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Cholera
(Imported from other countries)Cholera is caused by the bacterium Vibri cholerae. Vibri cholerae produces
cholera toxin, whose action on the mucosal epithelium is responsible for the
characteristic diarrhoea of this disease. Most people infected with the
bacterium do not become ill, although it will be 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 10% of ill persons develop typical cholera with
signs of moderate or severe dehydration.
Cholera occurs in parts of Africa and Asia.Reservoir
- Water and humans.
- Incubation period
- From a few hours to five days; usually two to three days.
Signs and Symptoms
- Asymptomatic illness is most frequent.
- Profuse watery stools
- Vomiting
- Rapid dehydration
- Circulatory collapse
- Death if untreated
Diagnosis
- Stool culture and sensitivity.
- Visualisation by dark field or phase microscopy of characteristic motility.
Treatment
- Prompt fluid therapy with adequate volumes of electrolyte solution should be
undertaken.
- Most cases of diarrhoea can be treated adequately by giving a solution of oral rehydration salts (the WHO/UNICEF standard sachet).
- Patients with severe dehydration require urgent intravenous fluid therapy with
Hartmann's solution or WHO solution or other similar fluid.
- Antibiotic treatment (prescribed by medical doctor, to which the strain is
sensitive) shorten the duration of diarrhoea and the duration of vibrio
excretion:
- Adults: Tetracycline drugs (if strain sensitive)
- Children: Co-trimoxazole (if strain sensitive).
Control and Prevention
- Contacts should be observed for five days from the date of last exposure. This
may include, for example, all air travellers on a flight from overseas.
- Effective food hygiene measures in endemic areas include cooking food
thoroughly and eating it while still hot; preventing cooked foods from being
contaminated by contact with raw foods, including water and ice, contaminated
surfaces or flies; and avoiding raw fruits or vegetables unless they are first
peeled.
- Washing hands after defecation, and particularly before contact with food or
drinking water, is equally important.
- Stool culture of any contacts with symptoms of diarrhoea and stool culture of
all household contacts, even if asymptomatic, should be undertaken.
- Cases should also be looked for among those possibly exposed to a common
source.
- Immunisation of contacts is not indicated.
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