Cholera is an intestinal disease that is caused by infection by the bacterium Vibrio cholerae. Primary symptoms include watery diarrhea and vomiting, which depending on the degree of illness may result in severe dehydration and electrolyte imbalance. The WHO reports an estimated 3-5 million cases a year, predominantly occurring in Asia and Africa with recent outbreaks in Haiti. Diarrheal diseases including cholera are the second leading cause of mortality in children under the age of 5 (Harris et al. 2012).
The first reported cases of cholera occurred in India where the disease has existed for centuries. Since 1817, however, the disease has spread beyond the Indian subcontinent and six world-wide pandemics have occurred between 1817 and 1923. The seventh pandemic began in 1961 in Indonesia and is currently ongoing (Harris et al. 2012). The bacteria is commonly present in coastal waters and estuaries around the world where they exist as individual organisms or in association with zooplankton and transmission mainly occurs from either contaminated food or water (Banerjee et al. 2014).
The bacterial component that results in the onset of symptoms is cholera toxin (CT), which is a protein complex that infects cells and elevates intracellular levels of cAMP, thus resulting in chloride secretion and diarrhea (Wernick et al. 2010). The accompanying dehydration and electrolyte imbalance can be managed by oral or intravenous rehydration methods. Effective antibiotic therapy can also shorten the duration of diarrhea and reduce the volume of stool loss by 50%. Dukoral, Shanchol, and mORCVAX constitute the oral vaccines that are currently available and provide 60–85% protective efficacy for 2–3 years. Other preventative measures include the provision of water and adequate sanitation (Harris et al. 2012).