Congenital toxoplasmosis--a report on the Danish neonatal screening programme 1999-2007

The prevention of congenital toxoplasmosis using a combination of Spiramycin and Cotrimoxazole: The long-time experience of a tertiary referral centre

BACKGROUND

Toxoplasmosis is a parasitic infection caused by Toxoplasma gondii and is responsible for gestational and congenital infections worldwide. The current standard therapy is based on the administration of Spiramycin to prevent trans-placental transmission. Other therapies are being studied to reduce the rates of foetal transmission and symptomatic congenital infection.

OBJECTIVES

We report our long-standing experience in maternal toxoplasmosis infection treatment using a combination of Spiramycin-Cotrimoxazole, assessing its effectiveness in preventing vertical transmission compared to the expected incidence of congenital infection.

METHODS

We retrospectively collected cases of pregnant women referred to our centre for suspected toxoplasmosis infection according to Lebech criteria, treated with Spiramycin-Cotrimoxazole.

RESULTS

Of 1364 women referred to our centre, postnatal follow-up of primary toxoplasmosis was available in 562 cases (73.9%). The overall vertical transmission rate was 3.4% in women treated immediately with Spiramycin-Cotrimoxazole after the diagnosis of infection. In comparison, it was 7.7% in women undergoing the same therapy but late or with poor compliance. The foetal transmission rate was 71.4% in untreated cases. All the infected newborns of mother treated adequately with Spiramycin-Cotrimoxazole were asymptomatic afterbirth, while 6/21 infected infants of the inadequate Spiramycin-Cotrimoxazole therapy group had postnatal sequelae (28.5%). The incidence of transmission after appropriate Spiramycin-Cotrimoxazole therapy was significantly lower than the expected rate reported in literature.

CONCLUSIONS

A combination of Spiramycin and Cotrimoxazole is safe and effective in preventing foetal congenital toxoplasmosis and reducing sequelae in case of in-utero infection. The timing and adherence to the therapy are crucial to lowering the risk of congenital infection and neonatal morbidity.

Anti-Toxoplasma gondii Antibodies in European Residents: A Systematic Review and Meta-Analysis of Studies Published between 2000 and 2020

Toxoplasmosis has a major impact on animal and public health. Information regarding the seroprevalence of human Toxoplasma gondii infections from a European perspective has not yet been compiled to date. Thus, the present review summarized available resident data from the period 2000-2020. The overall seroprevalence of anti-T. gondii IgG was 32.1%, with great variability between countries (n = 30). The subgroup analysis identified different pooled prevalence data depending on the geographic area (p < 0.0001), target population (p = 0.0147), and serological diagnosis assays used (p = 0.0059). A high heterogeneity (I2 = 100%, p < 0.001; Q = 3.5e+05, d.f. = 135, p < 0.001) and degree of publication bias (Egger's test = 6.14, p < 0.001) were observed among the 134 studies considered. The occurrence of anti-T. gondii IgM, which was reported in 64.7% of studies, reached a pooled seroprevalence of 0.6%. In addition, among the eight main risk factors identified, "contact with soil", "consumption of undercooked beef", and "intake of unwashed vegetables" were the most significantly associated with infections. The fact that one-third of the European population has been exposed to T. gondii justifies extra efforts to harmonize surveillance systems and develop additional risk-factor analyses based on detailed source attribution assessment.

Congenital toxoplasmosis: Should we still care about screening?

Prenatal systematic screening for congenital toxoplasmosis has been performed in Austria and France since 1975 and neonatal screening for congenital toxoplasmosis has been part of the New England Newborn screening program since 1986. In this narrative review we review the data leading up to the systematic screening programs in Austria and France, highlighting the main finding of the European Union funded research in the 1990s and early 2000s. Different descriptive studies of the effect of pre- or postnatal treatment are discussed. Toxoplasma gondii has different genetic lineages with different pathogenicity in humans. This means that results in areas with a low pathogenic lineage cannot be extrapolated to an area with highly pathogenic lineages. The importance of meat as a source of infection is discussed in the light of an increased prevalence of T.gondii in organic livestock production .

The disease burden of ocular toxoplasmosis in Denmark in 2019: Estimates based on laboratory testing of ocular samples and on publicly available register data

Background

Toxoplasma gondii is an important zoonotic protozoan parasite with worldwide distribution. Information on the contribution of ocular toxoplasmosis to the disease burden caused by this parasite is limited or lacking from many countries.

Methods

We estimated the minimum occurrence of ocular toxoplasmosis in Denmark using results from direct detection of T. gondii DNA with qPCR and determination of the Goldmann-Witmer coefficient on ocular samples submitted by ophthalmological clinics and departments to the national reference laboratory in 2003–2019. In addition, we inferred incidence estimates using retrospective data that are publicly available in the National Patient Register, and we used unstructured expert elicitation as the basis for sensitivity analyses. We estimated the disease burden of ocular toxoplasmosis in 2019 in disability-adjusted life years (DALYs).

Findings

Ocular samples from 263 individuals (median age 57 years, range 2–88) had been tested with at least one of the methods during 2003–2019, and 42 (16%) tested positive (median age 65 years, range 14–85). In 2019, five (16%) of 31 tested individuals were positive, giving a minimum annual incidence estimate of 0.09 per 100.000 population. From this, we calculated a disease burden of at least 4 DALYs (95% confidence interval, 3–5). The age range suggested that this figure represented postnatally acquired ocular toxoplasmosis. The disease burden of ocular toxoplasmosis due to congenital toxoplasmosis has been previously estimated to be at least 12 DALYs, resulting in an estimated minimum total disease burden due to ocular toxoplasmosis of 16 DALYs. In 2005–2018, the mean annual number of diagnoses of ocular toxoplasmosis reported to the National Patient Register was 186, and the corresponding disease burden estimate was 134 DALYs (95% confidence interval, 113–158). Sensitivity analyses focusing on incidence and severity resulted in disease burden estimates in the range of 9–523 DALYs.

Interpretation

Because most diagnoses of ocular toxoplasmosis are based on clinical observations, ophthalmoscopy, and serology without confirmatory testing, the disease burden caused by ocular toxoplasmosis is likely substantially higher than our minimum estimates. Our results indicate that ocular toxoplasmosis contributes to the disease burden caused by T. gondii in Denmark, but uncertainty about the incidence and severity precludes reliable estimation of its importance.

The cost-effectiveness of neonatal versus prenatal screening for congenital toxoplasmosis

Background

Congenital Toxoplasmosis (CT) can have severe consequences. France, Austria, and Slovenia have prenatal screening programs whereas some other countries are considering universal screening to reduce congenital transmission and severity of infection in children. The efficiency of such programs is debated increasingly as seroprevalence among pregnant women and incidence of congenital toxoplasmosis show a steady decrease. In addition, uncertainty remains regarding the effectiveness of pre- and postnatal treatments.

Method

To identify cost-effective strategies, prenatal and neonatal screenings were compared using a decision-analytic model based on French guidelines and current knowledge of long-term evolution of the disease in treated children. Epidemiological data were extracted from the scientific literature and clinical data from the French Lyon cohort. Strategies were compared at one year of age, when infection can be definitively evaluated, and at 15 years of age, after which validated outcome data become scarce. The analysis was performed from the French Health Insurance System perspective and included direct medical costs for pregnant women and their children.

Results

The 1-year Incremental Cost-Effectiveness Ratio showed that prenatal screening would require investing €14,826 to avoid one adverse event (liveborn with CT, fetal loss, neonatal death or pregnancy termination) compared to neonatal screening. Extra investment increased up to €21,472 when considering the 15-year endpoint.

Conclusions

Prenatal screening is cost-effective as compared to neonatal screening in moderate prevalence areas with predominant Type II strains. In addition, prenatal screening, by providing closer follow-up of women at risk increases the number of occasions for education avoiding toxoplasmosis.

Prevention and mitigation of congenital toxoplasmosis. Economic costs and benefits in diverse settings

Congenital toxoplasmosis (CT), the result of a primary infection of pregnant women with Toxoplasma gondii which was transmitted to the fetus, may result in mild to deep injuries occurring in the newborn or later in its development or in adolescence. The visual and cognitive impairment that can result imposes substantial economic costs on the individual and society. Numerous observational studies favor the conclusion that, with preventive measures currently available, it is possible to reduce the incidence of infections in pregnant women, the incidence of fetal infection by preventing transplacental transmission, and the gravity of injury in infected newborns. Treatment of infected newborns can also reduce the severity of consequences and the frequency of their occurrence later in life. Prevention programs, however, are applied in only a few countries; in most countries implementation of a national prevention program has not been considered or has been thought to be too expensive. This article lists the methods of prevention of CT and describes existing national prevention programs in France and Austria. It analyzes the economic costs and benefits of maternal screening for CT prevention and mitigation for society and for health systems. The economic feasibility of implementing national screening in low-prevalence, high-cost countries is illustrated with the example of the United States. New diagnostic tools are discussed and the implication of lower costs is considered, for countries with well-established screening programs as well as those with inadequate prenatal care networks.

The disease burden of congenital toxoplasmosis in Denmark, 2014

BACKGROUND

Congenital toxoplasmosis (CT) causes a substantial disease burden worldwide. The aim of this study was to estimate the disease burden of CT in Denmark, a developed country with free public healthcare and nationwide data available.

METHODS

Using data primarily from two public health surveillance programmes conducted between 1992 and 2007, we estimated the incidence, occurrence of sequelae, mortality and the burden of disease in terms of disability-adjusted life years (DALYs) of CT in Denmark in 2014.

FINDINGS

We estimated that 14 children were born with CT in 2014, of which six will have developed sequelae by the age of 12. CT resulted in a total disease burden of 123 DALYs (95% uncertainty interval [UI], 100-148), of which 78 (95% UI, 64-94) were due to foetal loss and 2 (95% UI, 1-3) were due to neonatal death; the remaining burden was due to moderate to severe life-long sequelae. A comparison of the estimated incidence of CT with the number of reported CT cases in 2008-2014 indicated that for each reported CT case, at least five other CT cases could be expected to have occurred and gone unreported.

INTERPRETATION

Early onset, severity, and life-long duration of sequelae have a major effect on the disease burden of CT. Our data suggest that CT is under-diagnosed or under-reported in Denmark. The estimated disease burden and public health impact in Denmark is lower than in other European countries, highlighting the need for country-specific studies.

Prevalence, incidence estimations, and risk factors of Toxoplasma gondii infection in Germany: a representative, cross-sectional, serological study

Representative data on the extent of endemicity, burden, and risk of human toxoplasmosis are scarce. We assessed the prevalence and determinants of seropositivity of Toxoplasma gondii among adult participants of a nationwide representative cross-sectional survey in Germany. Sera collected from a representative cohort of adults (age 18-79; n = 6,663) in Germany were tested for anti-T. gondii IgG antibodies. Interview-derived data were used to evaluate associated factors. Multivariable logistic regression was applied using sampling weights and accounting for survey design cluster effects. Seroprevalence increased from 20% (95%-CI:17-23%) in the 18-29 age group to 77% (95%-CI:73-81%) in the 70-79 age group. Male gender, keeping cats and BMI ≥30 were independent risk factors for seropositivity, while being vegetarian and high socio-economic status were negatively associated. Based on these data, we estimate 1.1% of adults and 1.3% of women aged 18-49 to seroconvert each year. This implies 6,393 seroconversions annually during pregnancies. We conclude that T. gondii infection in Germany is highly prevalent and that eating habits (consuming raw meat) appear to be of high epidemiological relevance. High numbers of seroconversions during pregnancies pose substantial risks for unborn children. Efforts to raise awareness of toxoplasmosis in public health programs targeting to T. gondii transmission control are therefore strongly advocated.

Survey of obstetrician-gynecologists in the United States about toxoplasmosis: 2012 update

PURPOSE

Toxoplasmosis, caused by the parasite Toxoplasma gondii, can have serious impacts on fetal development in the setting of acute maternal primary infection. The American College of Obstetricians and Gynecologists (ACOG) sought to determine current knowledge, practices, opinions, and educational preferences regarding T. gondii infection in pregnancy among ACOG members practicing prenatal care.

METHODS

ACOG sent a survey to 1,056 members chosen by stratified random sampling from membership lists, including 370 participants and 686 non-participants in the Collaborative Ambulatory Research Network (CARN). Mailings were sent up to four times to nonresponders.

RESULTS

Survey minimum response rates were 40.3% (CARN) and 19.7% (non-CARN); response rates adjusted for imputed non-eligibility were 59.7% (CARN) and 22.6% (non-CARN). Among providers, 80.2% had diagnosed no acute maternal T. gondii infections in the past 5 years, 12.7% correctly identified the screening role of the Toxoplasma avidity test, 42.6% performed serologic T. gondii screening for at least some asymptomatic pregnant women, and 62.1% of those who so did used appropriate approaches. Providers in the northeastern United States were 2.02 times more likely to routinely screen than those in the west (p = 0.025) and female providers were 1.48 times more likely than male providers (p = 0.047). The potential educational interventions considered useful by the most practitioners were updated ACOG guidelines on screening (81.4%) and management (71.7%) for acute T. gondii infection in pregnancy.

CONCLUSIONS

ACOG members would benefit from educational efforts targeted at risk factor counseling and screening approaches.

Intervention strategies to reduce human Toxoplasma gondii disease burden

Infection with Toxoplasma gondii is acquired through consumption of undercooked infected meat, or by uptake of cat-shed oocysts. Although congenital toxoplasmosis is generally considered to contribute most to the disease burden of T. gondii, ocular disease from acquired infection was recently shown to add substantially to the burden. In addition, toxoplasmosis in immune-compromised individuals usually results from reactivation of an infection acquired earlier in life. Nevertheless, prevention of toxoplasmosis commonly targets mainly pregnant women. We summarize current prevention strategies of congenital toxoplasmosis and evaluate options to improve protection of the general population (including pregnant women). To protect the general population, freezing of meat destined for raw or undercooked consumption is the most readily applicable option, especially when limited to meat from animals originating from nonbiosecure husbandry systems. In the long term, more health benefits are expected from cat vaccination; therefore, development of a cat vaccine and evaluation of its implementation is a research priority.

Universal newborn screening for congenital CMV infection: what is the evidence of potential benefit?

Congenital CMV infection is a leading cause of childhood disability. Many children born with congenital CMV infection are asymptomatic or have nonspecific symptoms and therefore are typically not diagnosed. A strategy of newborn CMV screening could allow for early detection and intervention to improve clinical outcomes. Interventions might include antiviral drugs or nonpharmaceutical therapies such as speech-language therapy or cochlear implants. Using published data from developed countries, we analyzed existing evidence of potential benefit that could result from newborn CMV screening. We first estimated the numbers of children with the most important CMV-related disabilities (i.e. hearing loss, cognitive deficit, and vision impairment), including the age at which the disabilities occur. Then, for each of the disabilities, we examined the existing evidence for the effectiveness of various interventions. We concluded that there is good evidence of potential benefit from nonpharmaceutical interventions for children with delayed hearing loss that occurs by 9 months of age. Similarly, we concluded that there is fair evidence of potential benefit from antiviral therapy for children with hearing loss at birth and from nonpharmaceutical interventions for children with delayed hearing loss occurring between 9 and 24 months of age and for children with CMV-related cognitive deficits. We found poor evidence of potential benefit for children with delayed hearing loss occurring after 24 months of age and for children with vision impairment. Overall, we estimated that in the United States, several thousand children with congenital CMV could benefit each year from newborn CMV screening, early detection, and interventions.

Presence and duration of anti-Toxoplasma gondii immunoglobulin M in infants with congenital toxoplasmosis

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.

Evaluation of a new protocol for retrospective diagnosis of congenital toxoplasmosis by use of Guthrie cards

The aim of this study was to assess the diagnostic value of IgM Western blotting (WB), IgA enzyme immunoassay (EIA), and DNA amplification by real-time PCR on Guthrie cards to retrospectively establish the diagnosis of congenital toxoplasmosis (CT). To this purpose, Guthrie cards were collected from 18 infants born to mothers with primary Toxoplasma gondii infection during pregnancy. Moreover, the analytical sensitivity of T. gondii PCR was assessed by testing mock dried blood specimens set up with several known DNA dilutions. IgM WB was demonstrated to be the most sensitive method. When the results of T. gondii DNA detection and specific IgM recovery were combined, retrospective CT diagnosis by using Guthrie cards was established in 3 out of 6 infected infants (sensitivity, 50%; 95% confidence interval, 26.8% to 73.2%). No positive PCR or serologic results were found in the group of 12 uninfected infants, demonstrating the excellent specificity of the three methods (95% confidence interval, 78.1% to 99.5%). The findings of the present study suggest that, in cases of missed diagnosis of CT at birth, analysis of Guthrie cards for children with compatible clinical findings after the perinatal period, in particular the combination of recovery of specific IgM antibodies and T. gondii DNA amplification, could be helpful. Nevertheless, since suboptimal conditions of storage of dried blood specimens can seriously affect sensitivity, negative results cannot rule out CT diagnosis. In contrast, because of the excellent specificity shown by IgM serologic testing and T. gondii DNA amplification on Guthrie cards, positive results obtained by either of the two methods should be considered diagnostic.

Neglected parasitic infections in the United States: toxoplasmosis

Toxoplasma gondii is a leading cause of severe foodborne illness in the United States. Population-based studies have found T. gondii infection to be more prevalent in racial/ethnic minority and socioeconomically disadvantaged groups. Soil contaminated with cat feces, undercooked meat, and congenital transmission are the principal sources of infection. Toxoplasmosis-associated illnesses include congenital neurologic and ocular disease; acquired illness in immunocompetent persons, most notably ocular disease; and encephalitis or disseminated disease in immunosuppressed persons. The association of T. gondii infection with risk for mental illness is intriguing and requires further research. Reduction of T. gondii in meat, improvements in hygiene and food preparation practices, and reduction of environmental contamination can prevent toxoplasmosis, but more research is needed on how to implement these measures. In addition, screening and treatment may help prevent toxoplasmosis or reduce the severity of disease in some settings.

Prenatal exposures associated with neurodevelopmental delay and disabilities

Neurobehavioral teratology refers to the study of the abnormal development of the structure and the behavioral functions of the central nervous system, which result from exposure to exogenous agents during prenatal development. The focus of this review is the effects of various prenatal exposures on human neurodevelopment. Studies that deal with the adverse effects of infectious agents (rubella, cytomegalovirus, and toxoplasma), teratogenic drugs (e.g., antiepileptic drugs such as phenytoin, valproate, and carbamazepine, coumarin derivatives, and retinoids), alcohol, and other substances of abuse will be reviewed. Additionally, prenatal exposure to industrial or environmental chemicals (e.g., lead, methylmercury, and polycarbonated biphenyls) as well as exposure of the embryo or fetus to high amounts of ionizing radiation will be addressed. Possible mechanisms of selected neurobehavioral teratogens will also be discussed.

A review on human toxoplasmosis

Toxoplasmosis is a worldwide infection caused by the intracellular parasite Toxoplasma gondii. At least a third of the world human population are infected with the parasite, making it one of the most successful parasitic infections. Primary maternal infection may cause health-threatening sequelae for the foetus, or even cause death in uterus. Reactivation of a latent infection in immune deficiency conditions such as AIDS and organ transplantation can cause fatal toxoplasmic encephalitis. Toxoplasmosis is a major cause of retinochoroiditis, especially in individuals with an impaired immune system. Despite the usually 'asymptomatic' nature of the infection, a significant burden imposed by the parasite necessitates the implementation of effective means for the prevention, diagnosis, and management of this disease. Laboratory diagnosis, i.e. PCR and serologic assays, plays the main role in the diagnosis of congenital infection and assists in the confirmatory diagnosis of toxoplasmic encephalitis and ocular toxoplasmosis. Here, we briefly review general aspects of Toxoplasma infection and focus on the diagnostic methods currently used in medical laboratories for the diagnosis of Toxoplasma infection.

Decision analysis, economic evaluation, and newborn screening: challenges and opportunities

The number of conditions included in newborn screening panels has increased rapidly in the United States during the past decade, and many more conditions are under consideration for addition to state panels. The rare nature of candidate conditions for newborn screening makes their evaluation challenging. The scarcity of data on the costs of screening, follow-up, treatment, and long-term disability must be addressed to improve the evaluation process for nominated conditions. Decision analyses and economic evaluations can help inform policy decisions for newborn screening programs by providing a systematic approach to synthesizing available evidence and providing projected estimates of long-term clinical and economic outcomes when long-term data are not available. In this review, we outline the types of data required for the development of decision analysis and cost-effectiveness models for newborn screening programs and discuss the challenges faced when applying these methods in the arena of newborn screening to help inform policy decisions.Genet Med advance online publication 5 April 2012.

Epidemiology of and diagnostic strategies for toxoplasmosis

The apicomplexan parasite Toxoplasma gondii was discovered a little over 100 years ago, but knowledge of its biological life cycle and its medical importance has grown in the last 40 years. This obligate intracellular parasite was identified early as a pathogen responsible for congenital infection, but its clinical expression and the importance of reactivations of infections in immunocompromised patients were recognized later, in the era of organ transplantation and HIV infection. Recent knowledge of host cell-parasite interactions and of parasite virulence has brought new insights into the comprehension of the pathophysiology of infection. In this review, we focus on epidemiological and diagnostic aspects, putting them in perspective with current knowledge of parasite genotypes. In particular, we provide critical information on diagnostic methods according to the patient's background and discuss the implementation of screening tools for congenital toxoplasmosis according to health policies.

Congenital parasitic infections: a review

This review defines the concepts of maternal-fetal (congenital) and vertical transmissions (mother-to-child) of pathogens and specifies the human parasites susceptible to be congenitally transferred. It highlights the epidemiological features of this transmission mode for the three main congenital parasitic infections due to Toxoplasma gondii, Trypanosoma cruzi and Plasmodium sp. Information on the possible maternal-fetal routes of transmission, the placental responses to infection and timing of parasite transmission are synthesized and compared. The factors susceptible to be involved in parasite transmission and development of congenital parasitic diseases, such as the parasite genotypes, the maternal co-infections and parasitic load, the immunological features of pregnant women and the capacity of some fetuses/neonates to overcome their immunological immaturity to mount an immune response against the transmitted parasites are also discussed and compared. Analysis of clinical data indicates that parasitic congenital infections are often asymptomatic, whereas symptomatic newborns generally display non-specific symptoms. The long-term consequences of congenital infections are also mentioned, such as the imprinting of neonatal immune system and the possible trans-generational transmission. The detection of infection in pregnant women is mainly based on standard serological or parasitological investigations. Amniocentesis and cordocentesis can be used for the detection of some fetal infections. The neonatal infection can be assessed using parasitological, molecular or immunological methods; the place of PCR in such neonatal diagnosis is discussed. When such laboratory diagnosis is not possible at birth or in the first weeks of life, standard serological investigations can also be performed 8-10 months after birth, to avoid detection of maternal transmitted antibodies. The specific aspects of treatment of T. gondii, T. cruzi and Plasmodium congenital infections are mentioned. The possibilities of primary and secondary prophylaxes, as well as the available WHO corresponding recommendations are also presented.

Investigation and management of Toxoplasma gondii infection in pregnancy and infancy: a prospective study

AIM

Toxoplasma gondii infection during pregnancy poses a serious risk to the fetus, therefore timely and accurate diagnosis is essential. The aim of this study was to estimate the frequency of congenital infection via evaluating mother's immunological status and the possibility to improving the diagnostic and therapeutic approaches.

METHODS

Eighty five mothers with Toxoplasma seroconversion and their offspring were enrolled (among them, 2 spontaneous abortions were documented in the first trimester). Prenatal PCR diagnosis was carried out on 50 patients (60%), with 7 positive cases (14%). Morphological ultrasound scanning revealed anomalies in one fetus. Long-term follow-up included general physical examinations, serological status tested using Western blot, neuro-radiological, ophthalmologic and neurologic examinations, psychological and developmental tests, visual evoked potential tests and audiology tests, as well as anti-Toxoplasma treatment regimes.

RESULTS

Fourteen (17%) of the infants were infected at one-year serological follow-up. Chi-square for linear trend of vertical transmission from the first to the third trimester was significant (P=0.009). Western blot analysis showed IgM and IgA in half of the infected infants. In 69 uninfected infants, anti-Toxoplasma IgG immunoblot analysis excluded infection within the 3 months in 18 infants (26%) and in the others within 6 months of life. The most relevant instrumental findings are described.

CONCLUSION

Western blot analysis may help to evaluate infection within the 6 months of life. The accuracy of ultrasound imaging to determine the brain damage in the fetus and newborns is doubtful, and should be combined with MR imaging. Multistep approaches can improve the timing of postnatal follow-up.

Clinical manifestations of ocular toxoplasmosis

Clinical manifestations of ocular toxoplasmosis are reviewed. Findings of congenital and acute acquired ocular toxoplasmosis include retinal scars, white-appearing lesions in the active phase often associated with vitritis. Complications can include fibrous bands, secondary serous or rhegmatogenous retinal detachments, optic neuritis and neuropathy, cataracts, increased intraocular pressure during active infection, and choroidal neovascular membranes. Recurrences in untreated congenital toxoplasmosis occur in teenage years. Manifestations at birth are less severe, and recurrences are fewer in those who were treated promptly early in the course of their disease in utero and in the first year of life. Severe retinal involvement is common at diagnosis of symptomatic congenital toxoplasmosis in the United States and Brazil. Acute acquired infections also may be complicated by toxoplasmic retinochoroiditis, with recurrences most common close to the time of acquisition. Suppressive treatment can reduce recurrent disease.

Newborn screening: how are we travelling, and where should we be going?

In general, newborn screening is now a highly successful enterprise. The introduction of tandem mass spectrometry in the mid-1990s changed the pace of screening, raising its profile and increasing its relevance to a wider range of health professionals. The clinical effectiveness is not in doubt for some conditions, but is lacking for others. Evaluation has major difficulties for the rarer disorders and has been sadly neglected. Partly because clinical effectiveness has not been enthusiastically addressed, but also because of undue caution on the part of regulators, who often seem to ignore available evidence, there are huge differences in the adoption of screening programmes in different jurisdictions. New treatments, especially mutation-specific treatments, and technological advances in diagnostic testing are being rapidly developed, and this will further change the face of newborn screening and probably magnify these differences. The challenges will be considerable, especially with the increasing availability of DNA testing at modest cost. It is likely that there will be pressure to change the aims of newborn screening to encompass "personalised medicine". We must all prepare in a thoughtful way for these future challenges.