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 O1 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 O1 in a setting with seasonal outbreaks where rapid tests are most urgently needed.