Identification of new world Leishmania using ribosomal gene spacer probes

DNA probes from the nontranscribed ribosomal spacer (NTS), of Leishmania garnhami and Leishmania braziliensis were constructed and tested for sensitivity and specificity against different Leishmania isolates. The L. garnhami probes were species-specific under hybridization conditions of high stringency, but displayed specificity for the mexicana complex under conditions of intermediate stringency. The L. braziliensis probes showed 'complex' specificity. RFLP for the nontranscribed spacer within the braziliensis complex revealed very homogeneous patterns even for organisms currently accepted as different species. A PCR assay for the detection of Leishmania from the braziliensis complex is presented.