CHOLERA

Sunday, April 9, 2023

CHOLERA

Presenter: Dr. J.J. Kambona


Case definition

• Cholera outbreak should be suspected when a patient older than 5 years develops severe dehydration or die from acute, severe, watery diarrhoea. Or

• If there is a sudden increase in the daily number of patients with acute watery diarrhoea, especially patients who pass ‘rice-water’ stools typical of cholera.


Systemic routine

1. Verification of the cholera.2. Confirmation of the existence of the cholera epidemic.3. Identification of the affected persons and their

characteristics.4. Definition and investigation of the population at risk.5. Formulation of a hypothesis as to source and spread of

epidemic.6. Management of the epidemic.7. Prevention of spread and commencement of control

measures.8. Writing a report.9. Continued surveillance of the population.


1. Verification of the cholera

Once the epidemic is notified:• Take the a detailed history from the

informants.• Make a tentative differential diagnoses:o Type of diagnostic specimen.o Kind of equipments.• Alert the laboratory which will process the

specimens.

1. Verification of the cholera.....

• Special arrangement:oStakeholders meeting.oTransport from the epidemic area at

awkward hours of the day or night.



2. Confirmation of the existence of cholera epidemic

• Obtain an approximate estimate of previous incidence of acute watery diarrhoea, both from clinics and hospital data and by questioning the local people.

• Demonstrate the existence of the epidemic by a graph of incidence against time and by mapping its geographic extent.


3. Identification of the affected persons and their characteristics

A. Case histories: Details of each confirmed or suspected case must be

taken in order to obtain a complete picture of the epidemic.

• Name.• Age.• Sex.• Occupation.• Place of residence.• Recent movements.• Details of symptoms (including time of onset).


3. Identification of the affected persons and their characteristics.....

• The details of what they have been eating or drinking , when and its source.

• Contact with a person with similar symptoms.

Record all information on specially prepared forms.

If large numbers of cases (> 1,000) are involved the data will require coding and analysis by computer.


3. Identification of the affected persons and their characteristics.....

B. Search for addition cases.

• The initial notification may come from the hospital, but visit:

o Dispensaries.o Health centers.

• Further inquiry in the villages.


4. Definition and investigations of the population at risk

A. Definition:• Analyse case histories to get a profile of patients

characteristics.• Epidemiological description:

Relate the profile to the characteristics and distribution of the entire population at risk.

• Attack rates = Number of cases

population at risk• If possible age/sex-specific attack rates should be

calculated.


A.Definition.....

• Point source epidemic:

Compare the characteristics of the cholera cases with those of people seemingly exposed to cholera source but not affected.


B. Investigations

I. Microscopic stool examination:• Direct: Vibrio cholerae are gram-negative and

curved (coma shaped) or straight bacillus.• Dark-field of the wet mount of fresh stool:

The organisms are mobile by means of a single flagellum. It can be confirmed by adding vibrio antisera, which results into cessation of motility of only the homologous organism.


Vibrio choleraeVibrio cholerae


B. Investigations…..

II. Stool analysis: Vibrio cholerae do not elicit an inflammatory

response and therefore, stool contains few leucocytes and no erythrocytes.

III. Haematological tests:• Full blood picture: Shows neutrophil

leucocytosis without a left shift when patients are first observed.


IV. Stool culture and sensitivity

Routine differential media:A. Triple sugar iron agar: Gives the non-pathogenic pattern of an acid (yellow)

slant, because of fermentation of sucrose contained in the media.

B. Alkaline enrichment media:• Peptone water (pH 8.5-9.0).• Media containing bile salts e.g. thiosulphate–citrate

bile-sucrose agar (pH 8.6). Sucrose fermenting vibrio cholerae grow as large, smooth, round yellow colonies that stand out against the blue-green agar.

4. Formulation of a hypothesis as to source and spread cholera

• Aims at knowing why, when and how the cholera occurred.

• Establish changed relevant previous conditions related the outbreak of cholera:

o Rains.o Water supply.o Sewage disposal.o Refuse collection.o Behavioural change.


4. Formulation of a hypothesis as to source and spread cholera.....

• Establish the:o Reservoir of vibrio cholerae.o Mode of exit from this reservoir or Source.o Mode of transmission to the next host.o The mode of entry.o The susceptibility of the host.


Treatment

• Look and establish cholera emergency treatment centre.

• Look for additional staff and trained them very rapidly. Health auxiliaries medical students or even the army may be available for this.

• Estimate the amount of drugs and other medical supplies and order them urgently.


Treatment

• Treatment of cholera should start before the diagnosis is confirmed.

1. Assess the dehydration and classify the degree of dehydration.

2. Rehydrate the patient and monitor frequently. Then, reassess hydration status.

3. Maintain hydration by replacing the ongoing fluid losses until diarrhoea stops.

4. Administer oral antibiotics to the patient with severe dehydration.

5. Feed the patient.

Finding Mild (3-5%) Moderate (6-9%) Severe (10%)

Pulse. Rate, volume is normal.

Rapid. Rapid and weak.

Systolic pressure. Normal. Normal to low. Low.

Respirations. Normal. Deep, rate may be increased. Deep, tachypnoeia.

Buccal mucosa. Tacky or slightly dry. Dry. Parched.

Anterior fontanelle. Normal. Sunken. Markedly sunken.

Eyes. Normal. Sunken. Markedly sunken.

Skin turgor. Normal. Reduced. Tenting.

Skin. Normal. Cool. Cool, mottled, acrocyanosis.

Urine output. Normal or mildly reduced.

Markedly reduced. Anuria.

Systemic signs. Increased thirst. Listlessness, irritability.* Grunting, lethargy, coma.*

Cholera cot


I. Severe dehydration

Ringer lactate is the fluid of first choice or if not available, give isotonic sodium chloride solution.

Amount of IV fluid: 100 ml/kg in 3 hours:

• 30 ml/kg as rapidly as possible (within 30 minutes).

• 70 ml/kg in the next 2 hours.

• Re-assess the patient after 3 hours.


II. Moderate dehydration

• Give 75 ml/kg of ORS solution for the first 4 hours.

• If the patient passes watery stools or wants more ORS solution than indicated, give more.

• Discard the leftover solution after 24 hours.

• Re-assess the patient after 4 hours.


III. Mild dehydration

– Give ORS packets to take at home, enough for 2 days (2000 ml/day).

– Demonstrate to the patient or caretaker how to prepare and give the solution.

– If diarrhoea stops, discharged patient should return for follow-up in 2 days.

Most patients absorb ORS solution to achieve hydration, even when they are vomiting.


III. Mild dehydration…..

Instruct the patient or the caretaker to return if any of the following signs develop:

• Increased number of watery stool.

• Marked thirst.

• Repeated vomiting.

• Any signs indicating other problems e.g. fever or blood in stool.


Oral antibiotics

• Azithromycin 1 g PO stat. Or

• Tetracycline 2 g PO stat. Or

• Doxycycline 300 mg PO stat. Or

• Ciprofloxacin 250 mg PO OD for 3 days or 1 g stat (not to exceed 1 g/dose).


Oral antibiotics…..

• Norfloxacin 400 mg PO bid for 3 days. Do not to exceed 800 mg/day. Or

• Erythromycin 40 mg/kg PO divided TID for 3 days. Or

• Co-trimoxazole 960 mg PO BID for 3 days.


Prevention

1. Early identification and case management.

2. Active surveillance and prompt reporting.

3. Water supply: Ensure a safe water supply (especially for municipal water system).

4. Improve sanitation and sewage disposal.

5. Making food safe for consumption by thorough cooking of high risk foods especially seafood and protecting it against flies.


Prevention…..

6. Health education through mass media: Insisting on:

• Importance of purifying water and cooking seafood.

• Washing hands after using the toilet and before food preparation.

• Recognition of the signs of cholera and location where treatment can be obtained to avoid delays in cases of illness.

7. Cholera vaccine.


Report writing and continued surveillance

• Categories of reports:

1. A popular account for laypeople.

2. An account for planners in the ministry of health or local authority.

3. A scientific report for publication in a medical journal.

• Continue surveillance of the population.


Thank you for your attention


References 1. Thaker V.V. Cholera. www.emedicine.com/ped/topic382.htm Last

updated May 1, 2006.2. Todd W.T.A., Lookwood D.N.J., Nye F.J., Wilkins E.G.L and Carey

P.B. infection and immune failure (cholera); Davidson’s principles and practice of medicine, 19th edition, chapter 1, page 44.

3. Sack D.A., Sack R.B., Nair G.B and Siddique A.K. Cholera; The Lancet, January, 17, 2004. 363 (9404): 223-233.

4.4. Butterton J.R. Approach to the patient with vibrio cholerae Butterton J.R. Approach to the patient with vibrio cholerae infection. infection. www.UpToDate.com Version 13.1; Last updated: Version 13.1; Last updated: January 27, 2004.January 27, 2004.

5.5. Barker D.J.P and Hall A.J. Investigation of epidemics; Practical Barker D.J.P and Hall A.J. Investigation of epidemics; Practical epidemiology.4epidemiology.4thth edition edition

http://www.emedicine.com/ped/topic382.htm

http://www.uptodate.com/

CHOLERA

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