Low incidence of toxoplasma infection during pregnancy and in newborns in Sweden

Congenital toxoplasmosis in humans: an update of worldwide rate of congenital infections

The morbidity due to congenital toxoplasmosis in humans is very high. Most of these infected children are likely to develop symptoms of clinical toxoplasmosis. Sequelae in fetus resulting from Toxoplasma gondii infections in women who become infected with this parasite during pregnancy can be devastating and enormous efforts are directed in some countries to prevent these consequences. Here, an update on congenital toxoplasmosis in humans, especially the rate of congenital infections in humans worldwide, is provided. Although several countries have surveillance programmes, most information on the rate of congenital transmission is from France and Brazil. Because of compulsory national screening programme in France to detect and treat women with recently acquired T. gondii infection with anti-toxoplasma therapy, the rate of congenital transmission and the severity of disease in children are declining. Infections by this parasite are widely prevalent in Brazil. The severity of clinical toxoplasmosis in Brazilian children is very high and may be associated with the genetic characteristics of T. gondii isolates prevailing in animals and humans in Brazil. Virtually little or no information is available on this topic from China, India and other countries in Asia.

Surveillance of foodborne parasitic diseases in Europe in a One Health approach

In 2012, WHO/FAO ranked 24 foodborne parasites (FBP) using multicriteria decision analysis (MCDA) to provide risk assessors with a basis for prioritising control of highly ranked FBP on the global level. One conclusion was that ranking may differ substantially per region. In Europe, the same methodology was used to rank FBP of relevance for Europe. Of the 24 FBP, the top-five prioritised FBP were identified for Europe as Echinococcus multilocularis, Toxoplasma gondii, Trichinella spiralis, E. granulosus, and Cryptosporidium spp., all of which are zoonotic. The objective of the present study was to provide an overview of surveillance and reporting systems in Europe for these top five prioritised FBP in the human and animal populations, to identify gaps, and give recommendations for improvement. Information on the surveillance systems was collected from 35 European countries and analysed according to the five different regions. For most FBP, human surveillance is passive in most countries and regions in Europe and notification differs between countries and regions. Adequate surveillance programmes for these FBP are lacking, except for T. spiralis, which is notifiable in 34 countries with active surveillance in susceptible animals under EU directive. Although human and animal surveillance data are available for the five prioritised FBP, we identified a lack of consistency in surveillance and reporting requirements between national experts and European bodies. Recommendations for improved surveillance systems are discussed.

Seroprevalence of Toxoplasma gondii among pregnant women attending antenatal clinics at Hawassa University comprehensive specialized and Yirgalem General Hospitals, in Southern Ethiopia

BACKGROUND

Toxoplasmosis is caused by infection with the protozoan parasite Toxoplasma gondii. It is acquired by consumption of raw or undercooked meat containing tissue cyst, food or water contaminated with oocyst and congenital infection through the placenta leading to serious congenital abnormalities in the fetus like miscarriage, stillbirth, intrauterine death and neurologic defects. Therefore; this study was aimed to determine the prevalence of toxoplasmosis infection and its possible risk factors associated with pregnant women attending antenatal clinics in Hawassa and Yiregalem Hospitals, Southern Ethiopia.

METHODS

A hospital-based cross-sectional study was conducted from December 2016 to May 2017. The study was done in antenatal care clinics of Hawassa and Yiregalem Hospitals in Southern, Ethiopia. Five hundred pregnant women were interviewed with a pretested structured questionnaire to collect risk factors and socio-demographic data. Blood samples were collected and serum was separated and tested for anti- Toxoplasma gondii antibodies using ELISA (Enzyme-linked Immunosorbent Assay). Data were analyzed using SPSS version 20 statistical software. The risk factors were tested for significance using Bivariate and multivariate analysis. P-value < 0.05 was considered statistically significant.

RESULTS

The weighted prevalence of this study was 81.8% for the anti- Toxoplasma gondii antibody. Almost all participants (99.6%) had no information about the disease. A significant association was observed between seroprevalence and contact with domestic cats (OR = 1.206, 95% CI (1.627-2.206, P = 0.043), consumption of raw meat (OR = 0.848, 95% CI: 1.517-2.941, P = 0.019) and unpasteurized milk (OR = 0.871, 95% CI 1.531-2.221, P = 0.032). A significant association was not observed between seroprevalence and age, history of abortion, and blood transfusion.

CONCLUSIONS

The findings of this study demonstrated a relatively higher prevalence of seropositivity than studies reported from other countries. Existence of domestic cats at home, consumption of undercooked meat and unpasteurized milk were identified as risk factors for T. gondii infection. Therefore, a health education program to increase the mother's knowledge about toxoplasmosis towards avoiding eating undercooked meat, contact with cats and consumption of unpasteurized milk during pregnancy is recommended. Furthermore, our results suggested that the implementation of newborn screening and follow-up testing can lead to reducing of toxoplasmosis associated complications.

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.

Congenital toxoplasmosis among Iranian neonates: a systematic review and meta-analysis

Toxoplasmosis is a serious zoonotic disease that can lead to abortion and congenital disorders and has a widespread global distribution in humans and animals. The objective of this review was to investigate the incidence of toxoplasmosis in Iranian neonates in order to obtain a comprehensive assessment of the overall situation of the disease for use in developing future interventions. Original studies investigating the incidence of Toxoplasma gondii infections in Iranian neonates were systematically searched in a number of English-language and Persian-language electronic databases. The search process resulted in the inclusion of a total of 11 studies in the systematic review, 10 of which were entered into the meta-analysis. The reviewed articles included 2,230 Iranian neonates investigated through January 1, 2018. Based on the retrieved studies, the overall weighted incidence rates of toxoplasmosis in the Iranian neonatal population and neonates with suspected congenital toxoplasmosis were estimated to be 0.64% (95% confidence interval [CI], 0.31 to 1.09) and 4.10% (95% CI, 2.68 to 5.77), respectively, using a fixed-effects model. The findings of the reviewed studies demonstrate that the incidence of toxoplasmosis is high in Iranian neonates. Accordingly, it can be concluded that toxoplasmosis is a serious public health concern that has been ignored by the Ministry of Health. Therefore, it is essential to perform further studies, in addition to implementing screening and detection programs, using standardized methods to estimate the incidence of toxoplasmosis in Iran and to determine its associated risk factors.

Utility of routine urine CMV PCR and total serum IgM testing of small for gestational age infants: a single center review

BACKGROUND

Due to the extremely low incidence of TORCH (toxoplasmosis, rubella, CMV, herpes simplex virus) infections, diagnostic testing of all small for gestational age (SGA) infants aimed at TORCH etiologies may incur unnecessary tests and cost.

OBJECTIVE

To determine the frequency of urine CMV PCR and total IgM testing among infants with birth weight <10% and the rate of test positivity. To evaluate the frequency of alternative etiologies of SGA in tested infants.

METHODS

Retrospective chart review of SGA infants admitted to the neonatal intensive care unit (NICU) at NYU Langone Medical Center between 2007 and 2012. Subjects were classified as being SGA with or without intrauterine growth restriction (IUGR). The IUGR subjects were then further categorized as having either symmetric or asymmetric IUGR utilizing the Fenton growth chart at birth. Initial testing for TORCH infections, which included serum total IgM, CMV PCR and head ultrasound, were reviewed and analyzed.

RESULTS

Three hundred and eighty-six (13%) infants from a total of 2953 NICU admissions had a birth weight ≤10th percentile. Of these, 44% were IUGR; 34% being symmetric IUGR and 10% asymmetric. A total of 32% of SGA infants had urine CMV PCR and total IgM tested with no positive results. As expected, significantly higher percentage of symmetric IUGR infants were tested compared to asymmetric IUGR and non-IUGR SGA infants, (64% vs. 47% vs. 19%) P≤0.01. However, 63% of infants with a known cause for IUGR had same testing done aimed at TORCH infections. We calculated additional charges of $64,065 that were incurred by such testing.

CONCLUSIONS

The majority of infants in our study who received testing for urine CMV PCR and total IgM aimed at TORCH infections had one or more other known non-infectious etiologies for IUGR. Because the overall yield of such testing is extremely low, we suggest tests for possible TORCH infections may be limited to symmetric IUGR infants without other known etiologies. Improved guidelines testing for TORCH infections can result in reducing hospital charges and unnecessary studies.

IgG Avidity Test in Congenital Toxoplasmosis Diagnoses in Newborns

The goal of this study was to investigate the importance of IgG avidity testing in newborns (NBs) diagnosed with early congenital toxoplasmosis. We collected samples from 88 puerperae infected by Toxoplasma gondii (T. gondii) and their NBs (48 acutely-infected puerperae (AIP) and 40 chronically-infected puerperae (CIP)), from two public maternity hospitals in Goiania city, Goias, Brazil, from 2010 to 2015. Specific anti-T. gondii IgM and IgG serum levels and IgG avidity tests were evaluated using chemiluminescence. Congenital toxoplasmosis was observed in 66.66% (n = 32) of NBs with AIP, 94.1% presenting low avidity (LA) and 51.61% presenting high avidity (HA) test results. The IgG and IgM levels of NBs with LA and their puerperae were higher in comparison with HA NBs and puerperae (p = 0.0001). The avidity tests showed 100% specificity and 50% sensitivity (p = 0.0001). NBs with LA had a 15-fold increased risk of developing congenital toxoplasmosis in comparison with HA NBs. The IgG avidity test could be used to assist in early congenital toxoplasmosis diagnoses in NBs and LA, identifying a greater probability of vertical transmission.

Toxoplasma gondii-A Gastrointestinal Pathogen Associated with Human Brain Diseases

Serious psychiatric disorders such as schizophrenia, bipolar disorder, and major depression are important causes of mortality and morbidity worldwide. While these are primarily diseases involving altered brain functioning, numerous studies have documented increased rates of gastrointestinal inflammation and dysfunction in many individuals with these disorders. Toxoplasma gondii is an apicomplexan protozoan intracellular parasite with a widespread distribution in both developed and developing countries. Toxoplasma organisms enter the ecosystem through the shedding of oocysts by Toxoplasma-infected felines. In almost all cases of postnatal human infection, Toxoplasma enters its hosts through the intestinal tract either by the ingestion of oocysts or by the consumption of meat from food animals which themselves were infected by Toxoplasma oocysts. It had previously been thought that most cases of Toxoplasma infection in immune competent children and adults were inapparent and asymptomatic. However, recent studies cast doubt on this concept as exposure to Toxoplasma has been associated with a range of acute and chronic symptoms. Of particular note has been the finding of an increased rate of a range of neurological and psychiatric disorders associated with serological evidence of Toxoplasma exposure. A role of Toxoplasma infection in brain diseases is also supported by the consistent finding of altered cognition and behavior in animal models of infections. Much of the attention relating to the role of Toxoplasma infection in neuropsychiatric disorders has focused on the brain, where Toxoplasma tissue cysts can persist for extended periods of time. However, recent discoveries relating to the role of the gastrointestinal tract in cognition and behavior suggest that Toxoplasma may also increase susceptibility to human brain diseases through immune activation, particularly involving the gastrointestinal mucosa. The study of the pathways relating to the pathobiology and immunology of Toxoplasma infection may provide insights into the pathogenesis of a range of human neuropsychiatric disorders as well as into cognitive functioning in otherwise healthy individuals.

Spiramycin/cotrimoxazole versus pyrimethamine/sulfonamide and spiramycin alone for the treatment of toxoplasmosis in pregnancy

OBJECTIVE

To compare the effectiviness of spiramycin/cotrimoxazole (Sp/C) versus pyrimethamine/sulfonamide (Pyr/Sul) and spiramycin alone (Spy) on mother-to-child transmission of toxoplasmosis infection in pregnancy.

STUDY DESIGN

Retrospective study of pregnant women evaluated for suspected toxoplasmosis between 1992 and 2011.

RESULT

A total of 120 mothers and their 123 newborns were included. Prenatal treatment consisted of spiramycin in 43 mothers (35%), spiramycin/cotrimoxazole in 70 (56.9%) and pyrimethamine/sulfonamide in 10 (8.1%). A trend toward reduction in toxoplasmosis transmission was found when Sp/C was compared with Pyr/Sul and particularly with Spy alone (P=0.014). In particular, Spy increased the risk of congenital infection when compared with Sp/C (odds ratio (OR) 4.368; 95% CI: 1.253 to 15.219), but there was no significant reduction when Sp/C was compared with Pyr/Sul (OR 1.83; 95% CI: 0.184 to 18.274).

CONCLUSION

The treatment based on Sp/C has significant efficacy in reducing maternal-fetal transmission of Toxoplasma gondii when compared with Pyr/Sul and particularly to Spy. Randomized controlled trials would be required.

Seroprevalence and Associated Risk Factors of Toxoplasma gondii in Pregnant Women Attending in Northwest Ethiopia

BACKGROUND

Toxoplasmosis is a major public health problem among immuno-compromised individuals. This study aimed to determine the seroprevalence and associated risk factors of Toxoplasma gondii infection among pregnant women with and out HIV infections.

METHODS

This cross sectional study was conducted among consecutive 385 pregnant women attended Antenatal Clinic from May 2010 to October 2011 at the Gondar University Teaching Hospital, Northwest Ethiopia. Venous blood was collected from each pregnant woman for testing HIV-1/2 and anti- Toxoplasma antibodies using rapid test kits. Data were entered and analyzed using SPSS version 20 statistical package.

RESULTS

The overall magnitude of T. gondii and HIV was 88.6% (341/385) and 11.2% (43/385), respectively. The seroprevalence of T. gondii was not different among HIV infected and non-infected pregnant women (88.4%, 38/ 43 vs 88.6%, 303/342). Keeping cats in house showed statistically significant association with seropositivity of toxoplasmosis (P<0.05).

CONCLUSION

Irrespective of HIV infection, high rate of T. gondii was detected among pregnant women. These high prevalences indicate the need for an intensified public health awareness to reduce both infections.

Toxoplasmosis--a global threat. Correlation of latent toxoplasmosis with specific disease burden in a set of 88 countries

BACKGROUND

Toxoplasmosis is becoming a global health hazard as it infects 30-50% of the world human population. Clinically, the life-long presence of the parasite in tissues of a majority of infected individuals is usually considered asymptomatic. However, a number of studies show that this 'asymptomatic infection' may also lead to development of other human pathologies.

AIMS OF THE STUDY

The purpose of the study was to collect available geoepidemiological data on seroprevalence of toxoplasmosis and search for its relationship with mortality and disability rates in different countries.

METHODS AND FINDINGS

Prevalence data published between 1995-2008 for women in child-bearing age were collected for 88 countries (29 European). The association between prevalence of toxoplasmosis and specific disease burden estimated with age-standardized Disability Adjusted Life Year (DALY) or with mortality, was calculated using General Linear Method with Gross Domestic Product per capita (GDP), geolatitude and humidity as covariates, and also using nonparametric partial Kendall correlation test with GDP as a covariate. The prevalence of toxoplasmosis correlated with specific disease burden in particular countries explaining 23% of variability in disease burden in Europe. The analyses revealed that for example, DALY of 23 of 128 analyzed diseases and disease categories on the WHO list showed correlations (18 positive, 5 negative) with prevalence of toxoplasmosis and another 12 diseases showed positive trends (p<0.1). For several obtained significant correlations between the seroprevalence of toxoplasmosis and specific diseases/clinical entities, possible pathophysiological, biochemical and molecular explanations are presented.

CONCLUSIONS

The seroprevalence of toxoplasmosis correlated with various disease burden. Statistical associations does not necessarily mean causality. The precautionary principle suggests however that possible role of toxoplasmosis as a triggering factor responsible for development of several clinical entities deserves much more attention and financial support both in everyday medical practice and future clinical research.

[Seroprevalence of toxoplasmosis in pregnant women in Annaba, Algeria]

BACKGROUND

The aim of the study was to estimate the seroprevalence and risk factors of toxoplasmosis in pregnant women in the department of Annaba, Algeria.

METHODS

We performed a cross-sectional study with analytical purposes. The study was collaboration between the laboratory of Parasitology-Mycology, Faculty of Medicine of Annaba and Parasite Biology Department at the Pasteur Institute of Algeria. A total of 1028 pregnant women who underwent prenatal diagnosis/visit were included over a period of 4 years from January 2006 to December 2009. Immunoglobulin G and M were assayed, using the microparticle enzyme method. The avidity test was used to determine the date of contamination according to age of pregnancy. Search for the parasite was made by inoculation of the placenta and cord blood in white mice. The study compared mother-to-child serological profiles using Western Blot (WB) IgG and IgM. Direct (not well-cooked meat) and indirect (presence of cat, gardening) indicators were recorded to search for parasite exposure.

RESULTS

Seroprevalence was 47.8 % (95 % CI: 44.8 to 51.0) and the rate of active toxoplasmosis was 1.1 % (95 % CI 0.6 to 1.8). According to their immune status, this was the first serology for 41 % (CI95 %: 38.0-44.0) of women; 12 % (CI95 %: 10.5-14.6) of primiparous women had only one serology test during their entire pregnancy. Major risk factors were consumption of poorly-cooked meat and exposure to cats.

CONCLUSION

Toxoplasmosis during pregnancy is a serious issue and an effective prevention program is needed.

Toxoplasmosis in pregnancy in an area with low seroprevalence: is prenatal screening still worthwhile?

BACKGROUND

The effectiveness of Toxoplasma gondii (Tg) screening during pregnancy in areas with a low prevalence of the infection is debated. We investigate the Tg serological status, the rate of primary infection in a cohort of pregnant women and the rate of congenital toxoplasmosis among their infants during a 3-year period in an urban area with low Tg prevalence.

METHODS

Demographic and Tg serological data for all pregnant women delivering from January 2009 to December 2011 were collected. All pregnant women with primary Tg infection during pregnancy and their infants were included in the study.

RESULTS

In early pregnancy, 10,347 women underwent prenatal screening and 2308 (22.3%) had anti-Tg. The seroprevalence among non-native women was significantly higher than that among native women [32.8% vs. 19.1%, relative risk: 1.71, P < 0.001]. The incidence rate of primary Tg infection during pregnancy was 0.77%. Immigrant women were more likely to be infected during pregnancy than Italian women (relative risk: 4.88, P < 0.001). Tg infection was more frequent in women coming from Africa, Asia, Eastern Europe and South America. The CT incidence rate was 0.06%. All congenitally infected infants were born to immigrant mothers.

CONCLUSIONS

Tg infection during pregnancy and congenital disease are more frequent in non-native mothers and their infants. Measures to prevent Tg exposition must be carefully explained to pregnant women, with a focus on specific habits in non-native women. Prenatal screening is still effective to select women for prenatal therapy aiming to decrease vertical transmission and to identify foetuses/newborns with congenital disease that could benefit from pre/postnatal antiparasitic therapy.

A dedicated surveillance network for congenital toxoplasmosis in Greece, 2006-2009: assessment of the results

BACKGROUND

Toxoplasmosis is caused by infection with the protozoan parasite Toxoplasma gondii. Acute infections in pregnant women may be transmitted to the fetus and cause severe illness. The purpose of this study was to establish a dedicated surveillance network (DSN) for congenital toxoplasmosis (CT) in Greece, in order to assess the birth prevalence of CT.

METHODS

A DSN of thirty clinicians was established for reporting CT cases from hospitals throughout Greece. The clinicians were selected on the basis that there was a high possibility the suspected cases would be referred to them from district hospitals or private clinics. Suspected cases of CT were reported on a monthly basis with a zero reporting card during a surveillance period from April 2006 to December 2009. A questionnaire was sent for any suspected case to record information including demographic parameters, clinical signs and symptoms and laboratory results. Serological and molecular confirmation of cases was performed by the Pasteur Hellenic Institute. All newborns suspected of CT received treatment and were serologically and clinically followed up for one year.

RESULTS

The monthly response rate reached 100%, although only after reminders sent to 65% of the participant physicians. Sixty-three suspected CT cases were recorded by the DSN during the study period including fourteen confirmed and seven probable cases. Ten cases (47.6%) presented with symptoms at birth. Chorioretinitis was the most prominent manifestation, occurring in five symptomatic CT cases (50%). No other symptoms appeared by the end of the one year clinical follow up. No case was recorded by the existing surveillance system of the Hellenic Center of Disease Control and Prevention (HCDCP) during the same time period. Birth prevalence was estimated at 0.45, 0.51 and 0.51 per 10,000 births for 2007, 2008 and 2009 respectively. The incidence rate of symptomatic CT at birth was estimated at 0.10 cases per 10,000 births per year in Greece (for the period 2007-2009).

CONCLUSION

The DSN for CT proved to be more sensitive than the classical notification system, easy in application and very efficient in reporting rare diseases such as CT. Similar DSNs could be used to provide useful information on other rare diseases.

Incidence of congenital toxoplasmosis in the City of Belém, State of Pará, Northern Brazil, determined by a neonatal screening program: preliminary results

INTRODUCTION

The aim of this study was to determinate the incidence of congenital toxoplasmosis among a group of newborns (NBs) from Belém using neonatal screening.

METHODS

Among the 6,000 newborns referred for investigation of genetic and metabolic diseases, 1,000 were selected for screening for congenital toxoplasmosis by determining the amount of IgM in the eluates of blood collected on filter paper. Positive tests were confirmed using paired serology of the NB and his mother.

RESULTS

Out of the 1,000 NBs assessed, one had a positive screening result that was confirmed by paired serology.

CONCLUSIONS

The incidence of congenital toxoplasmosis in Belém was 10/10,000 live NBs.

Birth prevalence and characteristics of congenital toxoplasmosis in Sergipe, North-east Brazil

OBJECTIVES

To estimate, by neonatal screening, the birth prevalence of congenital toxoplasmosis among live-born infants in Sergipe state, Brazil, and to investigate the clinical features of affected infants.

METHODS

Dried blood spot specimens obtained from 15 204 neonates were assayed for the presence of anti-T. gondii IgM antibodies. Duplicate retesting was done in infants with positive and borderline results. Confirmatory testing in peripheral blood samples consisted of testing for anti-T. gondii IgG and IgM in infants and mothers. Those with possible congenital toxoplasmosis were evaluated and followed up to a median age of 20 months. Congenital infection was confirmed in the presence of persisting anti-T. gondii IgG antibodies beyond 12 months of age. All infants with confirmed infection were treated with pyrimethamine, sulfadiazine and folinic acid for 1 year.

RESULTS

  Fifty-three infants had detectable IgM in dried blood spot specimens. Confirmatory testing was reactive in 39/50, of which, 38 completed follow-up. Six of 15 204 newborns were diagnosed with congenital toxoplasmosis, resulting in an estimated birth prevalence of four per 10 000 [CI 95% 1.4-8.0]. Four infants (67%) showed signs of congenital toxoplasmosis in their first year of life; three (75%) had retinochoroidal scars, and one had cerebral calcifications. Two infants remained asymptomatic until 20 months of age.

CONCLUSIONS

The birth prevalence of congenital toxoplasmosis is high in the Brazilian state of Sergipe, with most of the infants showing ocular lesions. Preventive measures are strongly warranted.

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.

First Colombian multicentric newborn screening for congenital toxoplasmosis

Aims

To determine the incidence of congenital toxoplasmosis in Colombian newborns from 19 hospital or maternal child health services from seven different cities of five natural geographic regions (Caribbean, Central, Andean, Amazonia and Eastern).

Materials and Methods

We collected 15,333 samples from umbilical cord blood between the period of March 2009 to May 2010 in 19 different hospitals and maternal-child health services from seven different cities. We applied an IgM ELISA assay (Vircell, Spain) to determine the frequency of IgM anti Toxoplasma. The results in blood cord samples were confirmed either by western blot and repeated ELISA IgM assay. In a sub-sample of 1,613 children that were negative by the anti-Toxoplasma IgM assay, the frequency of specific anti-Toxoplasma IgA by the ISAGA assay was determined. All children with positive samples by IgM, IgA, clinical diagnosis or treatment during pregnancy were recalled for confirmatory tests after day 10 of life.

Results

61 positive samples for specific IgM (0.39%) and 9 positives for IgA (0.5%) were found. 143 questionnaires were positive for a clinical diagnosis or treatment for toxoplasmosis during pregnancy. 109 out of the 218 children that had some of the criteria for postnatal confirmatory tests were followed. Congenital toxoplasmosis infection was confirmed in 15 children: 7 were symptomatic, and three of them died before the first month of life (20% of lethality). A significant correlation was found between a high incidence of markers for congenital toxoplasmosis and higher mean annual rainfall for the city.

Conclusions

Incidence for congenital toxoplasmosis is significantly different between hospitals or maternal child health services from different cities in Colombia. Mean annual rainfall was correlated with incidence of congenital toxoplasmosis.

Congenital toxoplasmosis can result in permanent sequel as blindness or neurological damage in children and it seems to be more severe in South America than in other continents. There is a lack of information about this frequency in Colombia, where no control program is established, although it is a recognized cause of potentially preventable congenital blindness. We propose the first Colombian multicentric study to determine the frequency and impact of congenital toxoplasmosis. More than 15,000 newborns in seven cities were studied. Newborns were tested at birth by doing a cord blood test for toxoplasmosis. Additionally, children from mothers with history of toxoplasmosis acquired during pregnancy were recalled for a follow-up. The program identified fifteen children otherwise undiagnosed; three of these children died as consequence of congenital toxoplasmosis. The frequency of the congenital infection varied significantly between cities, being higher in Armenia and Florencia, intermediate in Bogota, Bucaramanga and Barranquilla and very low in western cities such as Cucuta and Riohacha. For the first time a significant correlation was found between mean rainfall at the city and the incidence of this congenital infection.

[Toxoplasmosis in Sfax, Tunisia]

Abstract The frequency of toxoplasmosis depends on life-style and environment. Our objective was to study different epidemiological, clinical and biological aspects of toxoplasmosis in the Sfax area (Tunisia). This retrospective study has been performed on seria of 40,566 pregnant women in the Parasitology-Mycology Laboratory of Habib-Bourguiba Sfax hospital-Tunisia for 13 years from 1994 to 2006; 1,691 patients presenting with lymphadenopathy; 191 immunocompromised patients (78 HIV infected patients and 113 transplanted patients) and 21 patients presenting clinical signs of ocular toxoplasmosis. In pregnant women, the seroprevalence was 39.3% (15,952/40,567). Among 24,089 seronegative women, only 6,890 (28.6%) had been followed up during their pregnancy. An active toxoplasmosis possibly acquired during pregnancy was detected in 1.3% of cases. Sixteen congenital toxoplasmosis were detected. Toxoplasmosis was confirmed in 13.7% of the 169 patients with lymphadenitis. For HIV positive patients, 11.7% had cerebral toxoplasmosis. It revealed the HIV infection in four cases. Among transplant recipients, one case of active toxoplasmosis was diagnosed in a renal transplant recipient who received transplant from a seronegative donor. Twenty-one patients presenting toxoplasmic retinochoroiditis were treated by subconjonctival injections of clindamycin and systemic corticotherapy at a dose of 1 mg/kg per day. This clinical toxoplasmosis diversity explains the need for bioclinical confrontation to establish diagnosis.

Seroprevalence of Toxoplasma gondii infection among immigrant and native pregnant women in Eastern Spain

In European countries, toxoplasma antenatal screening is recommended to prevent toxoplasmosis. The seroprevalence of these infections in immigrants can be different than in native population. From February 2006 to June 2010, a cross-sectional study was carried out in all pregnant women attended at a reference unit in Elche, Spain. An enzyme immunoassay was used for detection of IgG antibodies against Toxoplasma gondii. For each immigrant woman, one Spanish pregnant woman of the same age cared for in the same day was recruited (Spanish control group). A total of 1,627 migrant pregnant women participated in this study. The adherence to screening among migrants was 91.9% (95% CI, 90.5-93.1%), similar than that found in Spaniards (92.2%; 95% CI, 90.8-93-4%). Among migrant women, 619 were positive for IgG anti-T. gondii antibodies (41.4%; 95% CI, 38.9-43.9%), compared with 12.0% (95% CI, 10.5-13.8%) among Spaniards (odds ratio (OR), 5.2 (95% CI, 4.3-6.3). Seroprevalence in pregnant women from Latin America, northern Africa, Eastern Europe, Africa Sub-Saharan and Western Europe was higher than in the Spanish control group (OR, 5.4, 5.8, 6.5, 5.4, and 2.4, respectively; p < 0.001). No Asian pregnant woman was immune. Seroprevalence increased with increasing age in migrant pregnant women: 15-25 years, 38.2%; 26-35 years, 40.7%; and 36-45 years, 52.8%. The seroprevalence of T. gondii infection in migrant pregnant women living in Spain was higher than in the native population. However, no cases were found in Asian immigrants, highlighting the importance of primary prevention of this infection in pregnant women coming from that geographic region.

Increased seroprevalence of Toxoplasma gondii in a population of patients with Bell's palsy: a sceptical interpretation of the results regarding the pathogenesis of facial nerve palsy

Facial nerve oedema and anatomical predisposition to compression within the fallopian tube seem to be the only generally accepted facts in the pathophysiology of Bell's palsy. Several infectious causes have been suggested as possible triggers of this oedema. Most of the suggested pathogens have been associated with facial nerve lesions during latent infections, reinfections or endogenous reactivations. The aim of this study was to investigate the seroprevalence of three such pathogens Toxoplasma gondii, Epstein-Barr virus (EBV) and cytomegalovirus (CMV) in a population of patients with facial nerve palsy. Fifty-six patients with Bell's palsy were included in the study. A group of 25 individuals with similar age and gender distribution was used as control. Seropositivity for T. gondii, EBV viral capsid antigen (VCA) and CMV-specific IgM and IgG antibodies was investigated 2-5 days after the onset of the palsy. Comparisons for both IgM and IgG antibodies against T. gondii attributed significantly higher seroprevalence in the patients' group than in the control group (p = 0.024 and 0.013, respectively). The respective examinations for EBV and CMV attributed no significant results. The roles of EBV and CMV in the pathogenesis of Bell's palsy were not confirmed by this study. However, a significantly higher seroprevalence of IgM- and IgG-specific T. gondii antibodies was detected in patients with Bell's palsy when compared to healthy controls. The possibility that facial nerve palsy might be a late complication of acquired toxoplasmosis may need to be addressed in further studies.

Prenatal treatment for serious neurological sequelae of congenital toxoplasmosis: an observational prospective cohort study

BACKGROUND

The effectiveness of prenatal treatment to prevent serious neurological sequelae (SNSD) of congenital toxoplasmosis is not known.

METHODS AND FINDINGS

Congenital toxoplasmosis was prospectively identified by universal prenatal or neonatal screening in 14 European centres and children were followed for a median of 4 years. We evaluated determinants of postnatal death or SNSD defined by one or more of functional neurological abnormalities, severe bilateral visual impairment, or pregnancy termination for confirmed congenital toxoplasmosis. Two-thirds of the cohort received prenatal treatment (189/293; 65%). 23/293 (8%) fetuses developed SNSD of which nine were pregnancy terminations. Prenatal treatment reduced the risk of SNSD. The odds ratio for prenatal treatment, adjusted for gestational age at maternal seroconversion, was 0.24 (95% Bayesian credible intervals 0.07-0.71). This effect was robust to most sensitivity analyses. The number of infected fetuses needed to be treated to prevent one case of SNSD was three (95% Bayesian credible intervals 2-15) after maternal seroconversion at 10 weeks, and 18 (9-75) at 30 weeks of gestation. Pyrimethamine-sulphonamide treatment did not reduce SNSD compared with spiramycin alone (adjusted odds ratio 0.78, 0.21-2.95). The proportion of live-born infants with intracranial lesions detected postnatally who developed SNSD was 31.0% (17.0%-38.1%).

CONCLUSION

The finding that prenatal treatment reduced the risk of SNSD in infected fetuses should be interpreted with caution because of the low number of SNSD cases and uncertainty about the timing of maternal seroconversion. As these are observational data, policy decisions about screening require further evidence from a randomized trial of prenatal screening and from cost-effectiveness analyses that take into account the incidence and prevalence of maternal infection. Please see later in the article for the Editors' Summary.

Toxoplasmosis not transmitted by cat bite, but high prevalence of antibodies to Toxoplasma gondii in patients bitten by their own cat

The aims of the study were to investigate the prevalence of antibodies to Toxoplasma gondii in a group of patients bitten by cats, and also to determine if toxoplasmosis can be transferred by cat bite. Seventy-two patients who attended the emergency wards at 3 hospitals in Stockholm, Sweden, due to infection by cat bite, were investigated for specific IgM and IgG antibodies to T. gondii in the acute phase, as well as in the convalescent phase about 2 weeks later. Specific IgG antibodies to T. gondii (> or =8 IU/ml) were found in 17/72 patients (24%) in the acute phase. No case of seroconversion occurred. Patients who were bitten by their own cat had positive antibody titres to T. gondii significantly more often than those bitten by a foreign cat; 30% and 5%, respectively (p = 0.02). This suggests that regular contact with cats may contribute to the transmission of the parasite.

Decreased prevalence and age-specific risk factors for Toxoplasma gondii IgG antibodies in The Netherlands between 1995/1996 and 2006/2007

To estimate the change in the seroprevalence and risk factors for toxoplasmosis in The Netherlands, a study was conducted in the general population in 2006/2007, similarly designed as a previous study in 1995/1996. Testing 5541 sera for IgG antibodies against Toxoplasma gondii showed a marked decrease of the overall seroprevalence to 26·0% [95% confidence interval (CI) 24·0-28·0], compared to 40·5% (95% CI 37·5-43·4) in 1995/1996. In women of reproductive age the seroprevalence decreased from 35·2% (95% CI 32·9-38·6) in 1995/1996 to 18·5% (95% CI 16·2-20·7) in 2006/2007, leaving the majority of pregnant women susceptible to primary infection with T. gondii and their babies to congenital toxoplasmosis. In participants aged ≥20 years, Toxoplasma seropositivity was associated with living in the Northwest, living in urban areas, low educational level, consumption of raw pork, keeping a cat, and not having occupational contact with clients or patients. For younger participants, risk factors were keeping sheep or cattle, consumption of raw unwashed vegetables and putting sand in the mouth.

[Toxoplasmosis and pregnancy]

Toxoplasmosis is the most common etiology of posterior uveitis. Toxoplasma gondii infection during pregnancy means either primary infection and risk of congenital toxoplasmosis or acute retinochoroiditis in a pregnant woman (risk of transmission, severity of injuries, therapeutics). Ingestion or manipulation of raw or undercooked meat is responsible for most contaminations (one- to two-thirds) in pregnant women. Toxoplasmosis seroprevalence is high in Europe, up to 54 % in southern European countries. Primary prevention advice is proposed to immunocompetent pregnant women who are seronegative for toxoplasmosis. The risk of transplacental transmission congenital toxoplasmosis during pregnancy is analyzed. The ocular lesions include retinochoroiditis and a number of other lesions. The departments of ophthalmology and of parasitology of Croix-Rousse University Hospital (Hospices Civils de Lyon) is currently following one of the largest cohorts of children infected with T. gondii (430 children alive in 2005). Our overall transmission rate during primary infection was 30 %. Retinochoroiditis incidence was 24 % in our prospective cohort. During follow-up, recurrences appeared in 29 % of cases. Acute toxoplasmic retinochoroiditis in pregnancy could be a risk of transplacental transmission due to potential parasitemia. Practices in cases of suspected or proved congenital infection are discussed. The antiparasitic drugs authorized during pregnancy are azithromycin and pyrimethamine. Azithromycin can be used alone but an association with pyrimethamine during the second trimester is useful in case of macular threat.

What do we know about risk factors for infection in humans with Toxoplasma gondii and how can we prevent infections?

Fourteen case-control studies evaluating the importance of different risk factors for infection of humans with Toxoplasma gondii were identified. Surprisingly, up to two-thirds of infections could not be explained by risk factors such as consuming raw or undercooked meat or poor kitchen hygiene. Few studies reported population attributable risk, and when reported, it was low. Protocols including questionnaires used for collecting data, age and socio-economic groups studied, and sample sizes varied among studies. There is a need for carefully planned, case-control studies to identify sources of infection with T. gondii in humans. New risk factors, such as the manufacture of organic meat, and possible ways to sterilize meat to inactivate T. gondii tissue cysts are discussed.

Toxoplasmosis snapshots: global status of Toxoplasma gondii seroprevalence and implications for pregnancy and congenital toxoplasmosis

Toxoplasma gondii's importance for humans refers mainly to primary infection during pregnancy, resulting in abortion/stillbirth or congenital toxoplasmosis. The authors sought to evaluate the current global status of T. gondii seroprevalence and its correlations with risk factors, environmental and socioeconomic parameters. Literature published during the last decade on toxoplasmosis seroprevalence, in women who were pregnant or of childbearing age, was retrieved. A total of 99 studies were eligible; a further 36 studies offered seroprevalence data from regions/countries for which no data on pregnancy/childbearing age were available. Foci of high prevalence exist in Latin America, parts of Eastern/Central Europe, the Middle East, parts of south-east Asia and Africa. Regional seroprevalence variations relate to individual subpopulations' religious and socioeconomic practices. A trend towards lower seroprevalence is observed in many European countries and the United States of America (USA). There is no obvious climate-related gradient, excluding North and Latin America. Immigration has affected local prevalence in certain countries. We further sought to recognise specific risk factors related to seropositivity; however, such risk factors are not reported systematically. Population awareness may affect recognition of said risks. Global toxoplasmosis seroprevalence is continuingly evolving, subject to regional socioeconomic parameters and population habits. Awareness of these seroprevalence trends, particularly in the case of women of childbearing age, may allow proper public health policies to be enforced, targeting in particular seronegative women of childbearing age in high seroprevalence areas.

Congenital toxoplasmosis: priorities for further health promotion action

Toxoplasmosis is a disease of considerable public health impact. As the transmission, occurrence and phenotype of this disease are influenced in a complex way by host genetics, immunity, behaviour and by the agent characteristics, prevention will not be simple. This article aimed to review studies defining seroprevalence of and characteristic sociodemographic, biological and lifestyle risk factors for Toxoplasma gondii infection in pregnant women, to evaluate screening and educational programmes, and to assemble recommendations for combating toxoplasmosis in populations at risk. Electronic databases were searched, using a specific search strategy, from 1975 to 2007. There is a high prevalence of T. gondii antibodies in pregnant women worldwide, with some geographic discrepancies attributed to climatic conditions, local food customs, hygiene, lifestyle and cultural differences. The main risk factors for toxoplasmosis in pregnant women are unsanitary feeding habits, poor immune system, contact with cats, contact with soil, pregnancy, number of births, older age, race, travelling outside the country, drinking beverages prepared with unboiled water, consumption of municipal or uncontrolled (well/spring) water and T. gondii strain virulence. Knowledge of these risk factors helps to identify priorities for further epidemiological work and defines effective preventive measures along five main themes of action: information and health education; screening of pregnant women and infants; limiting harm from risk behaviour; treatment of cases found to be at risk; and vaccination.

Toxoplasmosis

Infections with Toxoplasma gondii occur worldwide, but are especially prevalent in Europe, South America and Africa. The primary problem for the diagnosis of T. gondii infection is long-lasting IgM-antibodies, thus the presence of T. gondii-specific IgM-antibodies do not necessarily indicate an acute infection. The use of a Toxoplasma-specific IgG-avidity ratio, differentiated Western blots and two-dimensional immunoblots usually resolves diagnostic problems. There is no consensus on the best strategy to control congenital toxoplasmosis. Recent European prospective, but descriptive, studies including a meta-analysis of existing cohorts have found a surprisingly small effect on maternal-fetal transmission and clinical signs in children treated for T. gondii infection diagnosed by pre- and neonatal screening programmes. No randomised studies exist on the treatment of T. gondii infection in pregnant women and newborn children with congenital toxoplasmosis. Atovaquone is the most promising new drug available, but is not yet approved for use in pregnant women and small children.

Can the common brain parasite, Toxoplasma gondii, influence human culture?

The latent prevalence of a long-lived and common brain parasite, Toxoplasma gondii, explains a statistically significant portion of the variance in aggregate neuroticism among populations, as well as in the 'neurotic' cultural dimensions of sex roles and uncertainty avoidance. Spurious or non-causal correlations between aggregate personality and aspects of climate and culture that influence T. gondii transmission could also drive these patterns. A link between culture and T. gondii hypothetically results from a behavioural manipulation that the parasite uses to increase its transmission to the next host in the life cycle: a cat. While latent toxoplasmosis is usually benign, the parasite's subtle effect on individual personality appears to alter the aggregate personality at the population level. Drivers of the geographical variation in the prevalence of this parasite include the effects of climate on the persistence of infectious stages in soil, the cultural practices of food preparation and cats as pets. Some variation in culture, therefore, may ultimately be related to how climate affects the distribution of T. gondii, though the results only explain a fraction of the variation in two of the four cultural dimensions, suggesting that if T. gondii does influence human culture, it is only one among many factors.

Effectiveness of prenatal treatment for congenital toxoplasmosis: a meta-analysis of individual patients' data

BACKGROUND

Despite three decades of prenatal screening for congenital toxoplasmosis in some European countries, uncertainty remains about the effectiveness of prenatal treatment.

METHODS

We did a systematic review of cohort studies based on universal screening for congenital toxoplasmosis. We did a meta-analysis using individual patients' data to assess the effect of timing and type of prenatal treatment on mother-to-child transmission of infection and clinical manifestations before age 1 year. Analyses were adjusted for gestational age at maternal seroconversion and other covariates.

FINDINGS

We included 26 cohorts in the review. In 1438 treated mothers identified by prenatal screening, we found weak evidence that treatment started within 3 weeks of seroconversion reduced mother-to-child transmission compared with treatment started after 8 or more weeks (adjusted odds ratio [OR] 0.48, 95% CI 0.28-0.80; p=0.05). In 550 infected liveborn infants identified by prenatal or neonatal screening, we found no evidence that prenatal treatment significantly reduced the risk of clinical manifestations (adjusted OR for treated vs not treated 1.11, 95% CI 0.61-2.02). Increasing gestational age at seroconversion was strongly associated with increased risk of mother-to-child transmission (OR 1.15, 95% CI 1.12-1.17) and decreased risk of intracranial lesions (0.91, 0.87-0.95), but not with eye lesions (0.97, 0.93-1.00).

INTERPRETATION

We found weak evidence for an association between early treatment and reduced risk of congenital toxoplasmosis. Further evidence from observational studies is unlikely to change these results and would not distinguish whether the association is due to treatment or to biases caused by confounding. Only a large randomised controlled clinical trial would provide clinicians and patients with valid evidence of the potential benefit of prenatal treatment.

The national neonatal screening programme for congenital toxoplasmosis in Denmark: results from the initial four years, 1999-2002

AIMS

To describe the outcome of four years' nationwide neonatal screening for congenital toxoplasmosis in liveborn newborns.

METHODS

Congenital toxoplasmosis was diagnosed if specific Toxoplasma gondii IgM antibodies were detected in eluate from the PKU Guthrie filter paper card from a child. Infants diagnosed with congenital toxoplasmosis were examined for intracranial and retinal lesions and treated for three months with sulphadiazine, pyrimethamine, and folinic acid continuously.

RESULTS

Eluates from PKU-cards from 262 912 newborns were analysed. The birth prevalence of congenital toxoplasma infection was 2.1 per 10 000 liveborns. Congenital toxoplasmosis was suspected in 96 infants and confirmed in 55. Forty seven children were examined for intracranial and retinal lesions soon after birth; 12 had clinical signs at this first examination. Of these, 5 had intracranial calcifications, 2 had retinochoroidal lesions, 4 had intracranial calcifications and retinochoroidal lesions, and 1 had hydrocephalus, intracranial calcifications, and retinochoroidal lesions. Ninety four eyes were examined soon after birth; there were central retinochoroidal lesions in 9. Two children had macular lesion of both eyes, five had macular lesions of one eye. At 1 year of age, 10/68 eyes had central lesions, and at 3 years of age, 5/32 had central lesions. Thus new retinochoroidal lesions developed in three eyes in the observation period.

CONCLUSIONS

Neonatal screening is feasible for diagnosing children with congenital toxoplasmosis at birth in low endemic areas. Retinochoroiditis with macular lesion was diagnosed in 9.6% of the eyes at birth and in 15.6% of the eyes examined at 3 years of age.

Newborn screening for congenital toxoplasmosis: feasible, but benefits are not established

Perspective on the paper by Schmidt et al (see page 661)

Symptomatic toxoplasma infection due to congenital and postnatally acquired infection

AIMS

To determine the incidence and severity of symptomatic toxoplasma infection presenting during childhood due to congenital or postnatally acquired infection.

METHODS

Between 2002 and 2004, newly diagnosed children (<16 years) with signs or symptoms of congenital or ocular toxoplasmosis were reported by clinicians to the British Paediatric and Ophthalmic Surveillance Units or by toxoplasma referral laboratories. Confirmed cases were estimated to have a greater than 50% probability of congenital and/or ocular toxoplasmosis, based on clinical and serological findings.

RESULTS

Thirty eight children had confirmed toxoplasma infection. Twenty two (58%) were classified with congenital infection (cumulative incidence for England and Wales 1.62[corrected]/100,000 live births; 95% CI 0.85[corrected] to 2.83[corrected]), of whom 2 (9%) were stillborn, 7 (32%) live births had intracranial abnormalities and/or developmental delay (5 of whom had retinochoroiditis), and 10 (45%) had retinochoroiditis with no other abnormalities reported. A further 16 (42%) children were classified as infected after birth; all had retinochoroiditis.

CONCLUSIONS

The low burden of symptomatic congenital toxoplasmosis combined with the lack of evidence of an effective treatment support current policy not to offer prenatal or neonatal screening for toxoplasma infection. Primary prevention strategies need to address acquisition of infection in childhood which accounts for half the ocular disease due to toxoplasma infection in children in the UK and Ireland.

Association between prenatal treatment and clinical manifestations of congenital toxoplasmosis in infancy: a cohort study in 13 European centres

AIM

To determine the effectiveness of prenatal treatment for clinical manifestations of congenital toxoplasmosis.

METHODS

We prospectively identified 255 live-born infants with congenital toxoplasmosis using prenatal or neonatal screening. We determined the effect of prenatal treatment on the risks of intracranial or ocular lesions in infancy, accounting for gestational age at maternal seroconversion.

RESULTS

Prenatal treatment within 4 wk of seroconversion reduced the risk of intracranial lesions compared with no treatment (odds ratio, OR 0.28; 95% CI: 0.08-0.75), but there was no significant effect when initiated after 4 wk (OR 0.76; 95% CI: 0.35-1.59; overall p-value 0.19). Compared to spiramycin alone, no treatment doubled the risk of intracranial lesions (OR 2.33; 95% CI: 1.04-5.50), but the risk did not differ with pyrimethamine-sulphonamide treatment (overall p-value 0.52). There was no consistent relationship between the type or timing of treatment and the risk of ocular lesions. Gestational age at maternal seroconversion was inversely associated with the risk of intracranial but not ocular lesions.

CONCLUSION

Only early versus no prenatal treatment for intracranial lesions showed a statistically significant benefit. A large randomized controlled trial and/or meta-analysis of individual patient data from cohort studies is required to confirm these findings.

Biases in observational studies of the effect of prenatal treatment for congenital toxoplasmosis

The paper reviews methodological difficulties that arise when using observational studies to evaluate the effect of prenatal screening and treatment. The principle of each difficulty is described and then illustrated by a clinical example of toxoplasmosis in pregnancy and its consequences. Methods to deal with these difficulties are described. Given the limitations of existing observational studies and lack of randomised controlled trials, a systematic review of cohort studies offers the best approach for exploring potential biases.

Association between congenital toxoplasmosis and preterm birth, low birthweight and small for gestational age birth

OBJECTIVE

To determine the association between congenital toxoplasmosis and preterm birth, low birthweight and small for gestational age birth.

DESIGN

Multicentre prospective cohort study.

SETTING

Ten European centres offering prenatal screening for toxoplasmosis.

POPULATION

Deliveries after 23 weeks of gestation in 386 women with singleton pregnancies who seroconverted to toxoplasma infection before 20 weeks of gestation. Deliveries after 36 weeks in 234 women who seroconverted at 20 weeks or later, and tested positive before 37 weeks.

METHODS

Comparison of infected and uninfected births, adjusted for parity and country of birth.

MAIN OUTCOME MEASURES

Differences in gestational age at birth, birthweight and birthweight centile.

RESULTS

Infected babies were born or delivered earlier than uninfected babies: the mean difference for seroconverters before 20 weeks was -5.4 days (95% CI: -1.4, -9.4), and at 20 weeks or more, -2.6 days (95% CI: -0.5, -4.7). Congenital infection was associated with an increased risk of preterm delivery when seroconversion occurred before 20 weeks (OR 4.71; 95% CI: 2.03, 10.9). No significant differences were detected for birthweight or birthweight centile.

CONCLUSION

Babies with congenital toxoplasmosis were born earlier than uninfected babies but the mechanism leading to shorter length of gestation is unknown. Congenital infection could precipitate early delivery or prompt caesarean section or induction of delivery. We found no evidence for a significant association between congenital toxoplasmosis and reduced birthweight or small for gestational age birth.

[Toxoplasmosis and pregnancy. Multicenter study of 16,362 pregnant women in Barcelona]

BACKGROUND AND OBJECTIVE

The aim of this study was to know: 1) the prevalence of antibodies against toxoplasma in pregnant women, 2) the incidence of primary infection during pregnancy and 3) the prevalence of congenital toxoplasmosis.

SUBJECTS AND METHOD

Seroprevalence was prospectively analyzed in 16,362 pregnant women visited in 8 hospitals and 2 day care centers in Barcelona during 1999. Each participant laboratory included their own assays to detect toxoplasma-specific immunoglobulins IgM, IgA, IgG and IgG avidity antibodies. In case of positive specific IgM, a second serum sample was requested, which was processed in parallel with the first one. Three infection stages were defined: acute, possible and past (latent). Congenital infection was determined prenatally by polymerase chain reaction (PCR) in amniotic fluid or postnatally by serology in the newborn.

RESULTS

Seroprevalence was 28.6%. The incidence of primary infection during pregnancy was 1.02/1,000 susceptible pregnant women. Nine women out of 12 with an acute toxoplasma infection became seroconverted during their pregnancies and five of them had infants with congenital toxoplasmosis (vertical transmission: 41.6%). All four children born alive had no symptoms during their follow-up.

CONCLUSIONS

In this study, the prevalence of toxoplasmosis was low. Acute toxoplasmosis was detected mainly by seroconversion during pregnancy. The frequency of maternal-fetal transmission was near half of cases.