Cholera Definition
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Transcript 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