Download Cholera Definition

Cholera
Dept. Infectious Disease
Shengjing Hospital
CMU
Definition
 Violent infectious disease of intestinal tract
caused by vibrio cholerae
 International quarantine
 Pathogenic substance: choleragen
 Clinical features: profuse diarrhea & vomiting
Severe dehydration
Muscular cramps
Circulatory collapse
Renal failure
Etiology
 Causative organism: vibrio cholerae
 G-, short rod, similar to comma
 Smear:arrange in shoal of fish
 darting movement
 Clinical diagnosis
 growth on alkaline media
Etiology
 Pathogenicity- virulence
 Choleragen
 Endotoxin
 enzyme
Resistance: Sensitive to heat, acid,
common disinfectants. In river 1-3 weeks, sea
food 1-2 weeks
Etiology
Antigenicity:
 Smatic “O” Ag; Flagella Ag: same
Serotype:
 O1group: A, B, C AB- Ogawa,AC- Inaba, ABC-Hikojima
 Atypical O1 group:Non-pathogenic
 Non-O1 Group: O2-O200
O139
Biological type:
 Classical bio-type- O1group
 EL-Tor bio-type- O1group
 O139- Non-O1 Group
Epidemiology
 Source of infection
Patients --(mild 18%,
asymptomatic infection 75%);
Carrier
 Route of transmission
Fecal-oral route mode of spread:
water-borne(outbreak);
food-borne(small epidemic);
contagious spread
 Susceptibility
Epidemiology
Epidemic features
1. Endemic and exogenous
Classical biotype -- six outbreaks
Since 1961-- El-Tor biotype which resulted the
7th outbreak.
Since 1992--O139 biotype which resulted the
8th outbreak in the world.
2.Periodicity and seasons
The peak of epidemic is between July and
September summer & fall
Pathogenesis
Bacteria
Small intestine
Attach to brush border of epithelial cell
choleragen
endotoxin
Movement of bowel
B(binding subunit)
+
Specific receptor GM1
A1
CELL
Adenyl cyclase
ATP
Crypt cell:cl- H2o HCO3
cAMP
Cells of villus:Na+ reabsorb
Diarrhea, dehydration
Pathology and Pathogenesis
 Dominant pathological finding –
dehydration
 disturbance of electrolyte;
 metabolic acidosis
Clinical manifestation
Incubation period: 1 to 3 days
Typical cholera:
 Diarrhea & vomiting period:

Diarrhea:100%, rice watery stools with slightly fishy
smell;10-20t/d ,no pain, no tenesmus, no fever

Vomiting:80%,after onset of diarrhea,no
nausea,continuous and effortless.
Clinical manifestation
 Dehydration period:

Dehydration:

Circulatory collapse: hypovolemic shock

Muscular cramps: loss of Na+,in extremities(calves)
and abdominal muscles

Disturbance of electrolyte:

Renal failure: oliguria-anuria- uremia

Convalescent period:

Fever: in 1/3 patients
2 004年1月27日一名霍乱患者被送到赞比亚首都卢萨卡的马泰
罗霍乱治疗中心接受治疗
Bucket with typical rice-water stool of a patient with cholera
Clinical manifestation
 Clinical type:according to degree of
dehydration,BP,pulse,volume of urine

Mild type

Moderate type

Severe type

Fulminant type – Cholera Sicca
Laboratory Findings
 Blood picture: hemo-concentration
 Urine test: pro. + ~ ++, RBC
 Stool test:
 Direct observation:darting movement
Immobilized test:
 Smear: G- arrange in shoal of fish
 Culture: alkaline protein media
 Serological test: haemagglutination
Complications
Acute renal failure:
Acute pulmonary edema:
Diagnosis
 Epidemiologic data: travelling history; diet
history; contact history
 Clinical manifestation:
 Laboratory findings:
 Definite diagnosis:
 Symptoms plus culture positive
 Epidemiologic investigation, initial stool
culture positive, diarrhea before or after 5
days
 Epidemic period ,typical symptoms but
culture is negative, without any other reasons
Diagnosis
suspected diagnosis:
 Typical symptoms and first patient waiting
for the result of culture
 Epidemic period, contact history
(+),diarrhea without any other reasons
Differential diagnosis
 Acute bacteria gastroenteritis
 Viral gastroenteritis
 Acute bacillary dysentery
Treatment
 General treatment:
 isolation:when the symptoms disappear,stool cultures are negative for
2 times
 Fluid replacement:
 Intravenous fluid replacement:
kind of fluid:541/321, 5%GNS, 0.9%NS, Ringer’
volume of fluid:
speed of fluid replacement:
 Oral fluid replacement therapy:
Treatment

adult(ml/d)
 Mild
3000-4000
100-150
 Moderate 4000-8000
150-200
 Severe
200-250
8000-12000
child(ml/kg.d)
Treatment
 Etiological therapy:
Antibiotics: deoxycycline for 3 days
1.reduce the duration and volume of diarrhea
2.shorten the period of bacterial excreta from the feces
3.diminish carrier after disease
 Symptomatic therapy:
eliminate acidosis and hypokalemia
correct shock and heart failure
Prevention
Control of source of infection:
 isolation
 International quarantine for 5 days
 Interruption of route of transmission
 Protection of susceptible population :
Vaccinated with cholera vaccine
1.BS-WC 65-85% O1 Classical
2.CVD103-HgR 100% O1 group