Cholera

ConditionsDiseases List

Caused by Vibrio cholerae, inactivation of G protein

Vibrio choleraeG Protein

Route Of Transmission ROT:

• Ingestion

LOC:

• Contaminated water infects the small intestinal mucosa

Pathogenesis:

• Ingestion (triggers virulence gene expression)
• Adherence to small intestine mucosa
• Coloniation of small intestine mucosa
  • Does not invade tissue, utilizes toxins
• Protein Toxin - choleragen
  • Alpha subunit
  • A1 - Produces toxin activity
  • A2 - Peneratrtion of A subunit into the cell
    • Modifies a Galpha protein into the active state
  • Beta subunit
    • Binds to the intestine on the specific receptors of epith cell membrane
• Focus on Alpha subunit A1: Permament activation Protein Kinase A (PKA)
  • Catalyzes covalent modification of Galpha protein
    • Stabilizes the active GTP prolonging PKA activation
  • Causes cAMP levels to rise
  • Acivation of a chloride channel
  • Inhibits the Na-H exchanger by phospohrylation
  • Hypersecretion of salt, then water
  • Excessive NaCl in intestine pulls water into intestine

Symptoms:

• 2 times body weight in fluid 4-6 days

Treatment:

• NONE! self limiting
• Rehydration w/ GLC electrolyte solution antibiotics DO SHORTEN duration of illness

Prevention:

• Public health issues, clean water and food.
• Traveler’s should avoid, untreated water and ice, food made by street vendors, raw or partially cooked fish, shellfish, uncooked vegetables, lettuce.
• Exists in the environment in areas of the world where it is not currently a health problem. Thus keep sanitation standards high.

Additional Information:

• Wikipedia
• NIH: Choleragen