Cholera: something old, something new.

BACKGROUND: In the aftermath of a devastating earthquake in early 2011, Haiti fell victim to an outbreak of cholera that claimed thousands of lives and affected populations in nearby Dominican Republic, Venezuela, and even the United States. This was the first time cholera had been reported in Haiti in more than 100 years. The sudden appearance of cholera, a pathogen with no known non-human host, raised the question of how it was introduced to an island that has long been spared this disease. The purpose of this review is to provide an overview of the history of cholera, its pathophysiology and virulence factors, and current recommendations for treatment.
METHODS: Articles published in the past 10 years were identified by a search of the medical literature using PUBMED and reviewed. Bibliographies of each article also were reviewed for additional pertinent articles.
RESULTS: The recent epidemic was caused by a strain that has been responsible for disease in South Asia since 1961, the seventh and most recent strain identified since 1900. It is transmitted by the fecal-oral route. Once infected, the patient develops a rapidly dehydrating diarrheal illness caused by the cholera toxin, which activates cytoplasmic adenylate cyclase of the intestinal epithelial cells by adenosine diphosphate (ADP)-ribosylation of the stimulatory G protein. The high cyclic adenosine monophosphate (cAMP) concentrations activate the cystic fibrosis transmembrane conductance regulator, causing a dramatic efflux of ions and water from infected enterocytes and leading to watery diarrhea. The first line of therapy is oral hydration with intravenous fluids; antibiotics are reserved for patients with severe dehydration. Spread of cholera is preventable with simple modifications of hygiene and water preparation.
CONCLUSIONS: Cholera has re-emerged as a major infectious disease in the recent past, with a global increase in its incidence. Vaccination should be considered as an adjunct for controlling the epidemics and also for volunteer health care workers who provide services to underdeveloped nations. During an epidemic such as occurred in Haiti, use of antibiotics should be considered for all hospitalized patients. These endeavors should proceed in concert with much-needed improvements in sanitation and accessibility of potable water.