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Cholera |
Cholera is an acute diarrhoeal disease caused by
V.Cholerae (classical or El Tor biotypes). Majority of infections are mild or
asymptomatic. Typical cases are characterized by sudden onset of profuse, effortless,
watery diarrhea followed by vomiting, rapid dehydration, muscular cramps and sudden
suppression of urine. Unless there is a rapid replacement of fluids and electrolytes the
fatality rate may be as high as 30-40%.
Cholera has been present in India since antiquity. In Ayurveda it has been termed as
Vishuchika. Numerous social factors are responsible for the high occurrence rates of
cholera in India. These include certain human habits favoring water and soil pollution,
like open-air defecation, low standards of personal hygiene, lack of education, and poor
quality of life. However, there is a declining trend in the number of reported cases and
deaths due to Cholera in India.
Cholera affects all ages and both sexes, attack rates are highest in children. The
incidence of cholera tends to be highest in the lower socioeconomic groups, and this is
attributed mainly to poor hygiene. Transmission of infection occurs from man to man either
directly through contaminated fingers or indirectly through contamination of food and
water. Cooked food can also be contaminated via contaminated hands or flies. Fruits and
vegetables washed with contaminated water can be a source of infection. |
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Clinical features |
The main symptom of cholera is diarrhea. The onset
is abrupt with profuse, painless, watery diarrhea followed by vomiting. The patient may
pass as many as 40 stools in a day. The stool have a typical rice water appearance. The
patient soon passes into a stage of collapse due to dehydration. Death may occur at this
stage. The classical form of severe cholera occurs in only 5-10% of cases. In the rest,
the disease tends to be mild characterized by diarrhea with or without vomiting or marked
dehydration. Generally, mild cases recover in 1-3 days.
Cholera due to El Tor biotype differs from the classical cholera in the following respects
- a higher incidence of mild and asymptomatic infection
- fewer secondary cases in family members
- occurrence of chronic carriers
- as El Tor vibrios are more resistant they survive longer in the environment.
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Laboratory diagnosis of Cholera |
| The diagnosis of cholera can never be made with
certainity on clinical grounds. Laboratory examination is required for the confirmation of
diagnosis. The simplest method consists of demonstration of the typical motile bacteria in
the stool or vomitus of the patients. Serological and biochemical tests can also be
carried out back to
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Treatment |
| Cholera is now one of the most effectively treated
disease. Death rates have been brought down to less than 1% by effective rehydration
therapy. back to top |
Rehydration |
The introduction of oral rehydration, by WHO in
1971, has greatly simplified the treatment of cholera and other diarrhoeal diseases. The
aim of oral fluid therapy is to prevent dehydration and reduce death rates. As many as
90-95% of all cases of cholera and acute diarrhoea can be treated by oral fluids alone.
Packets of oral rehydration mixture are now freely available at all primary health
centres, sub-centres and hospitals. The contents of the packet are to be dissolved in one
litre of drinking water. The solution should be made fresh daily and used within 24 hours.
If the WHO mixture of salts is not available then a simple mixture consisting of table
salt (5g) and sugar (20g) dissolved in one litre of drinking water may be used until the
proper mixture is available.
- for children under 2 years of age give one teaspoon every 1 to 2 minutes, or offer
frequent sips out of a cup, for older children. Adults may drink as much as they like
- if the child vomits, wait for 10 minutes and try again, giving the solution slowly ; a
spoonful every 2 to 3 minutes.
- if the child is breast-fed, nursing should be pursued during rehydration
Intravenous rehydration therapy is required only for initial rehydration of severely
dehydrated patients who are unable to drink.
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Antibiotics |
| Antibiotics should be given as soon as vomiting has
stopped, which is usually 3 to 4 hours after rehydration. Commonly used antibiotics
include Doxycycline, Tetracycline, Trimethroprim and Sulphamethoxazole combination and
Furazolidone. back to
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Prevention of Cholera |
- Sanitation measures: As water is the most important vehicle for transmission of infection,
it is important to consume safe drinking water. So also food sanitation like eating hot
cooked food prepared in properly cleaned and dried utensils is important. It is also
equally important to maintain proper personal hygiene.
- Vaccination against cholera provides only around 50% protection for 3-6 months.
- Antibiotics like Tetracycline can be used to prevent secondary cases in close contacts.
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