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Cholera

Cholera

Diagnosis

1.
N/V, HA, intestinal cramping with no fever, hypokalemia

2.
Painless voluminous diarrhea:

Fluid losses up to 20 L/d

“Rice water” grayish diarrhea may exceed 1 L/hr

Micro exam of stool samples – few or no red or white cells

3.
Death from severe dehydration, hypovolemia and shock

4.
Darkfield or phase contrast microscopy: direct visualization of darting motile vibrio
History

1.
Doesn’t easily spread from person-to-person; not effective biological weapon

2.
Epidemic in Peru caused 250,000 cases in 1991
Pathophysiology

1.
Vibrio cholerae is short, curved, motile, gram-negative, non-sporulating rod

2.
Produces enterotoxin that inhibits absorbtion and enhances intestinal secretion; toxin is heat labile

3.
Found in uncooked shellfish and raw seafood

4.
Mortality (untreated) is 60%

5.
Incubation period 4 hrs to 5 d; average 2-3 d

6.
Infective dose: 10-500 organisms

7.
Duration: >1 wk

8.
Transmission:

Direct/indirect fecal contamination of water, foods, by heavily soiled hands or utensils

Not viable in pure water

Food transmission can be prevented by thorough cooking

9.
Most US cases associated with foreign travel

10.
Survive up to 24 hrs in sewage; 6 weeks in impure water containing organic matter

11.
Withstand freezing for 3 to 4 d

12.
Killed by dry heat at 117 deg C, by steam and boiling, by exposure to ordinary disinfectants, chlorination of water
Prevention

1.
Licensed, killed vaccine available:

Provides 50% protection lasting 6 mths

0.5 ml IM or SQ at 0 and 4 wks, booster q 6 mths
Isolation/Decontamination

1.
Standard precautions for healthcare workers

2.
Enteric precautions and careful hand-washing

3.
Use bactericidal solutions (hypochlorite)
Treatment

1.
Oral rehydration therapy

2.
IV fluid replacement with persistent vomiting or high rates of stool loss (>10ml/kg/hr); early & rapid rehydration can reduce mortality to <1%

3.
Tetracycline (500 mg q6h x 3 d) or doxycycline (300 mg once or 100 mg q12h x 3 d)

4.
Tetracycline resistance: ciprofloxacin (500 mg q12h x 3 d) or erythromycin (500 mg q6h x 3 d) or cotrimoxazole 5 mg/kg PO bid for 3 d
Disposition

1.
Admit if:

dehydrated and cannot take PO fluids

Immunocompromised

Severe electrolyte disturbance

Elderly

Acid/base disturbance

2.
Enteric precautions

3.
Notify CDC & local health dept

* Material is taken from the PEPID database
* Copyrighted material – All Rights Reserved
* For more information visit http://www.pepid.com

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