Multi‐Site DNA Polymorphism Analyses of Leishmania Isolates Define their Genotypes Predicting Clinical Epidemiology of Leishmaniasis in a Specific Region

Abstract

Leishmania isolates from 57 cases of human cutaneous (CL), human visceral (VL), and canine visceral (CVL) leishmaniasis in Turkey were grouped by multi-site DNA polymorphism analyses into five genotypes. The initial grouping was based on DNA heterogeneity of the faster-evolving mitochondrion (kinetoplast) minicircles and the intergenic regions of two nuclear repetitive genes. Taxonomic affiliation and phylogenetic relationships of the five genotypes were inferred by comparing them with reference species for sequence heterogeneity in a approximately 1.4 kb conserved single-copy gene, encoding N-acetylglucosamine-1-phosphate transferase (NAGT). Alignment of the available sequences revealed no gap, but up to 7% scattered base substitutions, suggesting that this functionally important gene is a suitable marker. Three genotypes are completely identical to the NAGTs of the reference species, identifying them as L. infantum, L. tropica. and L. major, respectively. The remaining two are recognized as L. major NAGT variants with one and four base substitutions, respectively. As expected, Maximum Likelihood analysis of the NAGT sequences separates them into three clades, corresponding to the three species. The majority of the isolates obtained are L. infantum and L. tropica, which have been known to cause infantile VL and anthroponotic CL in western and southeastern Turkey, respectively. Unexpected is the finding of Leishmania major variants and their dispersal, possibly as previously unrecognized clinico-epidemiologic entities of CL and VL.

Genetic Polymorphism and Molecular Epidemiology ofLeishmania(Viannia)braziliensisfrom Different Hosts and Geographic Areas in Brazil

“…Another cluster comprises parasites from rural localities in Espírito Santo and Pernambuco, where Lutzomyia whitmani is the principal vector species. Other studies using different molecular markers have demonstrated a geographic structuring of Leishmania parasites (2,16,23,33,34), and populations of L. (V.) braziliensis isolates collected from geographically closed areas seem to be more genetically similar (12,24). However, the present study indicates that the geographic structuring of L. (V.) braziliensis reflects the plasticity of these parasites to adapt to different vector species (or populations of this vectors) involved in the transmission cycle.…”

Antimonial Therapy Induces Circulating Proinflammatory Cytokines in Patients with Cutaneous Leishmaniasis

“…TNF-␣ has been shown to be a major NF-B-activating signal for macrophage activation (10). Thus, secretion of TNF-␣ by macrophages is sufficient to mediate production of NO and killing of L. major parasites (2). It has also been demonstrated that TNF-␣ levels were higher in the sera of pretreatment CL patients (16).…”

“…The protozoan parasite Leishmania major infects mononuclear phagocytes, and control of the infection depends on adequate activation of the infected macrophages to kill parasites and inhibit their replication (2). The microbicidal activity of macrophages in an inflammatory milieu has been related to production of a large number of cytokines and intermediary metabolites of oxygen and nitrogen (3,8,11).…”

Detection of Leishmania causing visceral leishmaniasis in the Old and New Worlds by a polymerase chain reaction assay based on telomeric sequences.

“…Confirmatory identification of nonreference strains was performed by either isoenzymatic, kinetoplast DNA (kDNA), or nuclear DNA sequences analyses. [6][7][8][9][10][11] The methods used for each strain are indicated in Tables 1 and 2. Some strains may not have been typed, although other isolates from the same sites were confirmed.…”