The Montpellier Leishmania Collection, from a Laboratory Collection to a Biological Resource Center: A 39-Year-Long Story.

We report the development of a laboratory collection of Leishmania that was initiated in 1975 and, after 39 years, has become an international Biological Resource Center (BRC-Leish, Montpellier, France, BioBank No. BB-0033-00052), which includes 6353 strains belonging to 36 Leishmania taxa. This is a retrospective analysis of the technical and organizational changes that have been adopted over time to take into account the technological advances and related modifications in the collection management and quality system. The technical improvements concerned the culture and cryopreservation techniques, strain identification by isoenzymatic and molecular techniques, data computerization and quality management to meet the changes in international standards, and in the cryogenic and microbiological safety procedures. The BRC is working toward obtaining the NF-S 96-900 certification in the coming years. Our long-term expertise in Leishmania storage and typing and collection maintenance should encourage field epidemiologists and clinical practitioners in endemic countries to secure their own strain collection with the help of the French BRC-Leish.

Single-molecule analysis of DNA replication reveals novel features in the divergent eukaryotes Leishmania and Trypanosoma brucei versus mammalian cells.

Leishmania and Trypanosoma are unicellular parasites that possess markedly original biological features as compared to other eukaryotes. The Leishmania genome displays a constitutive 'mosaic aneuploidy', whereas in Trypanosoma brucei, the megabase-sized chromosomes are diploid. We accurately analysed DNA replication parameters in three Leishmania species and Trypanosoma brucei as well as mouse embryonic fibroblasts (MEF). Active replication origins were visualized at the single molecule level using DNA molecular combing. More than one active origin was found on most DNA fibres, showing that the chromosomes are replicated from multiple origins. Inter-origin distances (IODs) were measured and found very large in trypanosomatids: the mean IOD was 160 kb in T. brucei and 226 kb in L. mexicana. Moreover, the progression of replication forks was faster than in any other eukaryote analyzed so far (mean velocity 1.9 kb/min in T. brucei and 2.4-2.6 kb/min in Leishmania). The estimated total number of active DNA replication origins in trypanosomatids is ~170. Finally, 14.4% of unidirectional replication forks were observed in T. brucei, in contrast to 1.5-1.7% in Leishmania and 4% in MEF cells. The biological significance of these original features is discussed.

Global distribution maps of the leishmaniases.

The leishmaniases are vector-borne diseases that have a broad global distribution throughout much of the Americas, Africa, and Asia. Despite representing a significant public health burden, our understanding of the global distribution of the leishmaniases remains vague, reliant upon expert opinion and limited to poor spatial resolution. A global assessment of the consensus of evidence for leishmaniasis was performed at a sub-national level by aggregating information from a variety of sources. A database of records of cutaneous and visceral leishmaniasis occurrence was compiled from published literature, online reports, strain archives, and GenBank accessions. These, with a suite of biologically relevant environmental covariates, were used in a boosted regression tree modelling framework to generate global environmental risk maps for the leishmaniases. These high-resolution evidence-based maps can help direct future surveillance activities, identify areas to target for disease control and inform future burden estimation efforts.

Global database of leishmaniasis occurrence locations, 1960-2012.

The leishmaniases are neglected tropical diseases of significant public health importance. However, information on their global occurrence is disparate and sparse. This database represents an attempt to collate reported leishmaniasis occurrences from 1960 to 2012. Methodology for the collection of data from the literature, abstraction of case locations and data processing procedures are described here. In addition, strain archives and online data resources were accessed. A total of 12,563 spatially and temporally unique occurrences of both cutaneous and visceral leishmaniasis comprise the database, ranging in geographic scale from villages to states. These data can be used for a variety of mapping and spatial analyses covering multiple resolutions.

Geographical distribution and epidemiological features of Old World Leishmania infantum and Leishmania donovani foci, based on the isoenzyme analysis of 2277 strains.

A series of 2277 Leishmania strains from Old World visceral leishmaniasis foci, isolated between 1973 and 2008, were studied by isoenzyme analysis. The strains were obtained from humans, domestic and wild carnivores, rodents and phlebotomine sandflies, and came from 36 countries. In all, 60 different zymodemes were identified and clustered by a phenetic analysis into 3 different groups corresponding to the typically visceralizing species L. donovani (20 zymodemes, 169 strains), L. archibaldi (3 zymodemes, 46 strains) and L. infantum (37 zymodemes, 2,062 strains). The taxonomic position of these isoenzymatic groups is discussed in view of contradictory results obtained from recent molecular studies.

Geographical distribution and epidemiological features of Old World cutaneous leishmaniasis foci, based on the isoenzyme analysis of 1048 strains.

A series of 1048 Leishmania strains from Old World cutaneous leishmaniasis foci, isolated between 1981 and 2005, were studied by isoenzyme analysis. The strains were obtained from humans, rodents, dogs and sandflies from 33 countries. The four typically dermotropic species, Leishmania major, L. tropica, L. aethiopica and L. killicki, were found. The viscerotropic species L. donovani and L. infantum, which can occasionally be responsible for cutaneous leishmaniasis, are not considered in this paper. Leishmania major was the least polymorphic species (12 zymodemes, 638 strains). Leishmania tropica was characterized by a complex polymorphism varying according to focus (35 zymodemes, 329 strains). Leishmania aethiopica, a species restricted to East Africa, showed a high polymorphism, in spite of a limited number of strains (23 zymodemes, 40 strains). Leishmania killicki, mainly restricted to Tunisia had a single zymodeme for 39 strains. Recently a parasite close to L. killicki (one zymodeme, two strains) was isolated in Algeria, which lead us to revise the taxonomic status of this taxon.

The potential effects of global warming on changes in canine leishmaniasis in a focus outside the classical area of the disease in southern France.

In 1994, an ecoepidemiologic study was carried out in the mid-Ariège valley (French Pyrenees) where autochthonous cases of canine leishmaniasis had been previously reported. Serologic samples were collected from 336 dogs in two groups of villages. The seroprevalences were 11.67% in the valley villages and only 1.43% in the foothill villages. Five lymph node biopsies were taken from serologically positive dogs, and resultant isolates were identified as Leishmania infantum zymodeme MON-1. Phlebotomine sandflies were collected in five locations by CDC light traps. Both of the known French vectors, Phlebotomus ariasi and P. perniciosus, were identified. Bioclimatic and floristic studies showed that this area is an enclave of the supra-Mediterranean climatic zone, containing a typically xerothermophilic Mediterranean flora. The Pyrenees Mountains are usually considered to be outside of the endemic range of leishmaniasis in southern France, and so our demonstration of a microfocus of canine leishmaniasis in the northern foothills is noteworthy. A second serologic survey carried out in 2007 (216 dogs) showed an inversion of the seropositive rates between the two groups of villages compared with those of 1994: only 2.72% in the valley villages and 11.32% in the foothills villages. The decrease of seroprevalence in the first area (valley villages) can be related to a considerable use of deltamethrin collars during the transmission season. The increase of seroprevalence of the foothill villages could be related to climatic conditions, since there was an increase of about 1 degrees C in the mean annual temperature.