PCR em tempo real no diagnóstico da toxoplasmose congênita / Real-time PCR in the diagnosis of congenital toxoplasmosis

O diagnóstico da toxoplasmose congênita apresenta limitações sendo, portanto, necessárias novas opções de exames. A análise do líquido aminiótico pela PCR em tempo real já se mostrou eficaz para confirmação da infecção fetal. No entanto, o seu desempenho em outras amostras biológicas ainda não está claro. O objetivo deste estudo é avaliar a PCR em tempo real no sangue da mãe e do recém-nascido assim como no líquido amniótico e placenta, no diagnóstico da toxoplasmose congênita. Esse é um estudo descritivo de gestantes com toxoplasmose acompanhadas no Rio de Janeiro, Brasil. Foi realizada PCR em tempo real em amostras de sangue materno, líquido amniótico, placenta e sangue dos recém-nascidos e o exame histopatológico das placentas. Também foram coletados dados clínicos e laboratoriais dos recém-nascidos. Foram acompanhadas 116 gestantes e analisadas 298 amostras. Uma (0,9%) gestante apresentou PCR positiva no sangue, três (3,5%) no líquido amniótico, uma (2,3%) na placenta e nenhum recém-nascido apresentou PCR positiva no sangue. O estudo histopatológico foi sugestivo de infecção por toxoplasmose em 24 (49%) placentas. Seis (5,2%) recém-nascidos foram diagnosticados com toxoplasmose congênita e apenas os casos com PCR positiva no líquido amniótico tinham associação do resultado da PCR com o diagnóstico de infecção congênita. Tanto as amostras de sangue materno quanto as de sangue dos recém-nascidos e placenta, não demonstraram ser promissoras no diagnóstico da toxoplasmose congênita. Novos estudos são necessários para avaliar o real papel do diagnóstico molecular em outros materiais biológicos que não o líquido amniótico.

The diagnosis of congenital toxoplasmosis has limitations so new options are needed. Real-time PCR analysis of amniotic fluid has proven effective for confirming fetal infection. However, its performance in other biological samples still needs to be determined. This study aims to evaluate the real-time PCR role in the blood of the mother and newborn as well as in the amniotic fluid and placenta, in congenital toxoplasmosis diagnosis. It is a descriptive study of pregnant women with toxoplasmosis followed in Rio de Janeiro, Brazil. Real-time PCR was performed on maternal blood, amniotic fluid, placenta, and newborn blood samples. In addition, a histopathological examination of the placentas was performed and data from the babies were collected. One hundred and sixteen pregnant women were followed and 298 samples were analyzed. One (0.9%) pregnant woman had positive PCR in the blood, three (3.5%) in the amniotic fluid, one (2.3%) in the placenta, and any newborn had positive PCR in the blood. The histopathological study suggested toxoplasmosis infection in 24 (49%) placentas. Six (5.2%) newborns were diagnosed with congenital toxoplasmosis and only the cases with positive PCR in amniotic fluid associated with the diagnosis of congenital infection. Neither maternal nor newborn blood and placenta samples have not shown promise in diagnosing congenital toxoplasmosis. Further studies are needed to evaluate the fundamental role of molecular diagnostics in others biological materials than amniotic fluid.

The imbalance of TNF and IL-6 levels and FOXP3 expression at the maternal-fetal interface is involved in adverse pregnancy outcomes in a susceptible murine model of congenital toxoplasmosis.

Vertical transmission of Toxoplasma gondii leads to adverse pregnancy outcomes depending on the time at which the infection occurs and the immunological state of the mother. C57BL/6 and BALB/c mice have been described as susceptible and resistant mouse lineages to congenital T. gondii infection, respectively. This study aimed to elucidate the systemic and local cytokine profile of pregnant mice infected with T. gondii and whether the expression of the transcription factor FOXP3, related to T regulatory cells, is associated with the resistance/susceptibility of these lineages of mice in the context of experimental congenital toxoplasmosis. For this purpose, C57BL/6 and BALB/c females were orally infected with the T. gondii ME-49 strain on the day of vaginal plug detection or day 14 of gestation, examined 7 or 5 days later, respectively, as models of early and late pregnancy. Cytokine levels were measured systemically and in the uterus/placenta. Additionally, the uterus/placenta were evaluated macroscopically for resorption rates and histologically for parasite and FOXP3 immunostaining. The FOXP3 protein expression was also evaluated by western blotting assay. It was found that, during early pregnancy, the infection leads to high IFN-γ, TNF and IL-6 levels systemically, with the TNF levels being higher in C57BL/6 mice. At the maternal-fetal interface, the infection induced high levels of IFN-γ in both mouse lineages; however, higher levels were observed in BALB/c, while high TNF and IL-6 levels were found in C57BL/6, but not in BALB/c mice. In contrast, in late gestation, T. gondii interfered less strongly with the cytokine profile. In early pregnancy, a reduction of FOXP3 expression at the maternal-fetal interface of infected mice was also observed, and the reduction was larger in C57BL/6 compared with BALB/c mice. Additionally, the parasite was seldom found in the uterus/placenta. Thus, the worse pregnancy outcomes observed in C57BL/6 mice were associated with higher TNF systemically, and TNF and IL-6 at the maternal-fetal interface, with lower FOXP3 expression.

Basic heel prick test: inclusion of screening, diagnosis and criteria for early confirmation of congenital infection by Toxoplasma gondii.

Toxoplasma gondii can cross the placental barrier, causing fetal infection with potentially severe sequelae. The aim of this study was to evaluate whether the serological screening for toxoplasmosis should be included in the basic neonatal heel prick test in order to establish criteria for the confirmation and/or exclusion of the diagnosis of congenital infection in newborns treated at three public health units in the metropolitan region of Goiania, Goias State, Brazil. Blood samples were collected on filter paper from newborns and later, peripheral blood samples from the mothers and their respective children were obtained to confirm or exclude the diagnosis of suspected congenital infection, by means of an enzyme-linked immunosorbent assay (IgM and IgG) and a polymerase chain reaction assay. From a total of 1,159 blood samples collected on filter paper, 43.92% were reactive to IgG and 0.17% to anti-T. gondii IgM and IgG. One hundred and twenty-seven paired samples (mother and child) were collected following consensual protocols for peripheral blood collection. Results obtained from the filter paper and peripheral blood of the newborns were 90.55% concordant. A comparison of the mother and child blood test results showed agreement regarding the detection of IgG in 90.48% of the samples. The parasite DNA was detected in the peripheral blood of one child. In view of the results obtained in this study, the inclusion of the serological screening for toxoplasmosis in the newborn heel prick test proved to be effective for the early detection of congenital T. gondii infection.

Congenital human toxoplasmosis caused by non-clonal Toxoplasma gondii genotypes in Argentina.

Toxoplasmosis, a worldwide distributed zoonosis, can be transmitted congenitally affecting fetuses and developing variable clinical signs. Different Toxoplasma gondii genotypes and infective dose are related factors with different clinical manifestations. Several studies indicate that atypical strains could produce more severe clinical manifestations compared to typical strains. Umbilical cord blood (n = 37) and placenta (n = 19) were collected at birth from women with acute T. gondii infection and processed for isolation by mice bioassay. Six isolates were obtained and identified as TgHm14-4Arg, TgHm15-02Arg, TgHm16-01Arg, TgHm16-02Arg, TgHm17-01Arg and TgHm17-02Arg. Three genotypes described previously on Toxo-DB were identified: #138 identified in chickens from Brazil, #182 isolated from eared doves from Brazil, #14 from wallaby kangaroos and chickens from Argentina, chickens from Brazil, Colombia, Chile and Venezuela, cats and dogs from Brazil and Colombia and also coyotes from USA indicating worldwide distribution of these genotypes. Two new allele combinations were obtained showing high genotypes diversity in Argentina. Four of the isolates (TgHm14-4Arg, TgHm15-02Arg, TgHm16-01Arg, TgHm16-02Arg) and two of them (TgHm17-01Arg, TgHm17-02Arg) produced chronic and acute infections in mice, respectively. Until now, seven T. gondii isolates have been obtained from humans in Argentina, and all were atypical or non-clonal genotypes. The identification of atypical strains causing congenital toxoplasmosis and circulating in our region, make important to perform the serological screenings according Argentine Consensus of Toxoplasmosis and to apply and monitoring treatments earlier in pregnancy. To achieve this aim, it is necessary to inform general population about T. gondii infection, diagnostics and control measures. These results should serve to generate awareness about congenital toxoplasmosis in South America.

Epidemiological profile of 39 cases of microcephaly caused by congenital infections diagnosed in the state of Rio Grande do Sul between 2015-2017

Introduction: Microcephaly is a clinical finding that can arise from congenital anomalies or emerge after childbirth. Maternal infections acquired during pregnancy can result in characteristic brain damage in the newborn (NB), which may be visible even in the fetal stage. To describe the epidemiological profile of newborns with reported microcephaly and diagnosed with congenital infections in the state of Rio Grande do Sul between 2015 and 2017. Methods: A cross-sectional study was carried out on data collected from the Public Health Event Registry as well as from medical records. The investigation included serologies for toxoplasmosis and rubella; polymerase chain reaction (PCR) for Zika virus (ZIKV) in the blood and cytomegalovirus in the urine; non-treponemal tests for syphilis; and brain imaging tests. Results: Of the 257 reported cases of microcephaly, 39 were diagnosed with congenital infections. Severe microcephaly was identified in 13 patients (33.3%) and 51.3% of the cases showed alterations in brain imaging tests. In relation to the diagnosis of congenital infections, three patients (7.7%) were diagnosed with ZIKV, nine (23.1%) with cytomegalovirus, nine (23.1%) with toxoplasmosis, and 18 (46.1%) with congenital syphilis. The three cases of ZIKV showed calcification in brain imaging tests, signs of arthrogryposis, excess occipital skin and irritability, characterizing the typical phenotype of ZIKV infection. Conclusions: Most cases of congenital infection had severe neurological lesions, particularly the cases of ZIKV, which can cause neurodevelopmental delays and sequelae in these infants throughout early childhood.

Establishing tools for early diagnosis of congenital toxoplasmosis: Flow cytometric IgG avidity assay as a confirmatory test for neonatal screening.

The aim of this study was to evaluate the performance of conventional serology (Q-Preven™ and ELFAVIDAS™) and flow cytometry-based serologic tools for early serologic diagnosis of congenital toxoplasmosis. The study groups included prospectively confirmed cases of congenital toxoplasmosis (TOXO=88) and age-matching non-infected controls (NI=15).The results demonstrated that all samples tested positive/indeterminate for anti-T. gondii IgM screening at birth using air-dried whole blood samples. Serum samples collected at 30-45days after birth tested positive for ELFAVIDAS™ IgG in both groups. While all NI tested negative for ELFAVIDAS™ IgM and IgA, only 78% and 36% of TOXO tested positive for IgM and IgA, respectively. Flow cytometry-based anti-T. gondii IgM, IgA and IgG reactivity displayed moderate performance with low sensitivity (47.6%, 72.6% and 75.0%, respectively). Regardless the remarkable specificity of IgG1, IgG2 and IgG3 subclasses for early diagnosis, weak or moderate specificity was observed (Se=73.9%, 60.2% and 83.0%, respectively). The analysis of IgG avidity indices (AI) demonstrated the highest performance among the flow cytometry-based methods (Se=96.6%; Sp=93.3%), underscoring the low avidity index (AI<60%) within TOXO (97.0%) in contrast with the high avidity index (AI>60%) in NI (93%). Analysis of anti-T. gondii IgG and IgG3 reactivity for mother:infant paired samples may represent a relevant complementary tests for early diagnosis. In conclusion, a feasible high-standard algorithm (Accuracy=97.1%) was proposed consisting of Q-Preven™ IgM screening at birth, followed by ELFAVIDAS™ IgM and flow cytometric IgG avidity analysis at 30-45days after birth as a high performance tool for early serological diagnosis of congenital toxoplasmosis.

Congenital toxoplasmosis and prenatal care state programs.

BACKGROUND: Control programs have been executed in an attempt to reduce vertical transmission and the severity of congenital infection in regions with a high incidence of toxoplasmosis in pregnant women. We aimed to evaluate whether treatment of pregnant women with spiramycin associated with a lack of monitoring for toxoplasmosis seroconversion affects the prognosis of patients. METHODS: We performed a prospective cohort study with 246 newborns (NB) at risk for congenital toxoplasmosis in Goiânia (Brazil) between October 2003 and October 2011. We analyzed the efficacy of maternal treatment with spiramycin. RESULTS: A total of 40.7% (66/162) of the neonates were born seriously infected. Vertical transmission associated with reactivation during pregnancy occurred in 5.5% (9/162) of the NB, with one showing severe infection (systemic). The presence of specific immunoglobulins (fetal IgM and NB IgA) suggested the worst prognosis. Treatment of pregnant women by spiramycin resulted in reduced vertical transmission. When infected pregnant women did not undergo proper treatment, the risk of severe infection (neural-optical) in NB was significantly increased. Fetal IgM was associated with ocular impairment in 48.0% (12/25) of the fetuses and neonatal IgA-specific was related to the neuro-ophthalmologic and systemic forms of the disease. When acute toxoplasmosis was identified in the postpartum period, a lack of monitoring of seronegative pregnant women resulted in a higher risk of severe congenital infection. CONCLUSION: Treatment of pregnant women with spiramycin reduces the possibility of transmission of infection to the fetus. However, a lack of proper treatment is associated with the onset of the neural-optical form of congenital infection. Primary preventive measures should be increased for all pregnant women during the prenatal period and secondary prophylaxis through surveillance of seroconversion in seronegative pregnant woman should be introduced to reduce the severity of congenital infection in the environment.

Prevalence of congenital toxoplasmosis among a series of Turkish women.

BACKGROUND: Toxoplasma gondii infection during pregnancy causes congenital malformations. Pregnant women should be screened for this infection since it is preventable and treatable. AIM: To study the sero prevalence of Toxoplasma gondii infection among pregnant women living in lzmir, Turkey. MATERIAL AND METHODS: A blood sample was obtained from 4651 women aged between 15 and 45 years, during their first trimester of pregnancy. IgM and IgG antibodies against Toxoplasma gondii were measured using an ELISA assay. Among women with both IgG and IgM antibodies positive, an IgG avidity test was performed, using a VIDAS kit. RESULTS: IgG antibodies were positive in 1871 (39.9%) participants. Of these, 48 (2.5%) also had positive IgM antibodies. In 41 of these 48 women, the IgG avidity test was performed and only one woman had a low avidity. This woman was treated with Spiramycin. Her offspring had an intrauterine growth retardation and oligohydramnios. A chorioretinitis was diagnosed in the offspring of other woman with both antibodies positive. CONCLUSIONS: In this series, the prevalence of congenital toxoplasmosis was low. However, women with positive antibodies against Toxoplasma Gondii should be further studied and followed during their pregnancy.

Prevalence of congenital toxoplasmosis among a series of Turkish women / Prevalencia de toxoplasmosis congénita en una serie de mujeres en Turquía

Background: Toxoplasma gondii infection during pregnancy causes congenital malformations. Pregnant women should be screened for this infection since it is preventable and treatable. Aim: To study the sero prevalence of Toxoplasma gondii infection among pregnant women living in lzmir, Turkey. Material and Methods: A blood sample was obtained from 4651 women aged between 15 and 45years, during their first trimester of pregnancy. IgM and IgG antibodies against Toxoplasma gondii were measured using an ELISA assay. Among women with both IgG and IgM antibodies positive, an IgG avidity test was performed, using a VIDAS kit. Results: IgG antibodies were positive in 1871 (39.9%) participants. Of these, 48 (2.5%) also had positive IgM antibodies. In 41 ofthese 48 women, the IgG avidity test was performed and only one woman had a low avidity. This woman was treated with Spiramycin. Her offspring had an intrauterine growth retardation and oligohydramnios. A chorioretinitis was diagnosed in the offspring of other woman with both antibodies positive. Conclusions: In this series, the prevalence of congenital toxoplasmosis was low. However, women with positive antibodies against Toxoplasma Gondii should be further studied and followed during their pregnancy.

Antecedentes: La infección por Toxoplasma gondii durante el embarazo causa malformaciones congénitas. Se debe efectuar serologíapara esta infección en mujeres embarazadas ya que es prevenible y tratable. Objetivo: Estudiar la seroprevalencia de infección por Toxoplasma gondii en mujeres embarazadas que viven en Esmirna, Turquía. Material y Métodos: Se obtuvo una muestra de sangre en 4.651 mujeres cuyas edades fluctuaban entre 15 y 45, años, durante su primer trimestre de embarazo. Los anticuerpos IgM e IgG en contra de Toxoplasma gondii se midieron por ELISA. En mujeres que tenían anticuerpos IgG e IgM positivos, un ensayo de avidez de IgG se efectuó utilizando el kit VIDAS. Resultados: Los anticuerpos IgG fueron positivos en 1.871 participantes (39,9%). De estas, 48 (2,5%) también tenían anticuerpos IgM positivos. En 41 de estas 48 mujeres, se efectuó el test de avidez y sólo una tenía una baja avidez. Esta mujer se trató con espiramicina y su producto de concepción tuvo un retardo de crecimiento intrauterino y un oligohidroamnios. Una corioretinitis se diagnosticó en el producto de concepción de otra mujer con ambos anticuerpos positivos. Conclusiones: La seroprevalencia de toxoplasmosis congénita en esta serie de pacientes fue baja, sin embargo, las mujeres con anticuerpos positivos deben ser tratadas y seguidas.

Association between IgG subclasses against Toxoplasma gondii and clinical signs in newborns with congenital toxoplasmosis.

BACKGROUND: The aim of this study was to evaluate the association between clinical signs of congenital toxoplasmosis and IgG subclasses found in newborns participating in the Minas Gerais State Neonatal Screening Program. METHODS: Neonates with confirmed congenital toxoplasmosis underwent standardized ophthalmologic evaluation, neuroimaging studies and hearing assessment, as well as enzyme-linked immunosorbent assay testing for total IgG and its subclasses (IgG1, IgG2, IgG3 and IgG4) against soluble (STAg) and recombinant (rSAG1 and rMIC3) antigens of Toxoplasma gondii. RESULTS: Newborns with congenital toxoplasmosis but without ocular lesions were more likely to present anti-rMIC3 total IgG when compared with those newborns with active or cicatricial retinochoroidal lesions. Detection of anti-rMIC3 IgG2 and IgG4 was associated with presence of retinochoroidal lesions and intracranial calcifications, with higher mean reactivity index values than unaffected newborns with congenital toxoplasmosis. Anti-STAg IgG3 was associated with newborns without neurologic damage. CONCLUSIONS: Specific subclasses of IgG antibodies reacting with recombinant antigens of T. gondii may serve as biomarkers of neurologic and ocular changes in newborns with congenital toxoplasmosis.

Seroprevalence of Toxoplasma infection among pregnant women in Bahia, Brazil.

Infection by Toxoplasma gondii represents a risk to fetal development during pregnancy. In this study, the serological profile of pregnant women from different regions of Bahia, Brazil, was determined. Tests were conducted at LACEN-BA (Salvador, Brazil). The mean age of the women was 24.5 years (±7.41 years) and 56.4% were positive for IgG and negative for IgM specific for T. gondii. Seronegative women represented 35.9% of the total (IgG- and IgM-negative) and inconclusive results comprised 4%. Differences were observed in distinct regions. Therefore, a preventive action must be reinforced in specific regions aimed at early diagnosis to minimise the risk of congenital toxoplasmosis development.

[Serologic profile of toxoplasmosis in pregnant women attended at a teaching-hospital in Recife]. / Perfil sorológico para toxoplasmose em gestantes atendidas em maternidade.

OBJECTIVES: To determine the serologic profile of toxoplasmosis and the main factors associated with susceptibility (patients without IgM and IgG antibodies) in pregnant women attended at a teaching-hospital in Recife, Brasil. METHODS: A cross-sectional study was carried out, enrolling 503 pregnant women submitted to serology for toxoplasmosis at IMIP (Recife) from October 2004 to April 2005. Anti-Toxoplasma IgG and IgM antibodies were studied by IFA. A short questionnaire was administered to patients to provide identification, demographic and obstetrical characteristics, past history of morbidity, habits and dwelling conditions. The chi-square and Fisher-exact tests were used at a 5% level of significance. RESULTS: Immunity for toxoplasmosis was present in 74.7%, susceptibility in 22.5% and "possible" active infection in 2.8% of patients. No significant associations were observed between toxoplasmosis susceptibility and age, location, conditions of morbidity, habits, dwelling conditions and sewage system, living with animals, pregnancy and gestational age. A significant association between toxoplasmosis susceptibility and schooling was found, with a higher frequency of susceptibility among women with eight or more years of schooling. CONCLUSION: Susceptibility for toxoplasmosis was relatively low in these prenatal patients and schooling was the only identifiable predictive factor.

Perfil sorológico para toxoplasmose em gestantes atendidas em maternidade / Serologic profile of toxoplasmosis in pregnant women attended at a teaching-hospital in Recife

OBJETIVOS: Determinar o perfil sorológico para toxoplasmose e identificar os principais fatores associados à susceptibilidade (pacientes com imunoglobulinas IgG e IgM ausentes) em gestantes atendidas em uma maternidade-escola do Recife. MÉTODOS: Realizou-se um estudo de corte transversal, incluindo 503 gestantes submetidas à sorologia para toxoplasmose no IMIP (Recife), no período de outubro de 2004 a abril de 2005. Realizou-se imunofluorescência indireta para pesquisa de IgG e IgM e um breve questionário foi aplicado às pacientes, descrevendo-se identificação, características demográficas e obstétricas, antecedentes mórbidos relevantes, hábitos de vida e tipo de moradia. Para análise estatística, utilizaram-se os testes Qui quadrado de associação e exato de Fisher, com um nível de significância de 5 por cento. RESULTADOS: Constatou-se imunidade para toxoplasmose em 74,7 por cento, susceptibilidade em 22,5 por cento e "possível" infecção ativa em 2,8 por cento das gestantes. Não se encontrou associação estatisticamente significativa entre susceptibilidade para toxoplasmose e idade, procedência, condições mórbidas, hábitos, condições de habitação, rede de esgotos, criação de animais domésticos, número de gestações e idade gestacional. Verificou-se uma associação significativa entre susceptibilidade para toxoplasmose e escolaridade, com uma maior freqüência de susceptibilidade entre mulheres com oito ou mais anos de estudo. CONCLUSÃO: A freqüência de susceptibilidade para toxoplasmose é relativamente baixa entre pacientes atendidas no pré-natal em nosso meio e nenhum outro fator preditivo além da escolaridade foi identificado.

OBJECTIVES: To determine the serologic profile of toxoplasmosis and the main factors associated with susceptibility (patients without IgM and IgG antibodies) in pregnant women attended at a teaching-hospital in Recife, Brasil. METHODS: A cross-sectional study was carried out, enrolling 503 pregnant women submitted to serology for toxoplasmosis at IMIP (Recife) from October 2004 to April 2005. Anti-Toxoplasma IgG and IgM antibodies were studied by IFA. A short questionnaire was administered to patients to provide identification, demographic and obstetrical characteristics, past history of morbidity, habits and dwelling conditions. The chi-square and Fisher-exact tests were used at a 5 percent level of significance. RESULTS: Immunity for toxoplasmosis was present in 74.7 percent, susceptibility in 22.5 percent and "possible" active infection in 2.8 percent of patients. No significant associations were observed between toxoplasmosis susceptibility and age, location, conditions of morbidity, habits, dwelling conditions and sewage system, living with animals, pregnancy and gestational age. A significant association between toxoplasmosis susceptibility and schooling was found, with a higher frequency of susceptibility among women with eight or more years of schooling. CONCLUSION: Susceptibility for toxoplasmosis was relatively low in these prenatal patients and schooling was the only identifiable predictive factor.

Construções e redefinições: as toxoplasmoses / Constructions and redefinitions: the toxoplasmosis

Esta tese tem como objeto o processo de redefinição da categoria diagnóstica infecção/doença Toxoplasmose. É um estudo qualitativo, inserido no campo science studies, de abordagem crítica reformista e de natureza empírico-analítica. Vincula-se à linha de pesquisa intitulada Instituições, saberes e práticas em saúde e ao projeto Os médicos e a ciência do Instituto de Medicina Social da Universidade do Estado do Rio de Janeiro. As unidades de análise foram: 1) Agentes envolvidos na produção do conhecimento científico em nível local; 2) Documentos normativos locais; 3) Documentos normativos nacionais e internacionais; 4) Instituição: Laboratório Reconhecer do Centro de Biociências e Biotecnologia (CBB), da Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF/Darcy Ribeiro). Como técnicas de pesquisa foram utilizadas a observação etnográfica, entrevistas e pesquisa documental da produção científica. Os pressupostos foram de que essa redefinição seja decorrente de uma construção (Hacking, 1999; Latour, 1997, 2000, 2001) e realizada em uma arena transepistêmica (Knor-Cetina, 1981). Foram acrescidos a esses conceitos, os de referência circulante (Latour, 2001) e os da taxonomia dos elementos dos objetos da ciência laboratorial, ou seja, os conceitos idéias, marcas e coisas (Hacking,1992). Considerando essa dinâmica, as redefinições em relação a essa infecção/doença estariam em um período de pouca estabilização, embora elas não se definiriam completa e eternamente pela dependência que possuem do invólucro espaço-temporal (Latour, 2001) e da referência circulante.

This thesis has as object the process of redefinition of the disgnostic categoryinfection/illness "Toxoplasmosis". It is a qualitative, inserted study in the field "science studies", of reformist critical boarding and empiricist- analytical nature. The line of intitledresearch is associated to it "Institutions, to know and practical in health" and to the project "the doctors and the science" of the Institute of Social Medicine of the University of the Stateof Rio De Janeiro. The units of analysis had been: 1) "involved Agents" in the production of the scientific knowledge in local level; 2) local normative Documents; 3) national and international normative Documents; 4) Institution: Laboratory To recognize of the Center of Biosciences and Biotechnology (CBB), of the State University of the Of the state of Rio deJaneiro North Darcy Ribeir (UENF/Darcy Ribeiro). As research techniques had been used the etnografic observation, interviews and documentary research of scientific production. The estimated ones had been of that this redefinition is decurrent of a "construction" (Hacking,1999; Latour, 1997, 2000, 2001) and carried through in a "transepistemic arenas" (Knor-Cetina, 1981). They had been increased to these concepts, of “circulating reference” (Latour, 2001) and of the taxonomy of the elements of objects of laboratorial science, that is, the concepts "ideas", “marks” and “things” (Hacking, 1992). Considering this dynamics, the redefinitions in relation to this infection/illness would be in a period of little stabilization, even so they are not defined completely and perpetual for the dependence that possess of the "pack space-weather" (Latour, 2001) and of the "circulating reference".

Congenital toxoplasmosis in two health institutions in Trinidad.

Toxoplasmosis is the most widespread zoonosis and an important human disease particularly in children where it could cause visual and neurological impairment and mental retardation. This study was conducted to determine the prevalence of toxoplasmosis, especially congenital toxoplasmosis in patients at two health institutions in Trinidad A total of 504 cord blood samples of newborn babies were collected: 174 from a women's hospital and 330 from a general hospital. In order to elicit aternal and prenatal risk factors for toxoplasmosis, mothers of the newborns completed a questionnaire. Enzyme-immuno assay (EIA) was used to detect IgG and IgM to Toxoplasma gondii. Overall, of 504 serum samples tested, 220 (43.7%) were seropositive for IgG while the prevalence of congenital toxoplasmosis as reflected by IgM was 0.4%. The prevalence of IgG and IgM by health institutions was not significantly different (p > 0.05; chi-square). The prevalence of toxoplasmosis using IgG was highest in neonates of mothers who were of East Indian descent (54.1%), had four children (52.9%), kept cats in households (47.7%), practised outdoor gardening (50.8%), consumed raw meat (66.7%), had experienced miscarriage(s) (47.3%), stillbirths (66.7%), or who had eye problem(s) (52.9%) and mental retardation (50.0%). The study prevalence of congenital toxoplasmosis revealed a high seroprevalence oftoxoplasmosis in neonates but there was 0.4% serological evidence of congenital disease. It indicates a need for sensitization of the population and healthcare workers and for follow-up of infected children for clinical evidence of the disease. This would be necessary to fully appreciate the impact of toxoplasmosis in Trinidad and Tobago. The differences from comparison groups were however not statistically significant (p > 0.05; chi-square).

Congenital toxoplasmosis in two health institutions in Trinidad / Toxoplasmosis congénita en dos centros de salud de Trinidad

Toxoplasmosis is the most widespread zoonosis and an important human disease particularly in children where it could cause visual and neurological impairment and mental retardation. This study was conducted to determine the prevalence of toxoplasmosis, especially congenital toxoplasmosis in patients at two health institutions in Trinidad A total of 504 cord blood samples of newborn babies were collected: 174 from a women's hospital and 330 from a general hospital. In order to elicit aternal and prenatal risk factors for toxoplasmosis, mothers of the newborns completed a questionnaire. Enzyme-immuno assay (EIA) was used to detect IgG and IgM to Toxoplasma gondii. Overall, of 504 serum samples tested, 220 (43.7%) were seropositive for IgG while the prevalence of congenital toxoplasmosis as reflected by IgM was 0.4%. The prevalence of IgG and IgM by health institutions was not significantly different (p > 0.05; chi-square). The prevalence of toxoplasmosis using IgG was highest in neonates of mothers who were of East Indian descent (54.1%), had four children (52.9%), kept cats in households (47.7%), practised outdoor gardening (50.8%), consumed raw meat (66.7%), had experienced miscarriage(s) (47.3%), stillbirths (66.7%), or who had eye problem(s) (52.9%) and mental retardation (50.0%). The study prevalence of congenital toxoplasmosis revealed a high seroprevalence oftoxoplasmosis in neonates but there was 0.4% serological evidence of congenital disease. It indicates a need for sensitization of the population and healthcare workers and for follow-up of infected children for clinical evidence of the disease. This would be necessary to fully appreciate the impact of toxoplasmosis in Trinidad and Tobago. The differences from comparison groups were however not statistically significant (p > 0.05; chi-square).

La toxoplasmosis es la zoonosis más extendida y una enfermedad humana importante, particularmente en niños, a quienes puede causar daño visual y neurológico, y retraso mental. Este estudio se llevó a cabo con el propósito de determinar la prevalencia de la toxoplasmosis, especialmente la toxoplasmosis congénita en pacientes de dos centros de salud en Trinidad. Se recogieron un total de 504 muestras de sangre de cordón umbilical de neonatos: 174 de mujeres en un hospital de mujeres y 330 en un hospital general. A fin de obtener información sobre los factores de riesgo maternos y prenatales en relación con la toxoplasmosis, las madres de los recién nacidos llenaron una encuesta. Un ensayo inmunoenzimático (EIE) fue usado para detectar anticuerpos IgG e IgM contra el Toxoplasma gondii. En general, de 504 muestras de suero examinadas, 220 (43.7%) resultaron seropositivas al IgG, mientras que la prevalencia de la toxoplasmosis congénita reflejada por el IgM fue 0.4%. La prevalencia de IgG e IgM por parte de las instituciones de salud no fue significativamente diferente (p > 0.05; chi-cuadrado). La prevalencia de la toxoplasmosis usando IgG fue más alta en los neonatos cuyas madres eran ascendencia indoriental (54.1%), tenían cuatro niños (52.9%), mantenían gatos en sus casas (47.7%), practicaban jardinería al aire libre (50.8%), consumían carne cruda (66.7%), habían tenido aborto(s) (47.3%), partos de feto muerto (66.7%), o tenían problema(s) de los ojos (52.9%) y retardo mental (50.0%). Este estudio de la toxoplasmosis congénita, reveló una alta seroprevalencia de toxoplasmosis en neonatos, pero hubo 0.4% de evidencia serológica de enfermedad congénita. Esto apunta a la necesidad de sensibilizar a la población y a los trabajadores del cuidado de la salud, e igualmente indica la necesidad de realizar seguimientos a los niños infectados, en busca de evidencia clínica de la enfermedad. Esto es necesario si se quiera valorar totalmente el impacto de la...

Clinical validation of a western blot assay for congenital toxoplasmosis and newborn screening in a hospital in Armenia (Quindio) Colombia.

Congenital Toxoplasma infection can only be discovered or prevented by the appropriate serological screening and subsequent treatment of the mother and her offspring. In Colombia, there is no obligatory Toxoplasma screening for pregnant women and both the reporting and follow-up of congenital toxoplasmosis cases is limited, thereby is a public health problem that have no been addressed by health authorities. The aim of this study was to investigate the occurrence of congenital toxoplasmosis in a public hospital from Armenia, Colombia. A total of 200 serum samples of cord blood were collected. We applied a western blot assay (ID Blot DPC Diagnostics, US) for Toxoplasma IgG, IgM and IgA antibodies that was validated in a cohort of children with confirmed presence or absence of congenital infection. The sensitivity of western blot assay was 91 per cent and the specificity was 100 per cent. In the cord blood samples, we found one infected child that died at day 4 of life and his infection was confirmed by PCR of the B1 specific Toxoplasma gene on brain biopsy. This results show a high prevalence (0.5 per cent, IC95 per cent 0.2-0.8) of Toxoplasma infection in Colombian newborns. Thus, we recommend additional studies to determine the cost-effectiveness of a newborn screening program for congenital toxoplasmosis in other settings in Colombia.

Incidence of congenital toxoplasmosis estimated by neonatal screening: relevance of diagnostic confirmation in asymptomatic newborn infants.

Congenital toxoplasmosis is rarely identified by routine clinical examination. The aim of this study was to estimate the incidence of the disease in the region of Ribeirão Preto, south-eastern Brazil. A definitive diagnosis was made on the basis of the persistence of anti-Toxoplasma IgG antibodies beyond 1 year of age. Blood samples obtained from 15,162 neonates and adsorbed onto filter paper were tested for anti-Toxoplasma IgM antibodies. Fifteen samples gave positive results. A definitive diagnosis was confirmed in five of the 13 infants (38.5%) who completed follow-up. These five infants presented with serum IgM and/or IgA antibodies, and clinical abnormalities. Disease incidence was estimated to be 3.3/10,000 (95% CI 1.0-7.7), indicating the need for preventive measures. Neonatal screening is feasible, but screening tests with a better performance are required; positive screening results must be carefully confirmed.

[Molecular and biological characterization of the CIBMUQ/HDC strain, a reference strain for Colombian Toxoplasma gondii]. / Caracterización biológica y molecular del aislamiento CIBMUQ/HDC, una cepa colombiana de referencia para Toxoplasma gondii.

There are few reports about characterization strains of Toxoplasma gondii that analyze the differences between isolates from Europe or United States with those obtained in South America. The current study analyzes virulence data from the mouse model, the gene SAG2 polymorphism by PCR-RFLP and microsatellite analysis in a single Colombian isolate. The strain was isolated from blood of a child with congenital toxoplasmosis, living in Armenia, Colombia. Analysis of virulence in the mouse showed that this strain has an LD100 of 10 tachyzoites. Both methods of genetic characterization demonstrated that this strain belonged to the clonal type 1 and was called HOM/CTCO/2002/CIBMUQ/BL/HDC (brief name: CIBMUQ/HDC). The CIBMUQ/HDC strain is the first Colombian strain available as a reference strain for national and international researchers.

Newborn screening for congenital infectious diseases.

To estimate the prevalence of congenital toxoplasmosis, Chagas disease, cytomegalovirus, and rubella, blood samples on dried blood spot (DBS) from neonates (day 3-20 of life) were screened for immunoglobulin (Ig) M against Toxoplasma gondii, cytomegalovirus, rubella virus, and IgG against Trypanosoma cruzi by methods used for serum and adapted for use with DBS. Positive samples were further analyzed for IgM and IgG in serum from neonates and mothers. DBS samples from 364,130 neonates were tested for Toxoplasma gondii-specific IgM, and 15,873 neonates were also tested for IgM against cytomegalovirus and rubella virus and for Trypanosoma cruzi-specific IgG. A total of 195 were diagnosed with congenital toxoplasmosis, 16 with cytomegalovirus, and 11 with congenital rubella. One newborn had a confirmed result for Chagas disease, and 21 mothers had positive serum antibodies. These results suggest that infectious diseases should be considered for future inclusion in programs for newborn screening of metabolic diseases in disease-endemic areas.