�ݺ�ߣ

DR.R.TAMILARASI,
DEPARTMENT OF COMMUNITY MEDICINE.

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

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

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.

V.cholerae
O1
Classical
Eltor
O139

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.

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

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

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

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

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

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.

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

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

 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

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

 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

 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

 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.

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.

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

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

�ݺ�ߣ

Cholera

Recommended

More Related Content

What's hot (20)

Similar to Cholera (20)

Recently uploaded (20)

Cholera