Cholera, caused by the bacterium Vibrio cholerae, primarily spreads through contaminated water and food, leading to severe watery diarrhea and vomiting. Globally, it affects 3-5 million people yearly, resulting in approximately 100,000-130,000 deaths, predominantly in the developing world. Control measures include proper sanitation, early case identification, and treatment with rehydration therapy and antibiotics.

1. Epidemiology & Control of
Cholera
AB RAJAR
ASSOCIATE PROFESSOR
COMMUNITY Medicine.

2. Introduction
• Cholera is an infection in the small intestine caused by the bacterium
Vibrio cholerae.
• The word cholera is from Greek: kholera from kholē "bile".
• The main symptoms are watery diarrhea and vomiting.
• Transmission occurs primarily by drinking water or eating food that
has been contaminated by the feces (waste product ).

3. Introduction
• It is an acute diarrheal disease caused by Vibrio Cholera typically
characterized by sudden onset of profuse,effortless,watery diarrhea
followed by vomiting, rapid dehydration, muscular cramps and
suppression of urine.

4. GLOBAL STATUS
• Cholera likely has its origins in the Indian Subcontinent; it has been
prevalent in the Ganges delta since ancient times.
• The disease first spread by trade routes (land and sea) to Russia in
1817, then to the rest of Europe, and from Europe to North America.
• Seven cholera pandemics have occurred in the past 200 years, with
the seventh originating in Indonesia in 1961.

5. SIZE OF THE PROBLEM GLOBALLY
• 140 000 – 290 000 cases were reported between 1997- 1998.
• In 1999, global incidence was about 254 000 , and Africa alone
accounted for about 81% of the global total number of cases.
• In 2000, multiple outbreaks were reported in populations in various
islands of Oceania .

6. SIZE OF THE PROBLEM GLOBALLY
• Cholera affects an estimated 3–5 million people worldwide, & causes
100,000–130,000 deaths a year as of 2010.
• This occurs mainly in the developing world.
• In the early 1980s, death rates are believed to have been greater than
3 million a year.
• Cholera remains both epidemic and endemic in many areas of the
world.

7. Epidemiology

8. Epidemiology [Distribution]
• TIME:
• More common in rainy season.
• PLACE:
• Poor sanitation.
• Flies.
• Contaminated water and food.
• Poor housing.
• Overcrowding during marriages and fairs.

9. Epidemiology [Distribution]
• PERSON:
• Age:
• Cholera affects all ages.
• Gender:
• Affects both sexes.
• Gastric acidity:
• It is as effective barrier. Conditions that reduces acidity cause increased
susceptibility to cholera.
• Blood types:
• O>> B > A > AB

10. EPIDEMIOLOGY [DISTRIBUTION]
• PERSON:
• Economic Status:
• Low socio-economic persons are more prone.
• Education:
• Lack of education increases the risk.
• Personal Hygiene:
• Poor hygiene also increases the risk.

11. EPIDEMIOLOGY [DETERMINANTS]
• PRIMARY DETERMINANTS:
• Agent:
• The etiological agent is Vibrio Cholera and has 2 major biotypes: classical and El Tor,
Currently, El Tor is the predominant cholera pathogen worldwide.
• Has over 150 identified serotypes based on O-antigen
• Only O1 and O139 are toxigenic and cause Cholera disease (Water-borne illness)
• Resistance:
• Boiling for few seconds kills Vibrio Cholera.
• Toxin Production:
• Vibrio Cholera multiplies in the small intestine of human and produces an exotoxin (
enterotoxin ) that produces diarrhea.

12. Epidemiology [Determinants]
• SECONDARY DETERMINANTS:
• Poor hygiene and sanitation.
• Large Families and Flies.

13. RISK FACTORS
Raw or
uncooked
food
• Contaminated seafood, even in developed
• Especially jellyfish
Hypochlor
hydria
• People with low levels of stomach acid
• Such as children, older adults, and some medication.
Type O
blood
• Reasons aren't entirely clear
• Twice more likely
Poor
sanitary
conditions
• Rare in developed countries
• Common in Asia, Africa and Latin America.

14. EPIDEMIOLOGY
• SOURCE OF INFECTION:
• Stools/Vomit of cases and carriers.
• PERIOD OF COMMUNICABILITY:
• A case is infectious for a period of 7-10 days.
• Convalescent carriers are infectious for 2 to 3 wks.
• Chronic carrier state may last from a month up to 10 years or even more.

15. EPIDEMIOLOGY
• MODE OF TRANSMISSION:
• Food Borne.
• Drinking contaminated water or other drinks.
• Eating contaminated food.
• By Contact:
• Contact with contaminated fingers of infected person.
• Reservoir of infection:
• Human beings.
• Portal of entry:
• Mouth.

16. INCUBATION PERIOD:
• Incubation Period:
• From few hours to 5 days.
• Infective dose:
• 1011 Organisms are required to produce disease.

17. CARRIERS IN CHOLERA .
• A cholera carrier may be defined as an apparently healthy person
who is excreting V. Cholera in stools.
• TYPES:
• 1. PRE-CLINICAL OR INCUBATORY CARRIER:
• There are potential patients having an incubation period of 1-5 days.
• 2.CONVALESCENT CARRIER:
• The patient may continue to excrete vibrios,during his/her convalescence for
2-3 weeks.

18. CARRIERS IN CHOLERA .
• 3.CONTACT OR HEALTHY CARRIER:
• As a result of subclinical infection contracted through association with source
of infection.
• The duration of contact carrier state is usually < 10 days.
• They play an important role in the spread OF CHOLERA.
• Stool culture is positive for V.cholera.
• 4. CHRONIC CARRIER:
• The longest carrier state was found to be over 10 years.
• Gall bladder is infected in chronic carrier.
• Antibody titer against V. Cholera rises and remains positive as long as the
person harbors the organism.

19. PATHOGENICITY
• Ingestion of V. cholerae.
• Resistant to gastric acid
• Colonize small intestine
• Virulence of Non-toxigenic V. cholera O1 strain not well understood
• Secrete enterotoxin

20. PATHOGENICITY
• Enterotoxin binds to intestinal cells
• Chloride channels activated
• Release Large quantities of electrolytes & bicarbonates
• Fluid hypersecretion
• Diarrhea
• Dehydration

21. CLINICAL FEATURES
• 1 STAGE OF EVACUATION:
• Onset is abrupt.
• Profuse, painless watery diarrhea followed by vomiting.
• Patient may pass as many as 40 stools per day.
• The stool may have rice water appearance.
• The diarrhea is frequently described as "rice water" in nature and
may have a fishy odor.

22. Typical "rice water" diarrhea

23. CLINICAL FEATURES
• 2.STAGE OF COLLAPSE:
• Stage of dehydration.
• Classical signs are sunken eyes, hollow cheeks, scaphoid abdomen
and washerman’s hands and feet, absent pulse,unrecordable BP,loss
of skin elasticity, shallow and quick respirations.
• The out put of urine decreases and patient may undergo into anuria.
• Restlessness, intense thirst, cramps in legs and abdomen.
• patient's skin turning a bluish-gray hue from extreme loss of fluids.
• Death may occur at this stage due to dehydration and acidosis.

24. CLINICAL FEATURES
• 3.STAGE OF RECOVERY:
• BP begins to rise.
• Temperature.
• Urine secretion is re-established.
• If anuria persists, the patient may die of renal failure.
• Mild cases take 1-3 days for recovery.

25. INVESTIGATIONS
• Stools for D/R and C/S.
• 1-3 liters of suspected water for examination.
• Suspected samples of food.
• Direct haemaglutination test.

26. DIAGNOSIS
• Stool culture
• Confirm presence of cholera toxin
• Cholera Rapid Test Dipsticks

27. COMPLICATIONS
severe dehydration
severe dehydration

28. 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.

29. Control and Treatment

30. CONTROL AND TREATMENT
• 1. Verification of the diagnosis.
• 2. Notification.
• Cholera is notifiable within 24 hrs.
• The number of cases and death are to be reported daily and weekly till the
area is declared free from cholera.
• 3. Early case Finding.
• 4.Establishament of Treatment Centers.
• Mildly dehydrated patients should be treated at home.
• Severely dehydrated patients requiring I/V fluid.

31. Control and Treatment
• 5.SANITATION MEASURES:
• Proper water control.
• Provision of effective excreta disposal system.
• Improvement of food sanitation.
• Concurrent and terminal disinfection.

32. CONTROL AND TREATMENT
• Continued eating speeds the recovery of normal intestinal function.
• The World Health Organization recommends this generally for cases
of diarrhea no matter what the underlying cause.
• A CDC training manual specifically for cholera states:
• “Continue to breastfeed your baby if the baby has watery
diarrhea, even when traveling to get treatment. Adults and older
children should continue to eat frequently.”

33. Control and Treatment
• FLUIDS:
• In most cases, cholera can be successfully treated with oral rehydration
therapy (ORT), which is highly effective, safe, and simple to administer.
• ELECTROLYTES:
• As there frequently is initially acidosis, the potassium level may be normal,
even though large losses have occurred.

34. Control and Treatment
• ANTIBIOTICS:
• Treatments for one to three days shorten the course of the disease
and reduce the severity of the symptoms.
• Doxycycline is typically used first line.
• Other antibiotics proven to be effective include cotrimoxazole,
erythromycin, tetracycline, chloramphenicol, and furazolidone.

35. VACCINE
• A number of safe and effective oral vaccine for cholera are available.
• Dukoral, inactivated whole cell vaccine, has an overall efficacy of
about 52% during the first year after being given and 62% in the
second year, with minimal side effects.
• It is available in over 60 countries.
• One injectable vaccine was found to be effective for two to three
years.
• Work is under way to investigate the role of mass vaccination.
• WHO recommends immunization of high risk groups, such as children
and people with HIV, in countries