Microbiology: A Systems Approach 4th Edition by Marjorie Kelly Cowan

Exercise 15

The Haitian Earthquake: Unexpected Devastation
On January 12, 2010, a 7.0 magnitude earthquake struck Haiti. The already poor and struggling nation was quickly reduced to rubble: 250,000 were killed, 300,000 were injured, and more than 1.3 million people were left homeless. As foreign nations rushed to aid the decimated country, displaced-persons camps cropped up all over the countryside, as Haiti attempted to rebuild. Ten months later, the devastated country was still rebuilding when reports of diarrheal disease began coming in from far-flung displaced-persons camps in the countryside. Stool samples were sent to hospitals in Port-au-Prince, and fears were confirmed: cholera-one of the most dreaded infections known to man. Infections with Vibrio cholerae spread quickly through the displaced-persons camps where clean water and sanitation were scarce. Between October and November 2010, a total of 11,125 cases and 724 deaths from cholera were confirmed, making it one of the worst cholera outbreaks in recorded history. Hospitals and clinics were already stretched thin with the wounded from the earthquake, and it was difficult to transport needed treatment and supplies through the earthquake-ravaged countryside. In a country where only 27% of the population had access to basic sewage treatment and over 70% had either rudimentary or no toilets in their households before the earthquake, the need for clean water became dire after the disaster struck.
What are the physiological characteristics of V. cholerae
How does V. cholerae cause such severe diarrhea
Vibrio cholerae is a gram-negative commashaped organism that can grow in brackish water, water that is less salty than seawater but saltier than freshwater. The organism can infect shellfish and plankton in coastal areas. Most often, the organism is transmitted through the fecal-oral route via unclean drinking water or contaminated food. Because Haiti had substandard sewage treatment even before the earthquake struck, its population was at even greater risk for a cholera outbreak after the disaster.

Infection with V. cholerae can be devastating, causing copious, watery diarrhea, with the loss of gallons of fluids and electrolytes within 1 to 2 days. Left untreated, cholera is fatal in 50% to 70% of the cases. The cholera toxin is the culprit behind these deadly symptoms. It is secreted after the organism has invaded the intestinal mucosa and is produced by the bacterium due to the presence of a lysogenic bacteriophage designated CTX . This complicated protein has the capacity to bind to cells, causing the cells to pump chloride ions outside of the cell and preventing sodium ions from entering. This creates a hypertonic environment in the lumen of the small intestine, which further pulls water from cells through osmosis. This creates the massive diarrhea, fluid, and electrolyte loss characteristic of cholera.
How is cholera treated