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This work reports on the whole-genome sequencing of Leishmania infantum chagasi from Honduras (Central America) and Brazil (South America).

The 503-antigen, the elongation factor (1-γ) found in the amastigote phase of Leishmania infantum chagasi, could integrate either kits of specific diagnostic assays or vaccines for visceral leishmaniasis. However, protein purification expressed in Escherichia coli is driven by several steps, namely, clarification and multisteps chromatography. Additionally, the removal of lipopolysaccharide (LPS/endotoxin) which triggers an immune response in the human body is needed since LPS interacts with the proteins impairing the chromatography steps. Aqueous two-phase systems (ATPSs) based on polyethylene glycol (PEG) 1500 and salt (K2HPO4 or (NH4), ethanol/salt, and acetonitrile/D-glucose were used for partitioning of 503-antigen expressed in recombinant E. coli M15 with simultaneous LPSs removal. System based on 30% PEG 1500 and 10% potassium phosphate with 20% (w/w) unclarified cell homogenate achieved protein recovery of 116.96 ± 3.45% and purification factor of 1.55 ± 0.01. Endotoxin was removed with values as high as 99.90% for all systems with partial purification of 503-antigen, thus eliminating a clarification step in the partial purification protocol of this antigen.

In this study a mathematical model was used to simulate the breakthrough curves of the recombinant 503 antigen of Leishmania infantum chagasi using immobilized metal affinity expanded bed adsorption chromatography. Initially, experimental curves were carried out in different conditions such as superficial liquid velocity, settled bed height as well as the initial 503 antigen concentration. The particle swarm optimization (PSO) algorithm was used for global parameter estimation by a general rate model, which proved to be an efficient tool for parameter estimation in chromatographic processes. Modeling and simulation of the 503 antigen breakthrough curves displayed a good performance during the estimation and validation stages. The highest global process efficiencies obtained was 88.8%. Finally, the validated model was used in the optimization stage, showing the process and column efficiencies of 89.2% and 75.9%, respectively. The results showed the applicability of this approach for modeling and optimization of chromatographic processes.

Leishmaniases are diseases caused by protozoan parasites of the genus Leishmania. Clinically, leishmaniases range from cutaneous to visceral forms, with estimated global incidences of 1.2 and 0.4 million cases per year, respectively. The treatment of these diseases relies on multiple parenteral injections with pentavalent antimonials or amphotericin B. However, these pharmaceuticals are either too toxic or expensive for routine use in developing countries. These facts call for safer, cheaper, and more effective new antileishmanial drugs. In this investigation, we describe the results of the assessment of the activities of a series of isobenzofuran-1(3H)-ones (phtalides) against Leishmania (Leishmania) infantum chagasi, which is the main causative agent of visceral leishmaniasis in the New World. The compounds were tested at concentrations of 100, 75, 50, 25 and 6.25 µM over 24, 48, and 72 h. After 48 h of treatment at the 100 µM concentration, compounds 7 and 8 decreased parasite viability to 4% and 6%, respectively. The concentration that gives half-maximal responses (LC50) for the antileishmanial activities of compounds 7 and 8 against promastigotes after 24 h were 60.48 and 65.93 µM, respectively. Additionally, compounds 7 and 8 significantly reduced parasite infection in macrophages.

Visceral leishmaniasis, a disease caused by Leishmania infantum chagasi, represents a major public health problem in many areas of the world. However, there is currently no vaccine for human use. The aim of this work was to purify the 503 antigen of Leishmania i. chagasi directly from unclarified Escherichia coli feedstock through expanded bed adsorption (EBA) chromatography. Batch experiments were performed to optimize the adsorption and elution conditions of the antigen onto a STREAMLINETM Chelating resin using two central composite rotatable designs (CCRD). The results showed that the optimal binding con- ditions of the 503 antigen were pH 8.0 in the presence of 2.4 M NaCl. For the elution of the target protein, the optimized conditions included the presence of 600.0 mM imidazole. The adsorption isothermal data of the 503 antigen were fitted to the Langmuir adsorption isotherm. The EBA experiment successfully recovered 59.2% of the 503 antigen from the unclarified E. coli homogenate with a purification factor of 6.0

Orientadora: Profa. Dra. Márcia Aparecida Sperança Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Biossistemas, São Bernardo do Campo, 2018. A leishmaniose compreende um grupo de doenças zoonóticas causadas por protozoários da família Trypanosoma e do gênero Leishmania, sendo transmitida por vetores flebotomíneos. O género Leishmania compreende 30 espécies, incluindo 20 espécies capazes de causar doença em humanos, com diferentes manifestações clínicas, que vão desde lesões assintomáticas, cutânea e mucocutânea, até a forma visceral grave, que é letal se não tratada. No continente americano, a leishmaniose visceral (LV) é causada por Leishmania infantum chagasi e o Brasil concentra 90% dos casos registrados na América Latina. O diagnóstico da LV na América apresenta dificuldades devido a reações cruzadas com outras tripanossomíases endêmicas. Além disso, os sinais clínicos e as alterações hematológias da LV são encontrados em outras doenças infecciosas e em alterações malignas hematológicas. Com o intuito de buscar ferramentas e estratégias para o diagnóstico diferencial da LV, neste trabalho foram desenvolvidos métodos de isolamento e detecção molecular de L. infantum chagasi, além da busca por características demográficas específicas e avaliação do diagnóstico diferencial da LV em aspirados de medula óssea de pacientes com sintomas de doença hematológica da região de Marília-SP, no período de 2010 a 2017. O método de isolamento de L. infantum chagasi foi realizado a partir de amostras de medula óssea e sangue periférico de indivíduos sintomáticos. O diagnóstico molecular por reação em cadeia da polimerase, convencional, foi desenvolvido utilizando como alvo o gene de cópia única que codifica a enzima quitinase de L. infantum, o qual permite o diagnóstico específico e direto a partir de diferentes amostras clínicas. Os testes apresentaram elevada especificidade e mostraram sensibilidade aumentada quando comparados com métodos utilizados rotineiramente nos serviços de saúde. Os resultados da análise demográfica e do diagnóstico diferencial a partir de aspirados de medula óssea de pacientes com suspeita de doenças hematológicas indicaram que 19,4% apresentaram LV, e que a população com maior risco possui menos de 20 anos. O estudo realizado demonstra que a investigação de LV em pacientes com alterações hematológicas é fundamental não só para identificar casos de LV, mas também para tratar corretamente os casos de doenças infecciosas e hematológicas associadas. Leishmaniasis covers a group of zoonotic diseases caused by protozoa parasites of the Trypanosoma Family and the genus Leishmania, being transmitted by phlebotomine insect vectors. The genus Leishmania comprises 30 species, including 20 species capable of causing disease in humans, with different clinical manifestations, ranging from asymptomatic, cutaneous and mucocutaneous lesions, to severe visceral form, which is lethal if untreated. In the American continent, visceral leishmaniasis (VL) is caused by Leishmania infantum chagasi and Brazil accounts for 90% of the Latin America registered cases. The diagnosis of VL in America presents difficulties due to cross-reactions with other endemic trypanosomiasis. In addition, clinical signs and VL hematological alterations are found in other infectious diseases and hematological malignancies. In order to search for tools and strategies for the differential VL diagnosis, in this work we have developed methods of isolation and molecular detection of L. infantum chagasi, as well as the search for specific demographic characteristics and evaluation of the differential diagnosis of VL in bone marrow biopsies of patients with symptoms of haematological diseases in the region of Marília-SP, from 2010 to 2017. The method of L. infantum chagasi isolation was performed from samples of bone marrow and peripheral blood of symptomatic individuals. Conventional polymerase chain reaction (PCR) was developed using the single copy gene encoding the chitinase enzyme of L. infantum, which allows specific and direct diagnosis from different clinical samples. Both diagnostic tests showed high specificity and increased sensitivity when compared with routinely used methods in health services. The results of the demographic analysis and the differential diagnosis from bone marrow biopsy of patients with supposed hematological diseases indicated that 19.4% had VL, and that the population with the highest risk is less than 20 years old. The present study demonstrates that the investigation of VL in patients with hematological alterations is fundamental not only to identify cases of VL but also to correctly treat cases of VL associated infectious and hematological diseases.

EnglishThe study aimed to investigate Leishmania infection in a population of dogs (92 animals) in a fishing area of Bonito Municipality, and evaluate comparatively the serological methods used, immunoenzymatic assay (ELISA), indirect immunofluorescence antibody test (IFAT), and rapid Dual Path-Platform test (DPP®). Blood and aspirate of bone marrow samples were used and parasitological investigation was also performed, such as parasite isolation in Neal, Novy, Nicolle (NNN) medium culture, Woo technique, Giemsa stained smears and specific identification by polymerase chain reaction (PCR). IFAT revealed 56/92 seropositive, the ELISA 8/92 and the DPP®41/92. Regarding the agreement between the serological tests by the Kappa index, there was a slight agreement between ELISA/IFAT and ELISA/DPP®, and fair agreement in IFAT/DPP®. The NNN culture was positive in three out of 21 dogs, and identified by PCR as Leishmania infantum chagasi. No samples were positive by the Woo technique. Our results showed low agreements between the serological tests recommended by the Brazilian Ministry of Heath, and it is necessary to associate other diagnostic techniques, such as parasitological tests and PCR, to increase the sensitivity for canine visceral leishmaniosis diagnosis, mainly regarding asymptomatic dogs in endemic areas. Key words: domestic dogs; serodiagnosis; ecotourism portuguesO estudo teve como objetivo verificar a infeccao por Leishmania em uma populacao de caes (n=92 animais) de uma area de turismo de pesca no municipio de Bonito e avaliar comparativamente os metodos sorologicos utilizados, ensaio imunoenzimatico (ELISA), reacao de imunofluorescencia indireta (RIFI) e teste rapido de plataforma dupla (DPP®). Testes parasitologicos tambem foram realizados, como o isolamento do parasita em meio de cultura Neal, Novy, Nicolle, tecnica de Woo, esfregacos em lâminas coradas com Giemsa e identificacao especifica pela reacao em cadeia da polimerase (PCR). A RIFI revelou sorologia positiva de 56/92, ELISA 8/92 e DPP®41/92. Quanto a concordância entre os testes sorologicos pelo indice Kappa, houve um ligeiro acordo entre ELISA/RIFI e ELISA/DPP®, e uma concordância razoavel entre RIFI/DPP®. A cultura NNN foi positiva em tres caes, e identificada por PCR como Leishmania infantum chagasi. Nenhuma amostra foi positiva pela tecnica de Woo. Nossos resultados mostraram baixas concordâncias entre os testes sorologicos recomendados pelo Ministerio da Saude, sendo necessario associar a outras tecnicas de diagnostico, como testes parasitologicos e PCR, para aumentar a sensibilidade ao diagnostico de leishmaniose visceral canina, principalmente, com relacao aos caes assintomaticos em areas endemicas. Palavras-chave: caes domesticos; sorodiagnostico; ecoturismo

Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. This disease occurs more frequently in third world countries, such as Brazil. The treatment is arduous, and is dependent on just a few drugs like the antimonial derivatives and amphotericin B. Moreover, these drugs are not only expensive, but they can also cause severe side effects and require long-term treatment. Therefore, it is very important to find new compounds that are effective against leishmaniasis. In the present work we evaluated a new group of synthetic amides against the promastigote and amastigote forms of L. infantum chagasi. The results showed that one of these amides in particular, presented very effective activity against the promastigotes and amastigotes of L. infantum chagasi at low concentrations and it also presented low toxicity for mammal cells, which makes this synthetic amide a promising drug for combating leishmaniasis.

Visceral leishmaniasis (VL) caused in the New World by Leishmania (Leishmania) infantum chagasi has dog as important peridomestic reservoir in its transmission cycle. Since VL in infected animals is similar to human VL, its study is interesting for human pathology. During Leishmania infection, insulin-like growth factor-I (IGF-I) plays a role in the host-parasite interaction, favoring parasite growth, particularly acting directly on Leishmania. We evaluated IGF-I mRNA expression in different organs/tissues, which was differently modulated in dogs naturally infected by L. (L.) infantum chagasi. We also evaluated the hepatic IGF-I mRNA and serum IGF-I levels in infected dogs. Hepatic mRNA IGF-I expression was higher in the infected dogs than in control animals. However, the serum levels of IGF-I, which are related to the production of this factor in the liver, were reduced in the infected dogs compared with the non-infected controls. Thus, we suggest interference in post-transcriptional processing in IGF-I production in active visceral leishmaniasis.

We report the case of a 66 year-old woman who presented nodular skin lesions on her back and upper extremities. Biopsy revealed amastigotes that were identified as Leishmania infantum-chagasi by PCR. Evaluation also showed hepatomegaly and pulmonary nodules. Treatment with amphotericin B led to complete resolution of skin lesions.

Visceral leishmaniasis (VL) is a serious lethal parasitic disease caused by Leishmania donovani in Asia and by Leishmania infantum chagasi in Southern Europe and South America. VL is endemic in 47 countries with an annual incidence estimated to be 500,000 cases. This high incidence is due in part to the lack of an efficacious vaccine. Here, we introduce an innovative approach to directly identify parasite vaccine candidate antigens that are abundantly produced in vivo in humans with VL. We combined RP-HPLC and mass spectrometry and categorized three L. infantum chagasi proteins, presumably produced in spleen, liver, and bone marrow lesions and excreted in the patients’ urine. Specifically, these proteins were the following: Li-isd1 ({"type":"entrez-protein","attrs":{"text":"XP_001467866.1","term_id":"146096614","term_text":"XP_001467866.1"}}XP_001467866.1), Li-txn1 ({"type":"entrez-protein","attrs":{"text":"XP_001466642.1","term_id":"146093061","term_text":"XP_001466642.1"}}XP_001466642.1), and Li-ntf2 ({"type":"entrez-protein","attrs":{"text":"XP_001463738.1","term_id":"146079258","term_text":"XP_001463738.1"}}XP_001463738.1). Initial vaccine validation studies were performed with the rLi-ntf2 protein produced in E. coli mixed with the adjuvant BpMPLA-SE. This formulation stimulated potent Th1 response in BALB/c mice. Compared to control animals, mice immunized with Li-ntf2 + BpMPLASE had a marked parasite burden reduction in spleens at 40 days post-challenge with virulent L. infantum chagasi. These results strongly support the proposed antigen discovery strategy of vaccine candidates to kala-azar and opens novel possibilities for vaccine development to other serious infectious diseases.

In order to better understand the epidemiological transmission network of leishmaniasis, an endemic disease in Northeast Brazil, we investigated the susceptibility of Spix yellow-toothed cavies (Galea spixii) to the Leishmania infantum chagasi parasite. Nine cavies were experimentally infected, separated into three groups and monitored at 30, 90 and 180 days, respectively. Amastigotes were identified in the spleen slides of two cavies killed 180 days after infection. Antibodies against the L. i. chagasi were identified in one of the cavies. This demonstrates that G. spixii is in fact capable of maintaining a stable infection by L. i. chagasi without alterations in biochemical and hematological parameters of the host and without perceivable micro and macroscopic lesions.

Environment influences the composition, distribution, and behavior of the vectors and mammalian hosts involved in the transmission of visceral leishmaniasis (VL), affecting the epidemiology of the disease. In Brazil, the urbanization process and canine cases of VL are indicators for local health authorities. This study aimed to investigate the occurrence of the canine visceral leishmaniasis (CVL) in Maranhao State, Brazil. Blood samples collected from 960 dogs from six municipalities and six different ecosystems (Baixada Maranhense, Mangue, Mata dos Cocais, Amazonia, Cerrado, and Restinga) to serological tests (enzyme-linked immunosorbent assay [ELISA], indirect fluorescence antibody test [IFAT], and chromatographic immunoassay methods [Dual Path Platform technology, DPP(®)]) and parasitological diagnosis. From serological tests, 11.14% (107) of the dogs were positive for CVL, with 59.16% (568), 14.5% (148), and 131% (126) positives to ELISA, DPP, and IFAT tests, respectively. Only seven animals (0.73%) were positive in a parasitological test. We also performed parasite isolation and phylogenetic characterization. All isolates of dogs obtained from Maranhao were grouped in a single branch with Leishmania infantum chagasi from Brazil. The ecosystem Amazonia presented the highest positivity rates to CVL in serological and parasitological tests. Brazilian biomes/ecosystems suffer large degradation and may favor, depending on climatic conditions, the installation of new diseases. In the case of VL, dogs are reservoirs of parasites and sentinels for human infection.

SUMMARY American tegumentary leishmaniasis (ATL) is an infectious disease caused by protozoa of the genus Leishmania, and transmitted by sandflies. In the state of Rio de Janeiro, almost all of the cases of American tegumentary leishmaniasis (ATL) are caused by Leishmania (Viannia) braziliensis, while cases of visceral leishmaniasis (VL) are caused by Leishmania (Leishmania) infantum chagasi. The resurgence of autochthonous VL cases in Rio de Janeiro is related to the geographic expansion of the vector Lutzomyia longipalpis and its ability to adapt to urban areas. We report the first case of leishmaniasis with exclusively cutaneous manifestations caused by L. (L.) infantum chagasi in an urban area of Rio de Janeiro. An eighty-one-year-old woman presented three pleomorphic skin lesions that were not associated with systemic symptoms or visceromegalies. Multilocus enzyme electrophoresis identified L. (L.) infantum chagasi, but direct smear and PCR of bone narrow were negative for Leishmania sp. (suggesting exclusively cutaneous involvement). We discuss the different dermatological presentations of viscerotropic leishmaniasis of the New and Old World, and the clinical and epidemiological importance of the case. Etiologic diagnosis of ATL based upon exclusive clinical criteria may lead to incorrect conclusions. We should be aware of the constant changes in epidemiological patterns related to leishmaniases.

Leishmania infantum chagasi is an intracellular protozoan parasite responsible for visceral leishmaniasis, a fatal disease in humans. Heparin-binding proteins (HBPs) are proteins that bind to carbohydrates present in glycoproteins or glycolipids. Evidence suggests that HBPs present on Leishmania surface participate in the adhesion and invasion of parasites to tissues of both invertebrate and vertebrate hosts. In this study, we identified the product with an HSP90 (heat shock protein 90) domain encoded by lipophosphoglycan ( LPG3) gene as a L infantum chagasi HBP (HBP Lc). Structural analysis using the LPG3 recombinant protein suggests that it is organized as a tetramer. Binding analysis confirms that it is capable of binding heparin with micromolar affinity. Inhibition of adenosine triphosphatase activity in the presence of heparin, molecular modeling, and in silico docking analysis suggests that heparin-binding site superimposes with the adenosine triphosphate–binding site. Together, these results show new properties of LPG3 and suggest an important role in leishmaniasis.

An autochthonous case of visceral leishmaniasis is reported in a dog (Canis familiaris) as an apparently natural infection in a non-endemic area. DNA obtained from spleen and liver samples produced the expected fragment in a Leishmania-specific rDNA-based nested-PCR assay. The PCR product, a 490 bp fragment, was sequenced and the nucleotide sequence was identical to that of Leishmania (Leishmania) infantum chagasi. These results are surprising since no autochthonous human or canine cases of visceral leishmaniasis have ever been reported in this municipality. This case suggests that natural transmission of this disease is occurring in this area.

In the United States, autochthonous cutaneous leishmaniasis caused by infection with Leishmania mexicana has been reported from Texas and Oklahoma. Here, we describe a child with 2 new features: cutaneous infection acquired outside of the south-central United States (in North Dakota) and infection caused by Leishmania donovani species complex.

A leishmaniose visceral (LV) é uma doença infecciosa crônica frequentemente fatal causada pela Leishmania infantum chagasi nas Américas. A enfermidade pode acometer vários órgãos, determinando diferentes manifestações clínicas. Contudo o envolvimento do coração raramente tem sido reportado em cães infectados por Leishmania sp. Dessa forma, descreve-se um caso de miocardite crônica com repercussões clínicas e patológicas em um cão naturalmente infectado por Leishmania infantum chagasi. A positividade para Leishmaniose Visceral foi determinada pela presença de anticorpos antiLeishmania sp. nos testes sorológicos (RIFI, ELISA e DPP) e confirmada por visualização de formas amastigotas de Leishmania sp. em punção aspirativa do linfonodo poplíteo. O exame cardiovascular revelou alterações radiográficas, eletrocardiográficas, na pressão arterial e nos biomarcardores cardíacos. Após eutanásia, amostras de tecido cardíaco foram avaliadas histologicamente e submetidas à imunomarcação, onde foi observado infiltrado mononuclear (plasmo-histiolinfocitário), com presença de estruturas arredondadas de coloracão marrom-amareladas (imunomarcadas), indicando formas amastigotas de Leishmania infantum chagasi no miocárdio. Os aspectos etiopatogênicos da leishmaniose visceral sobre o miocárdio neste caso podem estar relacionados tanto à presença do parasita quanto à resposta "reacional inespecífica" do tecido à agressão do parasita no organismo. Todavia ainda não se sabem se as cepas de Leishmania infantum chagasi da região semiárida paraibana apresentam algum tropismo por tecido cardíaco ou se induzem a reação imunológica cruzada, com implicações clínicas. Visceral leishmaniasis (VL) is a chronic, often fatal infectious disease caused by Leishmania infantum chagasi in the Americas. The disease can affect many organs and may express different clinical forms. However, the involvement of the heart has rarely been reported in dogs infected by Leishmania sp. Thus, we describe a case of chronic myocarditis with clinical and pathological effects in a dog naturally infected by Leishmania infantum chagasi. Positivity for Visceral Leishmaniasis was determined by the presence of anti-Leishmania sp. in serological tests (IFAT, ELISA and DPP) and confirmed by visualization of amastigote forms of the parasite in the popliteal lymph node aspiration samples. The cardiovascular clinical examination showed changes in the radiographic, ECG, blood pressure and heart biomarkers. After euthanasia, heart tissue samples were histologically examined and underwent our immunohistochemistry assessment, where mononuclear infiltrate was observed (plasma cells, lymphocytes and macrophages) with the presence of rounded brownish-yellow (immunomarked) cells, indicating amastigotes of Leishmania infantum chagasi within the myocardium. The etiopathogenic aspects of visceral leishmaniasis in the myocardium in this case may be related either to the presence of the parasite or the "nonspecific reactive" response of the tissue attributable to the aggression of the parasite in the body. However, it is not known if the strains of Leishmania infantum chagasi found in the semi-arid of Paraíba have some tropism for cardiac tissue or if they induce immunological cross-reaction with clinical implications.

Phylogenetic studies on trypanosomatid barcode using V7V8 SSU rRNA and gGAPDH gene sequences have provided support for redefining some trypanosomatid species and positioning new isolates. The genus Leishmania is a slow evolving monophyletic group and including important human pathogens. The phylogenetic relationships of this genus have been determined by the natural history of its vertebrate hosts, vector specificity, clinical manifestations, geographical distribution and molecular approaches using different markers. Thus, in an attempt to better understand the phylogenetic relationships of Leishmania species, we performed phylogenetic analysis on trypanosomatid barcode using V7V8 SSU rRNA and gGAPDH gene sequences among a large number of Leishmania species and also several Brazilian visceral Leishmania infantum chagasi isolates obtained from dogs and humans. Our phylogenetic analysis strongly suggested that Leishmania hertigi and Leishmania equatoriensis should be taxonomically revised so as to include them in the genus Endotrypanum; and supported ancient divergence of Leishmania enriettii. This, together with recent data in the literature, throws light on the discussion about the evolutionary southern supercontinent hypothesis for the origin of Leishmania ssp. and validates L. infantum chagasi from Brazil, thus clearly differentiating it from L. infantum, for the first time.

Visceral leishmaniasis (VL) is endemic in large cities in Brazil, including Natal. We determined the prevalence of asymptomatic human infection with Leishmania infantum chagasi and associated environmental risks around Natal. Infection was detected by Leishmania skin test (LST) and anti-leishmanial antibodies in humans and anti-leishmanial antibodies in dogs. Amongst 345 humans, 24.6% were seropositive, and 38.6% were LST-positive. Prevalence of positive serology was similar in both sexes and across all ages. However, positive LST responses increased with age, suggesting that LST is long-lasting and cumulative. Multinomial logistic analysis showed that LST response varied with location (P = 0.007) and that males were more frequently LST-positive (P = 0.027). Indicators of lower socioeconomic status associated significantly with human infection. Furthermore, there was geographic coincidence of seropositive humans and dogs (r = 0.7926, P = 0.011). These data suggest that dog and human L. i. chagasi infection are intimately interrelated in environmental conditions associated with low income.

Visceral leishmaniasis (VL) is a zoonosis caused by Leishmania infantum chagasi. The canids play an important role in its epidemiology as they are natural reservoirs. The present study aimed to investigate canine VL (CVL) in dogs from the city of Goiania. A group of 214 dogs (symptomatic and asymptomatic) was assessed. Blood samples, skin biopsies and lymph node aspirates were collected from the animals. Twenty dogs were positive by immunofluorescence antibody test (IFAT) while only 6 presented amastigotes in the direct microscopic examination (DME). The PCR tests, employed only for symptomatic animals or for those classified as positive by at least one of the two previous methods (n=81), were positive for 7 dogs. Positive samples by the DME were also positive by PCR. Only 7 out of 20 IFAT positive samples were confirmed by PCR. Species-specific PCR results confirmed the molecular identity of L. i. chagasi in these 7 animals. Among the samples confirmed by PCR, two corresponded to the first autochthonous cases of CVL, in the municipalities of Caldas Novas and Novo Brazil, and emphasized the urgent need to enhance control strategies for CVL in these localities. The study revealed the existence of CVL cases in dogs attending veterinary clinics in the city of Goiania.

INTRODUÇÃO: A leishmaniose visceral tem sido notificada em quase todos os estados do Brasil, e principalmente no norte de Minas Gerais, onde a doença é endêmica. Este estudo visou detectar a infecção natural de Lutzomyia longipalpis e identificar através da técnica de PCR/RFLP a espécie de Leishmania encontrada nos flebotomíneos do município de Janaúba. MÉTODOS: Utilizando-se armadilhas luminosas, foram capturadas 1.550 fêmeas de L. longipalpis, que agrupadas em pool de 10 exemplares foram submetidas à extração e amplificação de DNA, através das técnicas de PCR genérico e cacofonia. RESULTADOS: Dos 155 pools, seis apresentaram-se positivos para Leishmania sp., sendo a taxa de infecção do município de 3,9%. Através da PCR/RFLP determinou-se que o padrão de digestão das amostras positivas foi semelhante ao da cepa referência Leishmania chagasi (MHOM/BR/74/PP75). CONCLUSÕES: A detecção de infecção natural associada a estudos sobre a epidemiologia da LV sugere que L. longipalpis esteja envolvida na transmissão de L. infantum chagasi em Janaúba, principalmente nas áreas de intensa transmissão de LV. INTRODUCTION: Visceral leishmaniasis has been notified in nearly all states of Brazil, and particularly in the north of Minas Gerais, where the disease is endemic. The aim of this study was to detect natural infection of Lutzomyia longipalpis and, through the PCR/RFLP technique, identify Leishmania species found in sandflies in the municipality of Janaúba. METHODS: Using light traps, 1,550 females of L. longipalpis were caught and grouped into pools of 10 specimens to be subjected to DNA extraction and amplification, by means of generic PCR and cacophony. RESULTS: Out of the 155 pools, six were positive for Leishmania sp., and thus the infection rate in the municipality was 3.9%. Through PCR/RFLP, the digestion pattern among the positive samples was found to be similar to that of the reference strain of Leishmania chagasi (MHOM/BR/74/PP75). CONCLUSIONS: The detection of natural infection associated with studies on the epidemiology of visceral leishmaniasis suggests that L. longipalpis is involved in transmission of L. infantum chagasi in Janaúba, particularly in areas of intense transmission of visceral leishmaniasis.

Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasil. Secretaria de Sa?de do Munic?pio de Barcarena. Departamento de Sa?de P?blica. Barcarena, PA, Brasil. Universidade de S?o Paulo. Faculdade de Medicina. Departamento de Patologia. S?o Paulo, SP, Brasil. Universidade de S?o Paulo. Faculdade de Medicina. Departamento de Patologia. S?o Paulo, SP, Brasil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasill / Universidade Federal do Par?. N?cleo de Medicina Tropical. Bel?m, PA, Brasil. A leishmaniose visceral canina (LVC) ? reconhecida pelas caracter?sticas cl?nicas da doen?a e ? altamente letal. A infec??o, entretanto, pode ser totalmente assintom?tica em alguns c?es soropositivos, o que tem levantado quest?o pol?mica sobre a possibilidade desses animais, serem ou n?o uma fonte importante da infec??o para o flebotom?neo, Lutzomyia longipalpis, o principal vetor da leishmaniose visceral americana (LVA). Neste estudo foram examinados 51 c?es com LVC aguda, provenientes de ?rea end?mica de LVA no Estado do Par?, Brasil, e a carga parasit?ria, formas amastigotas de Leishmania (L.) infantum chagasi, na pele, linfonodo popl?teo e v?sceras (f?gado e ba?o) foi comparada com a de nove c?es assintom?ticos soropositivos (IFAT-IgG). Fragmentos de bi?psia desses tecidos obtidos post-mortem foram processados para an?lise atrav?s de imunohistoqu?mica, usando um anticorpo policlonal contra Leishmania sp. Os testes do Qui-quadrado (X2 ) e Mann Whitney foram usados para avaliar as m?dias da densidade de macr?fagos infectados (p < 0,05). Os resultados mostraram que n?o houve diferen?a (p > 0,05) na densidade de macr?fagos infectados da pele (10,7/mm2 x 15,5/mm2 ) e do linfonodo (6,3/mm2 x 8,3/mm2 ) entre c?es assintom?ticos e sintom?ticos. Entretanto, a densidade de macr?fagos infectados da v?scera de c?es sintom?ticos (5,3/mm2 ) foi maior (p < 0,05) que a de c?es assintom?ticos (1,4/mm2 ). Estes resultados sugerem, fortemente, que c?es naturalmente infectados por L. (L.) i. chagasi, assintom?ticos ou sintom?ticos, podem servir como fonte de infec??o, principalmente, considerando-se que a densidade de macr?fagos infectados da pele (10,7/mm2 x 15,5/mm2 ), local onde o flebotom?neo vetor Lu. longipalpis realiza a hematofagia, foi maior (p < 0,05) que as do linfonodo (6,3/mm2 x 8.3/mm2 ) e v?sceras (1,4/mm2 x 5,3/mm2) Canine visceral leishmaniasis (CVL) is recognizable by characteristic signs of disease and is highly lethal. The infection, however, may be quite inapparent in some seropositive dogs, and this has raised the polemic question as to whether or not such animals can be a source of infection for Lutzomyia longipalpis, the vector of American visceral leishmaniasis (AVL). In this study we have examined 51 dogs with acute CVL from an AVL area in Par? State, northern Brazil, and compared the parasite density, amastigotes of Leishmania (L.) infantum chagasi, in the skin, lymph node and viscera of symptomatic with that of nine asymptomatic but seropositive dogs (IFAT-IgG). Post-mortem biopsy fragments of these tissues were processed by immunohistochemistry, using a polyclonal antibody against Leishmania sp. The X2 and Mann Whitney tests were used to evaluate the means of infected macrophage density (p > 0.05). There was no difference (p %> 0.05) in the skin (10.7/mm2 x 15.5/mm2) and lymph node (6.3/mm2 x 8.3/mm2), between asymptomatic and symptomatic dogs, respectively. It was higher (p > 0.05), however, in the viscera of symptomatic (5.3/mm2) than it was in asymptomatic (1.4/mm2) dogs. These results strongly suggest that asymptomatic or symptomatic L. (L.) i. chagasi-infected dogs can serve as a source of infection, principally considering the highest (p > 0.05) parasite density from skin (10.7/mm2 x 15.5/mm2), the place where the vetor L. longipalpis takes its blood meal, compared with those from lymph node (6.3/mm2 x 8.3/mm2) and viscera (1.4/mm2 x 5.3/mm2).

Natural infections with Leishmania were found in females of the phlebotomine sand flies Lutzomyia neivai (Pinto) (=Nyssomyia neivai) and Lutzomyia sallesi (Galvao & Coutinho) (=Evandromyia sallesi) (Diptera: Psychodidae) from Lassance, in the Brazilian state of Minas Gerais. Promastigotes were found in the pyloric region of the former species and in the abdominal midgut of the latter species. Insects found to be infected by microscopic examination were macerated in saline solution and inoculated into hamsters. Subsequent analysis by polymerase chain reaction-restriction fragment length polymorphism revealed both isolates to belong to the species Leishmania infantum chagasi Cunha & Chagas.

Leishmanias can be produced by inoculation in conditioned McCoy cell culture growth medium (CGM). Leishmania (Leishmania) infantum chagasi (100 parasites) grown in NNN medium was inoculated in 2.5 mL CGM, kept in plates (24 wells) and its multiplication was observed for five days (120 hours). After day 5, the medium was saturated with the flagellate forms of the parasite (promastigotes). The reproduction of the leishmanias was observed every 24 hours and the number of parasites was calculated by counting the parasites in a drop of 10 µ L and photomicrographied. So the number of Leishmanias was adjusted to 1 mL volume. The advantage of the technique by isolation of Leishmania in CGM demonstrated in this study is its low cost and high efficacy even with a small quantity of parasites (10² promastigotes) used as inoculum. Additionally, isolation of the leishmania can be obtained together with an increase in their density (180 times) as observed by growth kinetics, within a shorter time. These results justify the use of this low-cost technique for the isolation and investigation of the behavior and multiplication of Leishmania both in vertebrates and invertebrates, besides offering means of obtaining antigens, whether whole antigens (leishmanias) or the soluble antigens produced by the parasites which may be useful for the production of new diagnostic kits.

Visceral Leishmaniasis is an endemic disease in Brazil caused by Leishmania infantum chagasi and its main vector species is the sand fly Lutzomyia longipalpis. Epidemiological studies have used conventional PCR techniques to measure the rate of infection of sand flies collected in the field. However, real-time PCR can detect lower parasite burdens, reducing the number of false negatives and improving the quantification of Leishmania parasites in the sand fly. This study compared genes with various copy numbers to detect and quantify L. infantum chagasi in L. longipalpis specimens by real-time PCR. We mixed pools of 1, 10 and 30 male sand flies with various amounts of L. infantum chagasi, forming groups with 50, 500, 5000 and 50,000 Leishmania parasites. For the amplification of L. infantum chagasi DNA, primers targeting kDNA, polymerase α and the 18S ribosome subunit were employed. Parasites were measured by absolute and relative quantification. PCR detection using the amplification of kDNA exhibited the greatest sensitivity among the genes tested, showing the capacity to detect the DNA equivalent of 0.004 parasites. Additionally, the relative quantification using these primers was more accurate and precise. In general, the number of sand flies used for DNA extraction did not influence Leishmania quantification. However, for low-copy targets, such as the polymerase α gene, lower parasite numbers in the sample produced inaccurate quantifications. Thus, qPCR measurement of L. infantum chagasi in L. longipalpis was improved by targeting high copy-number genes; amplification of high copy-number targets increased the sensitivity, accuracy and precision of DNA-based parasite enumeration.

Visceral Leishmaniasis by Leishmania infantum chagasi is an endemic zoonosis present in many areas of Brazil. This parasite needs reservoirs for maintenance of the infection and the presence of dogs in urban areas is a key factor for the spread of canine visceral leishmaniasis (CVL). The aim of this study was to report the first autochthonous case of CVL in the municipality of Iguatama, in west central region of Minas Gerais State. Dog infection by Leishmania infantum chagasi was confirmed in the municipality, previously considered as non-endemic area to CVL. The canine infection by Leishmania was confirmed by three immunological tests for antibodies: indirect immunofluorescence assay (IFA), rapid Dual Path Platform (DPP®) CVL immunochromatographic test, enzyme-linked immunosorbent assay (ELISA), and microscopic demonstration of Leishmania amastigotes in imprints of spleen and bone marrow stained by Giemsa. The species Leishmania infantum chagasi was confirmed by molecular diagnosis (PCR). Studies are being carried out, aiming to describe the importance and the prevalence of this disease in the region and factors associated with its transmission.