Lepromin and tuberculin tests in Venezuelan leprosy foci, induction of lepromin reactivity by BCG vaccination

ABSTRACT

The reactions to tuberculin and lepromin were studied in 8,353 inhabitants of leprosy foci in rural areas in Venezuela. Of this general group, a total of 1,356 (16.2 per cent) proved to be negative to the Mitsuda, test, while 5,205 (62.5 per cent) were Mantoux negative, In the group of Mitsuda-positive persons 44.8 per cent were also Mantoux positive, while in the Mitsuda-negative group only 3 per cent were Mantoux positive. In the Mantoux-positive group 99.5 per cent were Mitsuda-positive, while in the Mantoux-negative group 74.4 per cent were Mitsuda-positive. Considering that 16.2 per cent of the persons examined were found to be without protection against leprosy in the first tests, and taking into account that almost all lepromatous and indeterminate cases come from the lepromin negatives, which form the endemic matrix of the disease, there can be no doubt but that BCG vaccination will be an effective prophylaxis, at least in rural areas, when it can reduce the percentage of Mitsuda negative from 16.2 to 1.3 per cent.