Cholera is an acute diarrheal disease caused by the bacterium V. cholerae O1 and is both epidemic and endemic, primarily transmitted through contaminated water and food. Key factors influencing the disease include human carriers, environmental conditions like poor sanitation, and host factors including age and economic status. Prevention and control measures involve early diagnosis, treatment, sanitation improvements, and vaccination.

1. Vd Rakesh Shukla
Lecturer
Dept of swasthavritta
GAAC, Ahmedabad Vd Rakesh Shukla, GAAC, Ahmedabad

2. • Cholera is an acute diarrheal disease caused by
V.Cholerae 01(classical or El Tor ).
• Epidemiological features – it is both epidemic and
endemic.
• Agent factors
a) Agent: the organism that causes cholera is labeled as
V.cholerae O group 1 or vibrio cholera 01. The term
“epidemic strain” is also been used for these vibrios.
Vd Rakesh Shukla, GAAC, Ahmedabad

3. b) Resistance – V.cholerae are killed within 30 minutes by heating at
56 deg.C or within a few seconds by boiling. They remain in ice
for 4-6 weeks or longer. Drying or sunshine will kill them in a few
hrs. They are easily destroyed by coal tar disinfectant such as
cresol. Bleaching powered is another good disinfectant which
kills vibrios instant at 6mg/liter.
c) Toxin production – the vibrios multiply in the lumen of the small
intestine and produce exotoxin (enterotoxin) this toxin produces
diarrhea. The exotoxin has no effect on any other tissues expect
the interstitial epithelial cells.
d) Infective materials – stool and vomit of cases and carriers.
Vd Rakesh Shukla, GAAC, Ahmedabad

4. e) Reservoir of infection – humans are the only known reservoir.
They may be cases or carriers.
f) Cases – range from in apparent infections to severe ones.
g) Carriers – they are best detected by bacteriological
examinations of the purged stool by the administration of 30-
60 mg of magnesium sulfate in 100 ml of water by mouth.
h) Infective dose – cholera is dose related. Infection occurs when
the number of vibrios ingested exceeds the dose that is
infective for the individual.
i) Period of communicability – cholera is infectious for a period
of 7-10 days. Convalescent carriers are infectious for 2-3
weeks. The chronic carrier state may last for a month up to 10
years or more. Vd Rakesh Shukla, GAAC, Ahmedabad

5. Carriers in cholera: person who is excreting V.cholerae 01 in stools.
a) Preclinical or incubatory carrier: since the incubation period of
cholera is short (1-5 days) incubatory carriage is of short
duration.
b) Convalescent carrier: the patient who has recovered, may
continue to excrete vibrios for 2-3 weeks.
c) Contact or health carrier – subclinical infection contracted
through association with a source on infection, usually less than
10 days.
d) Chronic carrier – occurs infrequently, longest was more than 10
years. Here gall bladder is infected an antibody titer rises and
remains positive as long as the person harbors the organism.Vd Rakesh Shukla, GAAC, Ahmedabad

6. Host factors
a) Age – all age, in endemic areas highest among children
b) Sex – both sexes
c) Gastric acidity – destroyed in an acidity of pH 5 or lower
d) Population mobility – movement of population such as
pilgrimage, marriages, fair, and festivals results in
increase exposure of infection.
e) Economic status – highest in low socio economic group
due to poor hygiene
f) Immunity – vaccination gives only temporary, partial
immunity for 3-6 months. Vd Rakesh Shukla, GAAC, Ahmedabad

7. Environmental factors :
Poor sanitation, contaminated water and food, flies may
carry V.cholera but not vectors or proven importance.
Incubation period:
Few hours up to 5 days, commonly 1-2 days.
Pathogenesis :
The main symptom of cholera is diarrhea. The increase in
fluid is called diarrhea not increase in peristalsis.
Vd Rakesh Shukla, GAAC, Ahmedabad

8. Mode of transmission
a) Faecally contaminated water – such as wells, lakes,
streams, ponds, rivers, etc.
b) Contaminated food and drinks – such as bottle feeding,
unwashed fruits and vegetables or fruits and vegetables
washed with contaminated water, contaminated hands
and flies.
c) Direct contact – person top person transmission through
contaminated fingers while carelessly handling excreta
and vomit of patients.
Vd Rakesh Shukla, GAAC, Ahmedabad

9. Clinical picture – 3 stages
a) Stage of evacuation – onset is abrupt, with profuse, painless,
watery diarrhea followed by vomiting. The patient may pass
as many as 40 stools in a day. The stools may have “rice
water” appearance.
b) Stage of collapse: patient collapse due to dehydration. sunken
eyes, hollow cheeks, scaphoid abdomen, subnormal
temperature, washerman's hands and feet, absent pulse, un
recordable blood pressure, loss of skin elasticity, shallow and
quick respirations. Out put of urine decreases, restless and
complains of intense thirst and cramps in legs and abdomen.
Death may occur at this stage due to dehydration and acidosis
resulting from diarrhea.
Vd Rakesh Shukla, GAAC, Ahmedabad

10. c) Stage of recovery – if death does not occur, the patient
shows signs of clinical improvement. The blood pressure
begins to rise, temperature returns to normal, and urine
secretion is re-established.
Vd Rakesh Shukla, GAAC, Ahmedabad

11. Diagnosis
a) Collection of stools – by rubber catheter, rectal swabs,
cotton tipped rectal swabs.
b) Vomitus –never used because isolating vibros are much
less.
c) Water – 1-3 liters of suspected water should be collected
in sterile bottles.
d) Food samples – 1-3g samples of suspected food are
collected.
e) Transportation – should be transported in sterilized
McCartney bottles containing alkaline peptone water.
Vd Rakesh Shukla, GAAC, Ahmedabad

12. f) Direct examination – through microscope with dark field
illumination.
g) Culture methods – culture on Peptone Water Tellurite
medium and then on Bile Salt Agar Medium.
h) Characterization – translucent, smooth, moist etc.
i) Biochemical test – for cholera red reaction.
j) Future characterization– for biotypes of cholera.
Vd Rakesh Shukla, GAAC, Ahmedabad

13. Prevention and Control
1. Verification of the diagnosis
2. Notification
3. Early case finding
4. Establishment of treatment centers
5. Rehydration therapy - ORS (oral rehydration salt)
6. Adjuncts to therapy – Antibiotics
7. Epidemiological investigations –extent of outbreak
&transmission
Vd Rakesh Shukla, GAAC, Ahmedabad

14. 8. Sanitation measures – i) water control
ii) excreta disposal
iii) food sanitation
iv) disinfection
9. Chemoprophylaxis – tetracycline
10. Vaccination – parental and oral vaccines
11. Health education
Vd Rakesh Shukla, GAAC, Ahmedabad

15. Thank you
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Vd Rakesh Shukla, GAAC, Ahmedabad