Multilocus microsatellite typing reveals a genetic relationship but, also, genetic differencesbetween Indian strains of Leishmania tropica causing cutaneous leishmaniasis and thosecausing visceral leishmaniasis
Date
2014-03-24
Authors
Krayter, Lena
Bumb, Ram A
Azmi, Kifaya
Wuttke, Julia
Malik, Mariam D
Schnur, Lionel F
Salotra, Poonam
Journal Title
Journal ISSN
Volume Title
Publisher
BMC BIoMed Central
Abstract
Background: Leishmaniases are divided into cutaneous (CL) and visceral leishmaniasis (VL). In the Old World, CL
is caused by Leishmania (L.) major, L. tropica and L. aethiopica. L. tropica can also visceralize and cause VL. In India,
the large epidemics of VL are caused by L. donovani and cases of CL are caused by L. major and L. tropica. However,
strains of L. tropica have also been isolated from Indian cases of VL.
This study was done to see if Indian strains of L. tropica isolated from human cases of CL are genetically identical
to or different from Indian strains of L. tropica isolated from human cases of VL and to see if any genetic differences
found correlated with clinical outcome presenting as either CL or VL.
Methods: Multilocus microsatellite typing (MLMT), employing 12 independent genetic markers specific to L. tropica,
was used to characterize and identify eight strains of L. tropica isolated from human cases of CL examined in
clinics in Bikaner City, Rajasthan State, north-west India. Their microsatellite profiles were compared to those of 156
previously typed strains of L. tropica from various geographical locations that were isolated from human cases of
CL and VL, hyraxes and sand fly vectors.
Results: Bayesian, distance-based and factorial correspondence analyses revealed two confirmed populations:
India/Asia and Israel/Palestine that subdivided, respectively, into two and three subpopulations. A third population,
Africa/Galilee, as proposed by Bayesian analysis was not supported by the other applied methods. The strains of
L. tropica from Bikaner isolated from human cases of CL fell into one of the subpopulations in the population
India/Asia together with strains from other Asian foci. Indian strains isolated from human cases of VL fell into the
same sub-population but were not genetically identical to the Bikaner strains of L. tropica.
Conclusions: It seems that the genetic diversity encountered between the two groups of Indian strains is mainly
owing to their geographical origins rather than their different times of isolation. Also, the genetic differences seen
between the dermatotropic and viscerotropic strains might be connected with the difference in pathogenicity.