Cholera - Epidemiology and Prevention

Dr. Animesh Jain
Professor of Community Medicine,
Kasturba Medical College, Mangalore,
Manipal Academy of Higher Education, India

 https://time.com/4326858/game-of-thrones-jon-snow-prince-that-was-promised-theory/
20-Apr-20Cholera: Epidemiology & Prevention – Dr. Animesh Jain 2

https://en.wikipedia.org/wiki/Robert_Koch
 German researcher Robert Koch (seated) with his
assistant,Richard Pfeiffer. Photograph: Bettmann Archive
Source: https://www.theguardian.com/global-development-professionals-
network/2017/jul/12/diarrhoea-vomiting-sudden-death-choleras-nasty-
comeback#img-5
Robert Koch

 John Snow, the doctor who traced the source of cholera outbreaks in London in
1854. Photograph: Alamy
Source: https://www.theguardian.com/global-development-professionals-network/2017/jul/12/diarrhoea-vomiting-sudden-death-
choleras-nasty-comeback#img-5

Source: https://time.com/5820194/addresses-epidemiology/

 An engraving by William Heath showing a lady discovering the quality of the Thames’s
water. By the 1820s, public concern was growing at the increasingly polluted water supply.
Photograph: Science & Society Picture Library/Getty Images
Source: https://www.theguardian.com/global-development-professionals-network/2017/jul/12/diarrhoea-vomiting-sudden-death-choleras-nasty-comeback#img-5

 https://www.wired.com/2009/09/0908london-cholera-pump/

https://en.wikipedia.org/wiki/Robert_Koch
https://en.wikipedia.org/wiki/Filippo_Pacini

 This microscope slide, prepared by Pacini in 1854, was clearly identified as
containing the cholera bacterium.
https://en.wikipedia.org/wiki/Filippo_Pacini

 The Duke of Orleans visits the sick at L’Hotel-Dieu during France’s
cholera epidemic in 1832. Photograph: Print Collector/Getty Images
Source: https://www.theguardian.com/global-development-professionals-network/2017/jul/12/diarrhoea-vomiting-
sudden-death-choleras-nasty-comeback#img-5 20-Apr-20Cholera: Epidemiology & Prevention – Dr. Animesh Jain 10

 Mohammad Shubo is motionless when he is wheeled into the clinic. He had started
experiencing diarrhoea and vomiting that morning; by evening, he had no pulse.
 In an effort to rehydrate him quickly, the nurses give Shubo IV saline solution. His
reanimation seems almost uncanny – within half an hour he is able to sit up and
speak. He spends the next two days at the hospital to rehydrate and convalesce
before returning to his cramped quarters. If Shubo had arrived at the clinic just
10 minutes later he would have died, a nurse says.
Source: https://www.theguardian.com/global-development-professionals-network/2017/jul/12/diarrhoea-vomiting-
sudden-death-choleras-nasty-comeback#img-5

 After a 24- to 48-hour (sometimes up to 5 days) incubation period, symptoms begin
with the sudden onset of painless watery diarrhea that may quickly become
voluminous and is often followed by vomiting.The patient may experience
accompanying abdominal cramps, probably from distention of loops of small
bowel as a result of the large volume of intestinal secretions. Fever is typically
absent.
 Stool volume during cholera is more than that of any other infectious diarrhea.
Patients with severe disease may have a stool volume of more than 250 mL/kg body
weight in a 24-hour period. Because of the large volume of diarrhea, patients with
cholera have frequent and often uncontrolled bowel movements.
Source: https://emedicine.medscape.com/article/962643-clinical

 Metabolic and systemic manifestations
 After dehydration, hypoglycemia is the most common lethal complication of
cholera in children. Hypoglycemia is a result of diminished food intake during the
acute illness, exhaustion of glycogen stores, and defective gluconeogenesis
secondary to insufficient stores of gluconeogenic substrates in fat and muscle.
 Cholera causes bicarbonate loss in stools, accumulation of lactate because of
diminished perfusion of peripheral tissues, and hyperphosphatemia. Acidemia
results when respiratory compensation is unable to sustain a normal blood pH.

 Hypokalemia results from potassium loss in the stool, with a mean potassium
concentration of approximately 3.0 mmol/L. Because of the existing acidosis,
however, children often have normal serum potassium concentrations when first
observed, despite severe total body potassium depletion.
 Hypokalemia develops only after the acidosis is corrected and intracellular
hydrogen ions are exchanged for extracellular potassium. Hypokalemia is most
severe in children with preexisting malnutrition who have diminished body stores
of potassium and may be manifested as paralytic ileus.
 Rehydration therapy with bicarbonate-containing fluids can also produce
hypocalcemia by decreasing the proportion of serum calcium that is ionized.
Chvostek and Trousseau signs are often present, and spontaneous tetanic
contractions can occur.

 At the end of the lecture, the learner shall be able to
 List the characteristics of cholera.
 Enumerate the epidemiological factors of cholera
 Describe the epidemiology of cholera.
 Discuss the prevention and control of cholera.

 Acute diarrhoeal disease caused by a bacterium Vibrio cholerae.
 Most people get it from contaminated water or food.
 May cause extreme diarrhea, which can lead to dehydration and even death.
 Cholera probably originated in India, before spreading through the Middle East
and Russia, but it only arrived in England in 1831. At the time, there was no real
understanding that germs, or microorganisms, spread disease. Instead, the
“miasma theory”—the belief that disease came from vapors, or smells, arising from
decay—dominated among medical experts. Smells, in other words, weren’t just
signs of disease; they were the disease itself.

 When exactly cholera first affected people remains unclear.
 Early texts from India (by Sushruta Samhita in the 5th century B.C.) and Greece
(Hippocrates in the 4th century B.C. and Aretaeus of Cappadocia in the 1st century
A.D.) describe isolated cases of cholera-like illnesses.
 One of the first detailed accounts of a cholera epidemic comes from Gaspar
Correa—Portuguese historian and author of Legendary India—who described an
outbreak in the spring of 1543 of a disease in the Ganges Delta, which is located in
the south Asia area of Bangladesh and India.The local people called the disease
“moryxy,” and it reportedly killed victims within 8 hours of developing symptoms
and had a fatality rate so high that locals struggled to bury all the dead.
 Numerous reports of cholera manifestations along the West coast of India by
Portuguese, Dutch, French and British observers followed throughout the next few
centuries.
Source: https://www.history.com/topics/inventions/history-of-cholera

 The first cholera pandemic emerged out of the Ganges Delta with an outbreak in
Jessore, India, in 1817, stemming from contaminated rice.The disease quickly
spread throughout most of India, modern-day Myanmar, and modern-day Sri Lanka
by traveling along trade routes established by Europeans.
 By 1820, cholera had spread to Thailand, Indonesia (killing 100,000 people on the
island of Java alone) and the Philippines. From Thailand and Indonesia, the disease
made its way to China in 1820 and Japan in 1822 by way of infected people on
ships.
 It also spread beyond Asia. In 1821, British troops traveling from India to Oman
brought cholera to the Persian Gulf.The disease eventually made its way to
European territory, reaching modern-day Turkey, Syria and Southern Russia.
 The pandemic died out 6 years after it began, likely thanks to a severe winter in
1823–1824, which may have killed the bacteria living in water supplies.

 Unlike previous pandemics, which all originated in India, the seventh and current
cholera pandemic began in Indonesia in 1961. It spread across Asia and the Middle
East, reaching Africa in 1971. In 1990, more than 90 percent of all cholera cases
reported to WHO were from the African continent.
 In 1991, cholera appeared in Peru, returning to South America after being absent
for 100 years. It killed 3,000 people in Peru in this first year and subsequently
spread to Ecuador, Colombia, Brazil and Chile, and then Central America and
Mexico.
 Though the current cholera pandemic has affected some 120 countries, it’s largely
a disease of impoverished, less-developed nations.

 Though the current cholera pandemic has affected some 120 countries, it’s largely
a disease of impoverished, less-developed nations.
 In recent years, there have been a number of devastating outbreaks, including the
Zimbabwe outbreak of 2008–2009 that affected some 97,000 people (killing 4,200)
and the Haiti outbreak of 2010–2011, which followed the Haiti earthquake and
would affect more than 500,000 people.
 In 2017, outbreaks of cholera broke out in Somalia andYemen. By August 2017, the
Yemen outbreak affected 500,000 people and killed 2,000 people.

Source: http://gamapserver.who.int/mapLibrary/Files/Maps/Global_Cholera(WER)_2016.png

 Both and epidemic and endemic (seasonal fluctuations)
 Epidemic subsides gradually on its own once a peak is reached – self limiting
 Force of infection – through water; through contacts
 Tail of the epidemic – due to transmission through contacts even after water source
is taken care of.

 Old term describing a rare, severe form of cholera that occurs in epidemic cholera.
 Manifests as ileus and abdominal distention from massive outpouring of fluid and
electrolytes into dilated intestinal loops.
 Mortality is high, with death resulting from toxemia before the onset of diarrhea
and vomiting.
 Because of the unusual presentation, failure to recognize the condition as a form of
cholera is common.

 Vibrio cholerae serotype O1 (Classical & El Tor ) and O139
 O1 El Tor & O139 predominantly cause Cholera
 Comma shaped bacilli
 Gram negative aerobic or facultative anaerobic
 Antigenic structure consists of:
 Flagellar H antigen
 Somatic O antigen
 Killed in 30 min at 56 oC, few seconds by boiling.
 Remain in ice for 4 – 6 weeks or longer
 Bleaching powder 6mg/l is a good disinfectant 20-Apr-20Cholera: Epidemiology & Prevention – Dr. Animesh Jain 27

 Toxin production – Exotoxin (Enterotoxin)
 Reservoir of infection – Humans are ONLY known reservoir
 Case
 Carrier – Usually temporary rarely chronic
 Infective material – Stools & vomit
 Infective dose – High dose - 1011 organisms required.
 Period of communicability – Case - 7 -10 days; convalescent carrier –
2-3 weeks, Chronic – month to 10 years

Preclinical or Incubatory – during incubation – 1-5 days
Convalescent – After recovery from cholera attack.
May be 2-3 weeks
Contact or Healthy – Result of subclinical infection
Less than 10 days
Chronic – Infrequent – Up to 10 years

 Age – Children: Adults - 10:1; Elderly also more susceptible
 Gender – M: F – 1:1
 Population mobility
 Gastric acidity – pH 5 or lower is protective
 For those infected having blood type O, the disease is likely to be more severe
 Immunity – Less immunity higher risk
 Infection leads to immunity but NOT long lasting.
 Vaccination gives only partial and temporary immunity

 Poor sanitation
 Contaminated water, food,
 Flies
 Fomites?!
 Lack of education, human habits, poor quality of life.

 Incubation period – 1-2 days [range few hours to 5 days]
 Pathogenesis
20-Apr-20Cholera: Epidemiology & Prevention – Dr. Animesh Jain 32https://en.wikipedia.org/wiki/Cholera_toxin

https://www.slideshare.net/priyamadhababehera/cholera-27608178

https://www.researchgate.net/figure/Pathogenesis-of-cholera-in-humans-Once-in-the-human-host-after-reaching-the-
small_fig3_326359267

 75 – 85% cases are mild; only 5 – 10% show severe cholera.
Stage of Evacuation
 Abrupt onset – Painless, profuse watery diarrhea then vomiting. Up to 40 stools/d
Stage of Collapse
 Due to dehydration, classical signs.
Stage of Recovery
 If death doesn’t occur; Most mild cases recover within 1- 3 days

 Collection of stools
 Vomitus
 Water
 Food samples
 Although observed as a gram-negative organism, the characteristic motility
of Vibrio species cannot be identified on a Gram stain, but it is easily seen on direct
dark-field examination of the stool.

 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. Chemoprohylaxis
 10.Vaccination
 11. Health education

 https://www.physio-pedia.com/Dehydration

http://rehydrate.org/shows/management/diarrhoea-management-04.htm

Source:WHO. Ending Cholera—A Global Roadmap to 2030. Available from:
http://gamapserver.who.int/mapLibrary/Files/Maps/Global_Cholera(WER)_2016.png

http://rehydrate.org/shows/management/diarrhoea-management-04.htm

 Approach Considerations
 Rehydration is the first priority in the treatment of cholera. Rehydration is
accomplished in 2 phases: rehydration and maintenance.
 The goal of the rehydration phase is to restore normal hydration status, which
should take no more than 4 hours. Set the rate of intravenous infusion in severely
dehydrated patients at 50-100 mL/kg/hr. Ringer Lactate solution is preferred over
isotonic sodium chloride solution because saline does not correct metabolic
acidosis
 The goal of the maintenance phase is to maintain normal hydration status by
replacing ongoing losses.The oral route is preferred, and the use of oral
rehydration solution (ORS) at a rate of 500-1000 mL/hr is recommended.

 Which antibiotic should be used and who should receive it? The antibiotic of
choice in any individual context should be guided by the following principles:
 Antibiotics use should be selective and target those patients most likely to
benefit clinically
 Current or recent evidence that the predominant circulating cholera strain
remains sensitive to the selected antibiotic.Where feasible, regular monitoring of
cultured cholera strains for evolution in antibiotic resistance is recommended
during an outbreak.
 Antibiotics with proven single-dose efficacy are highly preferred to multi-dose
regimens.
 Availability, cost, and ease of implementation are taken into consideration.

 Antibiotic options for cholera are the tetracyclines, fluoroquinolones and
macrolides.
 Most V. cholerae are resistant to chloramphenicol, co-trimoxazole and furazolidone
which are therefore no longer used and will not be discussed further.
 The rationale for choosing an antibiotic should be based on efficacy, safety,
feasibility, availability, cost and local resistance patterns. All the classes of
antibiotics used for cholera are also used for other indications which add to the
overall antibiotic pressure on the development of resistance.
 Tetracyclines are the antibiotics for which there is the most clinical experience for
cholera and several clinical trials have shown their efficacy.
 Tetracycline and doxycycline are used for cholera.Tetracyclines are widely used
for other indications because of the broad spectrum of activity, low toxicity and
easy availability.

 Case definition for suspected cholera: In areas where a cholera outbreak has not
been declared: Any patient aged 2 years and older presenting with acute watery
diarrhoea and severe dehydration or dying from acute watery diarrhoea. In
areas where a cholera outbreak is declared: any person presenting with or dying
from acute watery diarrhoea.
 NOTE: all children from 6 months to 5 years of age with diarrhoea regardless of
cause or degree of dehydration should receive zinc sulfate, 20 mg p.o. per day for
10 days. Zinc sulfate has been demonstrated to reduce diarrhoea volume and
duration without risk of resistance.
 Zinc may reduce the absorption of some classes of some antibiotics including
ciprofloxacin. For best effect with these classes of drugs, antibiotics should be
administered 2 hours before zinc or 4-6 hours after zinc. Children receiving
therapeutic food for the treatment of severe acute malnutrition do not require zinc
supplementation as these foods contain sufficient zinc.

 There are currently three cholera vaccines recommended by the World Health
Organization (WHO).These are Dukoral, Shanchol, and Euvichol.
 All three require two doses to give full protection.
 In 2016, the U.S. Food and Drug Administration (FDA) approved Vaxchora, a single-
dose oral vaccine to prevent cholera for travelers. As of June 2016,Vaxchora was
the only FDA-approved vaccine for the prevention of cholera.
 https://www.cdc.gov/cholera/vaccines.html

 https://www.usiu.ac.ke/webapp/99/cholera-prevention-tips/

Source:WHO. Ending Cholera—A Global Roadmap to 2030.
Available from: http://gamapserver.who.int/mapLibrary/Files/Maps/Global_Cholera(WER)_2016.png

Source:WHO. Ending Cholera—A Global Roadmap to 2030. Available from:
http://gamapserver.who.int/mapLibrary/Files/Maps/Global_Cholera(WER)_2016.png

 Operationalises the new global strategy for cholera control at the country level and
provides a concrete path toward a world in which cholera is no longer a threat to
public health.
 By implementing the strategy between now and 2030, the Global Task Force on
Cholera Control (GTFCC) partners will support countries to reduce cholera deaths
by 90 percent.
 With the commitment of cholera-affected countries, technical partners, and donors,
as many as 20 countries could eliminate disease transmission by 2030.
 In October 2017, 35 GTFCC partners endorsed a call to action on ending cholera,
an unprecedented engagement to fight cholera through implementation of "Ending
Cholera – A Global Roadmap to 2030.
 All stakeholders to support cholera-affected countries and align energies, efforts,
and resources to end cholera transmission.

Source: https://www.who.int/cholera/task_force/technical-note-WASH-IPC-CTCCTU-2019.pdf?ua=1

 https://www.researchgate.net/figure/The-cholera-cot_fig2_51898494
Rice water stools Cholera cots

 Do you have any questions?
 Is there anything that you have not understood well?
 If none, let me ask you a few questions to check if I have been clear
 What are the symptoms of cholera?
 What are the environmental risk factors for cholera?
 What is Cholera sicca?
 WHO guidelines for cholera management?
 Declaration to end cholera.
Cholera: Epidemiology & Prevention – Dr. Animesh Jain 5720-Apr-20

 Park K.Textbook of Preventive & Social Medicine – 25th Ed
 IAPSM’s Textbook of Community Medicine – 1st Ed.
 Bhalwar R.Textbook of Community Medicine. 3rd Ed
 Suryakanta AH. Community Medicine with Recent advances. 3rd Ed.
 Further reading
 https://www.history.com/topics/inventions/history-of-cholera
 https://www.wired.com/2009/09/0908london-cholera-pump/
 https://time.com/5820194/addresses-epidemiology/
 https://www.khanacademy.org/science/health-and-medicine/gastrointestinal-system-
diseases/gastroenteritis/v/what-is-cholera
 The story of cholera https://www.youtube.com/watch?v=jG1VNSCsP5Q
* Not in standard reference format

You may reach me via
animesh.jain@manipal.edu and/or 9845032334

Cholera - Epidemiology and Prevention

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