Epidemiological and clinical features of Leishmania (Viannia) braziliensis American cutaneous and mucocutaneous leishmaniasis in the State of Espírito Santo, Brazil

Between 1985 and 2000, epidemiological surveys of the American tegumentary leishmaniasis (ATL) were carried out in several rural and urban communities in Espírito Santo, Brazil. A total of 100 stocks of Leishmania (comprising isolates from both human and canine hosts with ATL) were identified by two methods of molecular characterization, using specific monoclonal antibodies and multilocus enzyme electrophoresis. Parasite isolates from 19 municipalities were found to belong to the same zymodeme and serodeme type as of the Leishmania (Viannia) braziliensis reference strain. In contrast, our genotyping studies have shown intra-specific variation among these parasites (comparisons of the variability of the internal transcribed spacers between the small and large subunits of the rRNA genes of the 22 stocks studiedrevealed at least 11 genotypes). Two main clusters of L. (V.) braziliensis genotypes were observed, representing parasites collected from different endemic regions in the state, where transmission reflects distinct eco-epidemiological features. Infection with this pathogen was associated with the characteristic disease forms, but neither the clinical outcome nor the response to treatment could be related to the genetic polymorphism of the isolates, as defined by using the proposed methodology.

Study of the safety, immunogenicity and efficacy of attenuated and killed Leishmania (Leishmania) major vaccines in a rhesus monkey (Macaca mulatta) model of the human disease

We have compared the efficacy of two Leishmania (Leishmania) major vaccines, one genetically attenuated (DHFR-TS deficient organisms), the other inactivated [autoclaved promastigotes (ALM) with bacillus Calmete-Guérin (BCG)], in protecting rhesus macaques (Macaca mulatta) against infection with virulent L. (L.) major. Positive antigen-specific recall proliferative response was observed in vaccinees (79 percent in attenuated parasite-vaccinated monkeys, versus 75 percent in ALM-plus-BCG-vaccinated animals), although none of these animals exhibited either augmented in vitro gamma interferon (IFN-g) production or positive delayed-type hypersensitivity (DTH) response to the leishmanin skin test prior to the challenge. Following challenge, there were significant differences in blastogenic responses (p < 0.05) between attenuated-vaccinated monkeys and naïve controls. In both vaccinated groups very low levels of antibody were found before challenge, which increased after infective challenge. Protective immunity did not follow vaccination, in that monkeys exhibited skin lesion at the site of challenge in all the groups. The most striking result was the lack of pathogenicity of the attenuated parasite, which persisted in infected animals for up to three months, but were incapable of causing disease under the conditions employed. We concluded that both vaccine protocols used in this study are safe in primates, but require further improvement for vaccine application

Leishmania (Leishmania) major-infected rhesus macaques (Macaca mulatta) develop varying levels of resistance against homologous re-infections

Seven rhesus macaques were infected intradermally with 10(7) promastigotes of Leishmania (Leishmania) major. All monkeys developed a localized, ulcerative, self-healing nodular skin lesion at the site of inoculation of the parasite. Non-specific chronic inflammation and/or tuberculoid-type granulomatous reaction were the main histopathological manifestations of the disease. Serum Leishmania-specific antibodies (IgG and IgG1) were detected by ELISA in all infected animals; immunoblot analyses indicated that numerous antigens were recognized. A very high degree of variability was observed in the parasite-specific cell-mediated immune responses [as detected by measuring delayed-type hypersensitivity (DTH) reaction, in vitro lymphocyte proliferation, and gamma interferon (IFN-gamma) production] for individuals over time post challenge. From all the recovered monkeys (which showed resolution of the lesions after 11 weeks of infection), 57.2 percent (4/7) and 28.6 percent (2/7) animals remained susceptible to secondary and tertiary infections, respectively, but the disease severity was altered (i.e. lesion size was smaller and healed faster than in the primary infection). The remaining monkeys exhibited complete resistance (i.e. no lesion) to each rechallenge. Despite the inability to consistently detect correlates of cell-mediated immunity to Leishmania or correlation between resistance to challenge and DTH, lymphocyte transformation or IFN-gamma production, partial or complete acquired resistance was conferred by experimental infection. This primate model should be useful for measuring vaccine effectiveness against the human disease

Epidemiological and nosological aspects of Leishmania naiffi Lainson & Shaw, 1989

Leismania naiffi was isolated from 10 out of 64 armadillos (Dasypus novemcinctus) examined in Amazonas, Pará and Rondônia States in the Brazilian Amazon Region. The isolates were obtained in culture from samples of liver (3), spleen (3), lymph nodes (2), skin (1) and blood (1) from the infected animals. Heavy infections with the same parasite were detected for the first time in Psychodopygus squamiventris, a common man-biting phlebotomine, in amazonas and Pará. A new case of cutaneous leishmaniasis caused by L. naiffi is described from the Manaus area, making a total of three known cases of human infection by this parasite

Observaçöes sobre calazar em Jacobina, Bahia: VI. Investigaçöes sobre reservatórios silvestres e comensais / Observation on Kalazar in Jacobina, Bahia: VI. Investigations on wild reservoir and commensals

Durante os anos de 1982 a 1986, a investigaçäo sobre mamíferos comensais e silvestres, da periferia da cidade de Jacobina, Bahia, mostrou, ao lado do escasso número de exemplares, uma reduzida variedade específica dessa fauna. Capturou-se apenas 11 espécies, entre as quais, predominou o Didelphis a albiventris, que abrangeu 44% dos 213 espécimes capturados Didelphis albiventris, que abrangeu 44% dos 213 espécimes captura capturados. Entre os 193 com exames já concluídos, 84 eram exemplares de D. albiventris e 2 estavam infectados pela Leishmania donovani senso lato, 1 por L. mexicana amazonensis, 1 por L. braziliensis, subespécie e 3 por Trypanosoma cruzi. Também foram observadas formas suspeitas de serem amastigotas de leismanics, nos esfregaços de órgäos de 3 exemplares de Dasyprocta aguti, 1 Cercomys cunicularius-e 1 Oryzomys eliurus. O restante dos exemplares, inclusive 14 de Lycalopex vetulus, estava negativo para flagelados. Apesar de reforçado por outros indicadores epidemiológicos, como a predominância específica, a freqüência domiciliar, a atratividade para a vetora Lutzomya longipalpis, e a concomitância com casos humanos nos mesmos locais, o índice de 2,3% de infecçäo natural do Didelphis albiventris, näo autoriza a conclusäo definitiva de ser o marupial o mais importante reservatório natural da leishmaniose visceral em Jacobina

Natural infection of the opossum Didelphis albiventris (Marsupialia, Didelphidae) with Leishmania donovani, in Brazil

Um gambá, Didelphis albiventris, de Jacobina, Bahia, foi encontrado com infecçäo natural pela Leishmania donovani, sendo o primeiro mamífero silvestre näo-canídeo a ser achado com o agente do calazar nas Américas

Identification of Leishmania mexicana mexicana in the State of Sao Paulo, Brazil.

Foi identificado pela primeira vez a presenca de L. mexicana mexicana no Estado de Sao Paulo - Vale do Ribeira, a partir de casos humanos e de cao domestico, atraves da caracterizacao biologica (in vivo e in vitro) e bioquimica (enzimas)

Interactions between Leishmania mexicana mexicana promastigotes and amastigotes and murine peritoneal macrophages in vitro.

Celulas peritoneais de camundongos cultivadas in vitro foram infectadas com inoculos identicos de amastigotas (AM) e de promastigotas, respectivamente, virulentas (VP), avirulentas (AVP) e fixadas (FP) de uma mesma cepa de Leishmania m. mexicana.As monocamadas coradas com May-Grunwald-Giemsa foram examinadas em diferentes intervalos de tempo. Ao nivel de 3a. hora pos-infeccao o numero de macrofagos contendo parasitas variou entre 60,5% (VP) e 84% (AM) nas monocamadas expostas aos parasitas viaveis, comparados com 6,5% para aquelas expostas aos parasitas fixados.Entretanto, nesse tempo de interacao, houve alteracoes degenerativas parasitarias e o numero de macrofagos contendo parasitas intatos variou significantemente entre as celulas infectadas com AM (84%) e aquelas infectadas com VP (42%) ou AVP (40%). O numero medio de parasitas intatos/macrofago tambem diferiu significantemente entre as celulas infectadas com AM e aquelas infectadas com promastigotas viaveis ou fixadas. A analise quantitativa de parasitas intatos e degenerados indicou uma multiplicacao e destruicao parasitaria nas monocamadas infectadas com VP e sobrevivencia e multiplicacao parasitarias naquelas infectadas com AM. Em contraste, nao houve evidencia de multiplicacao de parasitas nas celulas infectadas com AVP. Exses resultados sugerem que os eventos cruciais que determinam a evolucao da infeccao ocorrem durante as primeiras 24 horas da interacao parasito-hospedeiro. Esses eventos sao aparentemente influenciados nao somente pela cepa do parasita ou do hospedeiro, mas tambem por variacoes ambientais induzidas em uma dada cepa parasitaria

Atypical epidermal alterations in chronic Leishmania mexicana mexicana lesions fo C3H mice.

Camundongos C3H cronicamente infectados com Leishmania mexicana mexicana, e em alguns grupos tratados com BCG ou levamisole apresentaram alteracoes epidemiologicas atipicas, incluindo hiperplasia pseudo-epiteliomatosa, displasia e hiperceratose.Estas alteracoes foram mais intensas em frequencia e intensidade durante o curso da infeccao, porem nao foram relacionadas com o tamanho de lesao ou com a carga parasitaria tissular. Animais controles, respectivamente, normais com mesma idade, tratados com BCG e levamisole, examinados simultaneamente, nao mostraram tais modificacoes epidermicas. Nos camundongos infectados, a derme e a hipoderme apresentaram um infiltrado inflamatorio contendo histiocitos, linfocitos e plasmocitos, acompanhando por vezes de neutrofilos e eosinofilos, o qual nao vario com a duracao da infeccao

Leishmanioses tegumentares: aspectos clinicos e imunopatologicos. (122 refs) / Cutaneous leishmaniasis: clinical and immunopathological aspects

Foi visto nesta revisao que os parasitas do genero Leishmania induzem uma variedade de respostas complexas nos hospedeiros vertebrados, efetuadas e/ou moduladas pelo seu sistema imunologico. Foi tambem salientado que o destino da Leishmania no interior de macrofagos depende de relacoes particulares parasito-hospedeiro, envolvendo nao apenas as propriedades intrinsecas do parasita, mas tambem as caracteristicas, geneticamente determinadas, da celula hospedeira ou das suas interacoes com outras celulas imunocompetentes. Atraves de uma revisao das evidencias consubstanciando esses conceitos, os mesmos foram aplicados na descricao do espectro clinico e imunopatologico da doenca humana, particularmente das leishmanioses cutaneas e mucocutaneas do Novo e do Velho Mundos. Finalmente, baseando-se nos resultados obtidos em modelos experimentais de leishmaniose cutanea, os quais reproduzem os achados das formas resolutiva e persistentes da doenca humana, o autor apresenta uma analise esquematica da evolucao das caracteristicas histopatologicas das lesoes leishmanioticas