| dc.description.abstract | In this study, Leishmania major and Leishmania
strains from Kenya were cloned by limiting
dilution. Population homogeneity of the strains was
determined by determining the infectivity of the clones
in Balb/e mice and their isoenzyme profiles.
Characterization of L. donovani isolates from kalaazar
endemic areas in Kenya was done by cellulose
acetate electrophoresis to determine strain variation.
High temperature adaptation of L. major strain was
done by repeated intraperitoneal passages in Balb/c mice
to determine whether this parasite ean viseeralize
without causing a cutaneous lesion.
Cloning of L. major strain CNLB 144) and L.
donovani strain CNLB 065) , was done by limiting
dilution. The obtained clones were used to infect Balb/c
mice. Results demonstrated that L. major strain is not
homogenous but consists of a genetically mixed
population. This was confirmed by finding of clones,
that although had the same zymodeme. showed a
difference in infectivity in mice. One clone was very
virulent and resulted in severe ulceration of the nasal
area of mice. L. donovani clones also showed
population homogeneity with reference to isoenzymes but
a difference in infectivity to mice. Only clone-l was
infective to Balb/c mice. These results are of great
significance to leishmaniasis vaccine production.
Presence of clonal homogeneity of a strain suggests that
one type of vaccine can be used in the treatment and
control of leishmaniasis.
Cellulose acetate electrophoresis of 15 L. donovani
isolates from Baringo, Turkana and Machakos Districts in
Kenya revealed low levels of variation in the parasite
genome. Only one isolate, NLB 659 from Baringo District
showed a different banding pattern for isocitrate
dehydrogenase (ICD) . This suggests that there is no
intraspecific variation of L. donovani strains in Kenya
or if it occurs, its in very low level .This is very
important in the treatment of visceral leishmaniasis
because L. donovani has been known to cause both kalaazar
and post- kala-azar dermal leishmaniasis.
Intraperitoneal
144) resulted in visce~alization of the parasite.
(NLB
The
passaging of L. major strain
incubation period became shorter with each successive
passage. The parasite behaved like viscerotropic
L.donovani since no conspicuous cutaneous lesion was
formed at the site of inoculation. Isoenzyme
electrophoresis of this viscerotropic L. major showed
enzyme profiles similar to those of the original stock
of L.major except for the enzymes glucose phophate
isomerase (GPI) and glucose 6 phosphate dehydrogenase
(G6PD). 3-4 months post-infection. some parasites
disseminated to the footpads and caused lesions.
This viscerotropism of L. ma}or in Balb/c mice
emphasizes the need to characterize Leishmania parasites
particularly those isolated from rodents before
making conclusions of their identity. | en |
