Detection of Leishmania causing visceral leishmaniasis in the Old and New Worlds by a polymerase chain reaction assay based on telomeric sequences

We present a new polymerase chain reaction assay based on telomeric sequenc es of Leishmania donovani. When this assay was used in dilutions of purifie d L. donovani DNA, a strong amplification signal was observed with 1 fg of DNA. In a specificity test that used purified DNA from Old World and New Wo rld Leishmania, the assay recognized all parasites isolated from patients w ith visceral leishmaniasis, except for 2 isolates of Leishmania colombiensi s from Venezuela and 1 isolate from Brazil. All Leishmania major and Leishm ania tropica isolates tested were negative, except for one isolate in each species. We also used the assay on fresh and archive bone marrow samples re covered from Giemsa-stained slides and from dried blood stains.