Validity of one step rapid visual test in detection of cholera carriers in Najaf, Iraq

Abstract EN

Background : Cholera is an endemic disease in Iraq, the most severe epidemic had occurred in 1966 as a continuity of the seventh pandemic.

Then subsequent less serious outbreaks occurred in 1999, 2003, and 2008 with a case fatality ratio of about 2 %.

Objective : to verify the sensitivity and specificity of immunochromatographic one step rapid test for V.

cholera among asymptomatic carriers using the culture as a validating diagnostic test.

Design : a cross–sectional study Materials & Methods : A total of 28000 stool samples were collected from individuals that were attending the primary health care centers in Najaf governorate during the months (August, September, October and November, 2008) which are considered the months of cholera season in Iraq.

The individuals were asymptomatic or suffering from mild diarrhea.

All the stool samples were examined for Vibrio cholerae by two methods ; the rapid visual test as a screening and the culture as a diagnostic test.

The ability of the rapid visual test had been compared with results of culture to assess the validity and prediction of this rapid test in our locality.

Results : from 28000 stool samples, 51 samples found to be carriers of V.

cholerae 01 of Inaba serotype with carrier detection rate of 182 per 100000 population.

The sensitivity and specificity of the one step rapid visual test were 84 % and 100 % respectively with ten false negative individuals.

The test revealed high predictive value for both positive and negative results.

Conclusion : the validity of the immunochromatographic one step rapid visual test (VC Dipstick) is so high that it can be applied to detect the carriers of Vibrio cholerae 01 during the expected cholera season.