Species delimitation in the genus Aloe has proved complicated due to interlocked morphologies. This study investigated the taxonomic relationships of Aloe macrocmpa Todaro and A. lateritia Engler using both morphological and molecular teclmiques. The morphological results indicated that the natme of variation in the populations of the two taxa is continuous. Microscopic studies of pollen grains and the leaf cuticle showed little differentiation among populations of the two taxa. The low genetic distances «0.3) between the populations studied are in support of the hypothesis that the populations may be conspecific, suggesting infraspecific rauk(s) for the taxa.
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Date
2005-05
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Addis Ababa University
Abstract
The various species of Leishmania cannot be distinguished morphologically, but the
treatment of leishmaniasis depends on the specific causative species. Thus accurate and
rapid diagnosis of the specific species of Leishmania should be available for effective
treatment of patients. Identification of Leishmania species in humans, in insect vectors
and reservoir hosts should be available before planning for large-scale epidemiological
survey, control programs and possible vaccine and/or drug trials.
Therefore, the aim of this work was to establish isoenzyme technique at AHRI as a gold
standard for species identification and introduce PCR-methods for species-specific
diagnosis of leishmaniasis directly from clinical materials. In this line, cultured parasites
from 55 localized cutaneous leishmaniasis (LCL) and 3 diffused cutaneous leishmaniasis
(DCL) cases), diagnosed at the All Africa Leprosy and Tuberculosis Research,
Rehabilitation and Training Center (ALERT) and from Ochollo village were analyzed.
Species typing with isoenzyme electrophoresis and PCR-based techniques showed that, in
all the cases, L. aethiopica is the aetiologic agent. Moreover, there was no strain difference
between those causing LCL and DCL. The comparison of the isoenzyme and the PCRbased
species typing techniques confirmed that the intergenic transcribed spacer-1
polymerase chain reaction-restriction fragment length polymorphism technique alone could
be used for species typing. The sensitivity and specificity of the technique shows its
potential for species specific diagnosis of leishmaniasis from clinical samples avoiding the
need for culture. Thus, effective species-specific treatment of patients, which is a
requirement in leishmaniasis, could be effected in a timely manner.
Key words: Leishmania aethiopica, Isoenzyme, ITS1-PCR-RFLP, ALERT, Ochollo
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Leishmania aethiopica, Isoenzyme, ITS1-PCR-RFLP, ALERT;Ochollo