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Leishmania are intracellular protozoan parasites that cause the vectorborne disease leishmaniasis, which occurs in [approximately equal to] 88 countries (1). Human infection can result in 2 main forms of disease, [...]

Tegumentary leishmaniasis (TL) is endemic but neglected in southern Europe. Therefore, this study aimed to analyze the Leishmania strains causing TL cases in northeastern Italy, where an upsurge of TL cases has been observed in the last decade. Sections from 109 formalin-fixed and paraffin-embedded (FFPE) biopsies of skin and mucosal tissues were collected from TL cases in the selected area. Two DNA targets were amplified and sequenced: the ribosomal internal transcribed spacer 1 (ITS1) and the heat-shock protein 70 gene (hsp70). An in silico analysis was also performed on 149 genomes belonging to the Leishmania donovani complex. A total of 88 out of 109 (80.7%) samples from 83 TL cases were successfully typed by ITS1 and/or hsp70. ITS1 analysis identified L. infantum in 67 cases (91.8%), while L. major (n = 4, 5.5%) and L. tropica (n = 2, 2.7%) were detected in the remaining cases that were categorized as imported. Further, the hsp70 typing of 75 autochthonous cases showed the presence of eight distinct sequence variants belonging to the Leishmania donovani complex, with high genetic variability when compared to known L. infantum populations. In conclusion, our findings show that peculiar L. infantum variants are emerging in the novel focus on TL in northeastern Italy. [ABSTRACT FROM AUTHOR]

Visceral leishmaniasis (VL), the fatal form of a parasitic disease caused by Leishmania donovani complex, has been known to exist in southern Somalia since the 1930s, but its presence in [...]

Visceral leishmaniasis (VL), also known as kala-azar, is a fatal vector-borne parasitic disease. Worldwide incidence is 500,000 cases per year; ≅ 90% of cases occur in India, Nepal, Bangladesh, Sudan, [...]

Background: Cutaneous leishmaniasis (CL) is frequent in travellers and can involve oro-nasal mucosae. Clinical presentation impacts therapeutic management. Methodology: Demographic and clinical data from 459 travellers infected in 47 different countries were collected by members of the European LeishMan consortium. The infecting Leishmania species was identified in 198 patients. Principal findings: Compared to Old World CL, New World CL was more frequently ulcerative (75% vs 47%), larger (3 vs 2cm), less frequently facial (17% vs 38%) and less frequently associated with mucosal involvement (2.7% vs 5.3%). Patients with mucosal lesions were older (58 vs 30 years) and more frequently immunocompromised (37% vs 3.5%) compared to patients with only skin lesions. Young adults infected in Latin America with L. braziliensis or L. guyanensis complex typically had an ulcer of the lower limbs with mucosal involvement in 5.8% of cases. Typically, infections with L. major and L. tropica acquired in Africa or the Middle East were not associated with mucosal lesions, while infections with L. infantum, acquired in Southern Europe resulted in slowly evolving facial lesions with mucosal involvement in 22% of cases. Local or systemic treatments were used in patients with different clinical presentations but resulted in similarly high cure rates (89% vs 86%). Conclusion/Significance: CL acquired in L. infantum-endemic European and Mediterranean areas displays unexpected high rates of mucosal involvement comparable to those of CL acquired in Latin America, especially in immunocompromised patients. When used as per recommendations, local therapy is associated with high cure rates. Author summary: Cutaneous and muco-cutaneous leishmaniasis (CL and MCL) are disfiguring diseases caused by a worldwide distributed parasite called Leishmania and its 20 species. Clinical manifestations span a wide continuum from single nodular lesion to disseminated form with mucosal involvement. No randomized clinical trial has ever been done exclusively in travellers and medical management is poorly evidence-based or based very predominantly on data obtained in endemic countries. Articles and reviews almost invariably propose a dichotomic view, with Old World CL described as a benign disease in contrast to New World CL strongly associated with destructive mucosal lesions. Our study is the first prospective clinical study providing a detailed description of the clinical presentation and risk of mucosal involvement in CL in several hundreds of patients , with frequent formal identification of the infecting Leishmania species. The harmonized data collection in patients infected in many transmission foci worldwide enabled direct comparisons of clinical patterns induced by different Leishmania species, and on the outcome following treatment with either local or systemic regimens. The study is based on an international harmonized data collection that allowed a wide capture of parasitologically confirmed cases. In striking contrast with previous assumptions, the study shows that CL acquired in Europe displays unexpected high rates of mucosal involvement comparable to those of CL acquired in Latin America, especially in immunocompromised travellers. It also shows that when used as per recommendations, local therapy is associated with high cure rates. [ABSTRACT FROM AUTHOR]

Abstract Background Peru is one of the Latin American countries with the highest malaria burden, mainly due to Plasmodium vivax infections. However, little is known about P. vivax transmission dynamics in the Peruvian Amazon, where most malaria cases occur. The genetic diversity and population structure of P. vivax isolates collected in different communities around Iquitos city, the capital of the Peruvian Amazon, was determined. Methods Plasmodium vivax population structure was determined by multilocus genotyping with 16 microsatellites on 159 P. vivax infected blood samples (mono-infections) collected in four sites around Iquitos city. The population characteristics were assessed only in samples with monoclonal infections (n = 94), and the genetic diversity was determined by calculating the expected heterozygosity and allelic richness. Both linkage disequilibrium and the genetic differentiation (θ) were estimated. Results The proportion of polyclonal infections varied substantially by site (11% - 70%), with the expected heterozygosity ranging between 0.44 and 0.69; no haplotypes were shared between the different populations. Linkage disequilibrium was present in all populations (IAS 0.14 - 0.61) but was higher in those with fewer polyclonal infections, suggesting inbreeding and a clonal population structure. Strong population differentiation (θ = 0.45) was found and the Bayesian inference cluster analysis identified six clusters based on distinctive allele frequencies. Conclusion The P. vivax populations circulating in the Peruvian Amazon basin are genetically diverse, strongly differentiated and they have a low effective recombination rate. These results are in line with the low and clustered pattern of malaria transmission observed in the region around Iquitos city.

Background: We designed a straightforward method for discriminating circulating Leishmania populations in the Indian subcontinent (ISC). Research on transmission dynamics of visceral leishmaniasis (VL, or Kala-azar) was recently identified as one of the key research priorities for elimination of the disease in the ISC. VL in Bangladesh, India, and Nepal is caused by genetically homogeneous populations of Leishmania donovani parasites, transmitted by female sandflies. Classical methods to study diversity of these protozoa in other regions of the world, such as microsatellite typing, have proven of little use in the area, as they are not able to discriminate most genotypes. Recently, whole genome sequencing (WGS) so far identified 10 different populations termed ISC001-ISC010. Methodology / Principle findings: As an alternative to WGS for epidemiological or clinical studies, we designed assays based on PCR amplification followed by dideoxynucleotide sequencing for identification of the non-recombinant genotypes ISC001 up to ISC007. These assays were applied on 106 parasite isolates collected in Nepal between 2011 and 2014. Combined with data from WGS on strains collected in the period 2002–2011, we provide a proof-of-principle for the application of genotyping to study treatment outcome, and differential geographic distribution. Conclusions / Significance: Our method can aid in epidemiological follow-up of visceral leishmaniasis in the Indian subcontinent, a necessity in the frame of the Kala-azar elimination initiative in the region. [ABSTRACT FROM AUTHOR]