Field evaluation of a rapid immunochromatographic dipstick test for the diagnosis of cholera in a high-risk population

Background: Early detection of cholera outbreaks is crucial for the implementation of the most appropriate control strategies. Methods: The performance of an immunochromatographic dipstick test ( Institute Pasteur, Paris, France) specific for Vibrio cholerae OI was evaluated in a prospective study in Beira, Mozambique, during the 2004 cholera season ( January-May). Fecal specimens were collected from 391 patients with acute watery nonbloody diarrhea and tested by dipstick and conventional culture. Results: The overall sensitivity and specificity of the rapid test compared to culture were 95% ( 95% confidence interval [CI]: 91% - 99%) and 89% ( 95% CI: 86% - 93%), respectively. After stratification by type of sample ( rectal swab/bulk stool) and severity of diarrhea, the sensitivity ranged between 85% and 98% and specificity between 77% and 97%. Conclusion: This one-step dipstick test performed well in the diagnosis of V. cholerae OI in a setting with seasonal outbreaks where rapid tests are most urgently needed.