CHOLERA

• Cholera


  A disease caused by the bacterium Vibrio cholerae
• Vibrio cholerae


  • The bacterium that causes cholera
• Cholera is a water-borne disease that occurs where people do not have access to proper sanitation (clean water supply) and/or uncontaminated food
• Infected people, three-quarters of whom may be symptomless carriers, pass out large numbers of bacteria in their faeces
• If the faeces of infected people contaminate the water supply, or if infected people handle food or cooking utensils without washing their hands

  Bacteria are transmitted to uninfected people
• To reach their site of action in the small intestine, the bacteria have to pass through the stomach
• If the contents of the stomach are sufficiently acidic (pH less than 4.5)


  The bacteria are unlikely to survive
• If the bacteria do reach the small intestine

  1. They multiply and secrete the toxin choleragen

  2. The toxin disrupts the functions of the epithelium lining the intestine, so that salts and water leave the blood

  3. The loss of salts and water causes severe diarrhoea

  4. The loss of fluid can be fatal if not treated within 24 hours
• Treating cholera


  1. Giving oral rehydration therapy if the person can drink

  2. Giving the solution intravenously to rehydrate the body if the person cannot drink

  3. Ensuring the patient's fluid intake equals fluid losses in urine and faeces

  4. Maintaining the osmotic balance of the blood and tissue fluids
• Cholera is now almost unknown in the developed world, as a result of sewage treatment and the provision of clean piped water, which is chlorinated to kill bacteria