Resumen Introducción. El prazicuantel es el único fármaco disponible comercialmente para la esquistosomiasis. La escasez actual de medicamentos alternativos y la falta de medidas preventivas eficaces aumentan su valor. La creciente prevalencia de la resistencia al prazicuantel bajo una presión prolongada del fármaco es, por tanto, un tema emergente. Objetivos. Superar la tolerancia al prazicuantel mediante nanotecnología después de la inducción en laboratorio de un aislamiento de Schistosoma mansoni con sensibilidad reducida al fármaco durante la fase intramolusco. Materiales y métodos. Los caracoles que liberaban cercarias se trataron con prazicuantel en dosis de 200 mg/kg dos veces por semana, seguidas de un intervalo de una semana, y luego se repitieron dos veces de la misma manera. La inducción exitosa de la sensibilidad reducida se confirmó in vitro mediante la reducción de la reacción de las cercarias al prazicuantel con respecto a su actividad de natación y el porcentaje de muerte en diferentes momentos de examen. El éxito en inducir una menor sensibilidad se confirmó in vitro mediante la reducción de la reacción de las cercarias al prazicuantel. Resultados. El tratamiento oral con una dosis única de prazicuantel de 500 mg/kg en ratones infectados con cercarias con sensibilidad reducida al prazicuantel, reveló una reducción no significativa (35,1 %) de la carga total de gusanos en comparación con los ratones de control no tratados. Los niosomas encapsulados en prazicuantel inoculados por vía oral contra S. mansoni con sensibilidad reducida al prazicuantel, permitieron reestablecer con éxito la sensibilidad del patógeno al medicamento, como lo demostró la medición de diferentes parámetros en comparación con los animales infectados no tratados con parásitos con sensibilidad reducida a prazicuantel. La carga media total de gusanos fue de 1,33 ± 0,52, con una reducción estadísticamente significativa del 94,09 %, y la erradicación completa de los gusanos machos adultos. Se obtuvo un aumento notable en el porcentaje de reducción del recuento de huevos en el tejido del hígado y el intestino (97,68 % y 98,56 %, respectivamente), asociado con un aumento masivo de huevos muertos y ausencia total de estadios inmaduros. Conclusión. Los niosomas encapsulados en prazicuantel restauraron la sensibilidad al fármaco contra gusanos adultos de S. mansoni con sensibilidad reducida al prazicuantel inducida en el laboratorio.

Abstract Introduction: Praziquantel (PZQ) is the only commercially available drug for schistosomiasis. The current shortage of alternative effective drugs and the lack of successful preventive measures enhance its value. The increase in the prevalence of PZQ resistance under sustained drug pressure is, therefore, an upcoming issue. Objective: To overcome the tolerance to PZQ using nanotechnology after laboratory induction of a Schistosoma mansoni isolate with reduced sensitivity to the drug during the intramolluscan phase. Materials and methods: Shedding snails were treated with PZQ doses of 200 mg/kg twice/ week followed by an interval of one week and then repeated twice in the same manner. The success of inducing reduced sensitivity was confirmed in vitro via the reduction of cercarial response to PZQ regarding their swimming activity and death percentage at different examination times. Results: Oral treatment with a single PZQ dose of 500 mg/kg in mice infected with cercariae with reduced sensitivity to PZQ revealed a non-significant reduction (35.1%) of total worm burden compared to non-treated control mice. Orally inoculated PZQ- encapsulated niosomes against S. mansoni with reduced sensitivity to PZQ successfully regained the pathogen’s sensitivity to PZQ as evidenced by measuring different parameters in comparison to the non-treated infected animals with parasites with reduced sensitivity to PZQ. The mean total worm load was 1.33 ± 0.52 with a statistically significant reduction of 94.09% and complete eradication of male worms. We obtained a remarkable increase in the percentage reduction of tissue egg counts in the liver and intestine (97.68% and 98.56%, respectively) associated with a massive increase in dead eggs and the complete absence of immature stages. Conclusion: PZQ-encapsulated niosomes restored the drug sensitivity against laboratory- induced S. mansoni adult worms with reduced sensitivity to PZQ.

Bioassay-guided isolation using an in vitro assay testing for anti- schistosomiasis yielded a novel triterpene saponin, asparagalin A, from the n-butanol extract of the roots of Asparagus stipularis Forssk., Asparagaceae. The structure was elucidated by spectroscopic analysis and chemical transformations. Administration of asparagalin A resulted in a retardation of worm growth and locomotion at the first day and showed a significant activity of egg-laying suppression at 200 µg/mL concentration.

This study was done to determine the occurrence of mycobacteria in the bloodstreams of patients with fever and advanced AIDS in a Brazilian hospital. We also verified the capability of an automated method for recovering these bacteria. During a period of 19 months, 254 patients with AIDS were evaluated. Blood cultures were generally submitted in pairs and drawn separately. Blood cultures were processed by the BACTEC 460TB System (Becton Dickinson Microbiology Systems, Sparks, MD), using the Bactec 13A media (Becton Dickinson Microbiology Systems, Sparks, MD). Of the 530 vials submitted, 77 (14.5%) from 41 (16%) patients were positive. Mycobacterium avium complex was recovered from 45 (58.4%) of the 77 positive vials, corresponding to 22 (53.6%) patients with positive blood cultures. The average time to detect Mycobacterium avium complex was 15 days. Mycobacterium tuberculosis was recovered from 26 (33.8%) of the 77 positive vials, corresponding to 15 (36.6%) patients with positive blood cultures, with an average detection time of 24 days. Other species of mycobacteria were recovered from 6 (7.8%) of the 77 vials, corresponding to 4 (9.8%) patients. M.avium complex was fairly prevalent (8.7%) in severely ill patients with AIDS in our hospital. M. tuberculosis was also an important (6.0%) agent of systemic bacterial infections in these patients. The rapid diagnosis of mycobacteremia was possible with the implementation of this automated technology.

A freqüência e descrição dos efeitos secundários à aplicação subcutânea da vacina antímalãrica SPf66 e placebo, são notificadas para cada dose nos participantes do estudo da eficácia vacinai no Brasil. Efeitos colaterais avaliados duas horas após a aplicação dos preparados foram detectados em 8,0%, 30,2% e 8,8% para a 1ª, 2ª e 3ª doses, respectivamente, no grupo de vacinados; e em 7,0%, 8,5% e 2,9% no grupo que recebeu o placebo. Reações tais como inflamação leve, nódulo e dor freqüentemente acompanhadas de prurido, foram as reações locais mais freqüentes em ambos os grupos (3,8%, 29,1% e 8,5% no gmpo vacinado, e 4,0%, 7,6% e 2,5% no grupo placebo). No grupo que recebeu a vacina, as reações locais foram mais freqüentes em mulheres após a 2ª dose. Os efeitos colaterais sistêmicos basearam-se em sinais e sintomas referidos pelos participantes. Foram mais freqüentes após a aplicação da 1ª dose em ambos os grupos (4,3%, no grupo de vacinados e, 3,0%, no grupo placebo). Alguns participantes referiram mialgias e febre. Nenhum efeito colateral grave foi detectado em nenhuma dose de aplicação ou grupo.

The frequency and description of side effects secondaiy to the subcutaneous application of SPf66 malaria vaccine and placebo are reported for each dose of application in the participants of the vaccine efficacy trial in Brazil. Side effects evaluated two hours after each application were detected in 8.0%, 30.2% and 8.8%, for the Is', and 3"' dose, respectively, in the SPf66group, and in 7.0%, 8.5% and 2.9% in the placebo group. Local reactions such as mild inflammation, nodule and pain or erythema frequently accompanied by pruritus were the most common reactions detected in both groups (3-8%, 29.1% and 8.5% in the SPf66 group and 4.0%, 7.6% and 2.5% in the placebo group). Among vaccinees, local side effects after the 2nd dose were more frequent in females. Systemic side effects were expressed mainly through general symptoms referred by the participants and were most frequent after the 1st dose in both groups (4.3% in the SPf66 group and 3-0% in the placebo group). Muscle aches and fever were refewred by few participants. No severe adverse reactions were detected for either dose of application or group.

O presente artigo descreve a população de estudo e o desenho do ensaio de campo de fase III da vacina sintética SPf66 no Brasil. São avaliados os princípios básicos de validade e precisão, essenciais para a estimação adequada da eficácia vacinal. Os resultados da análise exploratória de dados são discutidos assim como, a abordagem analítica para a estimação da eficácia vacinal. Este trabalho fornece o marco conceitual para futuras publicações.

This paper describes the study population and the study design of the phase III field trial of the SPf66 vaccine in Brazil. Assessment of validity and precision principles necessary for the appropriate evaluation of the protective effect of the vaccine are discussed, as well as the results of the preliminary analyses of the gathered data. The analytical approach for the estimation of the protective effect of the vaccine is presented. This paper provides the conceptual framework for future publications.

Mais de 500.000 casos novos de malária foram notificados no Brasil, em 1992. P.falciparum and P.vivax são as espécies responsáveis por 99,3% dos casos. O diagnóstico precoce é indispensável para início do tratamento adequado. Neste trabalho, apresentamos os resultados do método tradicional para detecção de plasmódios, gota espessa, e os resultados de métodos alternativos estudados: imunofluorescência indireta com anticorpo policlonal anti-P.falciparum e QBC-método, em grupos populacionais bem definidos. A análise dos resultados foi feita em relação à presença ou ausênsia de sintomas clínicos de malária. Também, diferentes classes de imunoglobulinas anti-P.falciparum foram quantificadas para auxiliar na análise global dos resultados, principalmente nos resultados discrepantes. Nós concluímos que os métodos alternativos são mais sensíveis do que a gota espessa e que a associação das informações epidemiológicas, clínicas e laboratoriais é necessária para definir a presença de malária.

In Brazil, more than 500,000 new cases of malaria were notified in 1992. Plasmodium falciparum and P.vivax are the responsible species for 99.3% of the cases. For adequate treatment, precoce diagnosis is necessary. In this work, we present the results of the traditional Plasmodia detection method, thick blood film (TBF), and the results of alternative methods: Immunofluorescence assay (IFA) with polyclonal antibody and Quantitative Buffy Coat method (QBC)® in a well defined population groups. The analysis were done in relation to the presence or absence of malaria clinical symptoms. Also different classes of immunoglobulins anti-P.falciparum were quantified for the global analysis of the results, mainly in the discrepant results. We concluded that alternative methods are more sensitive than TBF and that the association of epidemiological, clinical and laboratory findings is necessary to define the presence of malaria.

Nosso estudo envolveu a análise de cepas de Plasmodium falciparum provenientes da Região Amazônica Brasileira, coletadas no Laboratório de Malária da SUCEN. Os estudos "in vitro" foram efetuados com a cloroquina (46 ensaios), quinino (42 ensaios) e mefloquina (51 ensaios). Os resultados mostraram resistência de 100% em relação à cloroquina, 2,4% ao quinino e 31,4% à mefloquina, na análise "in vitro". Sete pacientes foram tratados com quinino isolado e nove com a associação mefloquina + pirimetamina-sulfadoxina, não mostrando correlação com os testes "in vitro".

The present study is concerned with the analysis of Plasmodium falciparum strains from the Brazilian Amazon Region, collected at the Malaria Laboratory - SUCENT. "In vitro" sensitivity tests were performed using chloroquine (46 samples), quinine (42 samples) and mefloquine (51 samples). Results have shown "in vitro" resistance to chloroquine in 100% of the tested samples, to quinine in 2.4% and to mefloquine in 3L4%. Seven patients were treated with quinine and nine with the triple combination (mefloquine plus sulfadoxine plus pyrimethamine). No correlation was shown between the therapeutic response and the "in vitro" tests.

Descreve-se investigação epidemiológica conduzida a partir da notificação de três casos suspeitos de febre amarela em moradores da região noroeste do Estado de São Paulo, Brasil, onde se identificou a presença de Aedes aegypti. Concluiu-se que se tratavam de casos de febre amarela silvestre adquirida em área endêmica do Estado vizinho de Mato Grosso. Apesar da presença de focos de Aedes aegypti nos locais de residência dos doentes, não foram encontradas evidências de transmissão do vírus amarílico nesses locais. O teste MAC ELISA mostrou-se de grande utilidade no rápido esclarecimento diagnóstico dos casos suspeitos da moléstia, ao lado das técnicas tradicionais, e no inquérito sorológico conduzido entre familiares, vizinhos e colegas de trabalho dos doentes.

An epidemiological investigation was carried out in the North-west region of the State of S. Paulo of Brazil with the purpose of clarifying three suspected cases of yellow fever that occurred in people resident in the area. In this region the presence of Aedes aegypti had been verified. It was concluded that the patients had contrated yellow fever during a trip to the forested region of the Mato Grosso State, where there are enzootic cycles of the virus. Despite of the presence of Ae. aegypti, no evidence of yellow fever transmission in the local population was detected. MAC ELISA (enzyme-linked immunosorbent assay with capture of IgM antibodies) proved very useful in the rapid diagnosis of suspected cases and in the serological investigation among the relatives, neighbors and schoolmates of the patients, providing additional support for the traditional techniques.

Descreve-se investigação epidemiológica conduzida a partir da notificação de três casos suspeitos de febre amarela em moradores da região noroeste do Estado de São Paulo, Brasil, onde se identificou a presença de Aedes aegypti. Concluiu-se que se tratavam de casos de febre amarela silvestre adquirida em área endêmica do Estado vizinho de Mato Grosso. Apesar da presença de focos de Aedes aegypti nos locais de residência dos doentes, não foram encontradas evidências de transmissão do vírus amarílico nesses locais. O teste MAC ELISA mostrou-se de grande utilidade no rápido esclarecimento diagnóstico dos casos suspeitos da moléstia, ao lado das técnicas tradicionais, e no inquérito sorológico conduzido entre familiares, vizinhos e colegas de trabalho dos doentes.

An epidemiological investigation was carried out in the North-west region of the State of S. Paulo of Brazil with the purpose of clarifying three suspected cases of yellow fever that occurred in people resident in the area. In this region the presence of Aedes aegypti had been verified. It was concluded that the patients had contrated yellow fever during a trip to the forested region of the Mato Grosso State, where there are enzootic cycles of the virus. Despite of the presence of Ae. aegypti, no evidence of yellow fever transmission in the local population was detected. MAC ELISA (enzyme-linked immunosorbent assay with capture of IgM antibodies) proved very useful in the rapid diagnosis of suspected cases and in the serological investigation among the relatives, neighbors and schoolmates of the patients, providing additional support for the traditional techniques.

Nove amostras de Plasmodium falciparum foram coletadas de migrantes infectados no Estado de Rondônia. Estas amostras foram mantidas em cultivo para caracterização por tipificação enzimática em acetato de celulose, sensibilidade á cloroquina, amodiaquina, mefloquina e quinino e análise da diversidade antigê-nica através de anticorpos monoclonais específicos. Os resultados obtidos mostraram variação entre todas as amostras estudadas: encontrou-se resistência crescente à cloroquina, resistência intermediária à amodiaquina e quinino e sensibilidade a baixos níveis de mefloquina; apenas dois isolados mostraram sensibilidade a todas as drogas. A tipificação enzimática mostrou presença de parasitas GPI 1 e 2 e ADA 1 e 2, enquanto que para PEP e LDH todas as amostras foram do tipo 1. Sorotipagem com anticorpos monoclonais PSA mostrou presença de três sorotipos diferentes (II, III e IV). Estes resultados mostraram: a) variação entre as amostras para os marcadores analisados; b) nesta região, para o pequeno número de amostras analisadas, não foram observadas diferenças significativas ou novos tipos de parasitas.

Nine samples of Plasmodium falciparum were collected from migrant workers who were infected in the State of Rondônia, Brazil. These samples were maintained in culture for characterization by enzyme typing using acetate cellulose electrophoresis, drug susceptibility to chlo-roquine, amodiaquine, mefloquine and quinine and antigenic diversity analysis using strain specific monoclonal antibodies. The results obtained have confirmed major variation among all samples studied: it was found consistent resistance to chloroquine moderated resistance to amodiaquine and quinine and susceptibility to low levels of mefloquine; only two isolates have shown susceptibility to all drugs in the in vitra assays. Enzyme typing showed presence of both GPI 1 and 2 and ADA 1 and 2 parasites, while for PEP and LDH all samples were type 1. Se-rotyping with PSA monoclonal antibodies showed presence of three different serotypes (II, III and IV). These results confirm: a) variation among samples for markers analysed; b) in this area and for the small number of samples studied, no significant differences or new types of parasites were seen.

Cento e dez pacientes com malária falciparum não complicada, provenientes da Amazônia brasileira, foram tratados com cloridrato de tetraciclina, na dose de 250 mg a cada 6 horas por 7 dias, associado ao sulfato de quinino na dose de 1,5 a 2,0 gramas/dia nos 3 ou 4 dias iniciais de tratamento. Os pacientes tiveram acompanhamento clínico e parasitológico por pelo menos 7 dias e em todos observou-se a negativação da parasitemia após o tratamento. Setenta e cinco pacientes foram acompanhados por 28 dias ou mais e destes 71 tiveram resposta do tipo Se4do tipo RI. O cloridrato de tetraciclina associado ao sulfato de quinino mostrou-se altamente eficaz no tratamento de malária falciparum não complicada, sendo bem tolerado e portanto útil na terapêutica das infecções por P. falciparum multirresistentes contraídas na Amazônia.

110 patients with P. falciparum malaria and no complications from the Brazilian Amazon region were treated with the association tetracycline hydrocloride (1 g/d during 7 days) and quinine sulphate (1.5 or 2 g/d during 3 or 4 days) at the beginning of treatment. All patients were followed for at least 7 days and no blood parasites were detected ont the 7th day. Seventy- five patients could be followed for 28 days or longer and 4 of them (5.3%) showed parasitemia again. These results support the efficacy of the association quinineplus tetracycline in the treatment of P. falciparum malaria infections from the Amazon region.