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Memórias do Instituto Oswaldo Cruz

Print version ISSN 0074-0276On-line version ISSN 1678-8060

Mem. Inst. Oswaldo Cruz vol. 92 no. 5 Rio de Janeiro Sept./Oct. 1997 


Cutaneous Leishmaniasis in Venezuela Caused by Infection with a New Hybrid between Leishmania (Viannia) braziliensis and L. (V.) guyanensis

Vol. 92(5): 581-582

Olinda Delgado, Elisa Cupolillo**/+, Rafael Bonfante-Garrido*, Silvia Silva, Edgar Belfort, Gabriel Grimaldi Jr**, Hooman Momen***

Instituto de Medicina Tropical, Universidad Central da Venezuela *Departamento de Parasitologia, Universidad Centro-Ocidental de Venezuela **Departamento de Imunologia ***Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz, Av. Brasil 4365, 21045-900 Rio de Janeiro, RJ, Brasil

Key words: Leishmania - Leishmania braziliensis - Leishmania guyanensis - hybrids - isoenzyme


American cutaneous leishmaniasis (ACL) has a relatively high prevalence and constitutes a serious health problem in Venezuela. The disease is endemic and widely distributed in the country in nearly all states (JV Scorza et al. 1985, Leishmaniasis in Venezuela, p. 283-296. In KP Chang & RS Bray (eds) Leishmania, vol.1, Elsevier, Amsterdam). More studies, however, are needed to determine better the epidemiological aspects of the various leishmaniases in the country, including their geographical distribution, etiological agents, zoonotic reservoirs and insect vectors.

Several Leishmania species are circulating in this country and have been indicated as responsible for different clinical forms of the disease (G Grimaldi et al. 1989 Am J Trop Med Hyg 41: 687-725). An extensive study was carried out regarding the etiological agent of cutaneous leishmaniasis in western Venezuela (R Bonfante-Garrido et al. 1992 Trans R Soc Trop Med Hyg 86: 141-148), where L. (Leishmania) venezuelensis and L. (Viannia) braziliensis were characterized. In the same study evidence for hybrid parasites between L. (V.) braziliensis and L. (V.) guyanensis were found in this region. The disease is a problem in other regions and its etiology needs to be investigated as well.

We have isolated several leishmanial strains from patients with ACL, representing a wide geographical distribution of Venezuela (Table). The isolates were characterized by isoenzyme electrophoresis. Procedures for growing the promastigotes and for preparation of samples have been already described (H Momen et al. 1985 Am J Trop Med Hyg 34: 1076-1084). Electrophoresis was carried out in agarose gel and the characterization was based on the profile for 18 loci (E Cupolillo et al. 1994 Am J Trop Med Hyg 50: 296-311). The isolates were compared with World Health Organization reference strains for L. (V.) braziliensis and L. (V.) guyanensis.

The presence of L. (V.) braziliensis was confirmed in this country. Parasites presenting an identical profile to L. (V.) guyanensis were detected. Among the isolates we found a new enzymatic variant (IOC/Z 67) of L. (V.) braziliensis, differing from the reference strain of L. (V.) braziliensis by the pattern for the enzymes PEPD and NH. Some isolates produced a profile with alleles identical to L. (V.) braziliensis variant (IOC/Z 67) for some loci and identical to L. (V.) guyanensis for other loci. Those isolates presented heterozygotic patterns for the loci 6PGDH and NH2 suggesting that they could be hybrid parasites with the putative homozygotics bands corresponding to those of zymodeme (IOC/Z 67) of L. (V.) braziliensis and L. (V.) guyanensis (Fig.).

We characterized parasites from several endemic foci in Venezuela and the following Leishmania types where found: L. (V.) guyanensis, L. (V.) braziliensis enzymatic variant (IOC/Z 67) and L. (V.) guyanensis/L. (V.) braziliensis hybrid.

The Leishmania types could not be correlated with clinical manifestation as we found the same type producing either cutaneous or mucosal lesion (L. (V.) braziliensis) and cutaneous or "esporotricoide" lesion (L. (V.) guyanensis). The hybrids parasites were associated with the classical cutaneous form of the disease.

Hybrids between Leishmania parasites have already been studied in other endemic regions. In the Old World the presence of hybrids between L. (L.) major and L. (L.) arabica (isolated from wild animals in a zoonotic focus) was reported based on phenotypic and genotypic characteristics (D Evans et al. 1987 Parassitologia 29: 165-173, JM Kelly et al. 1991 Mol Biochem Parasitol 46: 253-264). In the New World hybrids were observed between L. (V.) braziliensis and L. (V.) panamensis among human isolates in Nicaragua (M Darce et al. 1991 Trans R Soc Med Trop Hyg 85: 58-59, AA Belli et al. 1994 Parasitol 109: 435-442, HA Noyes et al. 1996 Am J Trop Med Hyg 55: 98-105) and between L. (V.) braziliensis and L. (V.) guyanensis in Lara State, Venezuela, infecting humans, dogs and Lutzomyia ovallesi (Bonfante-Garrido et al. loc. cit, H Momen et al. 1994, Population Genetics of Leishmania in the New World, p. 187-198. In AN Bhaduri et al. (eds) Current Trends in Leishmania Research, New Delhi), by isoenzyme analysis. The latter parasite has hybrid alleles different from the L. (V.) guyanensis/L. (V.) braziliensis hybrid described in this report. In Peru hybrids were found between L. (V.) braziliensis and L. (V.) peruviania as demonstrated by molecular karyotype (JC Dujardin et al. 1993 Ann Soc belge Méd Trop 73: 101-118).

In conclusion, these data do not proove that recombination occurs in Leishmania. However, it reinforces the idea that sexual reproduction may occur in Leishmania, but at a level as yet undefined. The rarity of this phenomenum may reflect the fact that progeny from occassional sexual reproduction within clonally reproducing populations may become detectable only when the hybrid phenotype confers a selective advantage. This process may be occurring in several endemic foci in Venezuela.

+Corresponding author.
Fax: + 55-21-280.1589.

Received 5 February 1997

Accepted 13 May 1997

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