Characterization and comparison of leishmania-like isolates from rodents, lizards and sand flies caught at Masinga location in Machakos district, Kenya

Abstract

A laboratory based study was designed to characterize 43 cryo-preserved Leishmania-like flagellates. These Leishmania-like flagellates were originally obtained from non-human hosts that included spiny mice (Acomys subspinosus), plated lizards (Gerrosaurus major) and sand flies of the Genus Sergentomyia caught at Masinga location, Machakos District in Kenya. Morphological features and isoenzyme banding patterns of the flagellates were studied. The isoenzyme markers which were used for isoenzyme electrophoresis included Malate dehydrogenase (MDH), Phosphoglucomutase (PGM), Glucose phosphate isomerase (GPI), Glucose 6-phosphate dehydrogenase (G6PD), Malic enzyme (ME), 6 phosphogluconate dehydrogenase (6PGD) and Mannose phosphate isomerase (MPI). The isoenzyme banding patterns of the flagellates’ lysates were compared with those of six WHO Leishmania reference strains and those of seven well characterized reference strains of Trypanosoma, Crithidia, Herpetomonas and Leptomonas species. The results showed that the morphological changes of the Leishmania-like flagellates in the growth medium were indistinguishable from those of Leishmania WHO reference strains used. The isoenzyme profiles of the flagellates were all distinguishable from the reference strains used except for isolate NLB-1236 from G. major which had an enzyme profile identical to that of L. tropica (NLB-305) in 6 enzymes (MDH, GPI, MPI, ME, PGM, and G6PD). The banding pattern of isolate NLB-1261 from A. subspinosus was indistinguishable from that of L. major (NLB-326) in 3 enzymes only (MDH, GPI and ME) while isolate NLB-1231 from A. subspinosus had an enzyme profile identical to those of L. tropica (NLB-305) and L. arabica (NLB-664) in six enzymes (MDH, GPI, ME, PGM, MPI, and 6PGD). More than 80% of the Leishmania-like flagellates had enzyme profiles indistinguishable from each other, in all the isoenzyme markers. The morphological traits of the flagellates suggested that they were Leishmania or strains closely related to Leishmania. Isoenzyme analysis suggested that Sergentomyia sand flies most likely feed on both lizards (reptiles) and rodents (mammals). There is need to carry further investigations on NLB-1236 (from plated lizards), NLB-1261 (from wild spiny mice) and NLB-1231 (from wild spiny mice).