Characterization of two isolates of Trypanosoma cruzi obtained from the patient Berenice, the first human case of Chagas' disease described by Carlos Chagas in 1909.

Two isolates of Trypanosoma cruzi were obtained from the patient Berenice, the first human case of Chagas' disease (Chagas 1909), when she was 55 and 71 years old, respectively. The isolates were characterized on the basis of their epimastigote-trypomastigote differentiation in liquid media and of the electrophoretic pattern of EcoR1 digestion products of kinetoplast DNA (k-DNA) minicircles (schizodeme) and isoenzyme patterns (zymodeme). Clear differences were found between the isolates, suggesting the occurrence of a heterogeneous population of T. cruzi in the infection of this patient.

Infecçäo experimental de caprinos com Strongyloides papillosus / Experimental strongyloidiasis in goats

Acompanhou-se a evoluçäo da infecçäo por Strongyloides papillosus em 14 caprinos sem raça definida, de três a seis meses de idade, inoculados com 3.000 larvas infectantes por kg de peso vivo. Os resultados mostraram que a suscetibilidade ao parasita näo está relacionada com a idade do animal, mas que o período de eliminaçäo de ovos de S. papillosus foi mais longo nos animais mais jovens. A necrópsia foram observadas alteraçöes histopatológicas que caracterizam enterite catarral aguda com pronunciada exulceraçäo simples da mucosa. A pesquisa de anticorpos da classe IgC, pelo ELISA, mostrou que esses anticorpos foram detectados a partir do 20§ dia após a inoculaçäo (DAI) até o 200§ DAI, quando os animais foram necropsiados. Os níveis máximos de anticorpos (título variando entre 1:5.120 a 1:40.960) foram observados entre o 30§ e o 130§ DAI

Eliminação de Toxoplasma gondii pela urina de camundongos durante a fase aguda da infecção experimental / Elimination of Toxoplasma gondii through urine of mice in the acute phase of experimental infection

Toxoplasma gondii tachyzoites from an avirulent strain, were used to subcutaneously infect mice (Swiss outbred strain). All died 7 to 9 days after infection (DAI) during acute phase infection. Eighty per cent eliminated T. gondii forms by urine. This was determined through infectivity test in normal mice (bioprove). Interstitial interbular hemorrhage were the more frequently observed lesion in renal histology. Whole erythrocytes could also be seen in some glomerular Bowmann's subcapsular space. T. gondii elimination mechanism is discussed, together with the relationship between these observations and natural toxoplasmosis transmission.

Toxoplasma gondii em caprinos inoculados experimentalmente / Toxoplasma gondii in tissues of experimentally infected goats

Toxoplasma gondii foi demonstrado em órgäos de 10 entre 12 caprinos inoculados pela via subcutânea com 10 elevado à sétima potência taquizoítos de uma cepa de virulência moderada do T. gondii (C4). O parasito näo foi demonstrado em órgäos de duas cabras näo gestantes que já apresentavam anticorpos anti-T. gondii antes do inóculo, mas foi evidenciado em uma cabra gestante que apresentava estes anticorpos previamente. Os órgäos mais frequentemente parasitados foram cérebro, coraçäo, músculo esquelético e diafragma. Um animal sacrificado no 60§ dia após a inoculaçäo (DAI) apresentou 91 por cento dos órgäos positivos, enquanto outro sacrificado no 561§ DAI, apresentou 17 por cento dos órgäos positivos. A presença do parasita em órgäos de caprinos com 505 a 561 dias de infecçäo indica a importância da carcaça destes animais na transmissäo da toxoplasmose devido ao costume comum de consumo desta carne no Brasil e em outras partes do mundo

[Elimination of Toxoplasma gondii through urine of mice in the acute phase of experimental infection]. / Eliminação de Toxoplasma gondii pela urina de camundongos durante a fase aguda da infecção experimental.

Toxoplasma gondii tachyzoites from an avirulent strain, were used to subcutaneously infect mice (Swiss outbred strain). All died 7 to 9 days after infection (DAI) during acute phase infection. Eighty per cent eliminated T. gondii forms by urine. This was determined through infectivity test in normal mice (bioprove). Interstitial interbular hemorrhage were the more frequently observed lesion in renal histology. Whole erythrocytes could also be seen in some glomerular Bowmann's subcapsular space. T. gondii elimination mechanism is discussed, together with the relationship between these observations and natural toxoplasmosis transmission.

Toxoplasmosis and mental retardation--report of a case-control study.

A case-control study evaluating the association between mental retardation and toxoplasmosis was conducted among 845 school children in Belo Horizonte, MG, Brazil. Cases (450) were mentally retarded children attending a public school for special education. Controls (395) were children from the regular public school system. Clinical and anthropometric examinations and interviews were carried out to determine risk factors for toxoplasmosis and mental retardation. Diagnosis of Toxoplasma gondii infection was based upon an indirect immunofluorescent test (IFA); 55% of cases and 29% of controls were positive. The Relative Odds of mental retardation in children with positive serology was 3.0 (95% CI 2.2-4.0). Maternal exposure to cats and contact with soil were associated with an increased risk of mental retardation. Retinochoroiditis was fourfold more prevalent among cases than controls and was only diagnosed in T. gondii IFA positive participants. Congenital toxoplasmosis, in its subclinical form, appears to be an important component in the etiology of mental retardation, especially in high risk (lower socio-economic) groups. The population attributable risk was estimated as 6.0-9.0%, suggesting the amount of mental retardation associated with this infection.

Diagnosis of caprine toxoplasmosis by a dot enzyme-linked immunosorbent assay

Foi avaliada a reaçäo imunoenzimática dot-ELISA, no imunodiagnóstico da toxoplasmose caprina, considerando a reaçäo de Imunofluorescência Indireta (RIFI) como reaçäo de referência. Para a avaliaçäo da dot-ELISA discos de nitrocelulose foram sensibilizados com 0,1 microgramas de proteína/ml de uma soluçäo antigênica obtida através da sonicaçäo de taquizoitas de Toxoplasma gondii. Esta concentraçäo antigênica foi considerada ótima na discriminaçäo de soros reagentes e näo reagentes. Foram testadas 169 amostras de soro, destas 115 (68 por cento) foram reagentes a antígenos de T. gondii, com títulos de anticorpos variando entre 1/16 e 1/16:384, quando testadas através da reaçäo de Imunofluorescência Indireta (RIFI); na dot-ELISA, 119 (70 por cento) foram positivas, com título variando entre 1/16 e 1/65.536. A comparaçäo entre as técnicas mostra os seguintes índices: co-positividade (sensibilidade) 0,89, co-negatividade (especificidade) 0,98, e Youden (concordância) 0,93, quando foi utilizado o título de 1/16 como discriminatório de reaçöes positivas e negativas. Utilizando como discriminatório o título de 1/64, os índices calculados foram co-positividade 0,97, co-negatividade 0,96 e Youden 0,93. Os resultados mostram a possibilidade da utilizaçäo da dot-ELISA no imunodiagnóstico da toxoplasmose caprina. A introduçäo desta reaçäo no imunodiagnóstico da toxoplasmose seria de grande importância, principalmente em estudos soro-epidemiológicos, já que a técnica pode ser realizada sob condiçöes de campo, pois nenhum equipamento especial é requerido para a sua execuçäo

Toxoplasmose experimental em cabras gestantes / Experimental toxoplasmosis in pregnant goats

Onze cabras gestantes sem raça definida foram inoculadas pela via subcutânea com 10 elevado à sétima potência taquizoítos de uma cepa de virulência moderada do Toxoplasma gondii (CA). Duas cabras gestantes foram usadas como controle näo inoculados. Foi observado transmissäo congênita do T. gondii em sete das oito cabras inoculadas entre o 52§ e o 67§ dia de gestaçäo (cinco abortos e dois partos normais com filhotes debilitados). Três cabras inoculadas entre o 100§ e o 133§ dia de gestaçäo pariram crias aparentemente normais, apesar da ocorrência de transmissäo congênita em um dos animais. Foi possível ainda evidenciar a transmissäo congênita do parasita em uma entre quatro cabras avaliadas em duas gestaçöes sucessivas. As cabras controle pariram crias aparentemente normais, não infectadas pelo T. gondii

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.

[Diagnosis of Trypanosoma cruzi infection in opossums, naturally infected, using indirect immunofluorescence reaction]. / Diagnóstico de infecção pelo Trypanosoma cruzi em gambas, naturalmente infectados, pela reação de imunofluorescência indireta.

One hundred and sixteen opossums captured in Bambuí, MG State, had an indirect fluorescent antibody test (IFAT) to detect circulating Trypanosoma cruzi antibodies. Forty-four of them (37.9%) reacted to T. cruzi, showing, titres ranging from 1:10 to 1:320. The parasite was demonstrated by parasitological examinations in 43 (97.7%) of these opossums. The IFAT presented co-positivity (97.7%) co-negativity (98.6%) and agreement (98.3%) rates when compared to xenodiagnosis and hemoculture. Considering the dilution 1:20 to discriminate reactions from the nonreactive ones, the IFAT is indicated as a diagnostic method, opossums. The IFAT on dry filter paper presented low rates of co-positivity (78.2%), agreement (76.0%) and consistent disagreement related to the non-reactive results.

Factors associated with AIDS and AIDS-like syndrome among homosexual and bisexual men in Minas Gerais, Brazil.

A case-control study to determine factors associated with AIDS and AIDS-like syndrome among homosexual/bisexual men was conducted in the State of Minas Gerais (Brazil). Eighty-three per cent (45 patients) of all AIDS/AIDS-like syndrome cases in homosexual/bisexual men reported in Minas Gerais between February, 1986 and June, 1987 were compared to 133 seronegative controls seen at the same clinic. Blood samples were tested by ELISA and confirmed by Western blot. Sex with men from the USA, sex with someone who developed AIDS, number of male partners (greater than or equal to 100 lifetime), age (greater than or equal to 30 years old) and ethnicity (white) were independently associated with AIDS/AIDS-like syndrome (Odds Ratios = 5.5, 4.3, 3.9, 3.5 and 2.7, respectively). Thirty-nine per cent of cases and 44% of controls reported bisexual activity during the previous two years. From these, a high proportion reported anal intercourse with women in the same period (53% of bisexual cases and 33% of bisexual controls). Bisexual men had more male partners than female partners in the previous two years (median male partners = 20 for cases and five for controls; median female partners = three for both cases and controls). This explains in part why the epidemic has increased more rapidly among men then among women in Minas Gerais, despite the large proportion of bisexuals with the disease.

PIP: A case control study to determine factors associated with AIDS and AIDS- like syndrome among homosexual/bisexual men was conducted in the state of Minas Gerais, Brazil. 83% (45 patients) of all AIDS/AIDS-like syndrome cases in this group of men reported in Minas Gerais between February 1986-June 1987 were compared to 133 seronegative controls seen at the same clinic. Blood samples were tested by ELISA and confirmed by western blot. Sex with men from the US, with someone who developed AIDS, number of male partners ( or = 100 lifetime), age ( or = 30 years old), and ethnicity (white) were independently associated with AIDS/AIDS-like syndrome (odds ratio=5.5, 4.3, 3.9, 3.5, and 2.7, respectively). 39% of cases and 44% of controls reported bisexual activity over the previous 2 years. From these, a high proportion reported anal intercourse with women in the same period (53% of bisexual cases and 33% of bisexual controls). Bisexual men had more male partners than female ones in the previous 2 years (median number=20 for cases and 5 for controls; median number of female partners=3 for both cases and controls). This explains in part why the epidemic has increased more rapidly among men than women in Minas Gerais, despite the large proportion of bisexuals with the disease.

Hemocultures for the parasitological diagnosis of human chronic Chagas' disease.

With the purpose of standardization of an hemoculture technique presenting a higher positive rate in the parasitological diagnosis of chronic Chagas' disease in patients with reactive serology (IFT, HA, CFT) the following schedule was used. Thirty ml of venous blood was collected with heparin and the plasma was separated by centrifugation (2.000 rpm/30'). The packed cells were washed with LIT medium or PBS which was then removed by centrifugation (2.000 rpm/15'). This material was sampled in 6 screw-tubes 18 x 200 with 6 ml of LIT medium and incubated at 28 degrees C. These incubated cultures at 28 degrees C were examined after 15, 30, 45 and 60 days. When the hemoculture was not immediately processed after blood collection, the plasma was removed and the sediment enriched with LIT medium and preserved at 4 degrees C. The Xenodiagnosis was performed according to Schenone's method used here as a reference technique. Among the various groups of patients examined by both techniques the best results obtained were: 55.08% of positivity for hemocultures against 27.5% for xenodiagnosis (X2 = 4.54, p = 0.05), with a tube positivity of 26.6%. Recommendation for screening trials of drug assays is the repetition of method on a same patient 2 or more times in different occasions, as used in xenodiagnosis.

Aspectos oftalmológicos da associaçäo toxoplasmose congênita-deficiência mental: estudo epidemiológico / Ophthalmological findings of congenital toxoplasmosis-mental deficiency: epidemiological study

O autor realizou investigaçäo oftalmológica em 403 crianças, sendo 230 portadoras de deficiência mental em graus variados (Casos) e 173 com desenvolvimento intelectual considerado como normal (Controles), todas integrantes do Sistema Operacional de Ensino da Secretaria de Estado da Educaçäo de Minas Gerais, com o objetivo principal de detectar alteraçöes oftalmoscópicas e correlacioná-las com a presença de infecçäo por Toxoplasma gondii e com a condiçäo de deficiência mental, através de análises de associaçäo ("Odds Ratio"). O estudo teve caráter simples-cego; o autor näo conhecia os resultados da sorología (RIF) quando da realizaçäo do exame oftalmológico. Além da lesäo clássica da toxoplasmose ocular, foram consideradas como sugestivas de toxoplasmose as pequenas lesöes de retinocoroidite cicatrizada, detectadas pelo examinador, que se caracterizavam por centro pigmentado, halo hipocrômico, tamanho variando entre meio a um diâmetro papilar, localizadas a distância variáveis do pólo posterior, sem extrapolar os limites equatoriais. A associaçäo destas lesöes com a infecçäo toxoplásmica foi bastante alta ("Odds Ratio" = 34,4). Foi verificado que estas lesöes estavam associadas a condiçäo de deficiência mental, com "Odds Ratio" igual a 4,4, levando o autor a concluir que, as crianças que apresentavam esta lesäo têm uma chance quatro vezes maior de serem portadoras de deficiência mental por toxoplasmose do que as crianças sem a lesäo. As lesöes de degeneraçäo da periferia da retina e a palidez da cabeça do Nervo Optico também mostraram-se associadas a deficiência mental, mas associaçäo possivelmente foi determinada pela presença de outros fatores causais que näo a toxoplasmose

[Comparative biological characterization of Berenice and Berenice-78 strains of Trypanosoma cruzi isolated from the same patient at different times]. / Caracterização biológica comparativa das cepas Berenice e Berenice-78 de Trypanosoma cruzi isoladas da mesma paciente em diferentes períodos.

The Berenice-78 strain of T. cruzi is very different from the Berenice strain isolated 16 years earlier from the same patient. The authors verified its high infectivity and low virulence for C3H inbred mice that survived the acute phase of infection. In these animals, it was verified that the tropism of parasites was more accentuated for cardiac and skeletal musculature and the parasitaemic level progressively increased with successive blood passages with posterior stability. In relation to Berenice strain the same characteristics were observed as described by Brener, Chiari & Alvarenga (1974). The increase in its virulence for albino mice was again demonstrated. The authors discussed the possibility of reinfection of the patient called Berenice and the importance of knowledge about T. cruzi strains of low virulence for laboratory animals.

Concanavalin a receptors on the cell membrane of Trypanosoma cruzi.

Epimastigotes and trypomastigotes of T. cruzi obtained from acellular culture as well as bloodstream trypomastigotes agglutinate with concanavalin A (Con A). Con A-binding sites were also localized on the cell membrane by using the Con A-horseradish peroxidase-diaminobenzidine method. Passage of epimastigotes and trypomastigotes from acellular culture through DEAE-cellulose column did not affect Con A-binding sites as detected by agglutination and electron miscroscopy.

Recovery from heart norepinephrine depletion in experimental Chagas' disease.

Norepinephrine (NE) was assayed fluorimetrically in the hearts of rats killed at different periods after inoculation with the Y strain of Trypanosoma cruzi. The levels of cardiac NE which, as reported previously, were not measurable 18, 22, and 32 days after inoculation became detectable at day 48. At day 70 these levels were around 50% of the control values and at day 97 normal values were attained in most animals. These results strongly suggest that sympathetic nerve fibers are destroyed in the acute phase of T. cruzi infection and regenerated during the chronic phase.