we skin tested 488 unvaccinated young nigerian workers , typical of tropical populations having high prevalences of tuberculosis , with 4 low-dose mantoux tests ( ppd-rt-23 , ppd-tuberculin , ppd-battey , and ppd-gause ) and with concentrated ( 2 mg/ml ) ppd by the heaf multiple-puncture method .
C0041296
tuberculosis
C0034131
ppd