsible for the near eradication of epidemic cholera. Sporadic cases occur when shellfish harvested from fecally polluted coastal waters are consumed raw. Cholera may also be transmitted by shellfish harvested from nonpolluted waters since V. cholerae O1 is part of the autochthonous microbiota of these waters. |
| 6. Frequency of Disease: | Fewer than 80 proven cases of cholera have been reported in the U.S. since 1973. Most of these cases were detected only after epidemiological investigation. Probably more sporadic cases have occurred, but have gone undiagnosed or unreported. |
| 7. The Usual Course of Disease and Some Complications: | Individuals infected with cholera require rehydration either intravenously or orally with a solution containing sodium chloride, sodium bicarbonate, potassium chloride, and dextrose (glucose). The illness is generally self-limiting. Antibiotics such as tetracycline have been demonstrated to shorten the course of the illness. Death occurs from dehydration and loss of essential electrolytes. Medical treatment to prevent dehydration prevents all complications. |
| 8. Target Populations: | All people are believed to be susceptible to infection, but individuals with damaged or undeveloped immunity, reduced gastric acidity, or malnutrition may suffer more severe forms of the illness. |
| 9. Analysis of Foods: | V. cholerae serogroup O1 may be recovered from foods by methods similar to those used for recovering the organism from the feces of infected individuals. Pathogenic and non- pathogenic forms of the organism exist, so all food isolates must be tested for the production of cholera enterotoxin. |
| 10. Selected Outbreaks: |
An incident of cholera in Indiana from imported food is reported in MMWR 44(20):1995 May 20 . See MMWR 44(11):1995 Mar 24 for an updated report on Vibrio cholerae O1 in the Western Hemisphere 1991-1994 and on V. cholerae O139 in Asia, 1994. Surveillance for cholera in Cochabamba Department, Bolivia is discussed in in this MMWR 42(33):1993 Aug 27. The cholera outbreak in Burundi and Zimbabwe is detailed in the following MMWR 42(21):1993 Jun 04. MMWR 40(49):1991 Dec 13 reports on a cholera outbreak associated with imported coconut milk. A report of a cholera incident in New York is found in MMWR 40(30):1991 Aug 01. Similar incidents in New Jersey and Florida are reported in MMWR 40(17):1991 May 03. A case of importation of cholera from Peru to the United States is detailed in MMWR 40(15):1991 Apr 19. The cholera outbreak in Peru is reported on in MMWR:40(6):1991 Feb 15, and the update of the South American endemic is in MMWR 40(13):1991 Apr 5. |
| For more information on recent outbreaks see the Morbidity and Mortality Weekly Reports from CDC. | |
| 11. Education |
The CDC has a brochure on the prevention of cholera
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| 12. Other Resources | A Loci index for genome Vibrio cholerae is available from GenBank. |
mow@cfsan.fda.gov
January 1992 with periodic updates
