CHOLERA

Roshni.R [3yr BAMS] Amrita school of Ayurveda9/2/2017

• Cholera is an acute diarrheal disease•Caused by Vibrio cholerae O1[classical/EL Tor biotype] & O139•Ranges from symptomless to severe infections • Majority of cases are asymptomatic and mild infection

• CLINICAL SYMPTOMS INCLUDE

SUDDEN ONSET OF PROFUSE VOMITINGEFFORTLESS WATERY DIARRHEA

FOLLOWED BY VOMITINGRAPID DEHYDRATIONMUSCULAR CRAMPSSUPPRESSION OF URINE

Case fatality is rapid unless there is rapid replacement of fluid and electrolytes

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CHOLERA

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Outbreaks in World caused by 2 sero groups O1 and O139Majority by O1

Also Global warming creates favorable environment for bacteriaCholera transmission is closely linked to inadequate environmental management

TYPICAL AT RISK AREAS ………………………………………….. a) Peri-urban areas b) Disaster resulting in disruption of water and sanitation systemc) Over crowed camps

It is the key indicator for social development

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NEW CHALLENGES

ARE• Emergence of new potent virulent stains

• Antimicrobial resistance

• Climate changes

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INDIA Cholera EL Tor biotype got introduced in India in 1964 Prior to this classical strain was widely prevalent West Bengal used to be the home of cholera before, but it is now overtaken by other states Disease is seen persisting as smouldering infection in new areas There have been no large scale epidemic of classical cholera since 1964 because the classical type have been replaced by Vibrio cholerae O1 EL Tor biotype

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EPIDEMOLOGICAL FEATURES OF CHOLERA

Cholera is both an epidemic and endemic disease Disease depends on characteristics of agent and environment

AGENT

Virulence

ENVIRONMENT

Number of susceptible

Opportunities for transmission

• unsafe drinking water

• Overcrowding

• Undercooked & contaminated

• food

• poor sanitation and hygiene

Introduction of cholera cannot be prevented but it creates problem to those places where there is poor sanitation

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Epidemics of cholera are characteristically abrupt, and have high potential to spread fast and cause deaths The epidemic reaches a peak and subsides gradually as “FORCE OF INFECTION” declines peak It is ultimately self limiting

Temporary infection Large no, of sub-clinical cases

FORCE OF INFECTIONa) Through water b) Through contacts

Elimination of contaminated water does not cause an end to the outbreak

instead it produce a TAIL due to continuation of transmission through contact.

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ENDEMICITY OF CHOLERA Endemicity is not stable like typhoid due to

Seasonal fluctuationsEpidemic outbreaks

Seasonal variations differs between regions and countries and changes with time EL Tor biotype have greater endemic tendency than classical biotype(ie: more of asymptomatic mild cases than classical)

INTER-EPIDEMIC PERIODS Cholera occurs @ INTERVALS even in endemic areas……Humans are the only KNOWN RESERVOIR then how Bacteria survives between outbreaks?????????????????????????????????? 3 Explanations………

Existence of long term carriersExistence of diminished but continuous transmission involving asymptomatic cases Persistence of organism in the form of “ free living” / altered form in the environment

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AGENT The organism which causes cholera is labeled as Vibro cholerae O1 & O139 Vibrios which are biochemically same as that of O1&O139 termed as non cholera vibrios Some of them are pathogenic to human ,may cause cholera like diarrhea but not termed as cholera . Hence it is important to the agent for special diagnosis

V.Cholerae having two biotypes CLASSICAL EL Tor

3 serological types OgawaInabaHikojima

Ogawa serotype is mostly seen in India ………..

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RESISTANCE

Heating at 56*c. killed within 30 minutes

Boiling within few seconds

Ice survive for 4-6 weeks[may be even longer] EASILY DESTROYED BY

Cresol Bleaching powder (6mg/L)

El Tor biotype is more resistant than classical

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TOXIC PRODUCTION

Multiply inside the lumen of small intestine Produce exotoxin This toxin produce diarrhoea …..effect on adenylate cyclase-cyclic AMP System of mucosal cells of small intestine exotoxin don’t have any effect on other cells

RESERVOIR OF INFECTION HUMAN BEING is the only reservoir

CASE : In apparent to severe [75% are asymptomatic but shed bacteria after 7- 1 1 14 days of infection] Among 20% develop will have severe watery diarrhoea and dehydration Low immunity people Malnourished children

CARRIERS : Carriers may be temporarily ,rarely,chronic Carriers excrete fewer vibrios than clinical cases Detected by bacteriological examination of purged stool purgation done through 30-60ml of MgSO4 in 100ml water

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INFECTIVE MATERIALS

Immediate infective materials stool and vomits of cases and carriers

INFECTIVE DOSE

Cholera is dose relatedNormal dose is 10^11 organisms for producing clinical illness

PERIOD OF COMMUNICABLITY

CASE : 7-10 daysCONVALSCENT CARRIERS : 2-3 WEEKS CHRONIC CARRIERS : one month to 10 years

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CARRIERS IN CHOLERACholera carrier can be defined as an apparently healthy person who is excreting V.Cholerae O1 in stools 4TYPES…………………………………………………………………………….

.Pre-clinical or incubatory carriers

Convalescent carriers

Contact or healthy carriers

Chronic carriers

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PRE CLINICAL OR INCUBATORY

Incubation period is short (1-5 days) Incubatory carriers are potential patients

CONVALESCENT CARRIER The patient recovered from an attack of cholera may continue to excreteduring convalescence for 2-3 days This stage occurs to a patient who have not received any proper antibiotic treatment Chronic or long term

CONTACT OR HEALTHY CARRIER

Subclinical infection acquired from case or carriers Duration is <10 days Gall bladder is not infective Stool culture is frequently +ve Play an important role in the spread of cholera

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CHRONIC CARRIER

Occurs infrequently Longest carrier state was found to be over 10 yearsGall bladder is infectiveThey excrete fewer vibrios than cases

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HOST FACTORS1) AGE & SEX : All ages and both sexes attack rate is heighest in children

2) GASTRIC ACIDITY : Vibrio destroyed in an acidity of pH5

3) POPULATION MOBILITY : Pilgrimages, fair, marriages

4) ECONOMIC STATUS: Lower socio economic groups 5)IMMUNITY : Attack confers immunity but duration is not known vaccination only give partial immunity for 3-6 months

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ENVIRONMENTAL FACTORS POOR ENVIRONMENTAL SANITATION

CONTAMINATED WATER AND FOOD

FLIES MAY CARRY VIBRIOS BUT NOT PROVEN LOW STANDARD OF PERSONAL HYGIENE ILLITERACY POOR QUALITY OF LIFE HABIT OF OPEN DEFECATION

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MODE OF TRANSMISSION FAECALLY CONTAMINATED WATER : Uncontrolled water sources such as wells lakes , rivers, streams CONTAMINATED FOOD AND DRINKS : Fruits and vegetables washed in contaminated water : contaminated through unclean hands and flies

DIRECT CONTACT : Person to person contaminated hands handling contaminated linen , formites

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INCUBATION PERIOD Few hours – 5 days ………….but commonly 1-2 days

PATHOGENESIS

mucus

MUCINASE

ENTEROTOXIN

HEAVY(H)

LIGHT(L)

ADENYL CYCLASE

c- AMP PATHWAY

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CLINICAL FEATURES 3 STAGES

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STAGE OF EVACUATION

Abrupt onset of profuse , painless, effortless, watery diarrhoea Followed by vomiting RICE WATER APPEARANCE OF STOOL 40 stools in a day

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STAGE OF COLLAPSE Patient soon passes to this stage due to dehydration CLASSICAL SIGNS :a) Sunken eyesb) Hollow cheeksc) Scaphoid abdomend) Sub-normal tempreturee) Washer man’s hand and feetf) Absent of pulse & low B.Pg) Loss of skin elasticityh) Shallow and quick respirationsi) Urine output decreases or may stopj) Cramps in legs and abdomenk) Intense thirst ,restless DEATH MAY OCCUR DUE TO SEVERE DEHYDRATION

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STAGE OF RECOVERY [ If death doesn't happen]

a) B.P began to rise

b) Temperature return to normal

c) Urine secretion is re established if it does not, it may meant that “ anuria ” has set in and patient may die due to renal failure

MILD CASES RECOVER IN 1-3 DAYS90% INFECTIONS OF EL Tor ARE MILD

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LAB DIAGNOSISCOLLECTION OF STOOLS :

a) A fresh specimen need to be collected before starting antibioticsb) RUBBER CATHETER

Soft rubber catheter ,sterilized by boilingLubricate with liquid paraffin introduced into rectum 4-5 cmVoided specimen can be directly collectedto the transport media [VR medium –Venkataraman-ramakrishnan medium]+alkaline peptone water

c) RECTAL SWAB swabs with 15-20 cm long sticks one end wrapped with absorbent cotton sterilized by autoclaving If no transport medium available dip in liquid Stool and pack in sterile plastic bag and tightly Seal it

VOMITUS : Never used

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SUSPECTED WATER SOURCE

1-3 Liters of suspected water is collected in sterile bottles Or add 1 volume 10% peptone water to 9 voulmes of suspected water

FOOD SAMPLES Suspected food 1-3 gm are collected in transport media

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DIRECT EXAMINATION

Dark field microscopy can diagnose within 80% of cases

In the dark field vibrios look like SHOOTING STARSIn dark sky

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CONTROL OF CHOLERABased on the guidelines of choler control by WHO

Verification of the diagnosis Notification Early case-finding Establishment of treatment centers Rehydration therapyAdjuncts to therapy Epidemiological investigations Sanitation measures ChemoprophylaxisVaccination

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1) VERIFICATION OF THE DIAGNOSIS Identify V.cholerae in stools

2) NOTIFICATION To the local health authority National government need to notice WHO within 24 hrs of its occurrence Since 2005 notification is not mandatory Weekly notification till the epidemic is over

3) EARLY CASE FINDING Search for cases [mild, moderate,severe]should be made in community to be able to initiate prompt treatment

4) ESTABLISHMENT OF TREATMENT CENTERS Mildly dehydrated should give ORS and should

send home Severe dehydrated persons should transfer to nearest hospital and should give ORS on the way In remote areas mobile teams should establish at district level

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5) TREATMENT REHYDRATION

Oral – I/V as needed

ANTIBIOTICSOrally , should be given after vomiting stopsTetracycline , Amphixillin ,Azithromycin etc.. are used

DO NOT GIVE :Antidiarrheal AntiemeticCorticosteriodsAntispasmodic

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6) EPIDEMOLOGICAL INVESTIGATIONS Define the extent of outbreak Identify mode of transport Identify control measures Can ask assistance from

NICD,New delhi NICED, Kolkata

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SANITATION MEASURES

WATER CONTROLProvide safe water for all purposes [drinking, cooking,washing]Chlorination , boiling store in covered vesselsProvision of piped water on permanent basis and eliminate unsafe water sources

EXCRETA DISPOSAL Provide simple free effective sanitary latrinesHEALTH EDUCATION for

Proper use of such facilitiesHand washing with soap water after defecationDangers of open defecation especially near water sources

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FOOD SANITATION Health education for cooked and hot food consumption Utensils should be cleaned and used

DISINFECTION Should be both concurrent and terminal Most effective : cresol Bleaching powder is also effective WHAT TO DISINFECT ??????????

StoolsVomitus ClothsLaterines House and neighborhood

CHEMOPROPHYLAXSIS Mass chemoprophylaxis is not advised as it is not effective Advised only for household community Tetracycline 500 mg [3days] OR Single dose of doxycyclin

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VACCINATIONSORAL VACCINES

Dukoral (WC) : Monovalent , Killed whole cells {WC} of V.cholerae Classical , El Tor , both Enaba & Ogawa + cholera toxin B subunit + BICARBONATE buffer + 3ml vial 2 ORAL DOSES

Sanchol & mORCVAX : Bivalent Based on O1 & O139 2 DOSES

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THANK YOU……