Cholera

Cholera. Cholera is caused by Vibrio cholerae, a Gram-negative bacteria. Some strains can synthesize an enterotoxin - the cholera toxin - which is responsible for the disease. Cholera has already caused seven pandemics since the beginning of the 19th century; the seventh started from Indonesia in 1961 and was provoked by the emergence of an epidemic clone, V. cholerae O1 El Tor. Most cases occure in South Asia, Africa, Haiti and most recently Yemen. Contamination is by ingestion, due to close contact with a patient, or by contaminated water and food. Patients present with acute watery diarrhea and vomiting as a result of the toxin-induced fluid intestinal leakage. The severity of dehydration determines the prognosis, which can be fatal in a few hours if intense rehydration is not started immediately. Prevention is based on universal access to water, sanitation and hand hygiene. An oral vaccine can help prevent or control epidemics.