Cholera

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Cholera

Cholera has smouldered in an endemic fashion on the Indian subcontinent for centuries. There are references to deaths due to dehydrating diarrhea dating back to the Hippocrates and Sanskirt writings. Epidemic cholera was described in 1563 by Garcia del Huerto, a Portuguese physician at Goa, India. The mode of transmission of cholera by water was proven in 1849 by John Snow, a London physician. In 1883, Robert Koch successfully isolated the cholera vibrio from the intestinal discharges of cholera patients and proved conclusively that it was the agent of the disease.
Cholera is an acute bacterial disease that affects the intestinal tract, characterized by watery diarrhoea that is caused by the bacterium Vibrio cholerae. Cholera is spread by eating food or drinking water contaminated with the bacteria. Although cholera was a public health problem in Europe one hundred years ago, modern sanitation and the treatment of drinking water have virtually eliminated the disease in developed countries. In third world countries, however, cholera is still a problem.
The genus Vibrio consists of Gram – negative straight or curved rods, motile by means of a singular polar flagellum. Vibrios are capable of both respiratory and fermentative metabolism O is a universal electron accepter; they do not denitrify. Most species are oxidase positive. In most ways vibrios are related to enteric bacteria, but they share some properties with pseudomonads as well. Vibrios are distinguished from enterics by being oxidasepositive and motile by means of polar flagella. Of the vibrios that are clinically significant to humans vibrio cholarae , the agent of cholera is the most important.
Vibrios are the most common organisms in surface waters of the world. They occur in both marine and fresh water habitats and in associations with aquatic animals. Some species are bioluminescent and live in mutualistic associations with fish and other marine life. Ot...