Diagnóstico y tratamiento de la infección congénita por Trypanosoma cruzi en Brasil / Diagnosis and treatment of congenital infection caused by Trypanosoma cruzi in Brazil

Diagnosis of congenital infection should be performed preferentially by the search of the parasite, through microhematocrit. Nevertheless, most of the infected mothers are living now in non-endemic areas, where the expertise for identification of the parasite is low. Furthermore, transmission near delivery or even at delivery do not allow that enough parasites will be detected when the baby is at the maternity. So, if parasites are not found or not searched, it is imperative that, in serologically confirmed mothers (two positive tests), the babies are recalled at six/eight months of age, to look for IgG antibodies. If they are present, the baby is infected and should be treated. Treatment in Brazil is with benznidazol, 10 mg/Kg/day, during 60 days. Certification of cure is obtained once a negative serology is obtained, as a rule after one year. A follow up each six months is suggested.

Transmisión congénita del Trypanosoma cruzi en Brasil: estimativa de prevalencia baseada en resultados preliminares de la encuesta nacional serológica en niños menores de cinco años, así como otras fuentes / Congenital transmission of Trypanosoma cruzi in Brazil: estimation of prevalence based on preliminary data of national serological surveys in children under 5 years old and other sources

A prevalence estimation of congenital transmission in Brazil is performed, based on several sources of recent data. From a serological survey conducted now in Brazil, with children below 5 years old, preliminary data from the state of Minas Gerais only 19/9,556 children did have antibodies against Trypanosoma cruzi. All 19 mothers were infected, but only one child persisted with antibodies on a second blood collection, hence diagnosed as congenital. The other were just passive transference of maternal antibodies. From a recent publication, 278 children born from 145 infected mothers were studied. Two cases (0.7%) were congenital. In other source, from 1,348 blood donors, 35 were born in non endemic areas. When 10 of them were called, 8 were born from infected mothers and five may be congenital. Finally, no infection was detected in 93 children born from 78 infected mothers. The reasons for this low prevalence are discussed, are lower than in other countries of the South Cone, that harbor also T. cruzi 2, but are unrecognized up to now.

Comparação entre o xenodiagnóstico clássico e artificial na fase crônica da doença de Chagas / Comparison between classical and artificial xenodiagnosis in chronic Chagas disease

Classical and artificial xenodiagnostic techniques made with Dipetalogaster maximus of first stage were performed simultaneously in 57 patients with chronic T. cruzi infection (22 male and 35 female patients, aged 7-80 years). With the exception of two patients with megaoesophagus, all had two previous positive serological reaction and a further test was done at the time of the examination. The patients came from the outpatient department of the university hospital or were resident in Mambaí, Goiás. Of the 57 patients, 24 (42%) had a positive xenodiagnoses. Of a total of 114 tests performed, 36(32%) were positive. Comparing the two xenodiagnostic techniques, no significant advantage was apparent statistically (p = 0.42), but the artificial technique has advantages because the blood is offered for triatomines through a device while in the classical technique, the triatomines suck through the patient's skin.

O xenodiagnóstico (xeno) clássico e artificial feitos com Dipatalogaster maximus de primeiro estágio foi realizado simultaneamente em 57 pacientes com infecção chagásica crônica (22 do sexo masculino e 35 do sexo feminino, com idades entre 7 e 80 anos). Exceto dois pacientes com clínica de megaesôfago, os demais tinham dois exames sorológicos prévios positivos sendo feita nova sorológia no decorrer do estudo. Os pacientes eram provenientes do ambulatório do Hospital Universitário de Brasília (HUB) ou eram residentes no município de Mambaí, GO. Dos 57 pacientes, 24 (42%) apresentaram xenodiagnósticos positivos. Dos 114 xenodiagnósticos realizados, 36 (32%) foram positivos. A comparação das duas técnicas não mostrou diferença estatisticamente significante (p = 0,42), porém o xeno artificial apresenta vantagem porque o sangue é oferecido aos triatomíneos através de um aparelho enquanto, no xeno clássico, os triatomíneos sugam através da pele do paciente

Trypanosoma cruzi and experimental Chagas' disease: characterization of a stock isolated from a patient with associated digestive and cardiac form

Um novo estoque de Trypanosoma cruzi isolado de paciente chagásico crônico, com a forma digestiva e cardiaca da doença, foi caracterizado através de infecçäo experimental em camundongos isogênicos A/Sn suscetíveis à infecçäo chagásica. As curvas de parasitemia mostraram picos de até 1,7x10**6 parasitas/ml näo se observando mortalidade até 300 dias após infecçäo. anticorpos da classe IgM foram encontrados na fase aguda até 40 dias e também na fase crônica e IgG foi detectada nas fases aguda e crônica. O exame histopatológico mostrou miotropismo para músculo liso do tubo digestivo e cardíaco

Megaesôfago e anticorpos anti-Trypanosoma cruzi / Megaesophagus and antibodies against Trypanosoma cruzi

Foram analisados 240 soros de pacientes portadores de megaesôfago atendidos no Hospital das Clínicas de Goiânia, pelas técnicas de hemaglutinaçäo indireta (HAI) e de aglutinaçäo direta com pré-tratamento com 2-mercaptoetanol (AD2ME). Em 179 casos, ambas as reaçöes sorológicas foram concordantemente positivas (74,6%). Em 35 casos (14,6%) as reaçöes sorológicas foram positivas com uma técnica e negativas com a outra, sendo que a repetiçäo de ambas as técnicas e/ou a realizaçäo das técnicas de imunofluorescência indireta (IFI) e de fixaçäo de complemento (FC), demonstraram finalmente a positividade destes 35 soros "duvidosos'. Conclui-se que 89,2% dos pacientes portadores de megaesôfago na amostra estudada apresentaram anticorpos anti-Trypanosoma cruzi, confirmando a sua etiologia chagásica. Nos restantes 26 casos (10,85) ambas as reaçöes foram concordantemente negativas. Esta ausência de anticorpos específicos foi confirmada por IFI e por FC. Em oito destes 26 casos, uma nova amostra de soro confirmou estes resultados. Em 24/26 casos, existiam antecedentes epidemiológicos de doença de Chagas, e em dois destes 24 casos houve confirmaçäo parasitológica (xenodiagnóstico positivo). O encontro de dois casos sorologicamente negativos com parasitas circulantes demonstra que a etiologia chagásica näo pode ser afastada, mesmo na ausência de anticorpos específicos, se existirem antecedentes epidemiológicos e indicadores clínicos da doença de Chagas

Estudo imunobiológico de estoques de Trypanosoma cruzi isolados de pacientes na fase aguda da doença de Chagas

Estoques de tripanossomas isolados de pacientes na fase aguda da doença de Chagas foram injetados em grupos de camundongos albinos não isogênicos nas doses de 10³, 10(4) e 10(5) parasitas/camundongos. O curso da infecção foi seguido por três meses. A pctrasitemia foi em geral baixa, com picos recorrentes, na maioria das vezes os animais evoluiam para cronicidade. Somente um estoque induziu alto índice de mortalidade. Os parasitas e as lesões apesar de detectadas no pico da parasitemia e restritos ao coração estavam ausentes aos três meses. Nesta época os perfis de Igs apresentaram diferenças marcantes. Grupos de animais que foram inoculados com estes estoques foram desafiados com doses letais da cepa Y ou CL. Em alguns casos obteve-se uma parasitemia, mas patente.

Ten stocks of trypanosomes isolated from patients at the acute phase of Chagas'disease were injected into groups of outbred normal mice at the doses of 10³, 10(4) and 10s5 parasites/mouse and the course of the infections followed up for 3 months. The parasitemia was usually low, with recurrent peaks, the animals evolving to chronicity, only one of them inducing high ratio of mortality. Pattems of parasitemia and mortality were essentially different for each stock studied; only one stock did show similar pattems to well known strains (Yand CL) commonly used in experimental work. Parasites and lesions, although detected at the peak of parasitemia and restricted to heart were absent after three months. At this period the Igs profiles showed striking differences with respect to their distribution. Groups of mice that had been inoculated with one of the stocks were challenged with the Y or CL strains. In some instances low parasitemias although patent were seen after the infecting dose.