COMPARISON OF NEW AND OLD-WORLD LEISHMANINS IN AN ENDEMIC REGION OF BRAZIL

The control of leishmaniasis depends on a knowledge of the magnitude o f the disease and of exposure to it, Delayed-type hypersensitivity tes ting can detect prior exposure to the parasite, but there is little ag reement regarding the choice of an antigen for such testing, New and O ld World leishmanins were tested in a study of patients with confirmed prior cutaneous leishmaniasis (CL), patients with confirmed prior Ame rican visceral leishmaniasis (AVL), and controls from areas in Espirit o Santo, Brazil, where leishmaniasis is not endemic, Biobras antigen ( a suspended mixture of Leishmania braziliensis guyanensis, Leishmania mexicana amazonensis, and Leishmania mexicana promastigotes) detected 100% of prior CL infections and thus was superior to the Old World ant igen, Leishmania major, which detected only 19% of these infections (P <.00001), Soluble New World antigens of Leishmania chagasi evoked a r esponse in 96% of cases of prior AVL, whereas the Old World counterpar t, Leishmania infantum, evoked a response in 71% of cases (P <.042), T esting of family members of patients with prior AVL showed greater uti lity of the New World leishmanins and suggested subclinical exposure o f a large number of healthy people in the hyperendemic region, New Wor ld skin-test antigens should be used in future epidemiological studies in the Americas to more accurately determine the extent of exposure.