Selection of a skin test antigen for American XXXX .

@entity1 @entity234 @entity1526 @entity281 @entity56 @entity2040 @entity3911 @entity378
Studies were designed to examine skin test responses to leishmanial antigens in American @entity234 (AVL) in Brazil. We found that after recovery from AVL, @entity1 had positive delayed @entity56 reactions to @entity3911 . Different amounts of a soluble extract obtained from @entity3911 chagasi promastigotes were compared with whole L. d. chagasi promastigotes in @entity1 with past AVL. The most effective soluble preparations tested contained 25 and 50 micrograms leishmanial protein. These produced positive responses in 95%-100% of the individuals with past AVL. The 25 micrograms protein dose was used in further studies. This preparation produced no positive responses in either normal controls, @entity378 @entity1 , or @entity2040 @entity1 , and less than 5% positive responses in @entity1 with @entity1526 . The same amount of soluble extract prepared from L. mexicana amazonensis produced 82% positive skin test responses in @entity1 with past AVL. When @entity1 living in an area endemic for AVL were skin tested with the 25 micrograms preparation of L. d. chagasi extract, 34.1% yielded positive tests with a low number of positive responses in young @entity1 and 48% positive in adults. Only 3.1% of the population studied had a history of AVL. We have found that positive delayed @entity56 response to a soluble @entity3911 extract is a sensitive and specific indicator of @entity281 with AVL.
