[Comparative controlled study on the use of benznidazole, nifurtimox and placebo, in the chronic form of Chagas' disease, in a field area with interrupted transmission. I. Preliminary evaluation]. / Estudo comparativo controloado com emprego de benznidazole, nifurtimox e placebo, na forma crônica da doença de Chagas; em uma área de campo com transmissão interrompida. I. Avalição preliminar.

A controlled clinical trial was carried out to evaluate the therapeutic efficacy and tolerance of nifurtimox and benznidazole in patients with chronic Chagas' disease. All patients had immunofluorescence and complement fixation reactions positives for T. cruzi antibodies and at least two xenodiagnoses positives in three performed before treatment, and they were submitted to clinical examinations, ECG and X-ray of the heart and esophagus. Of 77 patients studied, 27 were treated with nifurtimox and 26 with benznidazole in the dosage of 5 m/kg/day for 30 consecutive days, and 24 received a placebo in tablets similar to benznidazole. From the 77 patients, 64 (83.1%) accomplished the treatment: 23 (88.4%) with benznidazole, 19 (70.3%) with nifurtimox and 22 (91.6%) with placebo. The patients were evaluated, clinically, serologically and parasitologically (six xenodiagnoses within one year after treatment). The benznidazole group showed only 1.8% of positive xenodiagnoses post-treatment, the nifurtimox 9.6% and the placebo 34.3%. All serologic reactions continued positive and there were no clinical, ECG or X-ray changes one year after treatment.

Chagas' disease in the Brazilian Amazon. III. A cross-sectional study (1).

Two serological surveys for Chagas' infection were carried out, in 1991 and 1993, respectively, using a conglomerate family samples from the residents in the town of Barcelos (in the northern part of the State of Amazonas, on the right bank of the Rio Negro, 490 Km up-river from Manaus), using indirect immunofluorescent tests for anti-T. cruzi antibodies. In the first survey (1991), 628 blood samples from the residents of 142 dwellings were tested, showing positive in 12.7% for anti-T. cruzi antibodies and in 1993 an other 658 samples from residents of 171 dwellings showed positive in 13.7% of the tests, thus confirming the previous results. From 170 individuals with positive serology for T. cruzi antibodies, 112 (66%) were interviewed and submitted to electrocardiographic and clinical examinations; 82 (73.2%) of them gave consent for xenodiagnosis. From the 112 interviewed 52 (46.4%) recognized the triatomines as "piaçavas' lice", 48 (42.8%) knew the bugs from their work places being gatherers of piaçava fibers in rural areas and 19 (16.9%) said that have been bitten by bugs in their huts. Only 2 (2.4%) of 82 xenodiagnosis applied were positive for T. cruzi and 9 (8%) of the ECG had alterations compatible with Chagas' disease.

Chagas' disease in the Brazilian Amazon. II. A serological survey.

A serological survey, involving indirect immunofluorescence testing of blood sera samples, was carried out on the residents of one in every five dwellings in the town of Barcelos (in the northern part of the State of Amazonas, on the right bank of the Rio Negro, 490 Km from Manaus by river) and on the rural populations of the villages of Piloto and Marará (also on the right bank of the Rio Negro, 30 minutes by boat from Barcelos). A total of 710 sera samples were tested, 628 from the resident population in the town of Barcelos, 35 from Piloto and 47 from Marará. The tests were carried out using human anti-gammaglobulin type IgG (Biolab) and antigen from formolized culture of T. cruzi Y strain. The sera were serially diluted from 1:40 to 1:320 in PBS 7.2. Of the 710 samples examined 89 (12.5%) were positive for anti-T.cruzi antibodies: 2 of these (2.2%) at a dilution of 1:320; 12 (13.4%) at 1:160; 38 (42.6%) at 1:80; and the remainder at 1:40, giving a median serological dilution of 1:80. The following questions are discussed: the high serological prevalence for Chagas' infection found in our survey; the possibility of serological cross-reactions; the need for confirmatory tests for the positives reactions; and the strong correlation between our results and preliminary epidemiological data (such as the level of human contact with wild triatominae, know locally as "Piaçava's lice". We draw attention to the isolation by xenodiagnosis of one strain of T.cruzi from a patient with positive serology for Chagas' infection.

[Epidemiological, social, and sanitary aspects in an area of the Rio Negro, State of Amazonas, with special reference to intestinal parasites and Chagas' disease]. / Aspectos epidemiológicos, sociais e sanitários de uma área no Rio Negro, estado do Amazonas, com especial referência às parasitoses intestinais e à infecção chagásica.

A cross-sectional study was carried out on the residents of one in every four dwellings in the town of Barcelos (in the northern part of the State of Amazonas, on the right bank of the Rio Negro, 490 kilometers from Manaus by river), in order to evaluate social and sanitary conditions and specific indicators for intestinal parasites and Chagas' infection. During the survey, two questionnaires were applied, a household one to evaluate social and sanitary aspects, and an individual one, for social and epidemiological evaluation of the population conditions. A conglomerate family sample of 171 dwellings was studied. From each of the 658 habitants, a sample was requested for stool examination by Lutz sedimentation and Baermann-Moraes-Coutinho techniques modified by Willcox & Coura (1989), and blood was collected in filter paper for immunofluorescence test by Camargo (1966) and Souza & Camargo (1966) methods modified by Petana & Willcox (1975). The stool examination showed 69.4% of samples with one or more parasites. Ascaris lumbricoides was predominant with 51% of positivity and Entamoeba histolytica, although surveyed by a non-specific method, was present in 19.7%. Surprisingly, 20.1% of the 658 sera samples were reactive for T. cruzi antibodies at a dilution of 1:20 and 13.7% at 1:40. There was a strong correlation between this result and the level of human contact with wild triatomines, known locally as "piasava lice", and we succeeded in isolating by xenodiagnosis one strain of T. cruzi from one patient, a sixty-one-year old man (n. 209 -1), a native of the area, with positive serology for Chagas' disease and who worked in agriculture and transporting piasava and was very familiar with "piasava lice".

Evaluation of the xenodiagnosis of chronic Chagas patients infected ten years or over in an area where transmission has been interrupted--Iguatama and Pains, west Minas Gerais State, Brazil.

To evaluate the results of xenodiagnosis in chronic Chagas patients infected for ten years or over in an area where transmission has been stemmed as well as the performance of these tests applied one or more times to determine the presence of the parasite in serum-positive patients for Trypanosoma cruzi infection, 570 xenodiagnosis were performed in 246 patients by exposing each patient to 40 Triatoma infestans nymphs of 3rd/4th stage once, twice or three times, at 30 days intervals. The 570 xenodiagnosis showed overall positive results in 50.7% with a peak 78% in patients under 20 years of age, and 60.5% in those over 60. Of the 158 patients who underwent three xenodiagnosis, 51 (32.3%) had three positive tests, 48 (30.3%) had all negative results, and the remainder had alternating positive and negative findings. There was no difference in number of positive results between the 1st, 2nd and 3rd tests; however, the 1st and 2nd trials added up to 53.2% and the sum total of all three trials was 57.7%.

The efficiency of Lutz, Kato-Katz and Baermann-Moraes (adapted) techniques association to the diagnosis of intestinal helminths.

The association of Lutz/Kato-Katz and Lutz/Baermann-Moraes (adapted) techniques was used to improve better results that ranged from 0.4 to 11 times in the search of eggs of Ascaris lumbricoides, Schistosoma mansoni, Trichiuris trichiura, Taenia sp. and larvae of Strongyloides stercoralis.

[Development of chronic human chagas cardiopathy in the hinterland of the Paraíba State, Brazil, in a 4.5 year period]. / Evolução da cardiopatia chagásica crônica humana no Sertão do Estado da Paraíba, Brasil, no período de 4,5 anos.

Two sectional studies about chronic Chagas' disease were performed at a 4.5 year interval, involving the urban populations of Agua Branca, Catingueira, Emas, Imaculada, Mãe D'Agua, Olho D'Agua, Piancó and São José de Caiana counties in the Sertão region of the State of Paraíba. The evolution of heart disease was evaluated in 125 matched pairs of chronic chagasic and non-chagasic patients of the same sex, age and county of origin through electrocardiograms (ECG) at rest. The following evaluation criteria were considered: unchanged - no change in the original ECG pattern; progressive-changes in ECG pattern from normal to abnormal or deterioration of ECG abnormalities; and ECG normalization. In chagasic patients evolution of the disease was unchanged in 101 (80.8%), progressive in 13 (10.4%) and ECG normalization in 11 (8.8%), while those observed in non-chagasic patients were respectively values 117 (93.6%), 6 (4.8%) and 2%) patients. Findings indicate that the share of Chagas-linked etiological component affecting the development of chronic Chagas cardiopathy was 5.9% with an estimated annual average of 1.3%. There was no significant difference in the frequency of progressive disease between the sexes either in the chagasic or in the non-chagasic group. On the other hand, progression of heart disease occurred earlier among chagasic patients. Lethality caused by heart disease was 1.6% (2 cases) in the chagasic group and zero in the non-chagasic group during the period under survey. These morbidity and mortality rates were significantly lower than those found in endemic areas such as Virgem da Lapa and Pains-Iguatama in the State of Minas Gerais and can probably be attributed to the weaker pathogenic it of human infection by Trypanosoma cruzi in the Paraíba hinterland.

[A new design of the Baermann, Moraes, Coutinho's technique for the isolation of nematode larva]. / Nova concepção para o método de Baermann-Moraes-Coutinho na pesquisa de larvas de nematódeos.

We have adapted the Baermann-Moraes-Coutinho's technique and the results have demonstrated that more economy of material and physical space have been obtained becoming easier to work in the laboratory and in the field. The sensitivity of the adapted technique was somewhat higher for Strongyloides stercoralis (2.8%) when compared with the original technique and 6.5% for sedimentation methods.

[Parasitemia in chronic chagasic patients evaluated using the index of infected Triatoma in xenodiagnosis]. / Parasitemia em pacientes chagásicos crônicos avaliada pelo índice de triatomíneos infectados no xenodiagnóstico.

As part of a pre-treatment study of chronic Chagas infections, the parasitemia of 206 patients (85 men and 121 women, aged 7 to 80 y) from Virgem da Lapa, Minas Gerais State Brazil, was evaluated by three xenodiagnoses per patient during a one year period. Each time, 40 3rd or 4th instar nymphs of Triatoma infestans were applied. The parasitemia was arbitrarily classified as: not detected (when all nymphs were negative), low (when the number of infected nymphs was less than 2%), medium (when it was higher than 2% and up to 7%) and high (when higher than 7%). The parasitemia was not detected in 105 (51%) of the patients, and was considered low in 55 (26.7%), medium in 27 (13.1%) and high in 19 (9.2%). There was no significant differences in levels of parasitemia in relation to sex or age, but the high parasitemia was more frequent among the patients with chagasic cardiomyopathy. Persistent parasitemia (all three xenodiagnoses positive) was observed in 100% of the patients with high parasitemia, in 22.2% with medium and in none with low parasitemia.

[Morbidity in Chagas' disease. III. Longitudinal study of 6 years, in Virgem da Lapa, MG, Brazil]. / Morbidade da doenca de Chagas. III. Estudo longitudinal, de seis anos, em Virgem da Lapa, MG, Brasil.

In a clinical, radiological and electrocardiographical, follow-up study of the "case control" type performed in Virgem da Lapa, Minas Gerais State, Brazil, 124 chagasic patients were followed during six years. The results of the patients, the majority in the indeterminate form, did not register any change, in 32.2% there was a progress in the disease and in 5.6% the electrocardiogram returned to normal. These results when compared to that achieved by the control group, composed of pairs of non chagasic persons with the same age and sex, was shown to be 27.4% higher than among patients with positive serology. This factor represents the excess risk or exclusively chagasic component in the development of the disease. No differences were observed by sex related to the development of the disease. It was more premature and seven times more frequent however when related to the cardiopathy than to the megaesophagus. Both conditions occurring mainly in slight or moderate degree. In 192 chagasic patients and 188 non chagasic persons observed in that area in the same period, the mortality was 3.6 times higher among the chagasic patients with a letality due to cardiopathy of 8.9% without difference between sexes but more premature among the males. Sudden death was more frequent than that one caused by cardiac insufficiency. The prognostic was good for the patients with indeterminate and digestive forms and reserved for patients with the highest degree of cardiopathy.

[Morbidity in Chagas' disease. IV. Longitudinal study of 10 years in Pains and Iguatama, Minas Gerais, Brazil]. / Morbidade da doenca de Chagas. IV. Estudo longitudinal de dez anos emPains e Iguatama, Minas Gerais, Brasil.

An evolutive study of the "case-control" type was carried out in an endemic area of Chagas' disease in Minas Gerais State, Brazil, using two cross-section evaluations with an interval of ten years between them (1974-1984). Patients were paired for sex and age. In the first cross-section study 264 pairs one with a positive serology and the other with a negative serology for T. cruzi antibodies were included. In the second evaluation, ten years later, 235 patients among those with previous positive serology and 216 with negative serology were located, but only 110 pairs could be recomposed and reexamined (clinical examination, ECG and Rx of the heart and esophagus). The incidence of chagasic cardiopathy in the cases with positive serology but previously assymptomatic was 38.3% during the ten year period. On the other hand there was a deterioration in 24% of the patients with chagasic cardiopathy since the first examination. Considering all clinical forms of the disease in 34.5% of the patients the clinical situation deteriorated, in 57.3% there was no change and in 8.2% the situation improved. The general mortality in the period was 23% in the chagasic group and 10.6% in the control group, but the lethality by cardiopathy was 17% in chagasic group and only 23.3% in the control group. The mortality was twice as high in males than in females, mainly in the age group from 30 to 59 years.