Leishmania: Probable Genetic Hybrids between Species in Sudanese Isolates

Abstract

The horn of Africa bears the prunt of Leishmaniasis in the world where both Phlebotomus orientalis, the vector of Leishmania donovani and Phlebotomus papatasi, the vector of Leishmania major, exist. Visceral leishmaniasis (VL) caused by L. donovani is a major cause of morbidity and mortality in east Africa. The populations of east Africa are very dynamic in continuous movements between endemic areas of different leishmaniasis clinical forms. Molecular epidemiological studies have provided indirect evidence for genetic exchange between different strains of one Leishmania species. Only recently, genetic exchange between different Leishmania strains of one species was definitively demonstrated in vitro. Genetic exchange between different Leishmania species is probably an even rarer event. In this study, one hundred and seven L. donovani isolates were collected from lymph nodes/bone marrow aspirates, from patients from Sudan and Ethiopia. DNA was isolated from leishmania parasites using the High Pure PCR Template Preparation Kit. PCR products were sequenced using BigDye Terminator chemistry and analyzed using the ABI 3100 or 3730 Genetic Analyzers. Sequences were analyzed using CodonCode program (CodonCode Corporation) and MEGA. Sequences were submitted to Genbank and are accessible under accession numbers HM117696-HM117699. Our data showed hybridization between two divergent Leishmania species, L. donovani and L. major, possibly due to migration. Such hybridization may have clinical implications with respect to parasite fitness, vector adaptation and response to treatment.