Epidemiological Distribution of Different Vibrio cholerae Strains Causing Cholera Disease in Endemic Countries: A Review

Cholera is an acute severe watery diarrhoeal disease caused by a toxigenic strains of Vibrio cholerae. Significant clinical presentations characteristic of this disease include; asymptomatic intestinal colonization, accompanied by rapid fluid and electrolyte loss, cholera sicca (unusual accumulation of fluid in the intestinal lumen leading to circulatory collapse and death), significant hypovolemia and electrolyte abnormalities, abdominal pain and discomfort, borborygmi, and vomiting. However, diagnostic pointers like hypokalemia, hypo or hypernatremia, isonatremic dehydration, hypocalcemia, and acidosis may be seen. Yet, in complicated cases, Kidney failure with acute tubular necrosis due to anuria, low glycogen, inadequate gluconeogenesis, severe hypoglycemia, coma (in rare occasions), chronic enteropathy, malnutrition and pneumonia in children may occur. Since man is the natural host of this pathogenic bacterium (Vibio cholera), which he sheds into the environment through faeces or vomitus, its eradication has become difficult especially from their natural warm aquatic environmental reservoirs. The association of this disease with drinking water, and food, has been traced to the pollution of water sources (wells, rivers, streams and ponds) as well as food sources like vegetables (from gardens which are watered with sewage contaminated water from the environment). Cholera has become a night mare especially in continents like Asia and Africa, which lack adequate healthcare facilities and infrastructures. These areas represent the most endemic regions of the nearly 50 countries recorded to be endemic to cholera in the world. The World Health Organization reports that only an estimated 5–10% of the actual case number are officially reported annually worldwide. This review attempts to describe the epidemiological distribution of the various strains of Vibrio cholerae causing epidemics all over the globe.