Studies on Leishmaniae of Lizards

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Wadeeda Suliman, Forawi
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Lizards Mabuya striata were used for experimental study of the developmental stages and infectivity of three Leishmania isolates. The three isolates were: LIZ/KEN/ICIPE 140 (unidentified lizard isolate) MHOM/SU/SASKH L. major (identified lizard isolate) LIZ/RC/244 L. adleri (identified human isolate) The two developmental stages of leishmania, promastigotes and amastigotes, were detected in the lizard tissues at different time intervals post-inoculation. Promastigotes were seen in the lizard tissues up to 7 hours post-inoculation. At 14 hours post-inoculation only amastigotes could be seen in the various tissues. Amastigotes were detected in impression smears of the intraperitoneal fluid, liver and spleen of the lizards. They were also seen in histological sections of the liver, spleen and gut. The parasites were seen mainly in the macrophage cells of these tissues. Infectivity of the above mentioned isolates to the lizards was measured by counts of the number of amastigotes seen per macrophage cell and the percentage of macrophage cells infected in both liver and spleen. The isolate L 140 was found to be more infective to the lizards than L. major and L. adleri with a maximum number of 12.8 ± 6.0 amastigotes per macrophage cell and maximum percentage of 60'• macrophage cells infected. The isolates L 140 and L. major showed similar pattern of infectivity. In both cases infectivity decreased with time suggesting a transient infection to the lizard .The isolate L. adleri ,with is a typical lizard leishmania ,showed a different pattern where infectivity increased with time indicating a natural infection to the lizards. Inoculation of L 140 and L. adleri to mice showed that L. adleri had a transient infectivity to the mice where parasites could not be detected after the 5th week post-inoculation. L 140 isolate showed more persisting infectivity to the mice and amastigotes could be seen up to the 12th week post-inoculation. Experimental infection of four species of sand flies, namely sergentomyia ingrami, S. schwetzi, S. clydei and S. bedfordi, with Leishmania was carried out by feeding them on lizards inoculated with the isolates L 140, L. major and L. adleri. Two of the 120 flies fed on lizards inoculated with L. adleri, were found to harbour promastigotes. These were S. schwetzi and S. ingrami. None of the flies fed on lizards inoculated with L. major or L 140 was found to be infected. The ultra structure of the isolate L 140 showed that its characteristics are more comparable to those of mammalian leishmania. The comparative study of the three isolates L 140, L. major and L. adleri showed that L 140, isolated from a wild lizard, is more related to L. major than to L. adleri and could be of a mammalian origin. Hence if lizards can harbour mammalian leishmania they can then act as reservoir hosts or incidental hosts and play an important role in the epidemiology of human leishmaniasis.
Studies on Leishmaniae of Lizards.