Diagnosis of Cholera

Cholera can be diagnosed with the help of detailed patient history and stool examination.

A patient history of watery stools especially during an epidemic should raise the suspicion of cholera.

Stool examination-

Macroscopic / Gross Examination-

Stools resembles ‘rice water’ and contain mucus

Microscopic Examination-

Dark field microscopic examination of stool sample shows rapidly motile V.cholerae bacteria. Epithelial cells are also present in the stool sample.

Culture-

A stool culture may be done to confirm the presence of V. cholerae. Enrichment is done in alkaline peptone water at pH 8.7 for 6-8 hours incubation.

Typical yellow color colonies appear in thiosulfate-citrate-bile salts-sucrose (TCBS) agar after 18 hours of incubation. Organisms can be confirmed from culture by staining and examining under microscope.

Specific Tests-

Vibrio cholerae are further identified by slide agglutination tests using anti-O group 1 antiserum and by biochemical reactions.