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Multilocus microsatellite typing reveals a genetic relationship but, also, genetic differences between Indian strains of Leishmania tropica causing cutaneous leishmaniasis and those causing visceral leishmaniasis.

Krayter L, Bumb RA, Azmi K, Wuttke J, Malik MD, Schnur LF, Salotra P, Schönian G - Parasit Vectors (2014)

Bottom Line: 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.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.Also, the genetic differences seen between the dermatotropic and viscerotropic strains might be connected with the difference in pathogenicity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Microbiology and Hygiene, Charité-University Medicine Berlin, Hindenburgdamm 30, 12203 Berlin, Germany. lena.krayter@charite.de.

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.

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Factorial correspondence analysis. Phylogenetic relationship between the populations of L. tropica calculated by Factorial Correspondence Analysis (FCA). The Bikaner strains are circumscribed by a dotted line. Bayesian results are indicated by colours: background colours show main populations, coloured squares represent subcomponents within populations. The strains, one representative for each genotype, were assigned to the proposed populations before applying FCA.
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Figure 1: Factorial correspondence analysis. Phylogenetic relationship between the populations of L. tropica calculated by Factorial Correspondence Analysis (FCA). The Bikaner strains are circumscribed by a dotted line. Bayesian results are indicated by colours: background colours show main populations, coloured squares represent subcomponents within populations. The strains, one representative for each genotype, were assigned to the proposed populations before applying FCA.

Mentions: STRUCTURE analysis, which is based on Bayesian statistics and uses allele frequencies to study the nature and extent of genetic variation within and between populations, followed by ∆K calculation, which determines the most probable number of populations, revealed three main populations in the whole set of data that correlated largely with strains´ geographical origins: Asia/India, Israel/Palestine and Africa/Galilee. In Figures 1, 2 and 3, the coloured clouds and geometrical symbols indicate the main genetic populations and their subpopulations respectively, and reflect the assignment of the strains to genetic groups according to Bayesian statistics. The Indian strains isolated from cases of CL from Bikaner grouped together with the older Indian strains isolated from cases of VL from Bihar State and one additional strain from a case of VL from India, in the population Asia/India, which also contained strains from many Middle Eastern and other Asian foci, making a total of 64 strains. Here, 32 Turkish strains, of which 28 were isolated during a local outbreak near Sanliurfa, formed a distinct group. A second genetic subpopulation, designated India/Mix, in the population Asia/India comprised strains from different geographical locations, many of which shared an early time point of isolation. The second population, designated Israel/Palestine, as it contained 66 strains from Israel and Palestine and one from Egypt, separated into three genetic subpopulations that did not correlate with the geographical distribution of the locations from which the strains come from. The third population, designated Africa/Galilee comprised 33 strains, 23 strains from various parts of Africa, from its northern border to its southern one, and ten strains from one restricted focus north of the Sea of Galilee in Israel. The population Africa/Galilee separated into five genetic subpopulations. One subpopulation consisted of the ten strains from Galilee. The other four were given designations according to the geographical origins of the strains in them (KE/TN, NA/KE, TR/MA, and MA). As the subdivisions within the main populations were not well supported by the ∆K values (Additional file 2: Figure S1), sub-clustering was carefully re-evaluated using the other analytical methods described.


Multilocus microsatellite typing reveals a genetic relationship but, also, genetic differences between Indian strains of Leishmania tropica causing cutaneous leishmaniasis and those causing visceral leishmaniasis.

Krayter L, Bumb RA, Azmi K, Wuttke J, Malik MD, Schnur LF, Salotra P, Schönian G - Parasit Vectors (2014)

Factorial correspondence analysis. Phylogenetic relationship between the populations of L. tropica calculated by Factorial Correspondence Analysis (FCA). The Bikaner strains are circumscribed by a dotted line. Bayesian results are indicated by colours: background colours show main populations, coloured squares represent subcomponents within populations. The strains, one representative for each genotype, were assigned to the proposed populations before applying FCA.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3987047&req=5

Figure 1: Factorial correspondence analysis. Phylogenetic relationship between the populations of L. tropica calculated by Factorial Correspondence Analysis (FCA). The Bikaner strains are circumscribed by a dotted line. Bayesian results are indicated by colours: background colours show main populations, coloured squares represent subcomponents within populations. The strains, one representative for each genotype, were assigned to the proposed populations before applying FCA.
Mentions: STRUCTURE analysis, which is based on Bayesian statistics and uses allele frequencies to study the nature and extent of genetic variation within and between populations, followed by ∆K calculation, which determines the most probable number of populations, revealed three main populations in the whole set of data that correlated largely with strains´ geographical origins: Asia/India, Israel/Palestine and Africa/Galilee. In Figures 1, 2 and 3, the coloured clouds and geometrical symbols indicate the main genetic populations and their subpopulations respectively, and reflect the assignment of the strains to genetic groups according to Bayesian statistics. The Indian strains isolated from cases of CL from Bikaner grouped together with the older Indian strains isolated from cases of VL from Bihar State and one additional strain from a case of VL from India, in the population Asia/India, which also contained strains from many Middle Eastern and other Asian foci, making a total of 64 strains. Here, 32 Turkish strains, of which 28 were isolated during a local outbreak near Sanliurfa, formed a distinct group. A second genetic subpopulation, designated India/Mix, in the population Asia/India comprised strains from different geographical locations, many of which shared an early time point of isolation. The second population, designated Israel/Palestine, as it contained 66 strains from Israel and Palestine and one from Egypt, separated into three genetic subpopulations that did not correlate with the geographical distribution of the locations from which the strains come from. The third population, designated Africa/Galilee comprised 33 strains, 23 strains from various parts of Africa, from its northern border to its southern one, and ten strains from one restricted focus north of the Sea of Galilee in Israel. The population Africa/Galilee separated into five genetic subpopulations. One subpopulation consisted of the ten strains from Galilee. The other four were given designations according to the geographical origins of the strains in them (KE/TN, NA/KE, TR/MA, and MA). As the subdivisions within the main populations were not well supported by the ∆K values (Additional file 2: Figure S1), sub-clustering was carefully re-evaluated using the other analytical methods described.

Bottom Line: 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.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.Also, the genetic differences seen between the dermatotropic and viscerotropic strains might be connected with the difference in pathogenicity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Microbiology and Hygiene, Charité-University Medicine Berlin, Hindenburgdamm 30, 12203 Berlin, Germany. lena.krayter@charite.de.

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.

Show MeSH
Related in: MedlinePlus