Vibrio cholerae is the causative agent of the gastrointestinal disease cholera, noted for its characteristic dehydration and massive diarrhea. The disease devastated the world's populations in the nineteenth and early twentieth centuries, causing major pandemics. Although vaccines and therapeutic measures have since been developed, the disease is still a public health problem in parts of Africa, Asia, and Latin America, where health care is poor and extreme poverty precludes adequate medical care and preventive measures. An epidemic in central Africa in 1994 and 1995 presented case fatality rates as high as 30% in areas where medical facilities were limited.
Clinical symptoms appear soon after V. cholerae secretes the cholera toxin, an A-B-type toxin. The B subunit binds to galactose residues on the cell surface.14 The A subunit triggers the irreversible activation of the cell’s G proteins that causes efflux of ions and water into the intestinal lumen, leading to the watery diarrhea characteristic of cholera. Because of cholera’s severe incapacitating symptoms, its high rate of fatality when untreated, and the possibility of genetically engineering a more potent strain, V. cholerae represents a significant threat as a biological weapon.
Cholera was first observed on the Indian subcontinent, with mentions in Sanskrit writings of a dehydrating diarrhea disease.3 Epidemic cholera was first recorded in 1563. In 1854, John Snow hypothesized that water was the primary pathway of transmission for cholera following London’s Broad Street outbreak, which led to 56 deaths within 2 days. In 1883, Robert Koch isolated V. cholerae from the feces of cholera patients and identified it as the infective agent. In an 1884 paper, Koch described the bacteria as “comma-shaped.”12