[The detection of chronic Salmonella typhi carriers: a practical method applied to food handlers]

We evaluated the anti Vi test to detect S typhi carriers in 1006 food handlers of 65 locations in central Santiago (Chile): 710 males and 296 females, age range 17 to 67. Positive reactions were found in 27 subjects, titers varying from 1/40 in 9 to 1/160 in 1 subject. Culture of feces, along with urine and bile cultures in those with very high titers allowed isolation of S typhi in 2 subjects, one with a 1/40 titer, the other 1/160. None had clinical history of typhoid fever, both had received parenteral vaccination. These results compare favorably with the classic technique which would have required 3018 fecal cultures (vs 108 in the present study) and a total cost of US$ 1730 vs US$ 364. In addition, anti-Vi detection is readily accepted by the subjects. Therefore, we recommend this technique as a screening prior to culture techniques in the identification of chronic S typhi carriers.