Cholera is an acute intestinal infection caused by the bacterium Vibrio cholerae. It has a short incubation period, from less than one day to five days, and produces an enterotoxin that causes a copious, painless, watery diarrhoea that can quickly lead to severe dehydration and death if treatment is not promptly given.Vomiting may also occur. Most persons infected with V. cholerae do not become ill, although the bacterium is present in their faeces for 7-14 days. When illness does occur, more than 90% of episodes are of mild or moderate severity and are difficult to distinguish clinically from other types of acute diarrhoea. Less than 1O% of ill persons develop typical cholera with signs of moderate or severe dehydration.
TRANSMISSION & TREATMENT:
Cholera is spread by contaminated water and food. Rarely is cholera transmitted by direct person-to-person contact. Most cases of diarrhoea caused by V, cholerae can be treated adequately by giving a solution of oral or Intravenous rehydration salts and Antibiotics.When cholera occurs in an unprepared community, case-fatality rates may be as high as 50% — usually because there are no facilities for treatment, or because treatment is given too late.
EPIDEMIC CONTROL AND PREVENTIVE MEASURES:
When cholera appears in a community it is essential to ensure three things: hygienic disposal of human faeces, an adequate supply of safe drinking water, and good food hygiene. Effective food hygiene measures include cooking food thoroughly and eating it while still hot; preventing cooked foods from being contaminated by contact with raw foods, contaminated surfaces or flies; and avoiding raw fruits or vegetables unless they are first peeled.
The only cholera vaccine that is widely available at present is killed vaccine administered parenterally, which confers only partial protection (50% or less) and for a limited period of time (3-6 months maximum). No country requires proof of cholera vaccination as a condition for entry.