Double replicas allow the obtention of longitudinally freeze-fractured Trypanosoma cruzi

The double replica device was used to obtain freeze-fracture replicas of gently pressed cells, allowing the visualization of a large number of longitudinally fractured epimastigote and trypomastigote forms of Trypanosoma cruzi. This technique revealed large areas of the plasma membrane, the region of attachment of the flagellum to the cell body and the branched mitochondria.

Leishmania donovani donovani and Leishmania donovani chagasi as antigens in a direct agglutination assay for the diagnosis of kala-azar

The need for a reliable method for the immunological diagnosis of Kala-azar is imperative. Leishmania donovani donovani and L. donovani chagasi culture promastigotes were compared as antigens in a direct agglutination test (DAT) for the diagnosis of visceral leishmaniasis in Brazil. Both antigens were successfully employed for the DAT, Showing 100½ sensitivity and > 98% specificity when used to test sera from Brasilian and African Kala-azar, Chagas'disease, malaria, filaria and symphilis patients, and on sera from Brazilian controls. Cross-reactions were sometimes observed when cutaneous and cucocutaneous leishmaniasis patient sera were teste. The vross-reactions were completely abolished by the addition of 0.78% 2-mercaptoethanol to the serum diluent. These data show data that this improved Dat can be used for the diagnosis of visceral leishmaniasis in Brazil