RESUMO
Lutzomyia umbratilis is the main vector of Leishmania guyanensis in the Brazilian Amazon and in neighboring countries. Previous biological and molecular investigations have revealed significant differences between L. umbratilis populations from the central Brazilian Amazon region. Here, a phylogeographic survey of L. umbratilis populations collected from nine localities in the Brazilian Amazon was conducted using two mitochondrial genes. Statistical analyses focused on population genetics, phylogenetic relationships and species delimitations. COI genetic diversity was very high, whereas Cytb diversity was moderate. COI genealogical haplotypes, population structure and phylogenetic analyses identified a deep genetic differentiation and three main genetic groups. Cytb showed a shallower genetic structure, two main haplogroups and poorly resolved phylogenetic trees. These findings, allied to absence of isolation by distance, support the hypothesis that the Amazon and Negro Rivers and interfluves are the main evolutionary forces driving L. umbratilis diversification. The main three genetic groups observed represent three evolutionary lineages, possibly species. The first lineage occurs north of the Amazon River and east of Negro River, where Le. guyanensis transmission is intense, implying that L. umbratilis is an important vector there. The second lineage is in the interfluve between north of Amazon River and west of Negro River, an area reported to be free of Le. guyanensis transmission. The third lineage, first recorded in this study, is in the interfluve between south of Amazonas River and west of Madeira River, and its involvement in the transmission of this parasite remains to be elucidated.
Assuntos
Evolução Biológica , Insetos Vetores/genética , Leishmania guyanensis/patogenicidade , Leishmaniose Mucocutânea/transmissão , Filogenia , Psychodidae/genética , Animais , Brasil/epidemiologia , Citocromos b/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Expressão Gênica , Variação Genética , Haplótipos , Humanos , Proteínas de Insetos/genética , Insetos Vetores/classificação , Leishmania guyanensis/crescimento & desenvolvimento , Leishmaniose Mucocutânea/epidemiologia , Leishmaniose Mucocutânea/parasitologia , Mitocôndrias/enzimologia , Mitocôndrias/genética , Filogeografia , Psychodidae/classificação , Rios/parasitologiaRESUMO
BACKGROUND: Cutaneous leishmaniasis (CL) is an endemic disease in Brazil that is highly prevalent in the northern region of the country. Although there is a continuous and growing number of cases registered in the state of Roraima, there is limited information regarding the species of Leishmania that affect the human population. In this study, we aimed to characterize which Leishmania species cause human disease in those presenting with cutaneous leishmaniasis in endemic areas of the State of Roraima. METHODS: We conducted a prospective surveillance study between 2016 to 2018 in health centers located in the State of Roraima, Brazil. Participants with clinical suspicion of CL were enrolled and provided lesion samples for parasitological detection by microscopy. A subset of the samples was tested by polymerase chain reaction and sequencing of the internal transcribed spacer 1 (ITS-1 PCR) for molecular species identification. RESULTS: A total of 262 participants were enrolled in this study. Of those, 129 (49.27%) were positive by parasitological examination. Most positive subjects (81.58%) were male, and most cases presented a single lesion (80.26%). ITS-1 PCR and sequencing on a subset of 76 samples allowed us to detect nine different species of Leishmania: L. (V.) braziliensis, L (V.) panamensis, L. (V.) guyanensis, L. (V.) naiffi, L. (V.) shawi, L.(V.) utingensis, L. (V.) lindenbergi, L. (L.) amazonensis and L. (L.) mexicana. CONCLUSIONS: Our study provides the first assessment of circulating species of Leishmania in the State of Roraima, Brazil, and shows the high diversity in this region. This study opens the path for further research on the transmission of leishmaniasis in the northernmost Brazilian State including vector and reservoir surveillance as well as for intensification of investigation and control activities against CL in the region.
Assuntos
Leishmania/genética , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/epidemiologia , Adolescente , Adulto , Brasil/epidemiologia , Criança , Pré-Escolar , DNA de Protozoário/genética , Monitoramento Epidemiológico , Feminino , Humanos , Lactente , Recém-Nascido , Leishmania/classificação , Leishmania/isolamento & purificação , Leishmania/patogenicidade , Leishmania braziliensis/genética , Leishmania braziliensis/patogenicidade , Leishmania guyanensis/genética , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/parasitologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Análise de Sequência de DNA , Adulto JovemRESUMO
Leishmaniasis is a neglected, parasitic tropical disease caused by an intracellular protozoan from the genus Leishmania. Quinoline alkaloids, secondary metabolites found in plants from the Rutaceae family, have antiparasitic activity against Leishmania sp. N-methyl-8-methoxyflindersin (1), isolated from the leaves of Raputia heptaphylla and also known as 7-methoxy-2,2-dimethyl-2H,5H,6H-pyran[3,2-c]quinolin-5-one, shows antiparasitic activity against Leishmania promastigotes and amastigotes. This study used in silico tools to identify synthetic quinoline alkaloids having structure similar to that of compound 1 and then tested these quinoline alkaloids for their in vitro antiparasitic activity against Leishmania (Viannia) panamensis, in vivo therapeutic response in hamsters suffering from experimental cutaneous leishmaniasis (CL), and ex vivo immunomodulatory potential in healthy donors' human peripheral blood (monocyte)-derived macrophages (hMDMs). Compounds 1 (natural), 2 (synthetic), and 8 (synthetic) were effective against intracellular promastigotes (9.9, 3.4, and 1.6 µg/mL medial effective concentration [EC50], respectively) and amastigotes (5.07, 7.94, and 1.91 µg/mL EC50, respectively). Compound 1 increased nitric oxide production in infected hMDMs and triggered necrosis-related ultrastructural alterations in intracellular amastigotes, while compound 2 stimulated oxidative breakdown in hMDMs and caused ultrastructural alterations in the parasite 4 h posttreatment, and compound 8 failed to induce macrophage modulation but selectively induced apoptosis of infected hMDMs and alterations in the intracellular parasite ultrastructure. In addition, synthetic compounds 2 and 8 improved the health of hamsters suffering from experimental CL, without evidence of treatment-associated adverse toxic effects. Therefore, synthetic compounds 2 and 8 are potential therapeutic candidates for topical treatment of CL.
Assuntos
Antiprotozoários/farmacologia , Compostos Heterocíclicos com 3 Anéis/farmacologia , Leishmania guyanensis/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Alcaloides/farmacologia , Animais , Antiprotozoários/química , Cricetinae , Modelos Animais de Doenças , Compostos Heterocíclicos com 3 Anéis/química , Humanos , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/patologia , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Camundongos , Óxido Nítrico/genética , Folhas de Planta/química , Quinolinas/química , Quinolonas/farmacologia , Rutaceae/químicaRESUMO
Local therapies have been proposed as safe and effective alternatives to systemic drugs in cutaneous leishmaniasis (CL), especially among less severe cases. However, they are not widely available and used in endemic places, including Colombia, which has a high burden of disease. Further complicating the uptake of local therapies is that different treatment guidelines have been established by the World Health Organization (WHO) and Pan American Health Organization (PAHO). Using data from a large referral center in Colombia, we determined the proportion of patients who would be eligible for and potentially benefit from local therapies according to both international guidelines. The sample included 1,891 confirmed cases of CL aged ≥ 12 years, mostly infected with Leishmania Viannia panamensis (91%, n = 601/660), between 2004 and 2014. Overall, 57% of the sample had one lesion, whereas another 31% had two to three lesions. For 74% of patients, all lesions were in an area other than head or neck. The maximum lesion size was ≤ 3 cm for 58% and < 5 cm for 88% of the sample. Based on our data, up to 56% of patients could have been eligible for local therapies according to the WHO criteria. By contrast, only 23% were eligible according to the more restrictive PAHO criteria. Regardless, these data suggest that a substantial proportion of CL patients in Colombia may benefit from local therapies given their relatively mild presentation of disease and low risk of complications. Individualized risk-benefit assessment and guideline adjustments may increase local therapy eligibility and benefit a large number of patients.
Assuntos
Antimônio/uso terapêutico , Antiprotozoários/uso terapêutico , Leishmania braziliensis/efeitos dos fármacos , Leishmania guyanensis/efeitos dos fármacos , Leishmaniose Cutânea/terapia , Paromomicina/uso terapêutico , Pentamidina/uso terapêutico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Colômbia/epidemiologia , Estudos Transversais , Crioterapia/métodos , Feminino , Humanos , Hipertermia Induzida/métodos , Leishmania braziliensis/crescimento & desenvolvimento , Leishmania braziliensis/patogenicidade , Leishmania guyanensis/crescimento & desenvolvimento , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Índice de Gravidade de DoençaRESUMO
BACKGROUND: Cutaneous leishmaniasis (CL) is a serious health problem in Suriname. To expand the diagnostic options, two newly developed diagnostic tests, i.e. the rapid diagnostic test CL Detect™ Rapid Test (CL Detect) and the Loopamp™ Leishmania Detection Kit (Loopamp) were evaluated. METHODS: Diagnostic test performance was compared to the routine diagnostic approach in place, i.e. clinical symptoms combined with microscopy, and to polymerase chain reaction (PCR), which was used as a reference standard. The study population (n = 93) was a typical representation of the CL affected population in Suriname and mainly infected with Leishmania guyanensis. RESULTS: CL Detect had a very low sensitivity compared to microscopy (36.7%) or PCR (35.8%), due to a high number of false negative results. The specificity of the CL Detect compared to microscopy and PCR was 85.7 and 83.3% respectively. Loopamp sensitivity was 84.8% compared to microscopy and 91.4% compared to PCR. The Loopamp test had a moderate specificity (42.9%) compared to microscopy, but a good specificity compared to PCR (91.7%). CONCLUSION: The CL Detect is not likely to be a good replacement for the routine diagnostic procedure for CL in Suriname. The high sensitivity of the easy to perform Loopamp enables the implementation of sensitive molecular diagnosis in resource limited settings.
Assuntos
Leishmaniose Cutânea/diagnóstico , Testes Imediatos , Adulto , Cromatografia de Afinidade/métodos , Testes Diagnósticos de Rotina/métodos , Feminino , Humanos , Leishmania guyanensis/genética , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/patologia , Masculino , Microscopia , Reação em Cadeia da Polimerase/métodos , Sensibilidade e Especificidade , SurinameRESUMO
The establishment of Leishmania infection in mammalian hosts and the subsequent manifestation of clinical symptoms require internalization into macrophages, immune evasion and parasite survival and replication. Although many of the genes involved in these processes have been described, the genetic and genomic variability associated to differences in virulence is largely unknown. Here we present the genomic variation of four Leishmania (Viannia) panamensis strains exhibiting different levels of virulence in BALB/c mice and its application to predict novel genes related to virulence. De novo DNA sequencing and assembly of the most virulent strain allowed comparative genomics analysis with sequenced L. (Viannia) panamensis and L. (Viannia) braziliensis strains, and showed important variations at intra and interspecific levels. Moreover, the mutation detection and a CNV search revealed both base and structural genomic variation within the species. Interestingly, we found differences in the copy number and protein diversity of some genes previously related to virulence. Several machine-learning approaches were applied to combine previous knowledge with features derived from genomic variation and predict a curated set of 66 novel genes related to virulence. These genes can be prioritized for validation experiments and could potentially become promising drug and immune targets for the development of novel prophylactic and therapeutic interventions.
Assuntos
Leishmania guyanensis/genética , Leishmania guyanensis/patogenicidade , Animais , Colômbia , Variações do Número de Cópias de DNA , Feminino , Genoma de Protozoário , Leishmania braziliensis/genética , Leishmaniose Mucocutânea/parasitologia , Aprendizado de Máquina , Camundongos Endogâmicos BALB C , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNARESUMO
Leishmania (Viannia) guyanensis is a causal agent of American tegumentary leishmaniasis (ATL). This protozoan has been poorly investigated; however, it can cause different clinical forms of ATL, ranging from a single cutaneous lesion to severe lesions that can lead to destruction of the nasopharyngeal mucosa. L. (V.) guyanensis and the disease caused by this species can present unique aspects revealing the need to better characterize this parasite species to improve our knowledge of the immunopathological mechanisms and treatment options for ATL. The mechanisms by which some patients develop a more severe form of ATL remain unclear. It is known that the host immune profile and parasite factors may influence the clinical manifestations of the disease. Besides intrinsic parasite factors, Leishmaniavirus RNA 1 (LRV1) infecting L. guyanensis can contribute to ATL immunopathogenesis. In this review, general aspects of L. guyanensis infection in humans and mouse models are presented.
Assuntos
Interações Hospedeiro-Parasita/imunologia , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/patologia , Leishmaniavirus/patogenicidade , Mucosa/patologia , Animais , Modelos Animais de Doenças , Humanos , Imunidade Inata , Interleucina-17/biossíntese , Interleucina-17/imunologia , Leishmania guyanensis/imunologia , Leishmania guyanensis/virologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/parasitologia , Leishmaniavirus/fisiologia , Camundongos , Mucosa/imunologia , Mucosa/parasitologia , Nasofaringe/imunologia , Nasofaringe/parasitologia , Nasofaringe/patologia , Índice de Gravidade de DoençaRESUMO
BACKGROUND: The treatment of Leishmaniasis caused by Leishmania (Viannia) guyanensis is based on a weak strength of evidence from very few clinical trials and some case series reports. Current treatment guidelines recommend pentamidine isethionate or meglumine antimoniate (Glucantime) as the first-line choices. Both are parenteral drugs with a low therapeutic indexes leading to a high risk of undesired effects. Imidazole derivatives interfere with the production of leishmanial ergosterol, an essential component of their membrane structure. One drug that has been studied in different clinical presentations of Leishmania is fluconazole, a hydrophilic bis-triazole, which is easily absorbed through the oral route with a low toxicity profile and is considered safe for children. This drug is readily available in poor countries with a reasonable cost making it a potential option for treating leishmaniasis. METHODS AND FINDINGS: An adaptive nonrandomized clinical trial with sequential groups with dose escalation of oral fluconazole was designed to treat adult men with localized cutaneous leishmaniasis (LCL) in Manaus, Brazil. Eligible participants were patients with LCL with confirmed Leishmania guyanensis infection. RESULTS: Twenty adult male patients were treated with 450 mg of fluconazole daily for 30 days. One patient (5%) was cured within 30 days of treatment. Of the 19 failures (95%), 13 developed a worsening of ulcers and six evolved lymphatic spreading of the disease. Planned dose escalation was suspended after the disappointing failure rate during the first stage of the trial. CONCLUSION/SIGNIFICANCE: Oral fluconazole, at the dose of 450mg per day, was not efficacious against LCL caused by Leishmania guyanensis in adult men. TRIAL REGISTRATION: Brazilian Clinical Trial Registration (ReBec)-RBR-8w292w; UTN number-1158-2421.
Assuntos
Antiprotozoários/uso terapêutico , Fluconazol/uso terapêutico , Leishmania guyanensis/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Administração Oral , Adolescente , Adulto , Antiprotozoários/administração & dosagem , Brasil , Fluconazol/administração & dosagem , Mãos/diagnóstico por imagem , Mãos/parasitologia , Humanos , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/patologia , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados não Aleatórios como Assunto , Falha de Tratamento , Adulto JovemRESUMO
Cutaneous leishmaniasis typically presents as a painless papule progressing to an ulcer or plaque. In this case study of the ear, the disease manifested as a small painful bump progressing into redness and swelling about the ear with purulent drainage. After multiple oral/intravenous antipseudomonal, antistaphylococcal, and antifungal treatments, there was no improvement. The skin progressed to an erythematous plaque and hemorrhagic ulcer; punch biopsy and speciation revealed Leishmaniasis guyanensis. The patient was switched to a seven-dose course of intravenous L-amphotericin B (visceral leishmaniasis protocol). Within 21 days, pain and edema resolved and the ulcers healed. Three-month follow-up demonstrated no recurrence. Further studies are needed to evaluate the use of L-amphotericin B in Leishmaniasis guyanensis.
Assuntos
Orelha/parasitologia , Leishmaniose Cutânea/diagnóstico , Adulto , Anfotericina B/farmacologia , Anfotericina B/uso terapêutico , Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Orelha/lesões , Guiana , Perda Auditiva/etiologia , Humanos , Leishmania guyanensis/patogenicidade , Masculino , Otite Externa/diagnóstico , Otite Externa/fisiopatologia , ViagemRESUMO
The aim of this study was to characterize clinical field isolates of Leishmania spp. obtained from patients with American Tegumentary Leishmaniasis (ATL) who live in Goiás state, Brazil. The presumed areas of infection were in Goiás, Tocantins, and Pará states. Three isolates of parasites were identified as L. (Viannia) braziliensis and one as L. (V.) guyanensis. The in vitro growth profiles were found to be similar for all parasites. Nevertheless, in C57BL/6 mice, L. (V.) guyanensis infection was better controlled than L. (V.) braziliensis. Yet in C57BL/6 mice deficient in interferon gamma, L. (V.) guyanensis lesions developed faster than those caused by L. (V.) braziliensis isolates. In BALB/c mice, the development of lesions was similar for isolates from both species; however, on the 11th week of infection, amastigotes could not be observed in macrophages from L. (V.) guyanensis-infected mice. Thus, L. (V.) guyanensis can be circulating in Goiás, a state where autochthonous cases of this species had not yet been reported. Considering the difficulties to differentiate L. (V.) guyanensis from L. (V.) braziliensis at the molecular, morphological, and clinical (human and murine models) levels, the presence of L. (V.) guyanensis infections is possibly underestimated in several regions of Brazil.
Assuntos
Leishmania braziliensis/patogenicidade , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/parasitologia , Animais , Brasil , Humanos , Leishmania braziliensis/isolamento & purificação , Leishmania guyanensis/isolamento & purificação , Leishmaniose Cutânea/patologia , CamundongosRESUMO
Functional variations in the mannose-binding lectin (MBL2) gene causing low levels of serum MBL are associated with susceptibility to numerous infectious diseases. We investigated whether there is genetic association of MBL2 variant alleles with cutaneous leishmaniasis (CL) caused by Leishmania guyanensis. We used PCR-restriction fragment length polymorphism to genotype six MBL2 variants, three in the promoter region and three in the exon 1. An association was noted between the single nucleotide polymorphism -221X/Y of the MBL2 gene and CL (P=2.9 × 10(-6); odds ratio (OR)=1.9 (1.4-2.5) consistent with the hypothesis that the -221X allele confers high risk to development of CL among L. guyanensis-infected individuals. Furthermore, L. guyanensis-infected individuals bearing the codon 57 allele C had a higher risk of developing CL (P=5 × 10(-5); OR=1.9 (1.4-2.6)). The low MBL expressor haplotype LXPB was also associated to CL (P=6 × 10(-4)). This study raises the possibility that functional polymorphisms in MBL2 gene play a role in clinical outcome of Leishmania infection.
Assuntos
Predisposição Genética para Doença , Leishmaniose Cutânea/genética , Lectina de Ligação a Manose/genética , Polimorfismo de Nucleotídeo Único , Adulto , Brasil , Estudos de Casos e Controles , Feminino , Frequência do Gene , Haplótipos , Humanos , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/parasitologia , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Polimorfismo de Fragmento de RestriçãoRESUMO
The largest recorded outbreak of cutaneous leishmaniasis in Colombia's history occurred during 2005-2009 in soldiers of the Colombian Army, with ~40,000 cases. This outbreak was caused by the influx of military personnel into the jungle with the mission of combat illicit crops and the guerrilla. The soldiers remain for long periods within the rainforest and are exposed to the bite of infected sand flies. During the military activities, soldiers work with dogs specially trained to detect landmines, and therefore, dogs are also exposed to the infected sand flies and show high incidence of cutaneous leishmaniasis (CL). This work describes an epidemic outbreak of canine CL caused by Leishmania braziliensis and Leishmania panamensis in Colombia, South America. The clinical features of the disease and the response to treatment with pentavalent antimonials observed in 72 guard dogs from the Colombian Army are described. A program for prevention and control of canine CL is also discussed.
Assuntos
Surtos de Doenças , Doenças do Cão/epidemiologia , Leishmania braziliensis/patogenicidade , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/veterinária , Animais , Colômbia/epidemiologia , Cães/parasitologia , Feminino , Humanos , Leishmania braziliensis/efeitos dos fármacos , Leishmania braziliensis/isolamento & purificação , Leishmania guyanensis/efeitos dos fármacos , Leishmania guyanensis/isolamento & purificação , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/prevenção & controle , Masculino , Meglumina/uso terapêutico , Militares , Psychodidae/parasitologiaRESUMO
The main causative agent of cutaneous leishmaniasis (CL) in Suriname is Leishmania (Viannia) guyanensis. This case report presents a patient infected with Leishmania (Viannia) braziliensis, a species never reported before in Suriname. This finding has clinical implications, because L. braziliensis has a distinct clinical phenotype characterized by mucocutaneous leishmaniasis, a more extensive and destructive form of CL that requires different treatment. Clinicians should be aware that chronic cutaneous ulcers in patients from the Guyana region could be caused by L. braziliensis.
Assuntos
Leishmania braziliensis/isolamento & purificação , Leishmania guyanensis/isolamento & purificação , Leishmaniose Mucocutânea/diagnóstico , Adulto , DNA de Protozoário/genética , Humanos , Leishmania braziliensis/genética , Leishmania braziliensis/patogenicidade , Leishmania guyanensis/genética , Leishmania guyanensis/patogenicidade , Leishmaniose Mucocutânea/tratamento farmacológico , Leishmaniose Mucocutânea/fisiopatologia , Masculino , Pentamidina/uso terapêutico , Suriname , Resultado do TratamentoRESUMO
Domestic, synanthropic and wild hosts of Leishmania spp. parasites were studied in an area endemic for American tegumentary leishmaniasis (ATL), specifically in northern Minas Gerais State, Brazil. Domestic dogs and small forest mammals are reservoir hosts for L. (Leishmania) infantum. However, the role that these animals play in the transmission cycle of the Leishmania spp. that cause cutaneous leishmaniasis is not well known. This study evaluated 72 rodents, 25 marsupials and 98 domestic dogs found in two villages of the Xakriabá Indigenous Territory, an area of intense ATL transmission. A total of 23 dogs (23.47%) were shown to be positive according to at least one test; 8 dogs (8.16%) tested positive in a single serological test and 15 dogs (15.31%) tested positive by IFAT and ELISA. Eleven dogs were euthanised to allow for molecular diagnosis, of which nine (81.8%) tested positive by PCR for Leishmania in at least one tissue. Seven animals were infected only with L. (L.) infantum, whilst two displayed a mixed infection of L. (L.) infantum and L. (V.) braziliensis. Isoenzymatic characterisation identified L. (L.) infantum parasites isolated from the bone marrow of two dogs. Of the 97 small mammals captured, 24 tested positive for Leishmania by PCR. The results showed that L. (V.) braziliensis, L. (L.) infantum and L. (V.) guyanensis are circulating among wild and synanthropic mammals present in the Xakriabá Reserve, highlighting the epidemiological diversity of ATL in this region.
Assuntos
Medula Óssea/parasitologia , Doenças do Cão/parasitologia , Leishmania/patogenicidade , Leishmaniose Cutânea/epidemiologia , Marsupiais/parasitologia , Roedores/parasitologia , Animais , Brasil/epidemiologia , Reservatórios de Doenças , Doenças do Cão/genética , Doenças do Cão/transmissão , Cães , Ensaio de Imunoadsorção Enzimática , Humanos , Leishmania braziliensis/patogenicidade , Leishmania guyanensis/patogenicidade , Leishmania infantum/patogenicidade , Leishmaniose Cutânea/genética , Leishmaniose Cutânea/transmissão , Reação em Cadeia da PolimeraseRESUMO
Lutzomyia longipalpis females received single and mixed infections with Endotrypanum and Leishmania. Two biological parameters were analyzed: the percentage of infected females and the distribution of flagellates in the gut of the females. The principal comparisons were performed between (1) two strains of Endotrypanum, (2) cloned versus primary sample of one strain of Endotrypanum, (3) Endotrypanum versus Leishmania guyanensis, and (4) the pattern of flagellates behaviour by optical microscopy in females with single or mixed infection versus the identification of parasites isolated from digestive tracts by isoenzyme electrophoresis. Flagellates of Endotrypanum showed distinct patterns of infection suggesting that there is variation between and within strains. The distribution of Endotrypanum and L. guyanensis differed significantly in relation to the colonization of the stomodeal valve. In co-infection with L. guyanensis, a large number of flagellates were seen to be plentifully infecting the stomodeal valve in significantly more specimens than in females infected by Endotrypanum only. However, the electrophoretic profiles of isoenzymes of parasites recovered from all co-infected specimens corresponded to Endotrypanum. This suggests that the mere correlation sand fly infection-biochemical analysis of isolates may induce parasitological incorrect consideration.
Assuntos
Animais , Feminino , Isoenzimas/análise , Leishmania guyanensis/patogenicidade , Psychodidae/parasitologia , Trypanosomatina/patogenicidade , Sistema Digestório/parasitologia , Eletroforese em Gel de Ágar , Citometria de Fluxo , Interações Hospedeiro-Parasita , Leishmania guyanensis/enzimologia , Leishmania guyanensis/isolamento & purificação , Trypanosomatina/enzimologia , Trypanosomatina/isolamento & purificaçãoRESUMO
The immune mechanisms that underlie resistance and susceptibility to leishmaniasis are not completely understood for all species of Leishmania. It is becoming clear that the immune response, the parasite elimination by the host and, as a result, the outcome of the disease depend both on the host and on the species of the infecting Leishmania. Here, we analyzed the outcome of the infection of BALB/c mice with L. guyanensis in vivo and in vitro. We showed that BALB/c mice, which are a prototype of susceptible host for most species of Leishmania, dying from these infections, develop insignificant or no cutaneous lesions and eliminate the parasite when infected with promastigotes of L. guyanensis. In vitro, we found that thioglycollate-elicited BALB/c peritoneal macrophages, which are unable to eliminate L. amazonensis without previous activation with cytokines or lipopolysaccharide, can kill L. guyanensis amastigotes. This is the first report showing that infection of peritoneal macrophages with stationary phase promastigotes efficiently triggers innate microbicidal mechanisms that are effective in eliminating the amastigotes, without exogenous activation. We demonstrated that L. guyanensis amastigotes die inside the macrophages through an apoptotic process that is independent of nitric oxide and is mediated by reactive oxygen intermediates generated in the host cell during infection. This innate killing mechanism of macrophages may account for the resistance of BALB/c mice to infection by L. guyanensis.
Assuntos
Apoptose , Leishmania guyanensis/patogenicidade , Leishmaniose Cutânea/imunologia , Macrófagos/imunologia , Macrófagos/parasitologia , Explosão Respiratória , Animais , Células Cultivadas , Leishmania guyanensis/crescimento & desenvolvimento , Leishmaniose Cutânea/fisiopatologia , Ativação de Macrófagos/imunologia , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Espécies Reativas de Oxigênio/metabolismoRESUMO
Lutzomyia longipalpis females received single and mixed infections with Endotrypanum and Leishmania. Two biological parameters were analyzed: the percentage of infected females and the distribution of flagellates in the gut of the females. The principal comparisons were performed between (1) two strains of Endotrypanum, (2) cloned versus primary sample of one strain of Endotrypanum, (3) Endotrypanum versus Leishmania guyanensis, and (4) the pattern of flagellates behaviour by optical microscopy in females with single or mixed infection versus the identification of parasites isolated from digestive tracts by isoenzyme electrophoresis. Flagellates of Endotrypanum showed distinct patterns of infection suggesting that there is variation between and within strains. The distribution of Endotrypanum and L. guyanensis differed significantly in relation to the colonization of the stomodeal valve. In co-infection with L. guyanensis, a large number of flagellates were seen to be plentifully infecting the stomodeal valve in significantly more specimens than in females infected by Endotrypanum only. However, the electrophoretic profiles of isoenzymes of parasites recovered from all co-infected specimens corresponded to Endotrypanum. This suggests that the mere correlation sand fly infection-biochemical analysis of isolates may induce parasitological incorrect consideration.
Assuntos
Leishmania guyanensis/patogenicidade , Psychodidae/parasitologia , Trypanosomatina/patogenicidade , Animais , Sistema Digestório/parasitologia , Eletroforese em Gel de Ágar , Feminino , Citometria de Fluxo , Interações Hospedeiro-Parasita , Isoenzimas/análise , Leishmania guyanensis/enzimologia , Leishmania guyanensis/isolamento & purificação , Trypanosomatina/enzimologia , Trypanosomatina/isolamento & purificaçãoRESUMO
The cell surface plays an important role in the interaction of parasites with their hosts. Drug resistance in the protozoan Leishmania may involve changes in cell-surface composition, although it is not known whether infectivity is also affected. One sensitive and two glucantime-resistant lines of Leishmania (Viannia) guyanensis previously isolated were inoculated into hamsters. The sensitive line caused the disease to manifest earlier than the resistant lines. Imprinting analyses of infected macrophages showed that the sensitive line was more infective than the resistant cell lines. In vitro drug resistance was evaluated and the comparative analyses of dose-response curves showed that the susceptibility pattern of the sensitive line did not change after passage in animals, but a decrease in drug resistance was observed in resistant cell lines recovered from the mammalian host. Cell surface carbohydrates of sensitive and resistant cell lines were analysed before and after passage in animals by agglutination tests with several plant lectins. Passage in animals changed the agglutination pattern for many lectins from all three cell lines. Loss of reactivity to lectins seemed to be correlated with a decrease in infectivity of the parasite-resistant cell lines. This study opens possibilities for exploring the relationship between drug susceptibility, infectivity and surface carbohydrate composition of protozoan parasites.
Assuntos
Antiprotozoários/farmacologia , Glicoesfingolipídeos/metabolismo , Leishmania guyanensis/efeitos dos fármacos , Leishmaniose Mucocutânea/parasitologia , Meglumina/farmacologia , Compostos Organometálicos/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Antimônio/farmacologia , Cricetinae , Modelos Animais de Doenças , Resistência a Medicamentos , Lectinas/metabolismo , Leishmania guyanensis/metabolismo , Leishmania guyanensis/patogenicidade , Leishmaniose Mucocutânea/metabolismo , Masculino , Antimoniato de Meglumina , Mesocricetus , Fatores de TempoRESUMO
Metastatic disease is a major concern of dermal leishmaniasis caused by Leishmania of the Viannia subgenus. The golden hamster provides an experimental model of systemic dissemination and cutaneous metastasis of Leishmania Viannia. We have exploited this model to examine the expression of parasite virulence in cloned populations derived from a strain of L. guyanensis previously shown to be highly metastatic in the hamster. Metastatic capacity manifested as dissemination throughout the lymphoid organs; cachexia and secondary cutaneous lesions were found to differ among clones, yielding a spectrum of virulence. The metastatic phenotype of clonal populations was stable over 5 sequential passages in hamsters. In addition, the low or high propensity to disseminate and produce cutaneous metastatic lesions was reproduced. Capacity to disseminate from the inoculation site was conserved following subcloning of metastatic clones that had been passaged in culture for several generations; clinical manifestations, cachexia, and cutaneous metastatic lesions were variably expressed. Dissemination of parasites and cachexia were significantly related (P = 0.004). Overall, cachexia was an earlier manifestation of dissemination than cutaneous metastases (P < 0.001). The reproducible expression of virulence phenotypes by discrete populations of Leishmania in the golden hamster provides an experimental model for clinically relevant expression of virulence in human leishmaniasis.
Assuntos
Leishmania guyanensis/patogenicidade , Leishmaniose Mucocutânea/parasitologia , Animais , Medula Óssea/parasitologia , Cricetinae , Modelos Animais de Doenças , Feminino , Citometria de Fluxo , Leishmaniose Mucocutânea/patologia , Linfonodos/parasitologia , Masculino , Mesocricetus , Fenótipo , Inoculações Seriadas , Pele/parasitologia , Baço/parasitologia , VirulênciaRESUMO
We studied the susceptibility to Leishmania (Viannia) panamensis in strains of mice. The C57BL/6 strain was resistant and showed self-controlled lesion at the injected foot pad. The BALB/c and DBA/2J strains were susceptible and showed a foot swelling that started day 20 post-infection and progressed to a tumour-like lesion in later period of observation. The CBA/HJ strain was found to be of intermediary resistance. In contrast to other known cutaneous leishmaniasis in mice, the lesion in L. (V.) panamensis-infected mice was restricted to the inoculation site in the skin. In addition, we studied the development of cellular response and antibodies against Leishmania antigen in BALB/c and C57BL/6 strains. The proliferative response of lymph node cells against L. (V.) panamensis antigen was biphasic in both strains. An initial response was seen on day 20, followed by a refractory period between 40 and 80 days and a second response around fourth month post-infection. The response in the latter period was higher in C57BL/6 strain than in BALB/c strain. BALB/c strain presented much higher anti-Leishmania antibody level than C57BL/6 strain. The model and the correlation of immunological variables and the course of the infection are discussed.