Cholera is an acute diarrheal disease caused by the bacterium Vibrio cholerae. It remains a global threat, with an estimated 100,000-120,000 deaths per year. The disease spreads through contaminated food and water and outbreaks often occur in areas with poor sanitation and limited access to clean water. While most infected individuals are asymptomatic, cholera can cause severe dehydration and death if left untreated. Effective treatment involves oral rehydration therapy. Prevention relies on vaccination, improved water quality, sanitation and hygiene. The WHO recommends surveillance, preparedness, treatment and use of oral cholera vaccines to control outbreaks.

1. Cholera
Dr. Priyamadhaba Behera
References
WHO Document, 5th edition OTPH, 18th edition Harrison
principle of medicine, Articles however applicable
1

2. Cholera-Introduction
MIASMA
THEORIES
versus

3. • Are gram-negative rods that are facultativel
word cholera is a derivative of the Greek word “choler” meaning bile
• First discovered by Filippo Pacini in Italy in 1854, Pacini’s results were
published under the title, “Microscopic observation and pathological
deductions on cholera
• Robert Koch independently discovered a bacillus, the same that
Pacini discovered 30 years back

6. Epidemiology
• 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
6

7. Continued
• The first cholera pandemic occurred in the Bengal
region of India starting in 1817 through 1824.
• The disease dispersed from India to Southeast Asia,
China, Japan, the Middle East, and southern Russia.
• The second pandemic lasted from 1827 to 1835 and
affected the United States and Europe.
• It killed 150,000 Americans during the second
pandemic.
• The third pandemic erupted in 1839, persisted until
1856, extended to North Africa, and reached South
America, for the first time specifically infringing upon
Brazil.
7

8. Continued
• In Russia alone, between 1847 and 1851, more than
one million people perished of the disease
• Cholera hit the sub-saharan african region during
the fourth pandemic from 1863 to 1875
• The fifth pandemic raged from 1881–1896
• Sixth pandemics raged from 1899-1923
• Between 1900 and 1920, perhaps 8 million people
died of cholera in india
• These epidemics were less fatal due to a greater
understanding of the cholera bacteria
8

12. What Is the Current Situation?
Where are modern-day
An outbreak of cholera has been ongoing in epidemics of cholera?
Haiti since October 2010. According to the
Ministere de la Sante Publique et de la
Population (MSPP), as of August 4, 2013,
669,396 cases and 8,217 deaths have been
reported since the cholera epidemic began in
Haiti. Among the cases reported, 371,099
(55.4%) were hospitalized1
•
HAITI

13. Cholera : Causal Agent
•
•
•
•
Species: Vibrio Cholerae
Serogroup: O139 & O1
Biotypes :EL Tor Classic
Serotypes Hikojima, Ogawa& Inaba

14. Reservoir
• Humans are the main reservoir of vibrio cholerae.
Other potential reservoirs are water
• Vibrios grow easily in saline water and alkaline
media. They survive at low temperatures but do not
survive in acid media

15. Carriers and transmission
• The reservoir is mainly human, asymptomatic
(healthy) carriers and patients carry huge quantities
of vibrio in faeces and in vomit; up to 108 bacteria
can be found in 1 ml of cholera liquid
• The infective dose depends upon individual
susceptibility, but in general a 108 doses is needed
• Cholera is transmitted by a faecal-oral route

16. Transmission
• Cholera is transmitted by the fecal –oral route through contaminated
water & food
• The infection dose of bacteria required to cause clinical disease varies
with the source
• If ingested with water the infective dose should be higher
• When ingested with food fewer organism are required to cause the
disease

17. Period of communicability
 Infected persons (symptomatic or not) can carry and
transmit vibrios during 1-4 weeks
 A small number of individuals can remain healthy
carriers for several months.
 Incubation period-6hr to 5 days

18. RISK FACTORS
• Poor social and economic environment, precarious
living conditions Associated with insufficient water
supply (quantity and quality)
• Poor sanitation and hygiene practices
• High population density: internally displaced or
refugee Camps and slum populations
• Inhabitants of rural areas, particularly along rivers
and lake shores
• Diaster had took place

19. Case Definitions for Cholera
Suspected
 In an area where the disease is not known to be
present: severe dehydration or death from acute
watery diarrhoea in a patient aged 5 years or more;
 In an area where there is cholera endemic: acute
watery diarrhoea, with or without vomiting in a
patient aged 5 years or more
 Epidemic ongoing: acute watery diarrhoea with or
without vomitting

20. Case definition for cholera
Confirmed
• A suspected case that is laboratory-confirmed.
(Isolation of Vibrio cholerae O1 or O139 from stools in
any patient with diarrhoea is the laboratory criteria
for diagnosis)

21. Symptoms and signs
The stool has a characteristic appearance: a nonbilious,
gray, slightly cloudy fluid with flecks of mucus, no blood,
and a somewhat fishy, inoffensive odor. -"rice-water“
Clinical symptoms parallel volume contraction
At losses of <5% of normal body weight, thirst develops
5–10%, postural hypotension, weakness, tachycardia, and
decreased skin turgor are documented
>10%, oliguria, weak or absent pulses, sunken eyes (and, in
infants, sunken fontanelles), wrinkled ("washerwoman")
skin, somnolence, and coma are characteristic
Complications -include renal failure due to acute tubular
necrosis.
Muscle cramps are common d/o electrolyte imbalance
Fever is usually absent

22. Role of laboratory test
 Bacteriological confirmation is compulsory on
the first suspected cases, in order to:
Confirm cholera
 Identify the strain, biotype and serotype
 Assess antibiotic sensitivity

23. Laboratory Test
• Confirmation on 10 to 20 stool samples is sufficient.
Samples can be taken using different methods : filter
paper, Cary Blair medium or rapid tests
• Rapid tests can give a quick confirmation of a cholera
diagnosis, however, rapid tests
• Do not provide information on antibiotic
sensitivity nor can they be used for biotyping,and
therefore must always be followed by sampling

24. Selection of cases for bacteriologic sampling
• For confirmation of an outbreak, stool samples
should be collected from up to 10-20 previously
“untreated” cases who meet all of the following
criteria:
– onset of illness less than four days before
sampling
– currently having watery diarrhoea
– have not received antibiotic treatment for this
illness
Selection of transport media
Most reliable, currently available transport medium
is carry-blair

25. Collection of specimens
• Stool should be collected either by:
 Collecting a swab from a freshly passed stool
specimen (fresh stool should be less than 1
hour old) or from
 A swab of the rectal contents (rectal swab)

28. Antibiotics
 Should be given only in severe cases to reduce
the duration of symptoms and carriage of the
pathogen
 Selective chemoprophylaxis may be useful for
members of a household who share food and
shelter with cholera patient

29. Use of Ciprofloxacin : Offers short course for
cholera treatment
• Offers short course for cholera treatment
– Ease of administration: Single dose
– Assurance of patients compliance
– Reduction of cost of treatment
• Evidence: Single dose Ciprofloxacin (500 mg) is
shown to be effective in both adults and children
(Cure rate was 94% in adults and 60% in children:
Resolution of diarrhoea within 48 hours of the start
of treatment and no recurrence during 5 day stay in
the hospital1
(Ref: Lancet 1996; 348: 296-300 and Lancet 2005; 366: 1085-93)

30. Zinc Supplementation in Cholera : What is the
evidence ?
• Supplementation of zinc to the children with cholera
reduces both stool volume and duration of diarrhoea, an
effect that was more pronounced in malnourished
children 1
1.S.K. Roy, K E Islam, et al. Impact of Zinc on Children with Cholera. Presented during 10 th Annual Scientific
Conferences (ASCON) of ICDDR,B, Dhaka)

31. WHO and UNICEF’s Recommendation for
Zinc Supplementation
Age group
Dose
Duration
Infants under 6
months old
10 mg per day
10-14 days
Children above 6
months old
20 mg per day
10-14 days
Ref: WHO/UNICEF Joint Statement on Clinical Management of Acute Diarrhoea, May 2004

32. • Untreated cases: Average- 50%
Epidemics- 90%
• Treated cases: Less than 1%
What is the mortality rate of cholera?

34. WHO Global Task Force on Cholera
• Launched in 1992, 44th world health assembly
• Aim -reduce mortality and morbidity associated
with the disease and to address the social and
economic consequences of cholera
• Partnership brings together governmental and nongovernmental organizations, UN agencies, and
scientific institutions
• Develop technical guidelines and training materials
for cholera control

35. Current priority activities of WHO Global Task Force
on Cholera
• Encouraging improved surveillance , to identify high risk
areas and guide intervention
• Providing evidence based support to countries for
preparedness and response
• Gaining evidence on the use of oral cholera vaccines as
an additional public health tool to diminish incidence of
cholera in high risk areas and vulnerable groups
• Linking health and management of the environment in
order to improve access to safe water for vulnerable
populations and diminish incidence of waterborne
diseases

36. Prevention and control of cholera outbreaks: WHO
policy and recommendations
Main tools for cholera control
• Proper and timely case management in cholera
treatment centres
• Specific training for proper case management, including
avoidance of nosocomial infections
• Sufficient pre-positioned medical supplies for case
management (e.g. Diarrhoeal disease kits)
• Improved access to water, effective sanitation, proper
waste management and vector control
• Enhanced hygiene and food safety practices
• Improved communication and public information

37. Cholera vaccines
•WHO recommends that immunization with currently
available cholera vaccines be used in conjunction with the
usually recommended control measures in
-Areas where cholera is endemic
-Areas at risk of outbreaks
• Vaccines provide a short term effect while longer term
activities like improving water and sanitation are put in
place

38. Cholera vaccines
• Parenteral cholera vaccine not recommended by WHO (low
protective efficacy and adverse reaction)
• Two types of safe and effective oral cholera vaccines
currently available
 Both are whole-cell killed vaccines
 Both have sustained protection of over 50% lasting for two years in
endemic settings.
 Both vaccines are WHO-prequalified and licensed over 60 countries.
 Both vaccines are administered in two doses given between seven
days and six weeks apart
 Recently, however, researchers have suggested that oral cholera
vaccines induce “herd immunity”1
1.Ali M, Emch M, von Seidlein L, Yunus M, Sack DA, Rao M, Holmgren J, Clemens JD.Herd immunity conferred by killed oral cholera vaccines in
Bangladesh: areanalysis.Lancet. 2005 Jul 2-8;366(9479):44-9

39. •
•
•
•
Dukoral
Vaccine with the b-subunit
Given in 150 ml of safe water
Short-term protection of 85–90% against V.
Cholerae O1 among all age groups at 4–6
months following immunization
Shanchol
Provides longer-term protection against V.
Cholerae O1 and O139 in children under five
years of age

40. International Health Regulations
• 194 countries across the globe, including all the
Member States of WHO
• Aim- the international community prevent and
respond to acute public health risks that have the
potential to cross borders and threaten people
worldwide
• Surveillance for prevention, preparedness and early
warning
• Imposing travel and trade restrictions have proven
inefficient and risk to divert useful resources.
• WHO has no information -imported food from
affected countries has ever been implicated in
outbreaks of cholera in importing countries

41. WHO recommendations to unaffected
neighbouring countries
• Improve preparedness to rapidly respond to an
outbreak, should cholera spread accross borders,
and limit its consequences
• Improve surveillance to obtain better data for risk
assessment and early detection of outbreaks,
including establishing an active surveillance system

42. Measures should be avoided, (ineffective,
costly and counter-productive)
•
Routine treatment of a community with antibiotics,
or mass chemoprophylaxis (no effect on the spread
of cholera, can increase antimicrobial resistance and
provides a false sense of security)
• Restrictions in travel and trade between countries or
between different regions of a country (hampers
good cooperation spirit between institutions and
countries instead of uniting efforts)

43. Key messages
• Cholera is an acute diarrhoeal disease that can kill within
hours if left untreated
• There are 100 000–120 000 deaths due to cholera every year
of which only a small proportion are reported to WHO
• Up to 80% of cases can be successfully treated with oral
rehydration salts (ORS)
• About 75% of people infected with Vibrio cholerae O1 or
O139 do not develop any symptoms
• Typical at-risk areas of cholera include peri-urban slums with
limited access to safe drinking water and lack of proper
sanitation

44. Key messages
• Surveillance is paramount to identify vulnerable populations
living in hotspots
• Cholera is a preventable disease provided that safe water and
proper sanitation are made available
• Cholera is a preventable disease provided that safe water and
proper sanitation are made available
• Safe and effective oral cholera vaccines are now part of the
cholera control package
• Today, no country requires proof of cholera vaccination as a
condition for entry