The biology, epidemiology, pathogenesis, diagnostic techniques, and history of the introduction of Trypanosoma (Duttonella) vivax in the New World are reviewed. The two main immunological responses of trypanosome-infected animals - antibody production and immunodepression - are discussed in the context of how these responses play a role in disease tolerance or susceptibility. Isolation and purification of T. vivax are briefly discussed. The recent reports of bovine trypanosomiasis diagnosed in cattle on farms located in the Pantanal region of the states of Mato Grosso do Sul and Mato Grosso, Brazil, are also discussed.

O presente estudo objetivou descrever alguns fatores relacionados à positividade de cães para leishmaniose visceral, em área endêmica do Estado do Rio Grande do Norte. Foram analisados 198 cães, dos quais 62 foram recrutados de propriedades rurais e 136 de residências urbanas. O diagnóstico foi realizado através dos testes de imunofluorescência indireta e imunoadsorção enzimática. Dos cães analisados, 45% dos positivos eram provenientes da área rural e 35% da área urbana. Analisando a função dos animais, a prevalência foi de 50% dos cães de guarda nas áreas rural e de 43% na área urbana. Quanto aos cães que tinham contato com outros cães de origem rural ou urbana, a prevalência observada de foi 54% e 32%, respectivamente. No que se refere ao sexo, as fêmeas da zona rural foram mais prevalentes. Estes resultados sugerem uma atenção maior sobre o papel destes animais como reservatório dessa zoonose, como também na urbanização da leishmaniose visceral e o inquérito epidemiológico desta doença, no qual estas informações poderão contribuir para o planejamento de estratégias de controle do cão como reservatório doméstico.

This study aimed at describing several factors related to positive testing of dogs for visceral leishmaniasis, in an endemic area of the state of Rio Grande do Norte. Sera of 198 dogs were analyzed, 62 from rural properties and 136 from urban residences. Diagnosis was performed through indirect immunofluorescence and enzyme-linked immunosorbent assay. Forty five percent of positive dogs were from the rural area and 35% came from the urban area. Concerning the analysis of dogs' function, the watchdogs showed greater prevalence, with 50% prevalence in the rural area and 43% in the urban area. With regard to contact with other dogs and origin in rural or urban areas, the prevalence was 54% and 32% respectively. In relation to gender, females from the rural area were more prevalent. These results suggest more attention should be paid to dogs as reservoirs for this zoonosis, as well as their important role in the urbanization of Leishmaniasis and in epidemiological survey of the disease. These data can contribute to the planning of strategies for control, targeting dogs as domestic reservoirs.

Cutaneous biopsies (n = 94) obtained from 88 patients with American tegumentary leishmaniasis were studied by conventional and immunohistochemical techniques. Specimens were distributed as active lesions of cutaneous leishmaniasis (n = 53) (Group I), cicatricial lesions of cutaneous leishmaniasis (n = 35) (Group II) and suggestive scars of healed mucosal leishmaniasis patients (n = 6) (Group III). In addition, active cutaneous lesions of other etiology (n = 24) (Group C1) and cutaneous scars not related to leishmaniasis (n = 10) (Group C2) were also included in the protocol. Amastigotes in Group I biopsies were detected by routine histopathological exam (30.2%), imprint (28.2%), culture (43.4%), immunofluorescence (41.4%) and immunoperoxidase (58.5%) techniques; and by the five methods together (79.3%). In Group II, 5.7% of cultures were positive. Leishmanial antigen was also seen in the cytoplasm of macrophages and giant cells (cellular pattern), vessel walls (vascular pattern) and dermal nerves (neural pattern). Positive reaction was detected in 49 (92.5%), 20 (57%) and 4 (67%) biopsies of Groups I, II and III, respectively. Antigen persistency in cicatricial tissue may be related to immunoprotection or, on the contrary, to the development of late lesions. We suggest that the cellular, vascular and neural patterns could be applied in the immunodiagnosis of active and cicatricial lesions in which leishmaniasis is suspected.

The concept that microorganisms can modulate the host resistance was historically reviewed in the present article. The importance of African trypanosomiasis in the development of the research on immunosuppression as well as the impact of human immunodeficiency virus infection are discussed. Each day new opportunistic organisms establish a constant challenge for the correct diagnosis of concomitant infections in acquired immunodeficiency syndrome. The importance of parasite infection in the balance of host resistance in the third world was emphasized. Finally, some aspects of Leishmania as opportunistic organisms were presented.

Congenitally athymic nude Balb/c (nu/nu) and their phenothypically normal adult and neonate littermates (nu/+), the C3H/HeN as well, were intraperitoneally infected with two strains (Y or CL) of Trypanossoma cruzi. The nude mice and the neonates developed a severe parasitaemia, the susceptible C3H/HeN also presented high level and adult Balb/c mice presented parasitaemia similar to that observed in outbred mice. Erythematous skin lesions were observed initially in infected athymic nude and neonates, being charactherized by nests of amastigotes in the dermis; in C3H/HeN infected mice no nest of parasite was observed but a low-grade inflammatory reaction was seen. In adult Balb/c or OF1 outbred mice nest was found but discreet inflammatory reaction was observed in severe infections.

Different patterns of cutaneous leishmaniasis can be induced when a challenge of alike dose of Leishmania amazonensis amastigotes in various inbred strains was applied. Two strains of mice, the Balb/c and C57 BL/10J, showed exceptional suscepbility, and 10(elevado a sexta potência) amastigotes infective dose lead, to ulcerative progressive lesions with cutaneous metastasis and loss by necrosis of leg on wich the footpad primary lesion occured. Lesions were also progressive but in a lower degree when C3H/HeN and C57BL/6 were infected. Lesions progress slowly in DBA/2 mice presenting lesions wich reach a discreet peack after 12 weeks, do not heal but do not uncerate. DBA/2 mice is, therefore, a good model for immunomodualtion. In attempt to determine the influence of BCG in vaccination schedule using microsomal fraction, DBA/2 became an excellent model, since it is also a non-responder to BCG. Vaccination of DBA/2 mice, receiving the same 10(elevado a sexta potência) BCG viable dose and 10 *g or 50 *g of protein content of microsomal fraction, lead to a progressive disease with time course similar to those observed in susceptible non-vaccinated C57BL/10J mice after 6 months of observation. An enhancement of infection in BCG non-responder mice suggests that use of BCG as immunostimulant in humans could be critical for both vaccination and immunoprophylactic strategies.

De um grupo de 112 casos crônicos de Doença de Chagas recebidos, foi possível selecionar 32 casos dotados de dados clínicos e testes de diagnóstico completos que permitiram uma avaliação da resposta imunitária humoral em face de quadros clínicos e cardiológicos bem definidos. Observou-se um ligeiro aumento dos níveis de IgG, sem que houvesse significância destes resultados quando feita a comparação com um grupo de habitantes da região de Bambuí, cujos testes, empregados normalmente para diagnóstico da Doença de Chagas, foram negativos. Este grupo, que foi considerado como o "normal" da região, não apresentava nenhuma sintomatologia e, tanto quanto foi possível observar, gozava bom estado de saúde. Os níveis de IgM e IgA apresentavam-se dentro da faixa de normalidade, enquanto os títulos de anticorpos heterófilos, ficaram entre 1/56 e 1/112. Na Correlação que se tentou estabelecer entre anticorpos heterófilos e cardiopatias chagásicas constatou-se não existir, aparentemente, relação entre concentração e cardiopatia.

Since dibergent results were obtained by different authors about immunoglobulins concentration in sera from acute and chronic cases of Chagas disease, the problem was submited to statistical approach in field conditions in the endemic zone of Bambui, state of Minas Gerais, Brazil. Positives cases were considered in all individuals presenting evidences in parasitological, immunological or electrocardiographical examination living exactly in the same conditions, but without any evidence of infection under the same criteria. The sample consisted of 32 chronic cases and no significant difference in the immunoglobulins levels were detected in chronic cases of Chagas disease as compared with the control group. Heterophili antibodies are being determined in chronic cases and apparently there is no relationship between its concentration and pathogenic effects.

Os autores descrevem uma espécie do gênero Lankesterella considerada nova para a ciência, que ocorre com certa freqüência parasitando a rã Leptodactylus ocellatus no Brasil. Como os cistos dêste parasito, encontrados no SNC, foram anteriormente relacionados ao gênero Toxoplasma por outro autor, realizamos uma série de inoculações experimentais para eliminar a hipótese. Tanto as inoculações com amostra de Toxoplasma gondii de origem humana em anfíbios, como as de mascerados de SNC de rã contendo cistos em camundongos, foram negativas. As inoculações de T. gondii em anfíbios foram realizadas em temperatura ambiente que no Rio de Janeiro, na época era 30º-39ºC. Não encontramos, por outro lado, cistos no SNC de anfíbios do gênero Bufo, fato assinalado por outros autores. Realizamos algumas técnicas citoquímicas para melhor caracterização do parasito. Tendo em vista o grande número de hemoparasitos encontrados nas rãs brasileiras e as infecções múltiplas ocorrerem com freqüência, apresentamos também a incidência dêstes parasitos que compreendem os gêneros: Haemobartonella, Cytamoeba, Dactylosoma, Hepatozoon e Trypanosoma. Apresentamos também uma lista de todos os anfíbios examinados, bem como dados sôbre a distribuição geográfica dos hemoparasitos encontrados. Os autores chamam a atenção para o fato de Leptodactylus ocelllatus ser uma rã muito comum no Brasil e utilizada com muita freqüência em trablalhos experimentais de Bioquímica, Fisiologia, Bacteriologia, etc. No caso de infecção intensas por esporozoários os órgãos sofrem lesões extensas e por êste motivo julgamos necessário que em tais trabalhos experimentais êsse parasitismo seja levado em consideração.

Lankesterella alencari n. sp. a Sporozoa that occur in the blood and CNS of the South American frog Leptodactylus acellatus is described. Since the tissue forms of this parasite have been previously reported as belonging to the genus Toxoplasma, we attempted in fection of 2 species of amphibia (Bufo marinus an dLeptodactylus ocellatus) with a Toxoplasma strain of human origen; inoculation was by intraperitoneal injection of parasite-containing ascitic fluid from infected mice. Attempt of experimental inoculation of the parasite found in the CNS of L. ocellatus in a highly susceptible host (mice) was unsuccessful. These results suggest that Toxoplasma does not occur naturally in the amphibia; be related to Toxoplasma is excluded. The following genera of haematozoa found in brazilian amphibia have been considered briedfly: Haemobartonella, Cytamoeba, Dactylosoma, Hepatozoon and Trypanosoma.

Neste trabalho os autores discutem a posição sistemática do gênero Klossinemella Costa, 1961, propondo uma nova organização para a família Cobboldinidae Skrjabin, 1948. Apresentam a descrição das espécies dêste gênero (K. iheringi, K. conciliatus e K. travassosi sp. n.) e do ciclo evolutivo.

In the present work the authors give a new sistematic organization for the generic components of the family Cobboldinidae Skriabin, 1948. A new species of Klossinemella Costa, 1961 is described (K. travassosi) and the description of k. iheringi and K. conciliatus is given. Finally the authors discuss the biological cycle of Klossinemella Costa, 1961 in comparison with the cycle of Rondonia Travassos, 1919.

Neste trabalho os autores apresentam uma revisão da morfologia das gregarinas do gênero Stenophora Labbé, 1899, baseada principalmente em S. juli (Frantzius, 1848) Labbé, 1899. Caracterizam citoquìmicamente os elementos da estrutura nuclear, ficando evidenciado que o corpúsculo nuclear referido por muitos como um cariossomo apresenta reações positivas para o RNA, sendo portanto um nucléolo. O suco nuclear apresenta reações para o DNA pouco intensas, devido as granulações de cromatina se apresentarem muito finas. Fazem referências também à estrutura do nucléolo, que varia com as técnicas empregadas e salientam a necessidade de comparação dêstes resultados com aquêles obtidos com o auxílio da microscopia eletrônica e que são tratados no segundo trabalho desta série.

The present paper consists of a morphological revision of gregarines belonging to the genus Stenophora Labbé, 1899, specially referred to S. juli (Frantzius, 1848) Labbé, 1899. Nuclear compounds were cytochemically characterized and on account of the positive reactions for RNA the corpuscle generally referred as "caryosome" was to be a "nucleole". The finelly divided DNA of the nucleoplasm caused a weak reaction. The structure of the nucleole depends on the technic used. These results must be compared with those obtained with the electronic microscope.