Análise da freqüência de recaídas de malária por Plasmodium vivax em região não endêmica (São Paulo, Brasil)

Em virtude da existência de poucas informações, devidamente registradas, sobre freqüência e épocas de recaídas de malária por Plasmodium vivax, contraída no Brasil, foi analisada casuística observada em região não endêmica e constituída por pacientes corretamente tratados. O índice de recaídas documentadas em São Paulo, foi alto (24,5%), com desenvolvimento precoce na maioria das oportunidades, ou seja, em tempo inferior a três meses.

Epidemiological survey of Trypanosoma cruzi infection in North-Eastern Brazil using different diagnostic methods

A survey of the prevalence of Trypanosoma cruzi infection was carried out in Oitis, a small community in the State of Piaui, Brazil. Two hundred and sixty five individuals were screened by microscopic examination, hémoculture, indirect immunofluorescence (IFA), enzyme-linked immunosorbent assay (ELISA), and competitive enzyme-linked immunosorbent assay (C-ELISA) using the monoclonal antibody TCF87 against to a 25kd T. cruzi antigen. Seropositivity was 14.3% by the IFA test, 14.7% by ELISA, and 13.2% by C-ELISA. The C-ELISA using the TCF87 monoclonal antibody seems to be applicable in serodiagnosis of Chagas' disease.

Drug susceptibility of Plasmodium falciparum in the western Amazon region, state of Acre, Brazil

Field studies in the western Amazon region (state of Acre, Brazil) indicate that the 4-aminoquinolines, as well as the combined regimen with sulfadoxine-pyrimethamine, can no longer be recomended for the treatment and prophylaxis of P. falciparum infections in this region. Quinine remains an effective drug when used correctly. However, compliance problems arise due to the often occurring side-effects during a ten day regimen. Prospects of overcoming these constraints by combining a short course of quinine with other drugs are limited, because of the lack of suitable partner compounds. For this reason quinine/clindamycin appears to be a more practical therapy of P. falciparum malaria. In vitro data from this study suggest that mefloquine is another effective alternative for the treatment of falciparum malaria in this Amazon region.

Clonal variation within a mucosal isolate derived from a patient with Leishmania (Viannia) braziliensis infection

Three isolates over 5 years from a patient with persistent relapsing mucosal leishmaniasis due to Leishmania (Viannia) braziliensis and 7 clones from one of these isolates were studied by zymodemes and scrodemes analysis. Results showed evidences of clonal phenotypic variation. Eight isoenzymes markers demonstrated clear differences on Cellulose Acetate (CA) and thin starch gel electrophoresis. Also a panel of specific monoclonal antibodies showed such differences. Our observations provide additional evidence that Leishmania (Viannia) braziliensis is composed by subpopulations of parasites with peculiar biochemical and antigenic characteristics.

Plasmodium vinckei petteri: algunos aspectos de su esporogonia y esquizogonia exoeritrocitaria

Por medio de la infección experimental de Anopheles stephensi, a partir de ratones portadores de gametocitos de Plasmodium vinckei petteri, se realizó el estudio morfológico de la esporogonia, que comprende: la descripción del ooquineto, la evolución completa de los ooquistes y su transformación final en esporozoitos. Estos fueron empleados más tarde para infectar por via intravenosa nuevos ratones, a los que se realizó biopsias sucesivas, para el estudio de los esquizontes exoeritrocíticos, cuya morfología no difere de la de otras especies del grupo. Se determinó la duración mínima del ciclo hepático, que resultó ser de 61 horas. Estos datos, junto a otros que refieren las características del ciclo hemático, ayudan a completar la información que se tiene sobre la especie, que la hacen recomendable para su utilización como modelo experimental en el estudio de la malaria humana.

Trypanossoma cruzi: course of infection in platelets-depleted mice

The effect of platelet depletion on the course of Trypanosoma cruzi infection in BALB/c mice was investigated. Thrombocytopenia was achieved by inoculation of rabbit anti-platelet IgG during the parasitemic phase of the infection. The number of parasites in the blood of anti-platelet IgG treated was significantly higher than that of non-treated control mice, during the phase of high parasitemia. Cumulative mortality of platelet-depleted mice was consistently but not significantly higher than that of control mice up to the 32nd day of infection; from the 33rd day on they were equivalent, no mortalities occurring from then on, until observations were discontinued on the 60th day. These results suggest that platelets participate of the mechanisms of parasites removal from the bloodstream, but do not have an effective role in the mechanisms of defence against T. cruzi, during the acute phase of infection.

Exposure to acellular blood products and risk of HIV infection in hemophiliacs from Belo Horizonte, Brazil

Results of a HIV prevalence study conducted in hemophiliacs from Belo Horizonte, Brazil are presented. History of exposure to acellular blood components was determined for the five year period prior to entry in the study, which occurred during 1986 and 1987. Patients with coagulations disorders (hemophilia A = 132, hemophilia B = 16 and coagulation disorders other than hemophilia = 16) were transfused with liquid cryoprecipitate, locally produced, lyophilized cryoprecipitate, imported from São Paulo (Brazil) and factor VIII and IX, imported from Rio de Janeiro (Brazil), Europe, and United States. Thirty six (22%) tested HIV seropositive. The univariate and multivariate analysis (logistic model) demonstrated that the risk of HIV infection during the study period was associated with the total units of acellular blood components transfused. In addition, the proportional contribution of the individual components to the total acellular units transfused, namely a increase in factor VIII/IX and lyophilized cryoprecipitate proportions, were found to be associated with HIV seropositivity. This analysis suggest that not only the total amount of units was an important determinant of HIV infection, but that the risk was also associated with the specific component of blood transfused

Natural and experimental infection of planorbids from the Island of Santa Catarina (Brazil)

Studies on eight localities on the Island of Santa Catarina revealed the presence of three species of the molluscan family Planorbidae: Biomphalaria tenagophila, Drepanotrema cimex and Biomphalaria oligoza, the first one being naturally infected by Cercaria ocellifera, a furcocercaria with morphological characteristics of Cercaria caratinguensis, and by an unknown furcocercaria. Drepanotrema cimex was infected by a furcocercaria with characteristics of C. caratinguensis and by C. macrogranulosa. No natural infection was found in B. oligoza. B. tenagophila showed no susceptibility to the experimental infection by the BH-MG strain of Schistosoma mansoni from Belo Horizonte and maintained at laboratory in B. glabrata snails.

Possibility of in-hospital infection by Cryptococcus neoformans in patients with AIDS

The objective of the present work was to carry out a survey of soil samples taken from different areas of a hospital of infectious disease located in the city of Cordoba, where three AIDS patients were hospitalized during different periods in the same ward. The three of them returned with meningeal cryptococcosis between three or five months after having been discharged. Cryptococcus neoformans was isolated in 8/10 samples collected outside the hospital, near the pigeon house. The samples collected from the AIDS patients ward and its surroundings were negative. These findings suggest that the patients may have been infected by the fungus during their first stay in hospital.

Epidemiology of Schistosoma mansoni infection in a low-endemic area in Brazil: clinical and nutritional characteristics

A cross-sectional case-control study designed to evaluate the role of malnutrition in the association between the intensity of Schistosoma mansoni infection and clinical schistosomiasis, was conducted in an area with both low frequency of infection and low morbidity of schistosomiasis in Brazil. Cases (256) were patients with a positive stool examination for S. mansoni; their geometrical mean number of eggs/gram of feces was 90. Controls (256) were a random sample of the negative participants paired to the cases by age, sex and length of residence in the area. The clinical signs and symptoms found to be associated with S. mansoni infection, comparing cases and controls, were blood in stools and presence of a palpable liver. A linear trend in the relative odds of these signs and symptoms with increasing levels of infection was detected. Adjusting by the level of egg excretion, the existence of an interaction between palpable liver and ethnic group (white) was suggested. No differences in the nutritional status of infected and non-infected participants were found.

A randomized clinical trial with high dose of chloroquine for treatment of Plasmodium falciparum malaria in Brazil

This clinical trial compared parasitological efficacy, levels of in vivo resistance and side effects of oral chloroquine 25 mg/Kg and 50 mg/Kg in 3 days treatment in Plasmodium falciparum malaria with an extended followed-up of 30 days. The study enroled 58 patients in the 25 mg/Kg group and 66 in the 50 mg/Kg group. All eligible subjects were over 14 years of age and came from Amazon Basin and Central Brazil during the period of August 1989 to April 1991. The cure rate in the 50 mg/Kg group was 89.4% on day 7 and 71.2% on day 14 compared to 44.8% and 24.1% in the 25 mg/Kg group. 74.1% of the patients in the 25 mg/Kg group and 48.4% of the patients in the 50 mg/Kg group had detectable parasitaemia at the day 30. However, there was a decrease of the geometric mean parasite density in both groups specially in the 50 mg/Kg group. There was 24.1% of RIII and 13.8% of RH in the 25 mg/Kg group. Side effects were found to be minimum in both groups. The present data support that there was a high level resistance to chloroquine in both groups, and the high dose regimen only delayed the development of resistance and its administration should not be recommended as first choice in malaria P. falciparum therapy in Brazil.

Aplastic crisis due to human parvovirus B19 infection in hereditary hemolytic anaemia

Specific anti-B19 IgM was demonstrated in sera from three children showing transient aplastic crisis. A two years-old boy living in Rio de Janeiro suffering from sickle-cell anaemia showed the crisis during August, 1990. Two siblings living in Santa Maria, RS, developed aplastic crisis during May, 1991, when they were also diagnosed for hereditary spherocytosis. For a third child from this same family, who first developed aplastic crisis no IgM anti-B19 was detected in her sera.

Central nervous system involvement in Chagas' disease: an updating

A review was made of the available literature on central nervous system (CNS) involvement in Chagas' disease. Thirty-one works concerning the acute nervous form and 17 others dealing with the chronic nervous form, all presenting neuropathologic studies, were critically analysed. Based on this analysis, an attempt was made to establish the possible natural history of CNS involvement in Chagas' disease. Among others, the following facts stand out: 1) the initial, acute phase of Trypanosoma cruzi infection is usually asymptomatic and subclinical; 2) only a small percentage of cases develop encephalitis in the acute phase of Chagas' disease; 3) the symptomatic acute forms accompanied by chagasic encephalitis are grave, with death ensuing in virtually all cases as a result of the brain lesions per se or of acute chagasic myocarditis, this being usually intense and always present; 4) individuals with the asymptomatic acute form and with the mild symptomatic acute form probably have no CNS infection or, in some cases, they may have discrete encephalitis in sparse foci. In the latter case, regression of the lesions may be total, or residual inflammatory nodules of relative insignificance may persist. Thus, no anatomical basis exists that might characterize the existence of a chronic nervous form of Chagas' disease; 5) reactivation of the CNS infection in the chronic form of Chagas' disease is uncommon and occurs only in immunosuppressed patients.