Differential expression of genes in fetal brain as a consequence of maternal protein deficiency and nematode infection.

Maternal dietary protein deficiency and gastrointestinal nematode infection during early pregnancy have negative impacts on both maternal placental gene expression and fetal growth in the mouse. Here we used next-generation RNA sequencing to test our hypothesis that maternal protein deficiency and/or nematode infection also alter the expression of genes in the developing fetal brain. Outbred pregnant CD1 mice were used in a 2×2 design with two levels of dietary protein (24% versus 6%) and two levels of infection (repeated sham versus Heligmosomoides bakeri beginning at gestation day 5). Pregnant dams were euthanized on gestation day 18 to harvest the whole fetal brain. Four fetal brains from each treatment group were analyzed using RNA Hi-Seq sequencing and the differential expression of genes was determined by the edgeR package using NetworkAnalyst. In response to maternal H. bakeri infection, 96 genes (88 up-regulated and eight down-regulated) were differentially expressed in the fetal brain. Differentially expressed genes were involved in metabolic processes, developmental processes and the immune system according to the PANTHER classification system. Among the important biological functions identified, several up-regulated genes have known neurological functions including neuro-development (Gdf15, Ing4), neural differentiation (miRNA let-7), synaptic plasticity (via suppression of NF-κß), neuro-inflammation (S100A8, S100A9) and glucose metabolism (Tnnt1, Atf3). However, in response to maternal protein deficiency, brain-specific serine protease (Prss22) was the only up-regulated gene and only one gene (Dynlt1a) responded to the interaction of maternal nematode infection and protein deficiency. In conclusion, maternal exposure to GI nematode infection from day 5 to 18 of pregnancy may influence developmental programming of the fetal brain.

Prevalência de infecções congênitas e perinatais em gestantes HIV positivas da região metropolitana de Belo Horizonte / Prevalence of congenital and perinatal infection in HIV positive pregnant in Belo Horizonte metropolitan region

OBJETIVOS: Avaliar a prevalência de toxoplasmose, rubéola, citomegalovirose, hepatites B e C e sífilis (Torchs) em uma coorte de gestantes, bem como identificar os fatores sociodemográficos, clínicos e laboratoriais.MÉTODOS: Entre 1998 e 2013, foram atendidas 1.573 gestantes com sorologia positiva para o HIV em área metropolitana do Brasil, das quais 704 (44,8%) foram submetidas a algum dos testes sorológicos. Gestantes Torchs positivas (Gtp) foram consideradas aquelas com resultado positivo para uma dessas infecções, e gestantes Torchs negativas (Gtn) aquelas com resultados negativos para todas elas. As variáveis maternas investigadas foram: idade, estado civil, escolaridade, momento e forma de contágio da infeccção pelo HIV, contagem de linfócitos TCD4+, carga viral plasmática do HIV próxima ao parto e uso de terapia antirretroviral durante a gestação. As variáveis neonatais investigadas foram ocorrência de: transmissão vertical, prematuridade, baixo peso ao nascimento, complicações fetais, aborto e óbito fetal. Foram utilizadas razões de chance com intervalo de confiança de 95% para quantificar a associação entre as variáveis maternas e neonatais e a presença de Torchs.RESULTADOS: Entre as 704 gestantes, 70 (9,9%; IC95% 7,8-12,4) tinham alguma sorologia positiva para Torchs. Foram encontradas taxas: 1,5% (10/685) para a toxoplasmose; 1,3% (8/618) para rubéola; 1,3% (8/597) para citomegalovirose; 0,9% (6/653) para hepatite B e 3,7% (20/545) para hepatite C; e 3,8% (25/664) para sífilis. A transmissão vertical do HIV entre as gestantes Gtp foi 4,6% e de 1,2% entre as Gtn. As variáveis associadas à presença de Torchs na análise univariada foram: uso de terapia antirretroviral, transmissão vertical do HIV, baixo peso ao nascimento e complicações fetais.CONCLUSÃO: A prevalência das Torchs mostrou-se elevada para algumas infecções. Conclui-se que é importante manter o rastreamento de Torchs na gravidez, especialmente nas gestantes HIV positivas, para que se possa estabelecer diagnóstico e tratamento, e/ou medidas preventivas para evitar a transmissão materno-fetal.

PURPOSE: To evaluate the prevalence of toxoplasmosis, rubella, cytomegalovirus, hepatitis B&C and syphilis (Torchs) in a cohort pregnant women and to identify the sociodemographic, clinical and laboratory factors.METHODS: A total of 1,573 HIV-infected pregnant women from a Brazilian metropolitan region were studied between 1998 and 2013. The results of serological tests were available for 704 (44.8%) pregnant women. Pregnant women were considered to be Torchs positive (Gtp) when they had positive results for at least one of these infections, and to be Torchs negative (Gtn) when they had negative results for all of them. Maternal covariables were: age, marital status, educational level, time and mode of infection, CD4 lymphocyte count, viral load at delivery, and use of antiretroviral therapy (ARV). Neonatal covariables were: HIV infection, prematurity, low birth weight, neonatal complications, abortion and neonatal death. Odds ratios with 95% confidence interval were used to quantify the association between maternal and neonatal variables and the presence of Torchs.RESULTS: Among 704 pregnant women, 70 (9.9%; 95%CI 7.8-12.4) had positive serological tests for any Torchs factor. The individual prevalence rates were: 1.5% (10/685) for toxoplasmosis; 1.3% (8/618) for rubella; 1.3% (8/597) for cytomegalovirus; 0.9% (6/653) for hepatitis B and 3.7% (20/545) for hepatitis C; and 3.8% (25/664) for syphilis. The HIV Vertical HIV transmission was 4.6% among Gtp pregnant women and 1.2% among Gtn women. Antiretroviral therapy (ARV), vertical transmission, low birth weight and neonatal complications were significantly associated with Torchs positivity in univariate analysis.CONCLUSIONS: The Torchs prevalence found in the study was high for some infections. These findings emphasize the need to promote serological Torchs screening for all pregnant women, especially HIV-infected women, so that an early diagnosis can be made and treatment interventions can be implemented to prevent vertical HIV transmission.

Efecto de la infección congénita por Trypanosoma cruzi sobre el desarrollo intrauterino y la respuesta inmune fetal-neonatal / Effect of congenital infection by Trypanosoma cruzi on intrauterine development and the fetal-neonatal immune response

En la infección congénita por Trypanosoma cruzi la morbilidad y mortalidad varían desde casos asintomáticos hasta severos cuadros clínicos de la enfermedad. En recién nacidos infectados por T. cruzi se ha encontrado que no existe un perfil clínico determinado, puesto que durante el desarrollo intrauterino se producen diversas alteraciones, presentándose cambios en el perfil serológico y parasitológico. Algunos factores intrínsecos del hospedador, tales como: la barrera placentaria y la capacidad tanto de la madre como del feto de desarrollar una respuesta inmune específica capaz de controlar la multiplicación parasitaria podrían estar involucrados en tales diferencias. Otra posibilidad incluye el polimorfismo genético de T. cruzi, pues se considera que las cepas de mayor virulencia pueden atravesar con mayor facilidad la placenta y son más patógenas para el feto y/o neonato.

In congenital infection by Trypanosoma cruzi, morbidity and mortality vary from asymptomatic cases to severe clinical forms of the disease. It has been found that there is no specific clinical profile in newborns infected by T. cruzi, since during intrauterine development diverse pathological changes take place, causing alterations in the serological and parasitological profiles. Some intrinsic factors of the host, such as: the placental barrier and the ability of both, mother and fetus, to develop a specific immune response to control parasite multiplication, could be involved in such differences. Another possibility includes the genetic polymorphism of T. cruzi, since it is considered that strains of greater virulence can cross the placenta more easily and are more pathogenic to the fetus and/or the neonate.

Maternal Schistosomiasis japonica is associated with maternal, placental, and fetal inflammation.

Schistosomes infect ∼40 million women of childbearing age and result in the elaboration of proinflammatory cytokines that have been implicated in fetal growth restriction. In murine models and two observational studies in humans, schistosome infection during pregnancy was associated with reduced birth weight, although a recent treatment trial in Schistosoma mansoni did not detect this association. We conducted an observational study among 99 pregnant women living in an area of Schistosoma japonicum endemicity in the Philippines. We enrolled women at 32 weeks gestation and measured S. japonicum and geohelminth infection intensity. We collected maternal peripheral blood at 32 weeks gestation and placental and cord blood at delivery to assess inflammatory status. At delivery, we collected a placental-tissue sample and measured birth weight. In multivariate models adjusted for geohelminths, maternal schistosomiasis was associated with increased levels of inflammatory cytokines in maternal peripheral (tumor necrosis factor alpha [TNF-α] and interleukin 10 [IL-10]), placental (TNF-α, IL-6, TNF-α receptor II [RII], and IL-1ß), and cord (IL-1ß and TNF-α RII) blood, as well as acute subchorionitis and increased TNF-α production by syncytiotrophoblasts assessed by immunohistochemistry (all P < 0.05). After adjusting for confounders, placental IL-1ß, and TNF-α production by syncytiotrophoblasts was independently associated with decreased birth weight (both P < 0.05). Our data indicate that maternal schistosomiasis results in a proinflammatory signature that is detectable in maternal, placental, and fetal compartments, and a subset of these responses are associated with decreased birth weight. This potential mechanistic link between maternal schistosomiasis and poor birth outcomes will contribute to the debate regarding treatment of maternal schistosome infections.

The effect of placental malaria infection on cord blood and maternal immunoregulatory responses at birth.

Placental malaria (PM), a frequent infection of pregnancy, provides an ideal opportunity to investigate the impact on immune development of exposure of the foetal immune system to foreign Ag. We investigated the effect of PM on the regulatory phenotype and function of cord blood cells from healthy Gambian newborns and peripheral blood cells from their mothers, and analyzed for effects on the balance between regulatory and effector responses. Using the gold standard for classifying PM we further distinguished between resolved infection and acute or chronic PM active at the time of delivery. We show that exposure to malarial Ag in utero results in the expansion of malaria-specific FOXP3(+) Treg and more generalized FOXP3(+) CD4(+) Treg in chronic and resolved PM, alongside increased Th1 pro-inflammatory responses (IFN-gamma, TNF-alpha, IFN-gamma:IL-10) in resolved PM infection only. These observations demonstrate a clear effect of exposure to malarial Ag in foetal life on the immune environment at birth, with a regulatory response dominating in the newborns with ongoing chronic PM, while those with resolved infection produce both regulatory and inflammatory responses. The findings might explain some of the adverse effects on the health of babies born to women with PM.

Fetus-in-fetu: parasite or neoplasm? A study of two cases.

INTRODUCTION: Fetus-in-fetu is a rare congenital fetiform mass whose etiology is still controversial. We report two cases of fetus-in-fetu. CASE 1: A fetal retroperitoneal cystic tumor including two masses was detected by ultrasonography at 26 gestational weeks. The masses showed distinctive structures resembling a vertebral axis and were prenatally diagnosed as fetus-in-fetu. A resected specimen revealed two fetiform masses. CASE 2: An intracranial tumor with hydrocephalus was detected by ultrasonography at 19 gestational weeks. The pregnancy was terminated, and a postmortem examination revealed six fetiform masses with immature teratoma. DISCUSSION: The tumors may possibly consist of parasitic monozygotic diamniotic twins or highly differentiated teratomas.

Diagnosis of congenital toxoplasmosis: pre- and post-natal evaluation in Sicilian (Italy) epidemiological area. Preliminary data.

To evaluate the usefulness of conventional serological methods with western blot assay (WB) in congenital toxoplasmosis diagnosis, we prospectively enrolled in a clinical and serological follow-up all pregnant women with Toxoplasma gondii infection and their offspring, referred to us from October 2004. Western blot and standard serological test were performed on sera collected from mother during pregnancy and from mother and child at birth, at postpartum month 1-3-6-9 and 12. At this point in time, 22 pregnant women and 14 infants have completed the follow-up. 4 newborns were infected and 2 had specific toxoplasmosis anomalies at the birth. In mothers without seroconversion, the WB performed during pregnancy demonstrates the highest accordance with postnatal follow-up whereas in 1 case the negative result of PCR analysis was not confirmed by postnatal observation. The detection of anti-T gondii IgG against 8 kDa accessory antigenic band and against the accessory band included between 35 and 40 kDa band in immunoblot assay was useful for diagnosis of acute phase but did not improve the evaluation of comparative postnatal profile. Althougth few infants have concluded the postnatal follow-up, the preliminary results showed a greater value of using a IgM and IgA WB test than other standard method for the early diagnosis of toxoplasmosis at birth also in child born to treated mothers. The comparative anti-T gondii IgG immunoblot profile of mother and child permitted us to reduce the time of ruling out infection in newborns born to mothers with probable or possible infection and/or when prenatal diagnosis is negative or not performed.

Efecto de la infección aguda por diferentes cepas de Trypanosoma cruzi sobre el crecimiento intrauterino de fetos de ratón / Effect of the acute infection by different strains of Trypanosoma cruzi intrauterine growth of the mouse fetuses

El objetivo de este trabajo fue evaluar los efectos de la infección aguda materna con diferentes cepas de T. cruzi sobre el crecimiento intrauterino del ratón. Animales grávidos, de 60 días, fueron inoculados i.p. con 2 x 105 tripomastigotes sanguíneos de T. cruzi (cepa colombiana, Y, Bolivia o RC). Los resultados muestran que la infección afecta el crecimiento intrauterino, con reducción de peso y de longitud del cuerpo, longitud del cordón umbilical, relación peso corporal/peso placentario y relación peso corporal/longitud del cordón umbilical. Las cepas usadas muestran comportamiento diferente. En general, la menos perjudicial para el crecimiento fue la cepa RC, mientras que las más deletéreas fueron las cepas Bolivia e Y. Las curvas parasitemicas de estas cepas tienen el crecimiento más rápido, alcanzando el máximo al 5o y 7o día, respectivamente. Como la inoculación fue hecha de modo a coincidir los niveles máximos de parasitemia con el fin de la gravidez, estas cepas causan un proceso infeccioso más rápido, con altos índices de parasitemia, sin permitir la adaptación materna.

[Lesions in cross-breed pregnant cows, experimentally infected with Sarcocystis cruzi (Hasselmann, 1923) Wenyon, 1926 (Apicomplexa: Sarcocytidae)]. / Lesões em vacas mestiças gestantes, infectadas experimentalmente com Sarcocystis cruzi (Hasselmann, 1923) Wenyon, 1926 (Apicomplexa: Sarcocystidae).

To identify pathologic alterations, sixteen cows, in the last 3 months of gestation, all cross-breed, Holstein x Zebu, serum positive for Sarcocystis, were selected and divided into four groups of four animals each. The first group was considered as control and the other three groups were experimentally infected with 1x10(4) (2nd group), 5x10(4) (3rd group) and 1x10(5) (4th group) sporocysts obtained from dog's feces. The gross lesions in the cows were consisted of pale mucous membranes, paleness of the skeletal striated muscle and enlargement of lymph nodes, heart, liver, spleen and lungs. In the aborted fetus, the most prominent gross lesion were excess of fluid in peritoneal and thoracic cavities, and petecheas in the surface of intercostal muscles, thymus and spleen. On histological sections, no parasitic form was found in the tissues of the fetus, placenta or uterine tissue of the exposed cows. However, meronts, young and mature cysts of S. cruzi were observed in striated muscle. In the aborted fetus, hemorrhage, was the main histological lesion observed in brain, cerebellum and kidneys.

Fetal brain infections.

INTRODUCTION: Congenital infections can cause severe brain damage. As a result, it is very important to identify them early in their course so that treatment can be administered to the mother, if possible. The role of imaging is to determine the presence, if any, and the extent of brain damage in the infected fetus. Although MRI is most commonly used as an adjunct to sonography, when clinical suspicion is high in the setting of a normal ultrasound or to better define abnormalities detected by ultrasound, MRI is routinely used in toxoplasmosis seroconversion to definitively rule out brain lesions, even when the ultrasound scan is considered normal. MRI is also used serially throughout the pregnancy to check for the development of brain abnormalities; medical treatment results in excellent clinical outcome if the brain is normal. DISCUSSION: This article describes the indications, techniques, and findings that will allow proper use of fetal MRI in the setting of congenital infections.

Fetal Toxoplasma infection after oocyst inoculation of pregnant rats.

Six groups totalling 53 Wistar rats were fed 10(4)oocysts from one of six different Toxoplasma strains at 15 days of pregnancy. The overall transplacental transmission rate was 51%. This varied between 10% and 80%, dependent on the strain used. The strains of Toxoplasma which are more pathogenic for mice were transmitted transplacentally more frequently than the strains of intermediate or low pathogenicity. There were no statistically significant differences in the rate of congenital transmission of Toxoplasmain rats fed oocysts (present work) or cysts (previous work).

Transplacental toxoplasmosis in a reindeer (Rangifer tarandus) fetus.

Toxoplasma gondii infection was diagnosed in a full term stillborn reindeer (Rangifer tarandus) fetus. The fetus had encephalitis and placentitis associated with T. gondii. Tissue cysts were identified histologically in sections of brain and tachyzoites were present in placenta and the myocardium. Protozoa in the brain, heart, and placenta stained positively with T. gondii antibodies, but not with Neospora caninum antibodies in an immunohistochemical test. The dam of the fetus had a 1:12,800 titer to T. gondii in the modified agglutination test employing whole tachyzoites and mercaptoethanol. This is the first confirmed report of T. gondii infection in reindeer.

Otimizaçäo da reaçäo de polimerase em cadeia para detecçäo de Toxoplasma gondii em sangue venoso e placenta de gestantes / Optimization of Toxoplasma gondii detection by PCR in pregnants blood and placenta

A detecçäo de Toxoplasma gondii no sangue venoso e na placenta de gestantes pela reaçäo de polimerase em cadeia pode facilitar o diagnóstico préðnatal do toxoplasmose congênita. Foram avaliadas gestantes IgMðreagentes e os seus filhos. Além das dosagens de IgG, IgM, IgA e reaçäo de avidez de IgG (MEIA), foram realizadas a técnica de imunoperoxidase e a inoculaçäo em camundongos. De cada amostra foi efetuada amplificaçäo gênica com primers do gene B1 e novos primers do gene TGR (chamados ABGTg7 C1 e N1). É preciso observar que o tratamento poderia ser responsável por uma diminuiçäo da infecçäo. Desta forma, o diagnóstico negativo confirmaria a eficiência do tratamento preventivo na replicaçäo parasitária no útero. A reaçäo de polimerase em cadeia mostrouðse sensível e específica; evidenciou a presença de um a dez taquizoítas; pode ser utilizada com segurança e confiabilidade, além de tornar rápido o diagnóstico da toxoplasmose congênita, sendo, assim, ferramenta importante na avaliaçäo préðnatal

Prenatal toxoplasmosis diagnosis from amniotic fluid by PCR

Toxoplasmosis is one of the most common infections all over the world. Most cases are asymptomatic, except in immunosuppressed individuals and fetuses, which can be seriously damaged. Prenatal diagnosis should be made as soon as possible since treatment of the mother can minimize fetal sequelae. Our aim in this study was to test the polymerase chain reaction technique (PCR) in 86 samples of amniotic fluid from women who seroconverted during pregnancy. DNA was amplified using external primers and, in a second step, internal primers, in a nested PCR system. Samples were also inoculated into mice and the newborn were evaluated by T. gondii serology, skull x-ray, transfontanel ultrasound, fundoscopic examination, lumbar puncture and clinical examination. PCR was positive in seven cases and negative in 79. Among PCR-positive cases, two were negative by inoculation into mice and by clinical evaluation; among PCR-negative ones, three had clinical evidence of toxoplasmosis and one was positive after inoculation into mice. PCR showed values of sensitivity = 62.5 and specificity = 97.4; the values of inoculation into mice where 42.9 and 100, respectively. Although PCR should not be used alone for prenatal diagnosis of congenital toxoplasmosis, it is a promising method and deserves more studies to improve its efficacy.

Naturally-occurring Neospora caninum infection in an adult sheep and her twin fetuses.

Neospora caninum tissue cysts were found in the brains of surgically delivered twin fetuses at 119 days of gestation. In the brains of both fetuses, there was an inflammatory reaction involving perivascular cuffings of mononuclear cells, glial nodules. The dam of these fetuses died because of metritis. Histopathological examination of the ewe revealed N. caninum tissue cysts and focal gliosis with mononuclear cell cuffings. A N. caninum-specific DNA fragment was detected in a brain homogenate of the ewe by the polymerase chain reaction method. This is the first report of N. caninum infection in twin ovine fetuses and in an adult sheep.

Experimental porcine neosporosis.

Six gilts were inoculated intramuscularly with 2.5x10(6) tachyzoites of Neospora caninum on three different days of gestation to study the pathogenic effect of Neospora infection in pigs, including possible transplacental transmission. The gilts were euthanized 59, 30, and 9/10 days postinoculation (p.i.), corresponding to days 107, 102/106 and 110/111 of pregnancy. With the exception of one animal (euthanized day 9 p.i.) all gilts seroconverted as measured by the indirect, fluorescent antibody test (IFAT). Neosporosis with multifocal intralobular necrotizing hepatitis was seen in the two gilts inoculated 9/10 days before euthanasia. The uterus of one gilt inoculated 59 days before euthanasia revealed granulomatous and focal necrotizing endometritis with a corresponding multifocal necrosis of the trophoblasts of two fetuses. Transplacental neosporosis was indicated in the two fetuses by strongly elevated Neospora IFAT titres in pleural fluid and by the presence of multifocal necrotizing encephalitis and hepatitis together with non-suppurative myocarditis, pneumonitis, nephritis and hepatitis. Furthermore, N. caninum was re-isolated in cell culture from one of these fetuses. A third fetus from the same gilt revealed only disseminated, pinpoint necroses in the liver. Immunohistochemically, N. caninum tachyzoites were detected in association with histopathological changes in the liver and the endometrium of the gilts, and in the brain, liver, and allantochorion of the three fetuses.

Workshop summary: food safety: meat- and fish-borne zoonoses.

In this workshop, J.P. Dubey (USA), Th. Hiepe (Germany), and P. Deplazes (Switzerland), were invited speakers. The main areas covered were toxoplasmosis, microsporidiosis, trematode infections, taeniosis/cysticercosis and trichinellosis. The public health and economic impact of meat- and fish-borne parasitic zoonoses is considerable in terms of morbidity and even mortality in humans as well as in losses due to reduced productivity in animals and condemnation of parasitised meat and fish. In this context, the increasing demands of consumers for meat and fish free of pathogens and chemical residues has to be considered. Among the parasitic zoonoses some are widespread and frequent, for example toxoplasmosis. About 30-50% of women of child-bearing age are at risk of acquiring the infection during pregnancy with the potential of prenatal infection and severe disease of the foetus. In addition, toxoplasmosis plays an increasing role as an AIDS-associated infection. There are some recent indications that Toxoplasma infections acquired by adults by ingestion of sporulated oocysts may be more pathogenic than cyst-induced infections. In such cases, eye lesions are quite frequent and were previously thought to be predominantly acquired by prenatal infection (J.P. Dubey, USA). Fish- or crustacean-borne trematodes (species of Clonorchis, Opisthorchis, Paragonimus, intestinal flukes) infect about 39 million people, and about 550 millions are at risk (WHO, 1995). Other zoonotic infections are less frequent but may cause severe and lethal diseases, for example Taenia solium cysticercosis.

Ocular toxoplasmosis in the fetus. Immunohistochemistry analysis and DNA amplification.

PURPOSE: Ocular toxoplasmosis is often the result of a congenital infection. However, the earlier stages of the ocular lesions in the fetus have not been well studied. The purpose of the present study is to analyze the ocular findings in four aborted fetuses that were infected congenitally with Toxoplasma gondii. METHODS: Eight eyes from four fetuses of 22 to 27.5 weeks with T. gondii infection were studied by routine and immunohistochemical techniques. Two of the four were also examined by polymerase chain reaction (PCR). RESULTS: In two cases, the results of gross and histopathologic of the eyes were normal; marked retinal necrosis was present in the other two cases. Although no toxoplasmic cysts were identified by routine histopathologic examination, antigens of the tachyzoite were detected by immunohistochemistry analysis in the areas of retinal necrosis. In one of the cases with ocular lesions, the presence of T. gondii was confirmed by PCR. The presence of ocular lesions correlated with the severity of pathologic changes in the central nervous system. Large numbers of T cells were observed in the retinal lesions and in the choroid. CONCLUSION: Retinal necrosis, neovascularization, and marked chorioretinal inflammations despite the absence of bradyzoites are characteristic findings in the fetal eyes infected with T. gondii, and infiltrating T lymphocytes play a role in early recognition of the toxoplasma organism.

[Toxoplasmosis in pregnancy. Prevention, diagnosis, and therapy]. / La toxoplasmosi in gravidanza. Prevenzione, diagnosi e terapia.

Toxoplasmosis is a worldwide health problem. Infection of a pregnant woman can result in severe fetal morbidity or in subclinical neonatal infection; most subclinical cases will develop ocular and neurological sequelae. Fetal infection and clinical outcome is related to when in pregnancy toxoplasmosis was acquired. The risk of transmission increases from 14% in the first trimester to 29% in the second and 59% in the third. Conversely, clinical damage decreases from about 80% in the first to 10% in the third trimester, but up to 50% of patients with subclinical congenital toxoplasmosis will develop neurologic and ocular sequelae. Congenital toxoplasmosis can be prevented by identification of non immune women at the beginning of pregnancy, by giving information on how to avoid the infection and by a serological follow-up until the delivery. Serological follow-up is based on repeated testing for specific IgG and IgM, but other serologic methods are necessary to differentiate between acute and chronic infections and possibly on a single serum sample. Procedures to detect fetal infection are ultrasound examination, cordocentesis and amniocentesis; prenatal diagnosis relies on demonstration of toxoplasma in fetal blood or amniotic fluid by mouse inoculation. Very promising results have recently obtained by the PCR-method applied to amniotic fluid samples. All strongly suspected cases of acquired toxoplasmosis in pregnancy have to be treated.