Vibrio cholera is divided serologically into O1 and non-O1 strains based on reaction with antisera. The O1 strains have been the ones usually involved in serious outbreaks and produce toxin. Non-O1 strains often lack the cholera toxin gene.
General features:
(1) diarrhea
(2) nausea and vomiting
(3) abdominal cramps
(4) fever may or may not be present
The diarrhea may vary in severity, but typically is voluminous and resembles water that has been used to boil rice ("rice water"). A person with severe diarrhea may pass gallons of feces per in a day, requiring special cholera cots with beds to collect the outflow.
Clinical findings in severe disease:
(1) dehydration
(2) hypotension progressing to shock
(3) cardiac arrhythmias
(4) impaired consciousness progressing to coma
(5) renal failure
(6) in severe cases death may occur within a few hours or days if untreated
Laboratory findings:
(1) metabolic acidosis
(2) hypoglycemia
(3) hyponatremia
(4) hypokalemia
Non-O1 strains may be associated with bloody diarrhea, which is not seen with O1 strains.
Cholera sicca (cholera fulminans) refers to a rapidly fatal form of cholera which lacks diarrhea and vomiting. Fluid is secreted into the bowel lumen but it is not ejected (due to toxin-induced or hypokalemia-associated ileus).
