Species diversity of Leishmania (Viannia) parasites circulating in an endemic area for cutaneous leishmaniasis located in the Atlantic rainforest region of northeastern Brazil

Incidence of Human and Free-Ranging Wild Rodent Infections with Leishmania (Viannia) braziliensis, Aetiological Agent of Cutaneous Leishmaniasis

BACKGROUND

Human and wild rodent infection rates with Leishmania (Viannia) braziliensis are needed to differentiate transmission pathways in anthropogenically altered habitats.

METHODS

Human participants in northeast Brazil were tested by the leishmanin skin test (LST) and inspected for lesions/scars characteristic of American clinical leishmaniasis (ACL). Molecular (PCR/qPCR) test records of free-ranging rodents were available from a concurrent capture-mark-recapture study. Force of Infection (λ) and recovery (ρ) rates were estimated from cross-sectional and longitudinal datasets.

RESULTS

Cumulative prevalences of human LST+ves and ACL scar+ves were 0.343-0.563 (n = 503 participants) and 0.122-0.475 (n = 503), respectively. Active ACL lesions were not detected. Annual rates of LST conversions were λ = 0.03-0.15 and ρ = 0.02-0.07. The probability of infection was independent of sex and associated with increasing age in addition to the period of exposure. Rodents (n = 596 individuals of 6 species) showed high rates of exclusively asymptomatic infection (λ = 0.222/month) and potential infectiousness to the sand fly vector. Spatially concurrent rodent and household human infection prevalences were correlated.

CONCLUSIONS

Human exposure to L. (V.) braziliensis continues to be high despite the substantial drop in reported ACL cases in recent years. Spill-over transmission risk to humans from rodents in peridomestic habitats is likely supported by a rodent infection/transmission corridor linking houses, plantations, and the Atlantic Forest.

HRM Accuracy and Limitations as a Species Typing Tool for Leishmania Parasites

High Resolution Melting Analysis (HRM) has been pointed out as a suitable alternative method to detect and identify Leishmania species. Herein, we aimed to evaluate the sensitivity, specificity, accuracy, and limitations of a HSP70-HRM protocol both as a diagnostic scheme applied in clinical samples and as a species typing tool for laboratory research and reference services. Our data reveal the pronounced species-typing potential of the HSP70-HRM in DNA from cultured parasites. For clinical samples, however, we advise caution due to parasite load-dependent accuracy. In light of these findings and considering the importance of parasite load determination for clinical and research purposes, we recommend the integration of the presented typing scheme and the previously published Leishmania quantifying approach as combined tools for clinicians, surveillance, and research.

Genome Analysis of Triploid Hybrid Leishmania Parasite from the Neotropics

We discovered a hybrid Leishmania parasite in Costa Rica that is genetically similar to hybrids from Panama. Genome analyses demonstrated the hybrid is triploid and identified L. braziliensis and L. guyanensis-related strains as parents. Our findings highlight the existence of poorly sampled Leishmania (Viannia) variants infectious to humans.

Novel CRISPR-based detection of Leishmania species

Tegumentary leishmaniasis, a disease caused by protozoan parasites of the genus Leishmania, is a major public health problem in many regions of Latin America. Its diagnosis is difficult given other conditions resembling leishmaniasis lesions and co-occurring in the same endemic areas. A combination of parasitological and molecular methods leads to accurate diagnosis, with the latter being traditionally performed in centralized reference and research laboratories as they require specialized infrastructure and operators. Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) systems have recently driven innovative tools for nucleic acid detection that combine high specificity, sensitivity and speed and are readily adaptable for point-of-care testing. Here, we harnessed the CRISPR-Cas12a system for molecular detection of Leishmania spp., emphasizing medically relevant parasite species circulating in Peru and other endemic areas in Latin America, with Leishmania (Viannia) braziliensis being the main etiologic agent of cutaneous and mucosal leishmaniasis. We developed two assays targeting multi-copy targets commonly used in the molecular diagnosis of leishmaniasis: the 18S ribosomal RNA gene (18S rDNA), highly conserved across Leishmania species, and a region of kinetoplast DNA (kDNA) minicircles conserved in the L. (Viannia) subgenus. Our CRISPR-based assays were capable of detecting down to 5 × 10⁻² (kDNA) or 5 × 10⁰ (18S rDNA) parasite genome equivalents/reaction with PCR preamplification. The 18S PCR/CRISPR assay achieved pan-Leishmania detection, whereas the kDNA PCR/CRISPR assay was specific for L. (Viannia) detection. No cross-reaction was observed with Trypanosoma cruzi strain Y or human DNA. We evaluated the performance of the assays using 49 clinical samples compared to a kDNA real-time PCR assay as the reference test. The kDNA PCR/CRISPR assay performed equally well as the reference test, with positive and negative percent agreement of 100%. The 18S PCR/CRISPR assay had high positive and negative percent agreement of 82.1% and 100%, respectively. The findings support the potential applicability of the newly developed CRISPR-based molecular tools for first-line diagnosis of Leishmania infections at the genus and L. (Viannia) subgenus levels.

Study on the zoonotic cycle of tegumentary leishmaniasis in an endemic area of a metropolitan region in the Northeastern region of Brazil

This study was conducted to characterize the transmission cycle of the tegumentary leishmaniasis (TL) in an old colonization area at Pernambuco State, Brazil. The aims were to identify autochthonous cases, sandflies fauna, domestic animals as possible reservoir hosts and the Leishmania species involved in this endemic area. A total of 168 suspected human cases of TL and 272 domestic animals (canine, feline, equine, goat, and sheep) were included. The sandflies were captured and identified by species. Patients were predominantly male and the average age was 37+18.1 years old. Of 85 patients who had skin lesions, 25.6% of them had direct positive smears for TL and 34 isolates were identified as Leishmania (Viannia) braziliensis. The confirmation for TL diagnosed by molecular detection (PCR) was almost three times more sensitive than the direct test [p < 0.001; PR = 2.72] associated with clinical examination. The Kappa test on PCR between two different specimens, biopsy, and skin lesion swab was 60.8% (p < 0.001). More than 200 specimens of sandflies (80 males and 159 females) were captured and identified as Lutzomyia whitmani (99.6%) and Lu. evandroi (0.4%). The detection of L. (V.) braziliensis by Real-Time PCR in the blood of a captured fed female was positive in 59.3% of Lu. whitmani. Of the 272 domestic animals included, 61.76% were male (n = 168). Thirty-six animals (13.2%) had lesions compatible with TL (34 dogs, 1 cat and 1 sheep) and 3 of them, all dogs, had lesions on the snout, showing destruction of cartilage and mucosa. The study suggests the participation of domestic animals as possible reservoirs. However, further studies are necessary to better understand the transmission cycle and take recommended measures in order to control the disease.

Parasite species variation and impact of spatial displacement of the population on cutaneous leishmaniasis in Rio de Janeiro, Brazil

BACKGROUND

Cutaneous leishmaniasis results from complex interactions between human beings, vectors and the environment. Parasitic species differ in epidemiological and geographical contexts.

METHODS

We studied a retrospective cohort of 696 patients with cutaneous leishmaniasis treated at a reference centre in the state of Rio de Janeiro, Brazil, between 2000 and 2015. We analysed displacements due to work, leisure and migrations with identification of Leishmania species.

RESULTS

The geographic distribution of autochthonous cases showed that >95% of infections occurred in urban areas. In the state of Rio de Janeiro, most cases were concentrated in the cities surrounding forest parks and nature conservation areas. The same applies to the city of Rio de Janeiro, where these infections occurred in the neighbourhoods surrounding some mountain and forest areas. The non-displacement group included 575 (82.6%) patients and the displacement group included 121 (17.4%) patients. Leishmania (Viannia) braziliensis predominated in both groups. Other species were found in the displacement group.

CONCLUSIONS

The disordered urbanization of the state of Rio de Janeiro in recent decades has created conditions for the emergence of urban foci of transmission close to forest areas. Changes in the environment, movement of infected individuals and adaptation of sandflies may have contributed to this.

miR-548d-3p Alters Parasite Growth and Inflammation in Leishmania (Viannia) braziliensis Infection

American Tegumentary Leishmaniasis (ATL) is an endemic disease in Latin America, mainly caused in Brazil by Leishmania (Viannia) braziliensis. Clinical manifestations vary from mild, localized cutaneous leishmaniasis (CL) to aggressive mucosal disease. The host immune response strongly determines the outcome of infection and pattern of disease. However, the pathogenesis of ATL is not well understood, and host microRNAs (miRNAs) may have a role in this context. In the present study, miRNAs were quantified using qPCR arrays in human monocytic THP-1 cells infected in vitro with L. (V.) braziliensis promastigotes and in plasma from patients with ATL, focusing on inflammatory response-specific miRNAs. Patients with active or self-healed cutaneous leishmaniasis patients, with confirmed parasitological or immunological diagnosis, were compared with healthy controls. Computational target prediction of significantly-altered miRNAs from in vitro L. (V.) braziliensis-infected THP-1 cells revealed predicted targets involved in diverse pathways, including chemokine signaling, inflammatory, cellular proliferation, and tissue repair processes. In plasma, we observed distinct miRNA expression in patients with self-healed and active lesions compared with healthy controls. Some miRNAs dysregulated during THP-1 in vitro infection were also found in plasma from self-healed patients, including miR-548d-3p, which was upregulated in infected THP-1 cells and in plasma from self-healed patients. As miR-548d-3p was predicted to target the chemokine pathway and inflammation is a central to the pathogenesis of ATL, we evaluated the effect of transient transfection of a miR-548d-3p inhibitor on L. (V.) braziliensis infected-THP-1 cells. Inhibition of miR-548d-3p reduced parasite growth early after infection and increased production of MCP1/CCL2, RANTES/CCL5, and IP10/CXCL10. In plasma of self-healed patients, MCP1/CCL2, RANTES/CCL5, and IL-8/CXCL8 concentrations were significantly decreased and MIG/CXCL9 and IP-10/CXCL10 increased compared to patients with active disease. These data suggest that by modulating miRNAs, L. (V.) braziliensis may interfere with chemokine production and hence the inflammatory processes underpinning lesion resolution. Our data suggest miR-548d-3p could be further evaluated as a prognostic marker for ATL and/or as a host-directed therapeutic target.

A Systematic Review (1990-2021) of Wild Animals Infected with Zoonotic Leishmania

Leishmaniasis are neglected diseases caused by several species of Leishmania that affect humans and many domestic and wild animals with a worldwide distribution. The objectives of this review are to identify wild animals naturally infected with zoonotic Leishmania species as well as the organs infected, methods employed for detection and percentage of infection. A literature search starting from 1990 was performed following the PRISMA methodology and 161 reports were included. One hundred and eighty-nine species from ten orders (i.e., Carnivora, Chiroptera, Cingulata, Didelphimorphia, Diprotodontia, Lagomorpha, Eulipotyphla, Pilosa, Primates and Rodentia) were reported to be infected, and a few animals were classified only at the genus level. An exhaustive list of species; diagnostic techniques, including PCR targets; infected organs; number of animals explored and percentage of positives are presented. L. infantum infection was described in 98 wild species and L. (Viania) spp. in 52 wild animals, while L. mexicana, L. amazonensis, L. major and L. tropica were described in fewer than 32 animals each. During the last decade, intense research revealed new hosts within Chiroptera and Lagomorpha. Carnivores and rodents were the most relevant hosts for L. infantum and L. (Viannia) spp., with some species showing lesions, although in most of the studies clinical signs were not reported.

Laboratory Diagnosis of Cutaneous and Visceral Leishmaniasis: Current and Future Methods

Leishmaniasis is a neglected tropical disease with two main clinical forms: cutaneous and visceral leishmaniasis. Diagnosis of leishmaniasis is still a challenge, concerning the detection and correct identification of the species of the parasite, mainly in endemic areas where the absence of appropriate resources is still a problem. Most accessible methods for diagnosis, particularly in these areas, do not include the identification of each one of more than 20 species responsible for the disease. Here, we summarize the main methods used for the detection and identification of leishmaniasis that can be performed by demonstration of the parasite in biological samples from the patient through microscopic examination, by in vitro culture or animal inoculation; by molecular methods through the detection of parasite DNA; or by immunological methods through the detection of parasite antigens that may be present in urine or through the detection of specific antibodies against the parasite. Potential new methods that can be applied for laboratory diagnosis of leishmaniasis are also discussed.

Duplex qPCR for Leishmania species identification using lesion imprint on filter paper

BACKGROUND

American cutaneous leishmaniasis (ACL) is caused by different Leishmania parasites, which stimulate and direct the immune response against the infection.

OBJECTIVE

To evaluate the TaqMan probe technology applicability to diagnose and identifying of Leishmania spp. related to the ACL etiology.

METHODOLOGY

Through the MEGA 6.0 software, performed an in silico analysis using multiple alignments of Leishmania spp. which were available on GenBank for different genomic targets. The efficiency (e), specificity and detection limit (DL) were calculated for each system, these were associated to compose a duplex-qPCR (DqPCR). The samples of blood, lesion biopsy and lesion imprint on filter paper from patients residing in states of Amazonas (AM) and Pernambuco (PE)-Brazil, (cases and controls) were used to perform the DqPCR technique. The capacity to identify the Leishmania species was determined by comparison with isoenzymes method and sequencing analysis.

RESULTS

Internal Transcribed Spacer 1 (rDNA) was the target selected. Two sets of primers and probes were designed and combined: SVS for subgenus Viannia and LaS for L. (L.) amazonensis. The results were: SVSe = 93.24%, SVS DL = 50 fg/μL; LaSe = 89.3%, LaSLD = 5 fg/μL presented 100% of specificity. In total, 236 individuals participated of the present study, wherein were 101 blood samples, 33 biopsies and 147 lesion imprints. The imprint was the most sensitive sample, showing 83.06% of sensitivity, 86.96% of specificity and substantial agreement between the techniques analysis (k = 0.531; p < 0,001). Regarding the species identification, DqPCR and sequencing/isoenzymes have agreed at 100%, since the infection is caused by a single Leishmania species.

CONCLUSION

The DqPCR technique was applicable in diagnosis and identification of Leishmania spp. (subgenus Viannia and L. amazonensis). Furthermore, the lesion imprint is less invasive, allowing a fewer discomfort and greater acceptance by the patients, in addition of being low cost and easy handling.

Intraspecific Genomic Divergence and Minor Structural Variations in Leishmania (Viannia) panamensis

Leishmania (Viannia) panamensis is one of the most important Leishmania species associated with cutaneous leishmaniasis (CL) in Latin America. Despite its wide geographic distribution and pathogenic potential in humans and animals, the genomic variability of this species is low compared with other Leishmania species circulating in the same geographical area. No studies have reported a detailed analysis of the whole genome of L. panamensis from clinical isolates using DNA high-throughput sequencing to clarify its intraspecific genomic variability or plausible divergence. Therefore, this study aimed to evaluate the intraspecific genomic variability of L. panamensis from Colombia and Panama. A total of 22 genomes were analyzed, 19 from Colombian patients with CL and three genomes from Panama obtained from public databases. The phylogenomic analysis revealed the potential existence of three well-supported clades as evidence of intraspecific divergence. Additionally, the whole-genome analysis showed low structural variations in terms of ploidy, copy number variations, and single-nucleotide polymorphisms (SNPs). SNPs shared among all clades were identified, revealing their importance in different biological processes of L. panamensis. The findings not only expand our knowledge of intraspecific genomic variability of one of the most important Leishmania species in South America but also highlights the possible existence of different clades/lineages/subpopulations across a geographic scale.

American tegumentary leishmaniasis diagnosis using L. (V.) braziliensis fixed promastigotes: a comparative performance of serological tests and spontaneous cure identification

BACKGROUND

The present study aimed to demonstrate the applicability of a flow cytometry-based serology approach to identify spontaneous cure by the detection of immunoglobulin G, and also, the diagnosis and cure criterion by the IgG1 isotype in American Tegumentary Leishmaniasis - ATL caused by L. (V.) braziliensis. Also, a comparison between flow cytometry with the serological conventional technique was performed.

METHODS

Forty five individuals were included in study. They were assessed in two moments: First, 8 subjects spontaneously cured of ATL, 8 healthy individuals and 15 patients who had a positive diagnosis for ATL were selected before treatment to identify spontaneous cure by immunoglobulin G detection. Secondly, 14 patients who were positive for ATL were selected and had their blood collected before and 1, 2 and 5 years after treatment, respectively, for the diagnostic tests (ELISA and flow cytometry) and cure criterion evaluation using the IgG1 isotype.

RESULTS

The analysis of the mean percentage of positive fluorescent parasites (PPFP) along with the titration curves of IgG anti-fixed promastigotes of L.(V.)braziliensis, confirmed the applicability of this method for monitoring spontaneous cure in ATL with outstanding co-positivity (100%) and co-negativity (100%) performance indexes. Regarding the results of the comparison between flow cytometry and ELISA it was seen that there was a better accuracy of the first one in relation to the other. When IgG1 applicability was evaluated, it was observed that before treatment, 36.8% of the patients were negative; in patients 1 year post-treatment, 82.3%; 2 years post-treatment, 27.2% and in patients 5 years post-treatment, 87.5%. The overall analysis of the results suggests that flow cytometry can be applied to ATL detection, and that the use of IgG1 isotype has possibilities to contribute as a more specific diagnostic method.

CONCLUSIONS

Therefore, this area has great perspectives use for the diagnosis and cure criterion, and also it can be scaled up with the possibility to characterize the different clinical stages of the disease. Together, these findings demonstrate the applicability of a flow cytometry-based serology approach and opens up new avenues of research with this technique, such as the understanding the humoral response in ATL patients.

Further insight into the geographic distribution of Leishmania species in Peru by cytochrome b and mannose phosphate isomerase gene analyses

To obtain further insight into geographic distribution of Leishmania species in Peru, a countrywide survey, including central to southern rainforest areas where information on causative parasite species is limited, was performed based on cytochrome b (cyt b) and mannose phosphate isomerase (mpi) gene analyses. A total of 262 clinical samples were collected from patients suspected of cutaneous leishmaniasis (CL) in 28 provinces of 13 departments, of which 99 samples were impregnated on FTA (Flinders Technology Associates) cards and 163 samples were Giemsa-stained smears. Leishmania species were successfully identified in 83 (83.8%) of FTA-spotted samples and 59 (36.2%) of Giemsa-stained smear samples. Among the 142 samples identified, the most dominant species was Leishmania (Viannia) braziliensis (47.2%), followed by L. (V.) peruviana (26.1%), and others were L. (V.) guyanensis, L. (V.) lainsoni, L. (V.) shawi, a hybrid of L. (V.) braziliensis and L. (V.) peruviana, and Leishmania (Leishmania) amazonensis. Besides the present epidemiological observations, the current study provided the following findings: 1) A hybrid of L. (V.) braziliensis and L. (V.) peruviana is present outside the Department of Huanuco, the only place reported, 2) Many cases of CL due to L. (V.) lainsoni, an uncommon causative species in Peru, were observed, and 3) L. (V.) shawi is widely circulating in southern Amazonian areas in Peru.

Leishmaniasis, a neglected tropical disease (NTD) caused by the intracellular protozoa of the genus Leishmania, affects at least 12 million people in 96 countries. Peru is one of the most highly endemic countries for cutaneous leishmaniasis (CL), and our previous study identified Leishmania (Viannia) braziliensis, L. (V.) peruviana, and L. (V.) guyanensis in the tropical rainforest, in the Andean highlands, and in the northern and central rainforest areas, respectively, as the main CL-causative agents. In addition, distribution of L. (V.) lainsoni, L. (V.) shawi, a hybrid of L. (V.) braziliensis and L. (V.) peruviana, and Leishmania (Leishmania) amazonensis has been identified. Of these, one case each of L. (V.) shawi infection was reported from the Departments of Junin and Madre de Dios, while clinical cases due to the hybrid of L. (V.) braziliensis and L. (V.) peruviana were recorded only in the Department of Huanuco. To further elucidate the current geographic distribution of causative Leishmania species in Peru, a countrywide survey, including central to southern rainforest areas where little information on causative parasites is available, was performed based on the cytochrome b (cyt b) gene sequence and PCR-RFLP analysis of the mannose phosphate isomerase (mpi) gene by using FTA (Flinders Technology Associates) card-spotted samples and smear slides as DNA sources. In addition to current epidemiological observations, the current study revealed that 1) A hybrid of L. (V.) braziliensis and L. (V.) peruviana was identified, for the first time, outside the Department of Huanuco, 2) L. (V.) lainsoni, an uncommon CL-causative species in Peru, was predominantly found in the Department of Puno, where causative Leishmania species are not well-studied, and 3) New endemic foci of L. (V.) shawi were identified in central to southern rainforest areas of Peru.

Identification of divergent Leishmania (Viannia) braziliensis ecotypes derived from a geographically restricted area through whole genome analysis

Leishmania braziliensis, the main etiological agent of cutaneous leishmaniasis (CL) in Latin America, is characterized by major differences in basic biology in comparison with better-known Leishmania species. It is also associated with a high phenotypic and possibly genetic diversity that need to be more adequately defined. Here we used whole genome sequences to evaluate the genetic diversity of ten L. braziliensis isolates from a CL endemic area from Northeastern Brazil, previously classified by Multi Locus Enzyme Electrophoresis (MLEE) into ten distinct zymodemes. These sequences were first mapped using the L. braziliensis M2904 reference genome followed by identification of Single Nucleotide Polymorphisms (SNPs). A substantial level of diversity was observed when compared with the reference genome, with SNP counts ranging from ~95,000 to ~131,000 for the different isolates. When the genome data was used to infer relationship between isolates, those belonging to zymodemes Z72/Z75, recovered from forested environments, were found to cluster separately from the others, generally associated with more urban environments. Among the remaining isolates, those from zymodemes Z74/Z106 were also found to form a separate group. Phylogenetic analyses were also performed using Multi-Locus Sequence Analysis from genes coding for four metabolic enzymes used for MLEE as well as the gene sequence coding for the Hsp70 heat shock protein. All 10 isolates were firmly identified as L. braziliensis, including the zymodeme Z26 isolate previously classified as Leishmania shawi, with the clustering into three groups confirmed. Aneuploidy was also investigated but found in general restricted to chromosome 31, with a single isolate, from zymodeme Z27, characterized by extra copies for other chromosomes. Noteworthy, both Z72 and Z75 isolates are characterized by a much reduced heterozygosity. Our data is consistent with the existence of distinct evolutionary groups in the restricted area sampled and a substantial genetic diversity within L. braziliensis.

Leishmania braziliensis is the main etiological agent of cutaneous leishmaniasis (CL) in Latin America. In the Pernambuco state, a highly endemic area for CL in Northeastern Brazil, ten zymodemes have been previously described, identified through the detection of variations in the mobility of selected enzymes on gel electrophoresis (MLEE). Here we used next-generation genome sequencing to reevaluate the genetic diversity and relatedness between isolates representing these zymodemes. The genetic analysis clustered these isolates into three distinct phylogenetic groups, with those circulating in forested environments more related to each other (Z72 and Z75) and separated from the other eight isolates from more urbanized environments, but nevertheless forming two further groups. All ten isolates were definitely identified as L. braziliensis, including one from zymodeme Z26, previously identified as L. shawi through MLEE. Chromosome copy number variation was observed in all isolates studied, but restricted mainly to chromosome 31, with a single isolate (from zymodeme Z27) showing more than two copies of other chromosomes. A low heterozygosity observed only for both Z72/Z75 isolates also confirm differences associated with them. Our findings confirm that MLEE, despite still being considered the gold standard for characterization of Leishmania spp., does not reflect relevant information on intra-specific variations. It also highlights the substantial diversity observed between L. braziliensis isolates.

The applicability of real-time PCR in the diagnostic of cutaneous leishmaniasis and parasite quantification for clinical management: Current status and perspectives

Cutaneous leishmaniasis (CL) is spread worldwide and is the most common manifestation of leishmaniasis. Diagnosis is performed by combining clinical and epidemiological features, and through the detection of Leishmania parasites (or DNA) in tissue specimens or trough parasite isolation in culture medium. Diagnosis of CL is challenging, reflecting the pleomorphic clinical manifestations of this disease. Skin lesions vary in severity, clinical appearance, and duration, and in some cases, they can be indistinguishable from lesions related to other diseases. Over the past few decades, PCR-based methods, including real-time PCR assays, have been developed for Leishmania detection, quantification and species identification, improving the molecular diagnosis of CL. This review provides an overview of many real-time PCR methods reported for the diagnostic evaluation of CL and some recommendations for the application of these methods for quantification purposes for clinical management and epidemiological studies. Furthermore, the use of real-time PCR for Leishmania species identification is also presented. The advantages of real-time PCR protocols are numerous, including increased sensitivity and specificity and simpler standardization of diagnostic procedures. However, despite the numerous assays described, there is still no consensus regarding the methods employed. Furthermore, the analytical and clinical validation of CL molecular diagnosis has not followed international guidelines so far. A consensus methodology comprising a DNA extraction protocol with an exogenous quality control and an internal reference to normalize parasite load is still needed. In addition, the analytical and clinical performance of any consensus methodology must be accurately assessed. This review shows that a standardization initiative is essential to guide researchers and clinical laboratories towards the achievement of a robust and reproducible methodology, which will permit further evaluation of parasite load as a surrogate marker of prognosis and monitoring of aetiological treatment, particularly in multi-centric observational studies and clinical trials.

Leishmania (Viannia) braziliensis isolated from the saliva of patients in a cutaneous leishmaniasis-endemic area of northeastern Brazil

Several studies have described the use of non-invasive collection methods, mostly based on the detection of parasite DNA, for diagnosis. However, no Leishmania specimens have been isolated from saliva. Here, we report the first isolation of Leishmania braziliensis from the saliva of humans with cutaneous leishmaniasis but without lesions on their mucosa. The isolates were obtained from salivary fluid inoculated in hamsters and were tested by multilocus enzyme electrophoresis. Seven samples from 43 patients suspected of having the disease were identified for in vivo culture. These findings suggest that saliva is a clinical sample that allows the isolation of Leishmania sp.

Multiplex PCR as a tool for the diagnosis of Leishmania spp. kDNA and the gapdh housekeeping gene of mammal hosts

Background

The PCR assays usually employed for Leishmania diagnosis does not simultaneously detect a constitutive gene that would certify the viability of the DNA sample. We present a multiplex PCR approach for the simultaneous diagnosis of the Leishmania sp. kDNA fragment and a catalytic domain segment of a conserved region of the mammalian gapdh gene.

Methodology

The proposed multiplex protocol was designed through in silico PCR. The annealing temperature, concentration of primer pairs, number of cycles, distinct polymerase enzymes and premix kit were defined to achieve an optimal reaction. The DNA detection sensitivity was tested with different concentrations of known L. tropica DNA, and the reproducibility of the assay was confirmed using samples from 106 wild mammals that were previously subject to Leishmania sp. kDNA analysis through singleplex reactions.

Principal findings

The following optimal conditions were established: 95°C for 1 min followed by 30 cycles of 95°C for 30 s, 61°C for 30 s, and 72°C for 30 s and a final extension at 72°C for 1 min. The multiplex PCR system was capable of detecting 0.1 ng of L. tropica diluted in 100 ng of mammalian DNA. Of 51 kDNA samples that were previously found to be positive, 45 (88.2%) were positive for both targets, two were positive only for kDNA and four were negative for both. Of 55 kDNA samples that were previously identified as negative, 38 (69.1%) were positive for gapdh whereas the other 17 were negative for both targets.

Conclusions/Significance

The proposed multiplex PCR system allows the simultaneous detection of the gapdh gene and Leishmania sp. kDNA in tissue samples derived from distinct wild mammal species. The amplification of the gapdh mammalian gene in the same reaction ensures the quality and viability of the DNA in the sample, eliminating the possibility of false-negative results that would impair an accurate description of the infection rates in a given population.

Sand fly population dynamics and cutaneous leishmaniasis among soldiers in an Atlantic forest remnant in northeastern Brazil

Outbreaks of cutaneous leishmaniasis are relatively common among soldiers involved in nocturnal activities in tropical forests. We investigated the population dynamics of sand flies in a military training camp located in a remnant of Atlantic rainforest in northeastern Brazil, where outbreaks of cutaneous leishmaniasis have sporadically been described. From July 2012 to July 2014, light traps were monthly placed in 10 collection sites, being nine sites located near the forest edge and one near a sheep and goat stable. Light traps operated from 5:00 pm to 6:00 am, during four consecutive nights. Leishmania infection in sand flies was assessed using a fast real-time PCR assay. Cases of cutaneous leishmaniasis among soldiers were also investigated. In total, 24,606 sand flies belonging to 25 species were identified. Males (n = 12,683) predominated over females (n = 11,923). Sand flies were present during all months, being more numerous in March (n = 1,691) and April 2013 (n = 3,324). Lutzomyia choti (72.9%) was the most abundant species, followed by Lutzomyia longispina (13.8%), Lutzomyia complexa (5.3%), representing together >90% of the sand flies collected. Forty cases of cutaneous leishmaniasis were recorded among soldiers from January 2012 to December 2014. Leishmania isolates were obtained from eight patients and were all characterized as Leishmania braziliensis. Soldiers and anyone overnighting in Atlantic rainforest remnants should adopt preventative measures such as the use of repellents on bare skin or clothes and insecticide-treated tents.

Outbreaks of cutaneous leishmaniasis are relatively common among soldiers involved in nocturnal activities in tropical forests. However, there is limited information on the relationship between sand fly population dynamics and cases of cutaneous leishmaniasis in Atlantic forest remnants. In this study, we investigated the population dynamics of sand flies in a military training camp located in a remnant of Atlantic rainforest in northeastern Brazil, where outbreaks of cutaneous leishmaniasis have sporadically been described. In total, 24,606 sand flies belonging to 25 species were identified. Sand flies were present during all months, being more numerous in March and April 2013. Lutzomyia choti was the most abundant species and three pools of females belonging to this species were found to be positive for Leishmania braziliensis DNA. Our results suggest that the risk of cutaneous leishmaniasis by Leishmania braziliensis in Atlantic rainforest remnants is permanent and thus not dictated by sand fly population peaks. People overnighting in Atlantic rainforest remnants should adopt preventative measures such as the use of repellents on bare skin or clothes and insecticide-treated tents.

Polymeric Nanoparticles of Brazilian Red Propolis Extract: Preparation, Characterization, Antioxidant and Leishmanicidal Activity

The ever-increasing demand for natural products and biotechnology derived from bees and ultra-modernization of various analytical devices has facilitated the rational and planned development of biotechnology products with a focus on human health to treat chronic and neglected diseases. The aim of the present study was to prepare and characterize polymeric nanoparticles loaded with Brazilian red propolis extract and evaluate the cytotoxic activity of "multiple-constituent extract in co-delivery system" for antileishmanial therapies. The polymeric nanoparticles loaded with red propolis extract were prepared with a combination of poly-ε-caprolactone and pluronic using nanoprecipitation method and characterized by different analytical techniques, antioxidant and leishmanicidal assay. The red propolis nanoparticles in aqueous medium presented particle size (200-280 nm) in nanometric scale and zeta analysis (-20 to -26 mV) revealed stability of the nanoparticles without aggregation phenomenon during 1 month. After freeze-drying method using cryoprotectant (sodium starch glycolate), it was possible to observe particles with smooth and spherical shape and apparent size of 200 to 400 nm. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and thermal analysis revealed the encapsulation of the flavonoids from the red propolis extract into the polymeric matrix. Ultra performance liquid chromatography coupled with diode array detector (UPLC-DAD) identified the flavonoids liquiritigenin, pinobanksin, isoliquiritigenin, formononetin and biochanin A in ethanolic extract of propolis (EEP) and nanoparticles of red propolis extract (NRPE). The efficiency of encapsulation was determinate, and median values (75.0 %) were calculated using UPLC-DAD. 2,2-Diphenyl-1-picryhydrazyl method showed antioxidant activity to EEP and red propolis nanoparticles. Compared to negative control, EEP and NRPE exhibited leishmanicidal activity with an IC50 value of ≅38.0 μg/mL and 31.3 μg/mL, 47.2 μg/mL, 154.2μg/mL and 193.2 μg/mL for NRPE A1, NRPE A2, NRPE A3 and NRPE A4, respectively. Nanoparticles loaded with red propolis extract in co-delivery system and EEP presented cytotoxic activity on Leishmania (V.) braziliensis. Red propolis extract loaded in nanoparticles has shown to be potential candidates as intermediate products for preparation of various pharmaceutical dosage forms containing red propolis extract in the therapy against negligible diseases such as leishmaniasis. Graphical Abstract Some biochemical mechanisms of cellular debridement of Leishmania (V.) braziliensis species by the flavonoids of red propolis extract (EEP) or NRPE loaded with red propolis extract.

MOLECULAR CHARACTERIZATION OF AMERICAN CUTANEOUS LEISHMANIASIS IN THE TRI‑BORDER AREA OF ASSIS BRASIL, ACRE STATE, BRAZIL

In this study, Leishmaniaspecies were identified by Polymerase Chain Reaction (PCR). The epidemiology of patients suspected of having American Cutaneous Leishmaniasis in the municipality of Assis Brasil, Acre State, located in the Brazil/Peru/Bolivia triborder was also investigated. By PCR, the DNA of Leishmaniawas detected in 100% of the cases (37 samples) and a PCR-Restriction Fragment Length Polymorphism (RFLP) of the hsp 70gene identified the species in 32 samples: Leishmania (Viannia) braziliensis (65.6%) , L. (V.) shawi (28.1%) , L. (V.) guyanensis (3.1%) and mixed infection L. (V.) guyanensis and L. (Leishmania) amazonensis (3.1%)This is the first report of L. (V.) shawiand L. (L.) amazonensis in Acre. The two predominant species were found in patients living in urban and rural areas. Most cases were found in males living in rural areas for at least three years and involved in rural work. This suggests, in most cases, a possible transmission of the disease from a rural/forest source, although some patients had not engaged in activities associated with permanence in forestall areas, which indicate a possible sandflies adaptation to the periurban setting.

An Innovative Field-Applicable Molecular Test to Diagnose Cutaneous Leishmania Viannia spp. Infections

Cutaneous and mucosal leishmaniasis is widely distributed in Central and South America. Leishmania of the Viannia subgenus are the most frequent species infecting humans. L. (V.) braziliensis, L. (V.) panamensis are also responsible for metastatic mucosal leishmaniasis. Conventional or real time PCR is a more sensitive diagnostic test than microscopy, but the cost and requirement for infrastructure and trained personnel makes it impractical in most endemic regions. Primary health systems need a sensitive and specific point of care (POC) diagnostic tool. We developed a novel POC molecular diagnostic test for cutaneous leishmaniasis caused by Leishmania (Viannia) spp. Parasite DNA was amplified using isothermal Recombinase Polymerase Amplification (RPA) with primers and probes that targeted the kinetoplast DNA. The amplification product was detected by naked eye with a lateral flow (LF) immunochromatographic strip. The RPA-LF had an analytical sensitivity equivalent to 0.1 parasites per reaction. The test amplified the principal L. Viannia species from multiple countries: L. (V.) braziliensis (n = 33), L. (V.) guyanensis (n = 17), L. (V.) panamensis (n = 9). The less common L. (V.) lainsoni, L. (V.) shawi, and L. (V.) naiffi were also amplified. No amplification was observed in parasites of the L. (Leishmania) subgenus. In a small number of clinical samples (n = 13) we found 100% agreement between PCR and RPA-LF. The high analytical sensitivity and clinical validation indicate the test could improve the efficiency of diagnosis, especially in chronic lesions with submicroscopic parasite burdens. Field implementation of the RPA-LF test could contribute to management and control of cutaneous and mucosal leishmaniasis.

Cutaneous leishmaniasis is a parasitic disease transmitted by the bite of sandflies that produces skin ulcers. The severe, disfiguring form of the disease is characterized by parasite dissemination to the mucosa of the nose and palate. Current diagnosis is based on microscopy which has low sensitivity in chronic cases. Molecular methods (PCR) that detect parasite DNA are highly sensitive but costs and personnel training make it impossible to implement it in resource-limited areas. We developed a novel molecular method (RPA-LF) that could be applied in the field because it does not require sophisticated equipment. It is also very sensitive and specific to detect the principal Leishmania species that produce cutaneous leishmaniasis in Latin America. Future field implementation of RPA-LF could have a positive impact on disease management and control.

Real-time PCR for Leishmania species identification: Evaluation and comparison with classical techniques

BACKGROUND

Cutaneous leishmaniasis (CL) is a parasitic disease caused by various Leishmania species. Several studies have shown that real time quantitative PCR (qPCR) can be used for Leishmania spp. identification by analyzing the melting temperature (Tm). Thus, the aim of this study was to evaluate the viability of qPCR for differentiating eight closely related Leishmania species that cause the same clinical form of the disease and to compare the results with classical techniques.

METHODS

qPCR assays for standardizing the Tm using reference strains were performed. After the CL diagnosis on blood samples of domestic animals, positive samples were analyzed by their Tm and qPCR products were purified and sequenced. Ten human samples previously characterized by Multilocus Enzyme Electrophoresis (MLEE) were also analyzed by Tm. A Restriction Fragment Length Polymorphism (RFLP) assay, a reference test, was also standardized, by using the reference strains.

RESULTS

Through standardization of Tm for Leishmania spp., two Tm ranges were created for analysis: 1 (Tm = 78-79.99 °C) included Leishmania (V.) braziliensis, Leishmania (V.) panamensis, Leishmania (V.) lainsoni, Leishmania (V.) guyanensis and Leishmania (V.) shawi; and 2 (Tm = 80-82.2 °C) included Leishmania (V.) naiffi, Leishmania (L.) amazonensis and Leishmania (L.) mexicana. A total of 223 positive blood samples were analyzed, with 58 included in range 1 and 165 in range 2. L. (V.) braziliensis, L. (V.) panamensis and L. (V.) guyanensis were identified by sequencing, while L. (V.) braziliensis, L. (L.) mexicana and L. (V.) panamensis were identified by RFLP analysis. Ten human samples previously characterized by Multilocus Enzyme Electrophoresis (MLEE) were also analyzed by qPCR Tm analysis; five were classified in range 1 and five in range 2. A concordance of 80% was calculated between qPCR and the gold-standard (MLEE) with no significant difference between the methods (p = 0.6499); a similar result was observed for sequencing and qPCR (p = 0.2566). In contrast, a highly significant difference was observed for qPCR and RFLP (p < 0.001).

CONCLUSIONS

In this study, we demonstrated the potential use of qPCR as a tool for Leishmania species identification using two Tm ranges.

American tegumentary leishmaniasis: mRNA expression for Th1 and Treg mediators are predominant in patients with recent active disease

Besides the Th1×Th2 paradigm, Treg and Th17 cytokines may play a role in the response to American tegumentary leishmaniasis. Considering the sensitivity and accuracy of qPCR and the lack of studies using this approach, we evaluated mRNA expression for IFN-γ, TNF-α, IL-4, IL-10, IL-6, IL-17A, IL-22, TGF-β, Foxp3 and RORC in peripheral blood mononuclear cells (PBMC) from patients with active disease, after stimulation with L. (V.) braziliensis soluble or insoluble fractions. Our results show that the antigens promoted specific mRNA expression related to the immune response in patients with ATL, and the insoluble fraction seems to stimulate the immune response in a higher intensity. The pro-inflammatory response was also fueled by IFN-γ and TNF-α, probably due to the active disease. IL-4, in certain way, seems to regulate this response along with IL-10 that may be produced by Treg cells, which are supposedly present in the patients' samples due the evidenced expression of Foxp3, in the presence of AgIns. In contrast, down-regulated RORC suggests that the significant levels of IL-6 expressed in response to AgSol were not able to induce an expressive Th17 profile along with TGF-β, which might have predominantly contributed to the development of a regulatory profile in the active disease.

Species typing in dermal leishmaniasis

Leishmania is an infectious protozoan parasite related to African and American trypanosomes. All Leishmania species that are pathogenic to humans can cause dermal disease. When one is confronted with cutaneous leishmaniasis, identification of the causative species is relevant in both clinical and epidemiological studies, case management, and control. This review gives an overview of the currently existing and most used assays for species discrimination, with a critical appraisal of the limitations of each technique. The consensus taxonomy for the genus is outlined, including debatable species designations. Finally, a numerical literature analysis is presented that describes which methods are most used in various countries and regions in the world, and for which purposes.

Phenotypic characterization of Leishmania spp. causing cutaneous leishmaniasis in the lower Amazon region, western Pará state, Brazil, reveals a putative hybrid parasite, Leishmania (Viannia) guyanensis × Leishmania (Viannia) shawi shawi

We phenotypically characterized 43 leishmanial parasites from cutaneous leishmaniasis by isoenzyme electrophoresis and the indirect immunofluorescence antibody test (23 McAbs). Identifications revealed 11 (25.6%) strains of Leishmania (V.) braziliensis, 4 (9.3%) of L. (V.) shawi shawi, 7 (16.3%) of L. (V.) shawi santarensis, 6 (13.9%) of L. (V.) guyanensis and L. (V.) lainsoni, 2 (4.7%) of L. (L.) amazonensis, and 7 (16.3%) of a putative hybrid parasite, L. (V.) guyanensis/L. (V.) shawi shawi. McAbs detected three different serodemes of L. (V.) braziliensis: I-7, II-1, and III-3 strains. Among the strains of L. (V.) shawi we identified two populations: one (7 strains) expressing the B19 epitope that was previously considered to be species-specific for L. (V.) guyanensis. We have given this population sub-specific rank, naming it L. (V.) s. santarensis. The other one (4 strains) did not express the B19 epitope like the L. (V.) shawi reference strain, which we now designate as L. (V.) s. shawi. For the first time in the eastern Brazilian Amazon we register a putative hybrid parasite (7 strains), L. (V.) guyanensis/L. (V.) s. shawi, characterized by a new 6PGDH three-band profile at the level of L. (V.) guyanensis. Its PGM profile, however, was very similar to that of L. (V.) s. shawi. These results suggest that the lower Amazon region – western Pará state, Brazil, represents a biome where L. (V.) guyanensis and L. (V.) s. shawi exchange genetic information.

Polymorphisms and ambiguous sites present in DNA sequences of Leishmania clones: looking closer

In genetic studies of Leishmania parasites, co-dominant markers are chosen for their ability to detect heterozygous polymorphisms, to infer the occurrence of inbreeding and to resolve genetic variability. The majority of DNA sequence based reports perform conventional dye terminator cycle sequencing where perfectly ambiguous sites or double peaks in the chromatogram are interpreted as heterozygous strains. However, molecular peculiarities of the parasite such as aneuploidy, mixed populations and homologous recombination advise that data from regular DNA sequence analysis should be carefully evaluated. We report here a closer look at ambiguous sites observed in 6pgd DNA sequences obtained for a multilocus sequence analysis project on Leishmania (Viannia) strains. After comparing 286 DNA sequences from biological and molecular clones of six L. (Viannia) strains we could distinguish events that contribute to genetic variation in Leishmania (recombination, mutation, chromosomal mosaics). Also, the results suggest how diversity might not be completely revealed through regular DNA sequence analysis and demonstrate the importance for molecular epidemiology research to be aware of such possibilities while choosing samples for studies.

Population structure and evidence for both clonality and recombination among Brazilian strains of the subgenus Leishmania (Viannia)

Background/Objectives: Parasites of the subgenus Leishmania (Viannia) cause varying clinical symptoms ranging from cutaneous leishmaniases (CL) with single or few lesions, disseminated CL (DL) with multiple lesions to disfiguring forms of mucocutaneous leishmaniasis (MCL). In this population genetics study, 37 strains of L. (V.) guyanensis, 63 of L. (V.) braziliensis, four of L. (V.) shawi, six of L. (V.) lainsoni, seven of L. (V.) naiffi, one each of L. (V.) utingensis and L. (V.) lindenbergi, and one L. (V.) lainsoni/L. naiffi hybrid from different endemic foci in Brazil were examined for variation at 15 hyper-variable microsatellite markers.

Methodology/Principal findings: The multilocus microsatellite profiles obtained for the 120 strains were analysed using both model- and distance-based methods. Significant genetic diversity was observed for all L. (Viannia) strains studied. The two cluster analysis approaches identified two principal genetic groups or populations, one consisting of strains of L. (V.) guyanensis from the Amazon region and the other of strains of L. (V.) braziliensis isolated along the Atlantic coast of Brazil. A third group comprised a heterogeneous assembly of species, including other strains of L. braziliensis isolated from the north of Brazil, which were extremely polymorphic. The latter strains seemed to be more closely related to those of L. (V.) shawi, L. (V.) naiffi, and L. (V.) lainsoni, also isolated in northern Brazilian foci. The MLMT approach identified an epidemic clone consisting of 13 strains of L. braziliensis from Minas Gerais, but evidence for recombination was obtained for the populations of L. (V.) braziliensis from the Atlantic coast and for L. (V.) guyanensis.

Conclusions/Significance: Different levels of recombination versus clonality seem to occur within the subgenus L. (Viannia). Though clearly departing from panmixia, sporadic, but long-term sustained recombination might explain the tremendous genetic diversity and limited population structure found for such L. (Viannia) strains.

Cutaneous leishmaniasis (CL) constitutes a significant public health problem in all federal states of Brazil. Most cases are caused by parasites of the subgenus Leishmania (Viannia) which can cause a variety of clinical symptoms ranging from single or few lesions, disseminated CL with multiple lesions, to disfiguring forms of mucocutaneous leishmaniasis. This study has used a multilocus microsatellite typing approach for exploring the genetic diversity and population structure among 120 strains representing different subgenus L. (Viannia) species and different Brazilian CL foci. Genetic diversity within the subgenus was much higher than expected, especially within L. (V.) braziliensis, L. (V.) shawi, L. (V.) naiffi, and L. (V.) lainsoni which were all from the north of Brazil. These strains could not be assigned to well-defined populations, but presented a rather loosely associated group. Strains of L. (V.) braziliensis isolated along the Atlantic coast of Brazil and strains of L. (V.) guyanensis formed, however, two clearly separated populations exhibiting remarkable levels of sexual exchange. The latter finding is in contrast to previous studies suggesting clonal modes of propagation or inbreeding for natural populations of Leishmania parasites and might explain the genetic heterogeneity and limited population structure for Brazilian strains of subgenus L. (Viannia) observed in this study.

American tegumentary leishmaniasis caused by Leishmania (Viannia) braziliensis: assessment of parasite genetic variability at intra- and inter-patient levels

Background

The genetic variability of Leishmania (Viannia) braziliensis was assessed at intra and interpatient levels of individuals with different clinical manifestations of American tegumentary leishmaniasis (ATL).

Methods

Fifty-two samples, of which 13 originated from cutaneous lesions and 39 from mucosal lesions, provided by 35 patients, were examined by low-stringency single-specific-primer PCR (LSSP-PCR) and phenetic analysis. Genetic variability of L. (V.) braziliensis, in kinetoplast DNA (kDNA) signatures, was compared both from different patients and from different lesions of the same patient. Phenetic analysis was performed to evaluate the degree of heterogeneity of the kDNA minicircles. In order to evaluate inter and intrapatient L. (V.) braziliensis genetic variability, the percentage of shared bands and analysis of the coefficients of similarity were analyzed.

Results

Different genetic profiles, representing kDNA signatures of the parasite, were obtained by LSSP-PCR analysis of each sample. Phenetic analysis grouped genetic profiles of different levels of differentiation from more similar to most divergent. The percentage of shared bands at the inter and intrapatient levels was 77% and 89%, respectively. Comparison of the average inter and intrapatient coefficients of similarity and their standard deviations were statistically significant (p < 0.001).

Conclusion

Genetic variability at the intrapatient level was less pronounced than that between different patients. A conceptual model was proposed to better understand the complexity at both levels.

Biology of phlebotomine sand flies as vectors of disease agents

Phlebotomines are the sole or principal vectors of Leishmania, Bartonella bacilliformis, and some arboviruses. The coevolution of sand flies with Leishmania species of mammals and lizards is considered in relation to the landscape epidemiology of leishmaniasis, a neglected tropical disease. Evolutionary hypotheses are unresolved, so a practical phlebotomine classification is proposed to aid biomedical information retrieval. The vectors of Leishmania are tabulated and new criteria for their incrimination are given. Research on fly-parasite-host interactions, fly saliva, and behavioral ecology is reviewed in relation to parasite manipulation of blood feeding, vaccine targets, and pheromones for lures. Much basic research is based on few transmission cycles, so generalizations should be made with caution. Integrated research and control programs have begun, but improved control of leishmaniasis and nuisance-biting requires greater emphasis on population genetics and transmission modeling. Most leishmaniasis transmission is zoonotic, affecting the poor and tourists in rural and natural areas, and therefore control should be compatible with environmental conservation.

Occupationally acquired american cutaneous leishmaniasis

We report two occupationally acquired cases of American cutaneous leishmaniasis (ACL): one accidental laboratory autoinoculation by contaminated needlestick while handling an ACL lesion sample, and one acquired during field studies on bird biology. Polymerase chain reaction (PCR) assays of patient lesions were positive for Leishmania, subgenus Viannia. One isolate was obtained by culture (from patient 2 biopsy samples) and characterized as Leishmania (Viannia) naiffi through an indirect immunofluorescence assay (IFA) with species-specific monoclonal antibodies (mAbs) and by multilocus enzyme electrophoresis (MLEE). Patients were successfully treated with N-methyl-glucamine. These two cases highlight the potential risks of laboratory and field work and the need to comply with strict biosafety procedures in daily routines. The swab collection method, coupled with PCR detection, has greatly improved ACL laboratory diagnosis.

New insights on taxonomy, phylogeny and population genetics of Leishmania (Viannia) parasites based on multilocus sequence analysis

The Leishmania genus comprises up to 35 species, some with status still under discussion. The multilocus sequence typing (MLST)--extensively used for bacteria--has been proposed for pathogenic trypanosomatids. For Leishmania, however, a detailed analysis and revision on the taxonomy is still required. We have partially sequenced four housekeeping genes--glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), mannose phosphate isomerase (MPI) and isocitrate dehydrogenase (ICD)--from 96 Leishmania (Viannia) strains and assessed their discriminatory typing capacity. The fragments had different degrees of diversity, and are thus suitable to be used in combination for intra- and inter-specific inferences. Species-specific single nucleotide polymorphisms were detected, but not for all species; ambiguous sites indicating heterozygosis were observed, as well as the putative homozygous donor. A large number of haplotypes were detected for each marker; for 6PGD a possible ancestral allele for L. (Viannia) was found. Maximum parsimony-based haplotype networks were built. Strains of different species, as identified by multilocus enzyme electrophoresis (MLEE), formed separated clusters in each network, with exceptions. NeighborNet of concatenated sequences confirmed species-specific clusters, suggesting recombination occurring in L. braziliensis and L. guyanensis. Phylogenetic analysis indicates L. lainsoni and L. naiffi as the most divergent species and does not support L. shawi as a distinct species, placing it in the L. guyanensis cluster. BURST analysis resulted in six clonal complexes (CC), corresponding to distinct species. The L. braziliensis strains evaluated correspond to one widely geographically distributed CC and another restricted to one endemic area. This study demonstrates the value of systematic multilocus sequence analysis (MLSA) for determining intra- and inter-species relationships and presents an approach to validate the species status of some entities. Furthermore, it contributes to the phylogeny of L. (Viannia) and might be helpful for epidemiological and population genetics analysis based on haplotype/diplotype determinations and inferences.

Evaluation of anti-lived and anti-fixed Leishmania (Viannia) braziliensis promastigote IgG antibodies detected by flow cytometry for diagnosis and post-therapeutic cure assessment in localized cutaneous leishmaniasis

This study aims to investigate a flow cytometry performance-based methodology to detect anti-live (FC-ALPA-IgG) and anti-fixed (FC-AFPA-IgG) Leishmania (Viannia) braziliensis promastigote IgG as a means to monitor post-therapeutic cure of patients with localized cutaneous leishmaniasis (LCL). Serum samples from 30 LCL patients infected with L. (V.) braziliensis were assayed, comparing the IgG reactivity before and after specific treatment with pentavalent antimonial. Reactivities were reported as the percentage of positive fluorescent parasites (PPFP), using a PPFP of 60% as a cut-off value. In the serum dilution of 1:1024, the positive percentage of LCL serum sample for FC-ALPA-IgG and FC-AFPA-IgG was 86% and 90%, respectively, before treatment. Analysis of ∆PPFP that represents the difference between PPFP after and before treatment appeared as a new approach to monitor post-therapeutic IgG reactivity in LCL. Our data support the perspective of using FC-ALPA and FC-AFPA as a useful serologic tool for diagnosis and for post-therapeutic follow-up of LCL patients.

Public Knowledge about and Detection of Canine Visceral Leishmaniasis in Urban Divinópolis, Brazil

Background. Leishmaniases are diseases with a wide spectrum of clinical manifestations including cutaneous (CL) and visceral (VL) forms. Many factors may affect their occurrence and expansion including environmental, geographic, and social conditions. In the past two decades, Divinópolis, Minas Gerais State, Brazil, has exhibited the potential for a disease outbreak, with the appearance of CL, and VL cases (human and canine). Hence, this study was initiated to monitor public knowledge of the disease. Questionnaires were administered in four neighborhoods (Jardim Belvedere, Esplanada, Danilo Passos I and II) where most of the human and canine cases have been reported. The analyses demonstrated that public knowledge of the disease is sparse and fragmented. A strong perception of the dog as the main reservoir was observed. Five veterinary clinics were evaluated for the presence of canine VL using serological (RIFI and ELISA) and molecular (PCR-RFLP) techniques. This is the first study demonstrating the occurrence of Leishmania infantum in Divinópolis, suggesting a possible urbanization of VL.

Cutaneous leishmaniasis in northeastern Brazil: a critical appraisal of studies conducted in State of Pernambuco

American cutaneous leishmaniasis (ACL) is a complex disease with clinical and epidemiological features that may vary from region to region. In fact, at least seven different Leishmania species, including Leishmania (Viannia) braziliensis, Leishmania (Viannia) guyanensis, Leishmania (Viannia) lainsoni, Leishmania (Viannia) naiffi, Leishmania (Viannia) shawi, Leishmania (Viannia) lindenbergi, and Leishmania (Leishmania) amazonensis, have been implicated in the etiology of ACL in Brazil, and numerous phlebotomine sandfly species of the genus Lutzomyia have been regarded as putative or proven vectors. Because ACL is a focal disease, understanding the disease dynamics at the local level is essential for the implementation of more effective control measures. The present paper is a narrative review about the ACL epidemiology in Pernambuco, northeastern Brazil. Furthermore, the need for more effective diagnosis, treatment, control and prevention strategies for the affected populations is highlighted. This paper will provide researchers with a critical appraisal of ACL in Pernambuco. Hopefully, it will also be helpful for public health authorities to improve current control strategies against ACL at the state and country levels.

Natural Leishmania infection of Lutzomyia auraensis in Madre de Dios, Peru, detected by a fluorescence resonance energy transfer-based real-time polymerase chain reaction

Leishmania species of the Viannia subgenus are responsible for most cases of New World tegumentary leishmaniasis. However, little is known about the vectors involved in disease transmission in the Amazon regions of Peru. We used a novel real-time polymerase chain reaction (PCR) to assess Leishmania infections in phlebotomines collected in rural areas of Madre de Dios, Peru. A total of 1,299 non-blood fed female sand flies from 33 species were captured by using miniature CDC light traps. Lutzomyia auraensis was the most abundant species (63%) in this area. Seven of 164 pools were positive by PCR for Leishmania by kinetoplast DNA. The real-time PCR identified four Lu. auraensis pools as positive for L. (Viannia) lainsoni and L. (V.) braziliensis. The minimum infection prevalence for Lu. auraensis was estimated to be 0.6% (95% confidence interval = 0.20-1.42%). Further studies are needed to assess the importance of Lu. auraensis in the transmission of New World tegumentary leishmaniasis in hyperendemic areas of Peru.

Antigenic fractions of Leishmania (Viannia) braziliensis: the immune response characterization of patients at the initial phase of disease

American cutaneous leishmaniasis (ACL) has different clinical manifestations and these manifestations are dependent on the immunological status of the host. As CD4(+) and CD8(+) T cells and their mediators play a fundamental role in the host response to Leishmania and there is also a search for antigenic molecules to be used as future vaccines and tools for prognostic tests, this study characterized ACL patients' immune response after stimulation with soluble and insoluble fractions of L. (V.) braziliensis. We demonstrated a prevailing production of the Th2 cytokines, IL-4 and IL-10 and a specific production of IFN-γ and TNF-α in patients before treatment. There was also a predominance of CD4(+) T cells and a small percentage CD8(+) T cells. The insoluble antigenic fraction primarily stimulated CD4(+) T cells, while the soluble antigenic fraction showed a mixed profile, with CD4(+) T cells being the main responsible for Th2 cytokines and CD8(+) T cells for Th1 cytokines. Therefore, our results showed that a down-modulation of the Th1 type of response occurs in the initial phase of L. braziliensis disease, being the antigenic fractions capable of stimulating a specific immune response.

Microspatial distributional patterns of vectors of cutaneous leishmaniasis in pernambuco, northeastern Brazil

The purpose of this study is to analyze the spatial distribution and population trends through time of Lutzomyia species in a long-term focus of cutaneous leishmaniasis transmission in an Atlantic Forest area, northeastern Brazil. Sand fly populations of different ecological niches were monitored spatiotemporally in 2009. To summarize vegetation characteristics and phenology, we calculated the Normalized Difference Vegetation Index from Landsat images. Using niche modeling approaches, we assessed suites of environmental factors to identify areas of transmission risk. Although 12 species were detected, L. whitmani was the most abundant and broadly distributed across the area, particularly in peridomiciliary locations, and associated negatively with denser vegetation areas. On the other hand, L. complexa, L. sordelli, and L. tupynambai were found almost exclusively in forested areas (P < 0.05), and associated positively with denser vegetation. Lutzomyia species' occurrences are related to specific environmental combinations (with contrast among species) in the region.

Leishmania (Viannia) shawi purified antigens confer protection against murine cutaneous leishmaniasis

OBJECTIVE

Leishmania (Viannia) shawi was characterized only recently, and few studies concerning the immunogenic and protective properties of its antigens have been performed. The present study aimed to evaluate the protective potential of the five antigenic fractions isolated from L. (V.) shawi promastigotes in experimental cutaneous leishmaniasis.

MATERIALS AND METHODS

Soluble antigen from L. (V.) shawi promastigotes was submitted to reverse phase HPLC to purify F1, F2, F3, F4 and F5 antigens. BALB/c mice were immunized once a week for two consecutive weeks by subcutaneous routes in the rump, using 25 μg protein. After 1 week, groups were challenged in the footpad with L. (V.) shawi promastigotes. After 8 weeks, those same mice were sacrificed and parasite burden as well as the cellular and humoral immune responses were evaluated.

RESULTS

F1 and F5-immunized mice restrained lesion progression and parasite load in the skin. However, only the F1 group was able to control the parasitism in lymph nodes, which was associated with low IL-4 and high IFN-γ production; IgG2a isotype was increased in this group. Immunizations with F2, F3 and F4 antigens did not protect mice.

CONCLUSION

The capability of antigens to restrain IL-4 levels and increase IFN-γ was associated with protection, such as in immunization using F1 antigen.

Analysis of the protective potential of antigens released by Leishmania (Viannia) shawi promastigotes

Leishmania (Viannia) shawi causes cutaneous lesions in humans. Parasite antigens conferring significant protection against American tegumentar leishmaniosis (ATL) might be important for the development of effective vaccine. Therefore, this work evaluates the protective effect of antigenic fractions released by L. shawi. Antigens released by promastigotes to culture medium were concentrated and isolated by SDS-PAGE. The three main fractions LsPass1 (>75 kDa), LsPass2 (75-50 kDa) and LsPass3 (<50 kDa) were electro-eluted according with their molecular mass. Immunized BALB/c mice were challenged with L. shawi promastigotes and the course of infection monitored during 5 weeks. LsPass1-challenged mice showed no protection, however, a strong degree of protection associated to smaller lesions and high expression of IFN-γ and TNF-α by CD4(+) T, CD8(+) T and double negative CD4CD8 cells was achieved in LsPass3-challenged mice. Furthermore, LsPass2-challenged mice showed an intermediated degree of protection associated to high levels of IFN-γ, IL-4 and IL-10 mRNA. In spite of increased expression of IFN-γ and TNF-α, high amounts of IL-4 and IL-10 mRNA were also detected in LsPass3-challenged mice indicating a possible contribution of these cytokines for the persistence of a residual number of parasites that may be important in inducing long-lasting immunity. Therefore, LsPass3 seems to be an interesting alternative that should be considered in the development of an effective vaccine against ATL.

Endemic tegumentary leishmaniasis in Brazil: correlation between level of endemicity and number of cases of mucosal disease

The purpose of this study was to establish a correlation between the endemic level of tegumentary leishmaniasis in different regions of Brazil during 2002-2009 and the number of cases of mucosal or mucocutaneous leishmaniasis. The proportion of mucosal leishmaniasis was inversely correlated with prevalence of infection. In areas with a lower infection prevalence, the proportion of mucosal leishmaniasis increased (P < 0.05). The hypothesis of an Amazonian origin and dissemination through human migration is considered. Our results show that in regions with lower prevalence and endemically younger, the proportion of cases that evolve to the mucosal form is higher than in regions with higher prevalence and endemically older.

Spatial and temporal patterns of occurrence of Lutzomyia sand fly species in an endemic area for cutaneous leishmaniasis in the Atlantic Forest region of northeast Brazil

Sand fly populations of different ecological niches in the Amaraji endemic American Cutaneous Leishmaniasis (ACL) focus of the Pernambuco Atlantic Forest region of northeastern Brazil were monitored spatiotemporally. Lutzomyia whitmani was dominant in all niches but occurred in smaller numbers in forested locations. L. whitmani was significantly less seasonal than the other species, being present throughout the year while other species were more abundant between February and April. These results suggest that L. whitmani may potentially be the principal vector of ACL in the region, even though the sand fly fauna was diverse: 88% were L.whitmani and 12% belonged to 11 other species. Two other species, L. complexa (1.3%) and L. migonei (0.8%), considered to be ACL vectors in other regions, were also present. This detailed picture of the sand fly population's abundance and spatiotemporal distribution provides a basis for future modeling studies of forecasting sand fly activity patterns and ACL occurrence.

Characterization of Leishmania spp. causing cutaneous leishmaniasis in Manaus, Amazonas, Brazil

In the State of Amazonas, American tegumentary leishmaniasis is endemic and presents a wide spectrum of clinical variability due to the large diversity of circulating species in the region. Isolates from patients in Manaus and its metropolitan region were characterized using monoclonal antibodies and isoenzymes belonging to four species of the parasite: Leishmania (Viannia) guyanensis, 73% (153/209); Leishmania (Viannia) braziliensis, 14% (30/209); Leishmania (Leishmania) amazonensis, 8% (17/209); and Leishmania (Viannia) naiffii, 4% (9/209). The most prevalent species was L. (V.) guyanensis. The principal finding of this study was the important quantity of infections involving more than one parasite species, representing 14% (29/209) of the total. The findings obtained in this work regarding the parasite are further highlighted by the fact that these isolates were obtained from clinical samples collected from single lesions.

Use of FTA cards for direct sampling of patients' lesions in the ecological study of cutaneous leishmaniasis

The FTA card (Whatman) was assessed for its utility as a molecular epidemiological tool in collecting samples from patients with leishmaniasis in Peru because the card has a variety of merits; it is less invasive for patients and easy to handle for both physicians and other medical personnel for sample collection or diagnosis, in addition to its simplicity and easy countrywide and/or intercountry transportation for analysis. Samples were collected from 132 patients suspected of having leishmaniasis, and Leishmania species were successfully identified in samples from 81 patients in 15 departments of Peru by cytochrome b and mannose phosphate isomerase gene analyses. Of these, 61.7% were identified as Leishmania (Viannia) peruviana, 22.2% as L. (V.) braziliensis, 12.3% as L. (V.) guyanensis, 2.5% as L. (V.) shawi, and 1.2% as L. (V.) lainsoni. The three predominant species, L. (V.) peruviana, L. (V.) braziliensis, and L. (V.) guyanensis, were mainly found in the Andean highlands, in the tropical rainforest, and in northern and central rainforest regions, respectively. This is the first time L. (V.) shawi has been identified outside Brazil. The present study showed that the FTA card will be a useful tool for the ecological study of different forms of leishmaniasis. Furthermore, collecting samples directly from patients' lesions by using the FTA card eliminates (i) the possibility of contamination of Leishmania isolates during short- and/or long-term passages of culture in vitro in each laboratory and (ii) pain and suffering of patients from taking samples by skin biopsy.

Sequence analysis and PCR-RFLP profiling of the hsp70 gene as a valuable tool for identifying Leishmania species associated with human leishmaniasis in Brazil

Since the first report of the genus Leishmania, many species have been described. In Brazil, human leishmaniasis has been associated with eight Leishmania species, of which seven are responsible for cutaneous leishmaniasis (CL). In some endemic areas, CL is associated with only one species; however, in other areas, such as the Amazon, the etiology of CL can be assigned to many species. The multitude of highly similar Leishmania species in Brazil makes it difficult to develop an appropriate method of typing them. Most Leishmania species were first described based on epidemiological and biological characteristics, and these were later corroborated by Multilocus Enzyme Electrophoresis (MLEE), the gold standard technique for identifying Leishmania species. In an attempt to overcome the limitations of MLEE, many PCR-based methods have been developed and used for parasite identification. In the present study, we analyzed the sequence of the hsp70 gene in Leishmania species associated with human leishmaniasis in Brazil. This analysis led to the identification of restriction enzymes that could be used for PCR-RFLP-based identification. The results obtained were in complete agreement with those obtained by MLEE, suggesting that PCR-RFLP analysis of hsp70 could soon replace MLEE for routine Leishmania typing.