Cholera is an acute diarrheal disease caused by the bacterium Vibrio cholerae O1. It spreads through contaminated food or water and causes profuse watery diarrhea and vomiting that can lead to severe dehydration and death if untreated. The key aspects of cholera prevention and control include early detection and treatment with oral rehydration, antibiotic therapy, improved water and sanitation, vaccination in at-risk areas, and health education on hygiene practices. National programs in India have focused on these measures to reduce the burden of cholera.

1. DR.R.TAMILARASI,
DEPARTMENT OF COMMUNITY MEDICINE.

2. EPIDEMIOLOGY OF CHOLERA
 Introduction
 Agent, Host and Environment
 Sign and symptoms
 Complications.
 Prevention and Control
 National Programmes

3.  Cholera – an ACUTE DIARRHEAL DISEASE caused by
V.Cholerae O1.
 Symptomless to severe infections.
 Mostly asymptomatic.
 Case fatality rate – 30% to 40%

4. AGENT FACTORS
 Agent: Vibrio cholerae
 Has over 150 identified serotypes based on O-antigen
 Only the Epidemic strains - O1 and O139 are toxigenic and cause
Cholera disease (Water-borne illness)
 Source of infection: case of Cholera by Fecal-oral transmission
 Reservoir: Humans.
 Infective materials: stools and vomitus of cases and carriers.

5. V.cholerae
O1
Classical
Eltor
O139

6. Period of Communicability
During acute stage – 7 to 10 days
Convalescent carriers – 2 to 3 weeks; Chronic carriers – a
month upto 10 years
By end of week, 70% of patients non-infectious
 By end of third week, 98% non-infectious
INCUBATION PERIOD:Ranges from a few hours to 5 days.
Universal I/P is 5 days.

7. MODE OF TRANSMISSION
A.WATER : Primary ingestion of water (contaminated with
faeces)
OR
B.FOOD & DRINKS: Ingestion of food contaminated by dirty
water, faeces, soiled hands or flies. Eg: feeding bottle
OR
C.DIRECT CONTACT: The disease transmitted from one person to
another person in over crowded and unhygienic conditions.
Eg: fingers , linen, fomites

8. DEFINITION:
 Apparently healthy person who is excreting V.Cholerae O1 in
stools.
TYPES:
 A) PRE CLINICAL CARRIERS / INCUBATORY CARRIER- potential patients
 B) CONVALESCENT CARRIERS – 2 -3 weeks after recovery
 C) CONTACT OR HEALTHY CARRIERS – sub clinical cases
 D) CHRONIC CARRIERS – 10 years

9. HOST FACTORS
1. Age: Children: All ages.
2. Sex: Equal in both male and female.
3. Gastric acidity: PH of <5 will destroy vibrio.
4. Population mobility
5. Economic status: Lower SES.
6. Immunity: Less immune higher risk.
7. Blood types
O>> B > A > AB

10. ENVIRONMENTAL FACTORS
 At risk areas include peri urban slums, refugee camps where clean water and
sanitation are not met – LOW standards of hygiene.
 Consequences of a disaster
 Lack of education, poor quality of life

11. CLINICAL FEATURES
1) STAGE OF EVACUATION:
 The primary symptoms of cholera are profuse, painless diarrhea and
vomiting of clear fluid.
 Typical "rice water" diarrhea
 The diarrhea is frequently described as "rice water" in nature and may have a
fishy odour.
 An untreated person with cholera may produce
10 to 20 litres of diarrhea a day with fatalresults

12. SIGNS AND SYMPTOMs
2) STAGE OF COLLAPSE
 If the severe diarrhoea is not treated with intravenous rehydration, it
can result in life- threatening dehydration and electrolyte imbalances.
 Sunken eyes, hollow cheeks, scaphoid abdomen, decreased skin turgor
that causes wrinkled hands and skin, rapid pulse, low blood pressure,
sub normal temperature, shallow and quick respirations, decreased
urine output.
 Death due to acidosis.

13. SIGNS AND SYMPTOMs
3) STAGE OF RECOVERY:
 Severe form occur in 5-10 percent.
 Mild cases recover in 1 to 3 days.
El Tor vs Classical:
 A) higher mild & asymptomatic cases
 B) fewer secondary cases
 C) survive longer in extra intestinal environment
 D) occurrence of chronic carriers

14. COMPLICATIONS
 The degree and duration of fluid and electrolyte loss determines the
medical consequences of cholera.
 For example, renal failure may stem from the reduced fluid flow through the
kidneys; low blood sugar (hypoglycemia)
 may result in seizures or coma, especially in the young; or
 lowered potassium levels may trigger serious cardiac complications

15.  1) VERIFICATION OF DIAGNOSIS
 2) NOTIFICATION
 3) EARLY CASE FINDING
 4) ESTABLISHMENT OF TREATMENT CENTRES
 5) REHYDRATION THERAPY
 6) ADJUNCTS TO THERAPY
 7) EPIDEMIOLOGICAL INVESTIGATIONS
 8) SANITATION MEASURES
 9) CHEMOPROPHYLAXIS
 10) VACCINATION
 11) HEALTH EDUCATION

16. 1) VERIFICATION OF DIAGNOSIS – by bacteriological examination of stools.
2) NOTIFICATION – CHW/MPW to local health authority
IHR – within 24 hrs to WHO
3) EARLY CASE FINDING – HOUSE HOLD CONTACTS
4) ESTABLISHMENT OF TREATMENT CENTRES – easily accessible to
treatment – schools , public building.
5) REHYDRATION THERAPY
6) ADJUNCTS TO THERAPY – Antibiotics-floroquinalones, tetracyclines,
azithromycin, ampicillin.
7) EPIDEMIOLOGICAL INVESTIGATIONS

17.  8) SANITATION MEASURES
Water control: All water used for drinking, washing, or
cooking should be sterilized by either boiling,
chlorination, ozone water treatment, ultraviolet light
sterilization.
Excreta disposal: health education to use sanitary
latrine
Food sanitation: sale of foods under hygienic
conditions, eating cooked hot food, cooking utensils
should be clean and dry.
Disinfection: concurrent and terminal.
CONTROL OF CHOLERA

18.  9) CHEMOPROPHYLAXIS:
 Household contacts
 Closed community where cholera occurred
 Tetracycline – BD for 3 days
 500mg – adults
 125mg – 4-13 years
 50 mg – 0-3 years
 Doxycycline – single dose
 300 mg for adults
 6mg/kg for < 15 years

19.  10) VACCINATION:
 ORAL VACCINE:
A) Dukoral (WC-rBS) – heat killed whole cell vaccine
 Contains V.Cholerae O1- Classical & El Tor, Ogawa & Inaba and recombinant
cholera toxin B sbunit.
 3ml single dose vials with bicarbonate buffer.
 Vaccine and buffer ----------- water 150 ml > 5 years; 75 ml - 2-5 years;
 Dosage : 2 oral doses; at 7 days apart for adults and >= 6 years
3 oral doses; at 7 days apart for 2-5 years;
 Booster dose: after 2 years for adults and >= 6 years
every 6 months for 2-5 years;
Not for < 2 years.

20. B) Sanchol and mORCVAX
Contains both O1 and O139
DOSE: 2 doses at 4 weeks apart for >1 year;
BOOSTER: after 2 years
C) Euvichol
Same as Sanchol.

21.  11) HEALTH EDUCATION
 About ORT
 Benefits of early reporting to treatment
 Food hygiene practice
 Hand washing
 Cooked and hot food; safe water

22. DIARRHOEA DISEASE CONTROL PROGRAM
1980 -81 – NATIONAL CHOLERA CONTROL
PROGRAMME
1986 – 87 - ORAL REHYDRATION THERAPY
PROGRAMME
Main objective – prevent diarrhea associated deaths

23. THANK YOU