What is Cholera disease and its Diagnosis and controlling methods

Cholera is an acute diarrhoeal disease caused by V. Cholera 01 (Classical or E1 Tor).Cases ranges from symptomless to severe infections. Unless there is rapid replacement of and electrolytes, the case fatality may be as high as 30% to 40%.Cholera transmission Methods | Clinical diagnosis methods | How to control Cholera | Homeopathy Prevention

Problem Statement

Global experience of the current pandemic have shown that cholera can get introduced into any country, but create problem only in areas where other acute enteric infections endemic, i.e. where sanitation is defective. Currently the seventh pandemic which began in 1961 in Indonesia is still continuing. This pandemic is due to El Tor vibrio. India got involved in the pandemic in 1964.


Epidemiological Features

Choler is both epidemic and epidemic disease. Epidemics of Cholera are characteristically abrupt and often create an acute public health problem. The epidemics reach a peak and subsides gradually as the “force of infection” declines.

The “force of infection” is composed of 2 components, namely the force of infection through water and the force of infection through contacts.

The seasonal variation differs between countries and even between regions of same country.

Agent Factors:

  1. Agent: The organism that causes cholerae as V. cholera 0 Group 1 or Vibrio cholerae 01.Within the o Group 1, Classical and El Tor, have been differentiated Classical and El Tor are further divided into 3 serological types namely, Inaba, Ogawa, Hikojima.
  2. Resistance: V. Cholera are killed:-
    • within 30 minutes by heating at 56 deg. C or within few seconds by boiling.
    • by drying in sunshine as cresol.
    • by coal tar such as cresol.
    • By bleaching powder at 6mg / lit.

    They remain viable in ice for 4-6 weeks or longer.

  3. Toxin Production:
    The vibrios multiply in lumen of small intestine and produces an exotoxin.
  4. Reservoir of infection: The human being is the only known reservoir of cholera infection. He may be a case or carrier.
  5. Infective Material:The immediate source of infection are the stools and vomit of cases and carries. Large no. of  vibrios (about 107 to 109 vibrios per ml of fluid) are present in watery stool of cholera patients.
  6. Infective Dose: Cholera is dose related. A very high dose like 1011 organisms is required to produce the clinical disease.
  7. Period of Communicability: A case of cholera is infectious for period of 7-10 days. Convalescent carries are infectious for 2-3 weeks. The chronic carries state may last from a month upto 10 years or more.Carriers in Cholera: A cholera carrier may be defined as an apparently healthy person who is excreting V. Cholerae.
    • Preclinical or incubatory carrier: 1-5 days.
    • Convalescent carrier: Patient who have recovered from an attack of cholera – usually 2-3 week.
    • Contact or healthy carrier: This is the result of subclinical infection contracted through Association with source of infection, be it a case or infected environment. Usually less than 10 days.
    • Chronic carrier: A chronic carrier stage occurs infrequently.

Host factors:

  1. Age & Sex: Cholera affects all ages & both sexes.
  2. Gastric acidity: The vibrio cholerae destroyed in acidic ph 5 or low.
  3. Population mobility: Movement of population (e.g. pilgrimages marriages, fairs & festivals) results in increased risk of exposure.
  4. Economic status: Incidence of cholera tends to be highest in low socio economic group & this is attributable to poor hygiene.
  5. Immunity: Natural infection confers quits effective immunity.

Environmental Factors:

Mode of transmission

  1. Faecally contaminated water: uncontrolled water source such as wells, ponds, streams & rivers pose a great threat.
  2. Contaminated food and drinks
  3. Direct contact: Person to person transmission through contaminated fingers while carelessly handing excreta and vomit of patients and contaminated linen and formites.

Incubation Period: Few hours upto 5 days but commonly 1-2 days

Clinical Features:

  1. Stage of evacuation: onset abrupt with profuse, painless watery diarrhea followed by vomiting. Patients may pass stools 40 times per day. The stools may have rice water appearance.
  2. Stage of collapse: Patient soon passes in stage of collapse because of dehydration. Classical signs are: sunken eyes, hollow cheeks, scaphoid abdomen, subnormal temp. loss of skin elasticity. The output of urine decreases. Death may occur at this stage due to dehydration and acidosis.
  3. Stage of recovery: If death does not occur, the patient begins to show signs of clinical recovery.


Laboratory Diagnosis of Cholera:

  1. Collection of stools: A fresh specimen of stool should be colleted for laboratory examination.
  2. Vomitus: This is practically never used as the chance of isolating vibrios are much less & there is no advantage.
  3. Water: Samples containing 1-3 liters of suspect water should be collected in sterile bottles (for the filter method), or 9 volumes of the sample water added to 1 volume of 10% peptone water & dispatched to the laboratory by quickest method of transport.
  4. Food samples: Samples of food suspected to be contaminated with vibrio cholerae amounting to 1 to 3 gm. Are collected in transport media & sent to laboratory.
  5. Transportation: The stools should be transported in sterilized Mc Cartney bottles 30ml capacity containing alkaline peptone water or VR medium. The specimen should be transported in alkaline peptone water or Cary – Blair medium if it is collected by rectal swab.
  6. Direct examination: If a microscope with dark illumination is available, it may be possible to diagnose about 80% of the cases within a few minutes & more cases after 5-6 hours incubation in alkaline peptone water. In dark field, the vibrios evoke the image of many shooting stars in a dark sky.
  7. Culture method:5 to 1.0 ml of material is inoculated into peptone water tellurite medium for enrichment. After 4-6 hours subcultured on Bite salt agar medium. After overnight incubation plates are screened under obique illumination for vibrio colonies.
  8. Charaterisation:
    • Gram stain & motility: Gram negative & curved tods with characteristically scintillating motility in hanging drop preparation are very characteristic of V. cholerae.
    • Serological tests: Slide agglutination test.
    • Other tests are    –  direct haemagglutination test with chicken or
      sheep red blood cells-   Polymyxin B sensitivity test using 50microgm. discs-   Sensitivity to cholera phage iv-   V-p reaction-    Haemolysin tests


How to Control cholera

The following account is based on the “Guideline for Cholera Control” proposed by who


Homeopathy prevention:

  1. Identification of cases and their notification
  2. Health education – should be directed mainly regarding,
    • Effectiveness & preparation of ORS
    • The benefits of early reporting for prompt treatment.
    • Food hygiene practices
    • Hand washing after defection & before meals.
    • Benefits of cooked, hot foods & safe water.
  3. An active and passive surveillance for cases
  4. Distribution of ORS packets.
  5. Purification of water supply & proper excreta disposal.
  6. Ensure cholera vaccination, in people during fairs, festivals and large religious functions.e.g. Kumbha-melas