II. History
- Famous role in public health history
- Yemen as of 2016-2017 has the largest Cholera outbreak in history
- London Physician John Snow (1813-1858)
- Linked Cholera outbreak to Broad Street Pump in 1854
- Proved Cholera to be a Waterborne Illness
- Snow was also a proponent of Anesthesia in childbirth
- Knighted by Queen Victoria on birth of seventh child
III. Pathophysiology
- Incubation: 4 hours to 5 days (average 1-2 days)
- Causes Toxigenic, Secretory Diarrhea
- Enterotoxin adheres to intestinal epithelial cell
- Fluid loss occurs in Small Bowel
- Large Intestine is overwhelmed by large fluid volume
- Unable to reabsorb majority of fluid losses
- Organism survival
- Not viable in pure water (stable in salt water)
- Survives up to 24 hours in sewerage
- Survives in impure water with organics for 6 weeks
- Withstands freezing for 3-4 days
- Readily killed by drying, heat, or disinfectants
IV. Transmission
- Large infectious dose needed to cause disease
- Fecal contamination of food or water
- Heavily soiled hands or utensils
-
Biological Weapon
- Infective aerosol dose: 10-500 organisms
V. Symptoms
VI. Signs
- Dehydration
- Hypovolemia to shock
VII. Course
- Usual duration: 1 week
- Death may occur due to severe Dehydration if untreated
- Mortality rates approach 50% from Dehydration without aggressive Fluid Replacement
- Mortality 0.2% with aggressive rehydration (see below)
VIII. Labs
-
Stool microscopy
- No or minimal Fecal Occult Blood
- No or minimal Fecal Leukocytes
- Darting, motile short curved Gram Negative Rods
- Darkfield microscopy
- Phase contrast microscopy
IX. Management: Fluid and Electrolyte replacement
- See Oral Rehydration Therapy
- Aggressive fluid and Electrolyte replacement is the key to effective management (drops mortality from 50% to 0.2%)
- Lactated Ringers is preferred crystalloid if IV hydration is required
- Replace Electrolytes (e.g. Potassium)
X. Management: Antibiotics
- Indication: Moderate to severe disease
- Adult Preparations
- Tetracycline 500 mg four times daily for 3 days
- Doxycycline 300 mg x1 dose or 100 mg bid for 3 days
- Azithromycin 500 mg orally daily for 3 days (or 1 g for 1 dose)
- Erythromycin 250 mg orally three times daily for 3 days
- Ciprofloxacin 1 g orally for 1 dose
- Child Preparations
- Azithromycin 10 mg/kg/day orally daily for 3 days
- Erythromycin 30 mg/kg/day orally divided three times daily for 3 days
- References
- Gilbert (2016) Sanford Guide, accessed 9/12/2016
XI. Prevention
-
Water Disinfection
- Dry heat at 117 degrees C (steam or boiling)
- Short exposure to disinfectants
- Water chlorination
- Good Hygiene
- Frequent Hand Washing
- Exclusive use of safe water and food
-
Licensed killed Cholera Vaccine
- Indicated during epidemics
- Efficacy: 50-86% protection lasts only 6 months
- Vaccine schedule
- Initial Doses: 0 and 4 weeks
- Booster Doses: every 6 months
- References
XII. Prognosis: Indicators of severe disease and worse outcomes
- Difficult access to medical services
- Blood Type O (45% of U.S. persons)
- Low gastric acidity
- Antacid therapy
- Partial gastrectomy
XIII. Resources
- CDC Cholera
- WHO Cholera