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Five chromosomes and 17 isoenzyme loci were analysed in 4 allopatric populations of Leishmania (Viannia) peruviana, and molecular distances calculated with 2 estimators, Chromosomal Size Difference Index and Jaccard Distance. Chromosome and isoenzyme data were in overall concordance: 13/30 isolates clustered similarly on the dendrograms constructed from the different estimators, and a significant correlation (P

American tegumentary leishmaniasis (ATL) in Peru is mainly associated with Leishmania (Viannia) peruviana and L. (V.) braziliensis. These parasites are genetically related, and their characterization as distinct species is controversial. Despite their genetic similarity, each species is associated with different clinical manifestations of ATL; L. (V.) peruviana causes only cutaneous leishmaniasis, whereas L. (V.) braziliensis can cause both cutaneous and mucocutaneous leishmaniasis. Because the primary cutaneous lesions caused by infection with these species are indistinguishable, it is necessary to develop a suitable method to differentiate them in order to prevent possible metastasis to oropharyngeal mucosa. In the present study, we investigated the proteolytic profile of L. (V.) peruviana and L. (V.) braziliensis isolates from Peru by zymographic analysis in SDS-PAGE copolymerized with gelatin. Enzymes were characterized according to their pH range of activity and sensitivity to distinct peptidase inhibitors. We observed that L. (V.) peruviana isolates displayed three proteolytic bands with molecular masses ranging from 55 to 80. kDa, whereas L. (V.) braziliensis isolates showed six proteolytic activities between 55 and 130. kDa. Using specific inhibitors, we determined that these proteolytic activities are due to metallopeptidases and present optimal activity between the pH range 5.5 and 10.0. Our results suggest that the expression of metallopeptidases in L. (V.) peruviana and L. (V.) braziliensis isolates from Peru is species-specific.

Forty-one Leishmania peruviana isolates were selected along a north-south transect which crossed areas endemic for uta in three different biogeographical regions in the Peruvian Andes. The isolates were analysed by molecular karyotyping and hybridization with three chromosome-derived DNA probes. All the isolates could be distinguished from L. braziliensis by their pLb-134 hybridization patterns. However, the patterns with the other probes (pLb-168 and -22) could be used to cluster the Peruvian isolates in discrete groups (karyodemes) which varied in their level of similarity with L. braziliensis. The geographical distribution of these karyodemes supports the hypothesis that eco-graphical isolation has contributed to the heterogeneity of L. peruviana.

In order to initiate studies on the phenotypic properties of hybrids vs. their putative parents, the in vitro growth behaviour of promastigotes was compared for 15 stocks characterised as Leishmania (Viannia) braziliensis, Leishmania (Viannia) peruviana and putative hybrids (isolated from the Eastern Andean valley of Huanuco, Peru). Five sets of three stocks, each set including a L.(V.)braziliensis, a L.(V.)peruviana and a putative hybrid, were constituted randomly and counted daily close to isolation from man (ten to 18 subcultures). Hybrids and L.(V.)peruviana presented similar growth characteristics, and they displayed a growth capacity (growth rate and cell density at stationary phase) significantly lower than the one of L.(V.)braziliensis. Following prolonged in vitro maintenance of one of the sets, the hybrid kept its lower growth capacity. The contrast between the difficulty to grow in vitro these putative hybrids, and their high isolation rate from natural populations is discussed.

One of the objectives of a clinical and epidemiological study of Andean leishmaniasis (uta) in the Huayllacallán valley, Ancash, Perú, was to identify the vector(s) of its causative agent, Leishmania (Viannia) peruviana Vélez, 1913...