Toxoplasmosis congénita: Diagnóstico serológico, RPC, aislamiento y caracterización molecular de Toxoplasma gondii / Congenital toxoplasmosis: Serology, PCR, parasite isolation and molecular characterization of Toxoplasma gondii

Resumen Introducción El diagnóstico de toxoplasmosis congénita (TC) en el recién nacido es muy importante porque debe recibir tratamiento siempre, sintomático o no, para evitar o aminorar las secuelas de la enfermedad. Objetivo Evaluación comparativa de los métodos disponibles en la institución para el diagnóstico de TC. Materiales y Métodos Se evaluaron métodos diagnósticos en 67 niños cuyas madres cursaron toxoplasmosis aguda durante el embarazo. Se utilizó la técnica de Sabin Feldman para IgG al nacimiento y durante el seguimiento serológico hasta el año de vida. Para determinar IgM, IgA e IgE se utilizó la técnica immunosorbent agglutination assay (ISAGA). El diagnóstico directo se realizó por reacción de polimerasa en cadena (RPC), aislamiento y caracterización molecular del parásito. Resultados La sensibilidad (S) de ISAGA IgM fue 87%, ISAGA IgA 91% y la especificidad (E) fue 100% para ambas; cuando se realizaron en conjunto, la S aumentó a 98%. La detección de IgE contribuyó al diagnóstico cuando se la detectó sólo en la sangre del neonato y no en sangre materna. Se aisló el parásito en cuatro casos de TC, uno fue genotipo II y los otros tres, genotipos "atípicos". La S del aislamiento fue 80% y la E 100%. Conclusión Los métodos serológicos utilizados mostraron una buena eficacia diagnóstica. Un caso fue detectado sólo por el aislamiento y la caracterización molecular tiene gran valor epidemiológico.

Background. Congenital toxoplasmosis diagnosis in the newborn is a very important issue due to the need for early treatment to prevent future sequels. Aim To compare available methods at the institution for the diagnosis of congenital toxoplasmosis. Material and Methods In this study we have evaluated the different diagnostic tests used in 67 congenital exposed newborns, including serological tests, PCR, parasite isolation and molecular characterization. Results The ISAGA IgM and IgA tests showed sensitivity (Se) of 87 and 91%, respectively, and specificity (Sp) of 100%. When ISAGA IgM and IgA were performed simultaneously, the Se increased to 98% and the Sp was 100%. The presence of IgE contributed to the diagnosis when it was detected in the child's serum but not in maternal blood. In four congenital infected children the parasite was isolated and genotyped: one was genotype II and the other three were "atypical" genotypes. No parasite was isolated in children without congenital toxoplasmosis. Discussion Overall, serological tests showed a good diagnostic performance although in one case they were all negative and isolation was the only tool to identify the infection. We conclude that it is essential to use all diagnostic tests in every single exposed child, including if possible, molecular characterization due to its epidemiological implication.

Evaluation of the Western blotting method for the diagnosis of congenital toxoplasmosis / Avaliação do método Western Blotting para diagnóstico de toxoplasmose congênita

Abstract Objective: To evaluate the Western blotting method for the detection of IgG anti-Toxoplasma gondii (T. gondii) (IgG-WB) in the serum of children with suspected congenital toxoplasmosis. Methods: We accompanied 47 mothers with acquired toxoplasmosis in pregnancy and their children, between June of 2011 and June of 2014. The IgG-WB was done in house and the test was considered positive if the child had antibodies that recognized at least one band on IgG blots different from the mother's or with greater intensity than the corresponding maternal band, during the first three months of life. Results: 15 children (15.1%) met the criteria for congenital toxoplasmosis and 32 (32.3%) had the diagnosis excluded. The symptoms were observed in 12 (80.0%) children and the most frequent were cerebral calcification in 9 (60.0%), chorioretinitis in 8 (53.3%), and hydrocephalus in 4 (26.6%). IgM antibodies anti-T. gondii detected by chemiluminescence (CL) were found in 6 (40.0%) children and the polymerase chain reaction (PCR) for detection of T. gondii DNA was positive in 5 of 7 performed (71.4%). The sensitivity of IgG-WB was of 60.0% [95% confidence interval (CI) 32.3-83.7%] and specificity 43.7% (95% CI 26.7-62.3%). The sensitivity of IgG-WB increased to 76.0 and 89.1% when associated to the research of IgM anti-T. gondii or PCR, respectively. Conclusions: The IgG-WB showed greater sensitivity than the detection of IgM anti-T. gondii; therefore, it can be used for the diagnosis of congenital toxoplasmosis in association with other congenital infection markers.

Resumo Objetivo: Avaliar o método Western Blotting para detecção de IgG anti-Toxoplasma gondii (T. gondii) (IgG-WB) no soro de crianças com suspeita de toxoplasmose congênita. Métodos: Acompanhamos 47 mães com toxoplasmose adquirida na gravidez e seus filhos, entre junho de 2011 e junho de 2014. O IgG-WB foi feito internamente e o teste foi considerado positivo quando a criança apresentava anticorpos que reconheciam pelo menos uma banda nas manchas de IgG diferente das bandas da mãe ou com maior intensidade do que a banda materna correspondente, durante os primeiros 3 meses de vida. Resultados: Atenderam aos critérios para diagnóstico de toxoplasmose congênita 15 crianças (15,1%) e 32 (32,3%) tiveram o diagnóstico excluído. Os sintomas foram observados em 12 crianças (80%) e os mais frequentes foram calcificação cerebral em nove (60%), coriorretinite em oito (53,3%) e hidrocefalia em quatro (26,6%). Os anticorpos IgM anti-T. gondii detectados por quimiluminescência (QL) foram encontrados em seis crianças (40%) e a reação em cadeia da polimerase (RCP) para detecção do DNA de T. gondii foi positiva em cinco de sete reações (71,4%). A sensibilidade do IgG-WB foi de 60% [intervalo de confiança (IC) de 95%, 32,3 a 83,7%] e a especificidade foi de 43,7% (IC de 95%, 26,7 a 62,3%). A sensibilidade do IgG-WB aumentou para 76 e 89,1% quando relacionada à pesquisa de IgM anti-T. gondii ou à RCP, respectivamente. Conclusões: O IgG-WB mostrou maior sensibilidade do que a detecção de IgM anti-T. gondii; portanto, pode ser usado para o diagnóstico de toxoplasmose congênita em associação com outros marcadores de infecção congênita.

Presence and duration of anti-Toxoplasma gondii immunoglobulin M in infants with congenital toxoplasmosis / Presença e duração da imunoglobulina M anti-Toxoplasma gondii em lactentes com toxoplasmose congênita

OBJECTIVES: to investigate the rate of positivity for immunoglobulin M anti-Toxoplasma gondii (Toxo-IgM) in newborns with congenital toxoplasmosis, and the age when these antibodies become negative. METHODS: patients with congenital toxoplasmosis who started monitoring in a congenital infection clinic between 1998 and 2009 were included. Inclusion criteria were routine maternal or neonatal serological screening; diagnostic confirmation by persistence of immunoglobulin G anti-Toxoplasma gondii at age > 12 months, and Toxo-IgM screening in the neonatal period. To calculate the frequency of positive Toxo-IgM, cases detected by neonatal screening were excluded. For the study of the age when Toxo-IgM results became negative, patients with negative Toxo-IgM since birth and those in whom it was not possible to identify the month when the negative result was achieved were excluded. RESULTS: among the 28 patients identified through maternal screening, 23 newborns had positive Toxo-IgM (82.1%, 95% CI: 64.7-93.1%). When adding the 37 patients identified by neonatal screening, Toxo-IgM was positive in the first month of life in 60 patients, and it was possible to identify when the result became negative in 51 of them. In 19.6% of patients, these antibodies were already negative at 30 days of life; and in 54.9%, at 90 days. Among the 65 patients included in the study, 40 (61.5%) had some clinical alteration. CONCLUSIONS: even with high sensitivity methods, newborns with congenital toxoplasmosis can have negative Toxo-IgM at birth. In those who have these antibodies, the positive period may be quite short. It is important not to interrupt the monitoring of infants with suspected congenital toxoplasmosis simply because they present a negative Toxo-IgM result. .

OBJETIVOS: investigar a taxa de positividade para imunoglobulina M anti-Toxoplasma gondii (Toxo-IgM) em recém-nascidos com toxoplasmose congênita, e a idade de negativação desses anticorpos. MÉTODOS: foram incluídos pacientes com toxoplasmose congênita que iniciaram acompanhamento em uma clínica de infecções congênitas entre 1998 e 2009. Os critérios de inclusão foram toxoplasmose congênita detectada por triagem sorológica materna ou neonatal de rotina, confirmação diagnóstica por persistência de imunoglobulina G anti-Toxoplasma gondii com >12 meses e pesquisa de Toxo-IgM no período neonatal. Para o cálculo da frequência de positividade da Toxo-IgM foram excluídos os detectados por triagem neonatal. Para o estudo da época de negativação da Toxo-IgM foram excluídos os pacientes com Toxo-IgM negativa desde o nascimento e aqueles em que não foi possível identificar o mês da negativação. RESULTADOS: entre 28 pacientes detectados por triagem materna, 23 recém-nascidos tiveram Toxo-IgM positiva (82,1%, IC 95%: 64,7-93,1%). Somando-se os 37 pacientes detectados por triagem neonatal, a Toxo-IgM foi positiva no primeiro mês de vida em 60 pacientes e em 51 foi possível identificar a época de negativação. Em 19,6% dos pacientes esses anticorpos já eram negativos aos 30 dias e em 54,9% aos 90 dias. Entre os 65 pacientes incluídos no estudo, 40 (61,5%) apresentaram alguma alteração clínica. CONCLUSÕES: mesmo com métodos de alta sensibilidade, recém-nascidos com toxoplasmose congênita podem ter Toxo-IgM negativa ao nascer. Nos que apresentam esses anticorpos, o período de positividade pode ser bastante fugaz. É importante não interromper o monitoramento dos lactentes com suspeita de toxoplasmose ...

Early diagnosis of congenital toxoplasmosis in newborn infants using IgG subclasses against two Toxoplasma gondii recombinant proteins

The aim of this work was to evaluate the utility of ELISA-based testing of total IgG (IgGt) antibodies and its subclasses (IgG1, IgG2, IgG3 and IgG4) against soluble (STAg) and recombinant (rSAG1 and rMIC3) antigens of Toxoplasma gondii for diagnosing congenital toxoplasmosis. Sera from 217 newborns initially testing positive for specific IgM in filter paper dried blood spots were tested for specific IgM and IgG by ELFA-VIDAS®. Congenital toxoplasmosis was confirmed in 175 and ruled out in 42 infants. The validity of the ELISA tests was determined using the persistence of IgG antibodies (ELFA-VIDAS® kit) at the end of 12 months, which is considered the reference test for the diagnosis of congenital toxoplasmosis. The frequency of positivity with IgGt against STAg, rSAG1 and rMIC3 was found in 97.2%, 96.3% and 80.2%, respectively, of the newborns with confirmed congenital toxoplasmosis. IgG1 reacted with all three antigens, while IgG3 and IgG4 reacted preferentially with rMIC3. Higher mean values of reactivity (sample optical density/cut-off) were found for all subclasses when using rMIC3. All of the antigens showed high sensitivity and low specificity in detecting anti-T. gondii IgGt and IgG1 and low sensitivity and high specificity in detecting IgG3 and IgG4. In conclusion, the combined detection of IgG antibody subclasses against recombinant toxoplasmic antigens may be useful for the early diagnosis of congenital toxoplasmosis.

Toxoplasma gondii antibody profile in HIV-1-infected and uninfected pregnant women and the impact on congenital toxoplasmosis diagnosis in Rio de Janeiro, Brazil

OBJECTIVE: Compare the anti-T. gondii IgG titer between HIV-1 infected and non HIV-1 infected pregnant women and report three cases of congenital toxoplasmosis resulting from reactivation of infection during pregnancy of HIV-1 infected women. METHODS: This study was conducted among 2,270 pregnant women with chronic Toxoplasma gondii infection (absence of IgM and presence of IgG), including 82 HIV-1 infected and 2,188 non-infected women. RESULTS: The average anti-T. gondii IgG titer was 127 for the 2,188 non-HIV-1 infected women, and 227 for the 82 HIV-1-infected women (p = 0,007). These results suggested that higher anti-T. gondii IgG titers in HIV-1-infected pregnant women may not be indicative of an elevated risk for fetal infection. In this study three cases of congenital toxoplasmosis that resulted from infection reactivation during pregnancy of HIV-1-infected women were manifested by fetal death, symptomatic infection, and infant without symptoms, respectively. In two of these women, a ten-fold increase in IgG levels above used cutoff was observed (2,320 UI/mL and 3,613 UI/mL, respectively). In the third pregnant women anti-T. gondii IgG titers during pregnancy did not rise despite the occurrence of congenital toxoplasmosis (204; 198; 172 UI/mL). CONCLUSIONS: Congenital toxoplasmosis resulting reactivation of infection during pregnancy in the studied group leads us to believe that it is a public health problem, especially in our population, in which seroprevalence of T. gondii infections is high. These findings also suggest that special attention is necessary during pregnancy, because the serologic diagnosis may not be indicative of toxoplasmosis reactivation.

Rastreamento das infecções perinatais na gravidez: realizar ou não? / Perinatal infections screening during pregnancy: perform it or not?

Devido à conhecida importância das infecções adquiridas intraútero, vários serviços médicos em todo o mundo preconizam o rastreio das doenças passíveis de transmissão vertical. Entretanto, há muitos questionamentos na literatura a respeito da real relevância, custo-benefício e aplicabilidade do rastreamento. Corrobora essa assertiva a terapêutica ineficiente, a baixa prevalência para algumas dessas afecções e a reduzida confiabilidade e elevado custo de certos testes laboratoriais usados para o rastreamento. Por outro lado, o rastreio e posterior tratamento de algumas infecções resultam na diminuição da morbimortalidade, o que é de extrema relevância, uma vez que reduz sequelas fetais e auxilia na manutenção da saúde das gestantes. Mais estudos são necessários para o estabelecimento de um panorama completo a respeito do rastreamento das infecções perinatais, pois, além dos impasses expostos, é importante considerar as características epidemiológicas de cada população, o que requer pesquisas mais aprofundadas. Esta revisão da literatura teve como objetivo reunir evidências quanto à recomendação ou não do rastreamento destas doenças durante o pré-natal nas diversas entidades de relevância nacional e internacional.

Due to the importance of intrauterine acquired infections, severalguidelines suggest the screening of diseases that can be vertically transmitted. However, there are questionsabout the real relevance, cost-benefit and applicability of this practice. The absence of an efficient treatmentand the small prevalence of some of these disorders combined with the reduced reliability and high costsof some laboratorial tests used for screening, confirm this statement. On the other hand, the possibility oftreatment associated with the screening and the subsequent reduction of morbimortality are a very relevantpoint, once it attenuates fetal sequelae and helps keeping pregnant women health. More studies are needed toestablish a complete picture of the screening of perinatal infections because beyond the impasses presentedabove, it is important to consider the epidemiological characteristics of each population, which requires moreextensive research. This literature review attempted to gather information about the importance of the prenatalscreening of perinatal infections in different and relevant national and international entities.

Evaluation of Anti-Toxoplasma IgG, IgM, and IgA in Mothers with Spontaneous Abortion in Zanjan, Northwest Iran

Toxoplasma gondii is one of the major agents of infectious abortions and due to its worldwide distribution can threat healthy pregnant women who had no previous exposure to this parasite. The present study was designed to investigate the contribution of T. gondii to spontaneous abortions in Zanjan, Northwest of Iran, using ELISA method. Blood Samples were collected from 264 mothers referred to the provincial hospitals of Zanjan due to spontaneous abortion. The sera were isolated and subjected to evaluate the anti-Toxoplasma IgG, IgM and IgA antibodies. The results showed IgG positive (IgG+) in 99 cases (37.5%). A total of 68 women (25.8%) showed seroconversion with IgM or IgA or both IgM and IgA. They included: IgM+ in 21 (8.0%), IgA+ in 23 (8.7%) and both IgM+ and IgA+ in 24 (9.1%) subjects. In 23 cases, positive titers of IgM and IgG were accompanied. In general, the analysis of anti-Toxoplasma antibody patterns, showed that about 17% of the spontaneous abortions were associated with serological patterns of acute infection. According to these findings, a considerable proportion of spontaneous abortions can be attributed to T. gondii in the study area.

Congenital toxoplasmosis: evaluation of serological methods for the detection of anti-Toxoplasma gondii IgM and IgA antibodies

A study was carried out to evaluate the presence of serological markers for the immunodiagnosis of the vertical transmission of toxoplasmosis. We tested the sensitivity, specificity and predictive values (positive and negative) of different serological methods for the early diagnosis of congenital toxoplasmosis. In a prospective longitudinal study, 50 infants with suspected congenital toxoplasmosis were followed up in the ambulatory care centre of Congenital Infections at University Hospital in Goiânia, Goiás, Brazil, from 1 January 2004-30 September 2005. Microparticle Enzyme Immunoassay (MEIA), Enzyme-Linked Fluorescent Assay (ELFA) and Immune-Fluorescent Antibody Technique (IFAT) were used to detect specific IgM anti-Toxoplasma gondii antibodies and a capture ELISA was used to detect specific IgA antibodies. The results showed that 28/50 infants were infected. During the neonatal period, IgM was detected in 39.3 percent (11/28) of those infected infants and IgA was detected in 21.4 percent (6/28). The sensitivity, specificity and predictive values (positive and negative) of each assay were, respectively: MEIA and ELFA: 60.9 percent, 100 percent, 100 percent, 55.0 percent; IFAT: 59.6 percent, 91.7 percent, 93.3 percent, 53.7 percent; IgA capture ELISA: 57.1 percent, 100 percent, 100 percent, 51.2 percent. The presence of specific IgM and IgA antibodies during the neonatal period was not frequent, although it was correlated with the most severe cases of congenital transmission. The results indicate that the absence of congenital disease markers (IgM and IgA) in newborns, even after confirming the absence with several techniques, does not constitute an exclusion criterion for toxoplasmosis.

Estudio multicéntrico para la prevención de la toxoplasmosis prenatal en Buenos Aires / Multicenter study on the prevention of congenital toxoplasmosis in Buenos Aires

La toxoplasmosis es una infección causada por Toxoplasma gondii, parásito intracelular de distribución universal cuya tasa de seroprevalencia varía según la región. En el feto o recién nacido la infección causa morbilidad y mortalidad. El presente trabajo es una evaluación práctica de las propuestas del Consenso Argentino de Prevención de la Toxoplasmosis Prenatal. Participaron 9 hospitales de Buenos Aires y Conurbano donde se atendieron 19825 partos entre el 1º de mayo del 2006 y el 30 de abril del 2007. Se realizaron pruebas de tamizaje serológico en 13632 embarazadas con determinaciones de IgG e IgM por método de ELISA. La prevalencia de anticuerpos IgG específicos anti Toxoplasma gondii fue del 49%. Los sueros clasificados con criterio de infección reciente se remitieron al laboratorio del Hospital Alemán para ampliar el estudio. A los recién nacidos de estas madres se les efectuó control clínico y serológico. El análisis de los resultados de las 351 muestras enviadas confirmó que 121 (32%) pacientes podrían haberse infectado durante el embarazo, en 176 (46%) se descartó la infección reciente, en 37 embarazadas (10%) la serología no fue concluyente y en 47 (12%) faltó la fecha de gestación para su interpretación. Se efectuó control clínico y serológico a 94 recién nacidos de madres con infección durante el embarazo y se detectaron 5 toxoplasmosis congénitas con daño fetal, una microcefalia y cuatro coriorretinitis. El estudio permitió validar las guías y recomendaciones del Consenso Argentino de Toxoplasmosis Congénita.

Toxoplasmosis is an infection caused by Toxoplasma gondii, an intracellular parasite of universal distribution, with a variable prevalence depending on the region. This infection causes both morbidity and mortality in the fetus and newborn. The present study is an evaluation of the Argentine Consensus Guidelines regarding prenatal prevention of toxoplasmosis. Screening tests in pregnant women were done in nine different hospitals within the city of Buenos Aires and surroundings, where 19825 births between May 1st 2006 and April 30th 2007 were registered. Screening tests were done in 13632 pregnant women, using IgG and IgM determinations by ELISA. If acute infection was suspected, the patient‘s serum was sent to the reference laboratory to fulfill the pending tests: Sabin Feldman, ISAGA M, ISAGA A, ISAGA E and avidity. Clinical and serologic evaluation was done to all newborn of these mothers. Three hundred and fifty one specimens were sent and analyzed. Conclusions from the analysis were as follows: 121 (32%) patients probably acquired the infection during pregnancy, in 176 (46%) patients, acute infection was excluded, in 37 women (10%) serologic results were inconclusive, and in 47 (12%) the interpretation of results was impossible due to lack of information on the exact gestational age. Clinical and serologic control was performed in 94 newborns of mothers infected during pregnancy, and 5 congenital toxoplasmosis were detected, with fetal damage, four corioretinitis and one case of microcephaly. This study allowed us to validate the Argentine Consensus of Congenital Toxoplasmosis Guidelines.

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.

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...

Maternal serum IgA as a predictor of congenital toxoplasmosis

Maternal seroconversion for Toxoplasma gondii during pregnancy is said to have a good role for diagnosis of congenital infection. To determine whether maternal serum levels of antibodies against Toxoplasma gondii parasite are associated with definite fetal parasitic infection and consequent pathology or not. Maternal serum IgA levels against toxoplasma gondii were measured in 29 patients with strongly suspected congenital toxoplasmosis [maternal IgM seroconversion with fetal pathology] out of 200 patients with suspected pathology. Their pregnancies were complicated by hydrocephalus [Group I, n=17], hydropes fetalis and other congenital anomalies [Group II, n=6], and fetal loss [Group III, n=6]. They were compared with 17 women with negative IgM and normal pregnancies as a control group [Group IV]. All cases were examined by ultrasonography for obtaining amniotic fluid samples during pregnancy. After termination; if possible; fetal cord serum samples were drawn for measuring the same antibodies. Also, placental imprints, placental samples and umbilical cord samples were prepared for microscopic detection of the parasite. Hydrocephalic cases with or without meningornyelocele were treated by neonatal shunt operations with or without repair. Cases presented by maternal IgM seroconversion against toxoplasma gondii during pregnancy with suspected pathology [hydrocephalus, other anomalies, and abortions] showed significantly higher maternal specific toxoplasma IgA levels than the control group [166.7 +/- 27.2, 165.7 +/- 21.1, and 149.7 +/- 9.1 respectively vs. 127.2 +/- 15.3, p<0.001]. Microscopic parasitic detection was positive in 3/11 [27.3%] in the amniotic fluid and in 1/11 [9.1%] in placental imprints of these cases. Conventional serological neonatal testing for specific toxoplasma IgA revealed sensitivity and specificity of 77.8% and 100% respectively. The combination of the results of conventional serological neonatal testing for specific toxoplasma IgA with the results of parasitic detection [amniotic fluid and placenta] resulted in sensitivity and specificity of 94.4 and 100 respectively. Detection of specific toxoplasma gondii IgA antibody response by ELISA is more reliable than IgM level for diagnosis of congenital toxoplasmosis

Prevalence of congenital cytomegalovirus and Toxoplasma antibodies in Thailand.

Prevalence of CMV and toxoplasmosis antibodies were determined among normal newborn infants, suspected congenital neonates and pregnant women. Seropositive rates of CMV and toxoplasmosis were similar. Most of the pregnant women had CMV antibodies. The in-house ELISA for detection of Toxoplasma antibodies was developed and compared with the commercial kit with sensitivity and specificity of 90.47% and 96.74% respectively.

Lack of evidence for superantigen activity of Toxoplasma gondii towards human T cells

Toxoplasma gondii is an obligatory intracellular parasite whose life cycle may include man as an intermediate host. More than 500 million people are infected with this parasite worldwide. It has been previously reported that T. gondii contains a superantigen activity. The purpose of the present study was to determine if the putative superantigen activity of T. gondii would manifest towards human T cells. Peripheral blood mononuclear cells (PBMC) from individuals with no previous contact with the parasite were evaluated for proliferation as well as specific Vá expansion after exposure to Toxoplasma antigens. Likewise, PBMC from individuals with the congenital infection were evaluated for putative Vá family deletions in their T cell repertoire. We also evaluated, over a period of one year, the PBMC proliferation pattern in response to Toxoplasma antigens in patients with recently acquired infection. Some degree of proliferation in response to T. gondii was observed in the PBMC from individuals never exposed to the parasite, accompanied by specific Vá expansion, suggesting a superantigen effect. However, we found no specific deletion of Vá (or Valpha) families in the blood of congenitally infected individuals. Furthermore, PBMC from recently infected individuals followed up over a period of one year did not present a reduction of the Vá families that were originally expanded in response to the parasite antigens. Taken together, our data suggest that T. gondii does not have a strong superantigen activity on human T cells

Experimental toxoplasmosis in Balb/c mice: prevention of vertical disease transmission by treatment and reproductive failure in chronic infection

In a study of congenital transmission during acute infection of Toxoplasma gondii, 23 pregnant Balb/c mice were inoculated orally with two cysts each of the P strain. Eight mice were inoculated 6-11 days after becoming pregnant (Group 1). Eight mice inoculated on the 10th-15th day of pregnancy (Group 2) were treated with 100 mg/kg/day of minocycline 48 h after inoculation. Seven mice inoculated on the 10th-15th day of pregnancy were not treated and served as a control (Group 3). Congenital transmission was evaluated through direct examination of the brains of the pups or by bioassay and serologic tests. Congenital transmission was observed in 20 (60.6 per cent) of the 33 pups of Group 1, in one (3.6 per cent) of the 28 pups of Group 2, and in 13 (54.2 per cent) of the 24 pups of Group 3. Forty-nine Balb/c mice were examined in the study of congenital transmission of T. gondii during chronic infection. The females showed reproductive problems during this phase of infection. It was observed accentuated hypertrophy of the endometrium and myometrium. Only two of the females gave birth. Our results demonstrate that Balb/c mice with acute toxoplasmosis can be used as a model for studies of congenital T. gondii infection. Our observations indicate the potential of this model for testing new chemotherapeutic agents against congenital toxoplasmosis.

Toxoplasmosis en recien nacidos en el Hospital Jaime Oliver Pino, de San Pedro de Macoris

Se realizó un estudio prospectivo y analítico, utilizando la técnica de la observación participativa, de toxoplasmosis en recién nacidos. Se investigaron 100 pacientes realizándoles en sangre la prueba de hemaglutinación indirecta, buscando títulos de anticuerpos contra el toxoplasma Gondii. Encontramos una frecuencia de un 8% de casos positivos, lo cual es elevado comparándolo con otros estudios realizados en el país

Importancia del diagnóstico inmunológico en la toxoplasmosis congénita / Importance of immunologic diagnosis in congenital toxoplasmosis

Se exponen de forma breve el cuadro clínico dependiente de la transmisión intraútero de la toxoplasmosis y la importancia de su diagnóstico. Se señalan algunos de los métodos inmunológicos más utilizados para la detección de los anticuerpos antitoxoplasma y su interpretación en la toxoplasmosis congénita