Members of the genus Vibrio are defined as Gram-negative, asporogenous, motile rods that are straight or comma-shaped. Vibrio cholerae is a strictly aqueous organism and brackish and marine waters are natural environments for the etiologic agents of cholera, Vibrio cholerae O1 or O139. The main route of transmission is fecal-oral, indirectly via polluted water supplies or irrigation water. Another common source is contaminated shellfish that is raw or undercooked.
Cholera is an infection of the small intestines caused by cholera enterotoxin (CT) producing Vibrio cholerae of serogroups O1 and O139. Other serogroups and non-toxigenic strains may cause similar diseases but are rarely involved in large outbreaks and are not reported by the WHO as cholera.
The symptoms are often mild, but up to 10% of patients may experience classical cholera symptoms with profuse watery diarrhea (“rice water stool”) and often vomiting. This can lead to rapid dehydration (up to 25 liters per day) and electrolyte imbalance. Standard treatment consists of oral rehydration therapy with a sugar and electrolyte solution or, in severe cases, intravenous rehydration. Untreated cholera is often fatal due to dehydration and shock.