V. cholerae

• Where can V. cholera survive?


  • Most common species to infect humans
  • can survive in freshwater
• What does V. cholera cause?


  • cholera (particularly O1 EI Tor Strain)
• How are humans infected?


  • ingesting contaminated food and water
• What is the most important virulence factor of V. Cholera?


  • Cholera toxin
  • targets intestinal epithelial cells and causes massive electrolyte and water loss
  • Gene for cholera toxin carried on bacteriophage
• When do cholera outbreaks frequently occur?


  • after natural disasters in areas were cholera is endemic
• What is cholera characterized by?


  • severe dehydration
  • loss of body weight
  • sunken eyes
  • metabolic acidosis due to loss of bicarbonate ions
  • hypokalemia
  • hypovolemic shock
• What can cholera lead to?


  • muscle cramping
  • kidney failure
  • coma
  • death
  • mortality is 60% in untreated patients
• How is Cholera diagnosed?


  • usually based on characteristic diarrhea
  • explosive, watery, colorless, odorless, typically flecked with mucus (rice water stool); patient history
• How is Cholera treated?


  • Fluid and electrolyte replacement
  • antimicrobial drugs are not very effective; however doxycycline is drug of choice
• How is Cholera prevented?


  • adequate sewage and water treatment can limit spread
  • Oral vaccine against O1 strains provides protection for 2 years