111 research outputs found
The Genetic Relationship between Leishmania aethiopica and Leishmania tropica Revealed by Comparing Microsatellite Profiles
Background Leishmania (Leishmania) aethiopica and L. (L.) tropica cause
cutaneous leishmaniases and appear to be related. L. aethiopica is
geographically restricted to Ethiopia and Kenya; L. tropica is widely
dispersed from the Eastern Mediterranean, through the Middle East into eastern
India and in north, east and south Africa. Their phylogenetic inter-
relationship is only partially revealed. Some studies indicate a close
relationship. Here, eight strains of L. aethiopica were characterized
genetically and compared with 156 strains of L. tropica from most of the
latter species' geographical range to discern the closeness.
Methodology/Principal Findings Twelve unlinked microsatellite markers
previously used to genotype strains of L. tropica were successfully applied to
the eight strains of L. aethiopica and their microsatellite profiles were
compared to those of 156 strains of L. tropica from various geographical
locations that were isolated from human cases of cutaneous and visceral
leishmaniasis, hyraxes and sand fly vectors. All the microsatellite profiles
were subjected to various analytical algorithms: Bayesian statistics,
distance-based and factorial correspondence analysis, revealing: (i) the
species L. aethiopica, though geographically restricted, is genetically very
heterogeneous; (ii) the strains of L. aethiopica formed a distinct genetic
cluster; and (iii) strains of L. aethiopica are closely related to strains of
L. tropica and more so to the African ones, although, by factorial
correspondence analysis, clearly separate from them. Conclusions/Significance
The successful application of the 12 microsatellite markers, originally
considered species-specific for the species L. tropica, to strains of L.
aethiopica confirmed the close relationship between these two species. The
Bayesian and distance-based methods clustered the strains of L. aethiopica
among African strains of L. tropica, while the factorial correspondence
analysis indicated a clear separation between the two species. There was no
correlation between microsatellite profiles of the eight strains of L.
aethiopica and the type of leishmaniasis, localized (LCL) versus diffuse
cutaneous leishmaniasis (DCL), displayed by the human cases
Moroccan Leishmania infantum: genetic diversity and population structure as revealed by multi-locus microsatellite typing
Leishmaniasis in Germany
In 2000, a reference center was created to systematically record leishmaniases in Germany. We analyzed 58 cases of leishmaniases imported during a 2-year period. These findings will serve as a baseline for the sandfly vector’s anticipated northward move because of global warming and as an advisory for immunocompromised persons traveling to leishmaniasis-endemic areas
Leishmania donovani populations in Eastern Sudan: temporal structuring and a link between human and canine transmission.
BACKGROUND: Visceral leishmaniasis (VL), caused by the members of the Leishmania donovani complex, has been responsible for devastating VL epidemics in the Sudan. Multilocus microsatellite and sequence typing studies can provide valuable insights into the molecular epidemiology of leishmaniasis, when applied at local scales. Here we present population genetic data for a large panel of strains and clones collected in endemic Sudan between 1993 and 2001. METHODS: Genetic diversity was evaluated at fourteen microsatellite markers and eleven nuclear sequence loci across 124 strains and clones. RESULTS: Microsatellite data defined six genetic subpopulations with which the nuclear sequence data were broadly congruent. Pairwise estimates of FST (microsatellite) and KST (sequence) indicated small but significant shifts among the allelic repertoires of circulating strains year on year. Furthermore, we noted the co-occurrence of human and canine L. donovani strains in three of the six clusters defined. Finally, we identified widespread deficit in heterozygosity in all four years tested but strong deviation from inter-locus linkage equilibrium in two years. CONCLUSIONS: Significant genetic diversity is present among L. donovani in Sudan, and minor population structuring between years is characteristic of entrenched, endemic disease transmission. Seasonality in vector abundance and transmission may, to an extent, explain the shallow temporal clines in allelic frequency that we observed. Genetically similar canine and human strains highlight the role of dogs as important local reservoirs of visceral leishmaniasis
Multilocus Microsatellite Typing reveals intra-focal genetic diversity among strains of Leishmania tropica in Chichaoua Province, Morocco
AbstractIn Morocco, cutaneous leishmaniasis (CL) caused by Leishmania (L.) tropica is a major public health threat. Strains of this species have been shown to display considerable serological, biochemical, molecular biological and genetic heterogeneity; and Multilocus Enzyme Electrophoresis (MLEE), has shown that in many countries including Morocco heterogenic variants of L. tropica can co-exist in single geographical foci. Here, the microsatellite profiles discerned by MLMT of nine Moroccan strains of L. tropica isolated in 2000 from human cases of CL from Chichaoua Province were compared to those of nine Moroccan strains of L. tropica isolated between 1988 and 1990 from human cases of CL from Marrakech Province, and also to those of 147 strains of L. tropica isolated at different times from different worldwide geographical locations within the range of distribution of the species. Several programs, each employing a different algorithm, were used for population genetic analysis. The strains from each of the two Moroccan foci separated into two phylogenetic clusters independent of their geographical origin. Genetic diversity and heterogeneity existed in both foci, which are geographically close to each other. This intra-focal distribution of genetic variants of L. tropica is not considered owing to in situ mutation. Rather, it is proposed to be explained by the importation of pre-existing variants of L. tropica into Morocco
Leishmania siamensis als Erreger von autochthoner kutaner Leishmaniose bei Pferden in Deutschland - eine neue Infektionskrankheit in Mitteleuropa?
Aus mitteleuropäischer Sicht ist die durch Parasiten verursachte und von Sandmücken übertragene Leishmaniose eine in Ländern tropischer und subtropischer Regionen
auftretende Infektionskrankheit. In zunehmendem Maße werden jedoch autochthone Fälle in Mitteleuropa, insbesondere in Süddeutschland, verzeichnet. Dies ist vermutlich auf die globale Erwärmung und die Ausdehnung des Verbreitungsgebietes der Sandmücken nach Norden zurückzuführen. Die vorliegende Arbeit befasst sich mit der Identifizierung und phylogenetischen Charakterisierung der Erreger dieser Fälle. Dazu wurden verschiedene Marker im Leishmaniengenom sequenziert und mit bekannten Arten verglichen. Die untersuchte DNA stammte von autochthonen kutanen Leishmaniosen bei Pferden und einem Rind, die in den letzten zehn Jahren in Deutschland und der Schweiz auftraten. Aufgrund identischer Sequenzen konnten die Parasiten als L. siamensis identifiziert bzw. verifiziert werden, eine erst im Jahr 2008 neu beschriebene Art, die in Thailand humane viszerale Leishmaniose verursacht. Die phylogenetischen Analysen zeigten die Ähnlichkeit von L. siamensis mit weiteren bisher nicht identifizierten Stämmen aus Martinique und Ghana, die kutane Leishmaniose bei Menschen verursachen. Um die Frage zu beantworten, ob sich die Leishmaniose zu einer in Mitteleuropa endemischen zoonotischen Krankheit entwickeln könnte, müssen weitere Studien über kompatible Vektoren, mögliche Reservoire und zur Virulenz durchgeführt werden
temporal structuring and a link between human and canine transmission
Background Visceral leishmaniasis (VL), caused by the members of the
Leishmania donovani complex, has been responsible for devastating VL epidemics
in the Sudan. Multilocus microsatellite and sequence typing studies can
provide valuable insights into the molecular epidemiology of leishmaniasis,
when applied at local scales. Here we present population genetic data for a
large panel of strains and clones collected in endemic Sudan between 1993 and
2001. Methods Genetic diversity was evaluated at fourteen microsatellite
markers and eleven nuclear sequence loci across 124 strains and clones.
Results Microsatellite data defined six genetic subpopulations with which the
nuclear sequence data were broadly congruent. Pairwise estimates of FST
(microsatellite) and KST (sequence) indicated small but significant shifts
among the allelic repertoires of circulating strains year on year.
Furthermore, we noted the co-occurrence of human and canine L. donovani
strains in three of the six clusters defined. Finally, we identified
widespread deficit in heterozygosity in all four years tested but strong
deviation from inter-locus linkage equilibrium in two years. Conclusions
Significant genetic diversity is present among L. donovani in Sudan, and minor
population structuring between years is characteristic of entrenched, endemic
disease transmission. Seasonality in vector abundance and transmission may, to
an extent, explain the shallow temporal clines in allelic frequency that we
observed. Genetically similar canine and human strains highlight the role of
dogs as important local reservoirs of visceral leishmaniasis
Moroccan Leishmania infantum: Genetic Diversity and Population Structure as Revealed by Multi-Locus Microsatellite Typing
Leishmania infantum causes Visceral and cutaneous leishmaniasis in northern Morocco. It predominantly affects
children under 5 years with incidence of 150 cases/year. Genetic variability and population structure have been
investigated for 33 strains isolated from infected dogs and humans in Morocco. A multilocus microsatellite typing
(MLMT) approach was used in which a MLMtype based on size variation in 14 independent microsatellite markers
was compiled for each strain. MLMT profiles of 10 Tunisian, 10 Algerian and 21 European strains which belonged to
zymodeme MON-1 and non-MON-1 according to multilocus enzyme electrophoresis (MLEE) were included for
comparison. A Bayesian model-based approach and phylogenetic analysis inferred two L.infantum sub-populations;
Sub-population A consists of 13 Moroccan strains grouped with all European strains of MON-1 type; and subpopulation
B consists of 15 Moroccan strains grouped with the Tunisian and Algerian MON-1 strains. Theses subpopulations
were significantly different from each other and from the Tunisian, Algerian and European non MON-1
strains which constructed one separate population. The presence of these two sub-populations co-existing in
Moroccan endemics suggests multiple introduction of L. infantum from/to Morocco; (1) Introduction from/to the
neighboring North African countries, (2) Introduction from/to the Europe. These scenarios are supported by the
presence of sub-population B and sub-population A respectively. Gene flow was noticed between sub-populations A
and B. Five strains showed mixed A/B genotypes indicating possible recombination between the two populations.
MLMT has proven to be a powerful tool for eco-epidemiological and population genetic investigations of Leishmania.The fieldwork and data collection was granted by Pastur Institute in Morocco for Dr. Meryem Lemrani. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Variability of Cutaneous Leishmaniasis Lesions Is Not Associated with Genetic Diversity of Leishmania tropica in Khyber Pakhtunkhwa Province of Pakistan.
Leishmania tropica is the causative agent of cutaneous leishmaniasis in Pakistan. Here, intraspecific diversity of L. tropica from northern Pakistan was investigated using multilocus microsatellite typing. Fourteen polymorphic microsatellite markers were typed in 34 recently collected L. tropica isolates from Pakistan along with 158 archival strains of diverse Afro-Eurasian origins. Previously published profiles for 145 strains of L. tropica originating from different regions of Africa, Central Asia, Iran, and Middle East were included for comparison. Six consistently well-supported genetic groups were resolved: 1) Asia, 2) Morroco A, 3) Namibia and Kenya A, 4) Kenya B/Tunisia and Galilee, 5) Morocco B, and 6) Middle East. Strains from northern Pakistan were assigned to Asian cluster except for three that were placed in a geographically distant genetic group; Morocco A. Lesion variability among these Pakistani strains was not associated with specific L. tropica genetic profile. Pakistani strains showed little genetic differentiation from strains of Iraq, Afghanistan, and Syria (FST = 0.00-0.06); displayed evidence of modest genetic flow with India (FST = 0.14). Furthermore, genetic structuring within these isolates was not geographically defined. Pak-Afghan cluster was in significant linkage disequilibrium (IA = 1.43), had low genetic diversity, and displayed comparatively higher heterozygosity (FIS = -0.62). Patterns of genetic diversity observed suggest dominance of a minimally diverse clonal lineage within northern Pakistan. This is surprising as a wide clinical spectrum was observed in patients, suggesting the importance of host and other factors. Further genotyping studies of L. tropica isolates displaying different clinical phenotypes are required to validate this potentially important observation
Epidemiological and clinical features of cutaneous leishmaniases in Jenin District,Palestine, including characterisation of the causative agents in clinical samples
During 2002–2009, 466 cases of cutaneous leishmaniasis (CL) were reported from Jenin
District, Palestine, affecting both genders. The average annual incidence was 23 cases per
100 000 inhabitants, increasing with age in children. Most cases presented a single lesion,
generally on the face. Diagnosis and species identification was done by applying internal
transcribed spacer 1 (ITS1) RFLP analysis to 47 isolates, of which 44 (93.6%) were Leishmania
tropica and 3 (6.4%) were L. major. RFLP analysis was also performed on 256 skin tissue scrapings
spotted onto filter papers, showing that 138 (53.9%) were positive, of which 50.7% were
infected with L. tropica, 17.4% with L. major and 2.9% with L. donovani s.l., and 29.0% could
not be identified. This is the first report from Palestine on human CL caused by L. infantum.
Nine of the strains of L. tropica were subjected to multilocus enzyme electrophoresis, six
of which belonged to the zymodeme MON-137 and three to a new zymodeme (MON-307).
This separation was corroborated by excreted factor serotyping. This observation modifies
the classical epidemiological view of CL in Palestine. Jenin District is an active focus of CL
caused by L. tropica, where Phlebotomus sergenti, the putative vector, is abundant. These
data suggest that CL is a zoonotic infection, but an animal reservoir has not been found.This research was supported by the
Deutsche Forschungsgemeinschaft (DFG) as part of a
German–Israeli–Palestinian co-operation project on the
Emergence of Cutaneous Leishmaniasis in the Middle East:
an investigation of Leishmania tropica in the Palestinian
Authority and Israel
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