CHOLERA

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CHOLERA

• Charles A. Schable, M.S.
• Senior Public Health Advisor

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Vibrio cholerae
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Vibrios

• Gram negative rods
• comma shaped
• facultative anaerobes
• oxidase positive
• simple nutritional requirements
• readily cultivated

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Occurrence - cholera

• Developing Nations
• Industrialized World
• uncommon
• traveler
• ingestion of sea-food

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Transmission and Incubation

• Transmission occurs through ingestion of food or
  water contaminated directly or indirectly with
  feces or vomitus of infected persons
• Vibrio cholerae can persist in water for long
  periods
• Incubation period is from a few hours to 5 days,
  but usually 2-3 days
• Patient is communicable up to a few days after
  recovery occasionally a carrier state may
  persist for months

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Cholera toxin - Choleragen

• B binds to gangliosides
• provides channel for A
• A catalyses ADP-ribosylation
• regulator complex
• activates adenylate cyclase

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Cholera - therapy

• massive secretion of ions/water into
• gut lumen

• dehydration and death

• therapy
• fluid replacement
• antibiotic therapy

• vaccination
• partially effective
• not generally used
• international travelers

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Example of Choleras Lethality

• A particularly explosive outbreak of Cholera
  occurred among Rwandan refugees in Goma, Zaire,
  in July, 1994
• In little over one month there were approximately
  70,000 cases and 12,000 deaths

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Vibrio parahemolyticus

• raw sea-food
• grows best in high salt
• not common in developed nations
• diarrhea