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Toxoplasmosis is a common infection worldwide caused by Toxoplasma gondii , an intracellular parasite. The prevalence of Toxoplasmosis ranges from 17.5% to 69.5% in Turkey. Toxoplasmosis is mostly asymptomatic. It may cause fetal mortality in case of vertical passage. The most common clinical findings in congenital toxoplasmosis are chorioretinitis, hydrocephalus and cerebral calcification. Another group of susceptible patients for Toxoplasma gondii are immunesuppressive patients. Reactivation of a latent infection in the case of immunodeficiency can lead to fatal toxoplasmic encephalitis. Serological diagnostic methods based on the detection of specific antibodies for Toxoplasma gondii are the most commonly used diagnostic methods. However, it may be difficult to interpret the results in pregnant women, neonates, and the patients receiving treatment. It is stated that using more than one method together to improve the reliability of the diagnosis is a more accurate approach. In the prenatal diagnosis of congenital toxoplasmosis, in patients with immunodeficiency, in ocular toxoplasmosis, the polymerase chain reaction is seen as having a higher sensitivity. The aim of this review is to present the general features, diagnostic methods and current approaches in toxoplasma infection, an important public health problem.

Introduction: Toxoplasma gondii is the most common protozoan parasite in developed nations. Up to 43% of the French population may be infected, depending on eating habits and exposure to cats, and almost one third of the world human's population may be infected. Two types of infection have been described: a congenital form and an acquired form. Although the medical profession treats these latent cases as asymptomatic and clinically unimportant, results of animal studies and recent studies of personality profiles, behavior, and psychomotor performance have led to reconsider this assumption., Preclinical Data: Among rats: parasite cysts are more abundant in amygdalar structures than those found in other regions of the brain. Infection does not influence locomotion, anxiety, hippocampal-dependent learning, fear conditioning (or its extinction) and neophobia in rats. Rats' natural predator is the cat, which is also T. gondii's reservoir. Naturally, rats have an aversion to cat urine, but the parasite suppresses this aversion in rats, thus influencing the infection cycle. Tachyzoites may invade different types of nervous cells, such as neurons, astrocytes and microglial cells in the brain, and Purkinje cells in cerebellum. Intracellular tachyzoites manipulate several signs for transduction mechanisms involved in apoptosis, antimicrobial effectors functions, and immune cell maturation. Dopamine levels are 14% higher in mice with chronic infections. These neurochemical changes may be factors contributing to mental and motor abnormalities that accompany or follow toxoplasmosis in rodents and possibly in humans. Moreover, the antipsychotic haloperidol and the mood stabilizer valproic acid most effectively inhibit Toxoplasma growth in vitro with synergistic activity., Clinical Data: The effects of the parasite are not due to the manipulation in an evolutionary sense but merely due to neuropathological or neuroimmunological effects of the parasite's presence. Toxoplasmosis and schizophrenia: epidemiological studies point to a role for toxoplasmosis in schizophrenia's etiology, probably during pregnancy and early life, this association being congruent with studies in animal models indicating that animal exposures of the developing brain to infectious agents or immune modulating agents can be associated with behavioral changes that do not appear until the animal reaches full maturity. Psychiatric patients have increased rates of toxoplasmic antibodies, the differences between cases and controls being greatest in individuals who are assayed near the time of the onset of their symptoms. The increase of dopamine in the brain of infected subjects can represent the missing link between toxoplasmosis and schizophrenia. Toxoplasmosis and Obsessive Compulsive Disorder (OCD): the seropositivity rate for anti-T. gondii IgG antibodies among OCD patients is found to be significantly higher than the rate in healthy volunteers. Infection of basal ganglia may be implicated in the pathogenesis of OCD among Toxoplasma seropositive subjects. Toxoplasmosis and personality: infected men appear to be more dogmatic, less confident, more jealous, more cautious, less impulsive and more orderly than others. Conversely, infected women seem warmest, more conscientious, more insecure, more sanctimonious and more persistent than others. It is possible that differences in the level of testosterone may be responsible for the observed behavioral differences between Toxoplasma-infected and Toxoplasma-free subjects., Conclusion: In the future two major avenues for research seem essential. On one hand, prospective studies and research efforts must still be carried out to understand the mechanisms by which the parasite induces these psychiatric disorders. On the other hand, it has not yet been demonstrated that patients with positive toxoplasmic serology may better respond to haloperidol's or valproic acid's antiparasitic activity. These results may appear as a major issue in the drug's prescribing choices and explain variability in response to the treatment of patients with schizophrenia that is not explained by the genetic polymorphism., (Copyright © 2012 L'Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.)

Background: One of the major consequences of pregnant women becoming infected by Toxoplasma gondii is vertical transmission to the fetus. Although rare, congenital toxoplasmosis can cause severe neurological or ocular disease (leading to blindness), as well as cardiac and cerebral anomalies. Prenatal care must include education about prevention of toxoplasmosis. The low prevalence of the disease in the Canadian population and limitations in diagnosis and therapy limit the effectiveness of screening strategies. Therefore, routine screening is not currently recommended., Objective: To review the prevention, diagnosis, and management of toxoplasmosis in pregnancy., Outcomes: OUTCOMES evaluated include the effect of screening on diagnosis of congenital toxoplasmosis and the efficacy of prophylaxis and treatment., Evidence: The Cochrane Library and Medline were searched for articles published in English from 1990 to the present related to toxoplasmosis and pregnancy. Additional articles were identified through references of these articles., Values: The quality of evidence is rated and recommendations made according to guidelines developed by the Canadian Task Force on Preventive Health Care (Table)., Benefits, Harms, and Costs: Guideline implementation should assist the practitioner in developing an approach to screening for and treatment of toxoplasmosis in pregnancy. Patients will benefit from appropriate management of this condition., Sponsor: The Society of Obstetricians and Gynaecologists of Canada., Recommendations: 1. Routine universal screening should not be performed for pregnant women at low risk. Serologic screening should be offered only to pregnant women considered to be at risk for primary Toxoplasma gondii infection. (II-3E) 2. Suspected recent infection in a pregnant woman should be confirmed before intervention by having samples tested at a toxoplasmosis reference laboratory, using tests that are as accurate as possible and correctly interpreted. (II-2B) 3. If acute infection is suspected, repeat testing should be performed within 2 to 3 weeks, and consideration given to starting therapy with spiramycin immediately, without waiting for the repeat test results. (II-2B) 4. Amniocentesis should be offered to identify Toxoplasma gondii in the amniotic fluid by polymerase chain reaction (a) if maternal primary infection is diagnosed, (b) if serologic testing cannot confirm or exclude acute infection, or (c) in the presence of abnormal ultrasound findings (intracranial calcification, microcephaly, hydrocephalus, ascites, hepatosplenomegaly, or severe intrauterine growth restriction). (II-2B) 5. Amniocentesis should not be offered for the identification of Toxoplasma gondii infection at less than 18 weeks' gestation and should be offered no less than 4 weeks after suspected acute maternal infection to lower the occurrence of false-negative results. (II-2D) 6. Toxoplasma gondii infection should be suspected and screening should be offered to pregnant women with ultrasound findings consistent with possible TORCH (toxoplasmosis, rubella, cytomegalovirus, herpes, and other) infection, including but not limited to intracranial calcification, microcephaly, hydrocephalus, ascites, hepatosplenomegaly, or severe intrauterine growth restriction. (II-2B) 7. Each case involving a pregnant woman suspected of having an acute Toxoplasma gondii infection acquired during gestation should be discussed with an expert in the management of toxoplasmosis. (III-B) 8. If maternal infection has been confirmed but the fetus is not yet known to be infected, spiramycin should be offered for fetal prophylaxis (to prevent spread of organisms across the placenta from mother to fetus). (I-B) 9. A combination of pyrimethamine, sulfadiazine, and folinic acid should be offered as treatment for women in whom fetal infection has been confirmed or is highly suspected (usually by a positive amniotic fluid polymerase chain reaction). (I-B) 10. Anti-toxoplasma treatment in immunocompetent pregnant women with previous infection with Toxoplasma gondii should not be necessary. (I-E) 11. Women who are immunosuppressed or HIV-positive should be offered screening because of the risk of reactivation and toxoplasmosis encephalitis. (I-A) 12. A non-pregnant woman who has been diagnosed with an acute Toxoplasma gondii infection should be counselled to wait 6 months before attempting to become pregnant. Each case should be considered separately in consultation with an expert. (III-B) 13. Information on prevention of Toxoplasma gondii infection in pregnancy should be made available to all women who are pregnant or planning a pregnancy. (III-C).

The prevention of congenital toxoplasmosis is based on providing information to women, serologic diagnosis and treatment of the infected mother and child. In this article we present the results of 12 years of implementation of a congenital toxoplasmosis prevention program in which we measured the mother's infection incidence rate, the transmission rate and the number and severity of infection in newborns. The study was performed on 12035 pregnant women in the period 2000-2011. The prevalence rate of antibodies against Toxoplasma gondii was 18.33% (2206/12035). Thirty-seven out of 9792 susceptible women presented acute infection and the mother's infection incidence rate was 3.78 per 1000 births. The transplacental transmission rate was 5.4% (2/37). Two newborns presented congenital toxoplasmosis infection, one had no clinical signs while the other presented strabismus and chorioretinitis. Thirty-five infected mothers and the two children with congenital infection were treated. The transmission rates obtained allow consider this prevention program as a valid resource to minimize the impact of congenital toxoplasmosis.

Objectives: The objectives of this study were to analyze the association between the classification of toxoplasmosis in the pregnant woman (TP) according to the classification of Lebech et al. and the incidence of congenital toxoplasmosis (CT), also taking into consideration prenatal treatment., Methods: A clinical cohort study of 524 children followed-up until 1 year of age was conducted. Adjusted odds ratios (OR) were estimated by logistic regression., Results: Of 519 pregnant women, 61.3% were not classified due to the incompleteness of hospital records. Among the pregnant women classified as confirmed cases of TP (n=19), the CT risk was six times greater than in the probable/possible group. No case of CT was identified in the group of pregnant women classified as unlikely to have TP. The children with no prenatal treatment (46.2% n=242/524) presented a risk almost three times greater of CT than the treated children (OR 2.77, 95% confidence interval (CI) 1.54-4.97; p=0.001). Complete prenatal treatment was identified as a protecting factor for CT (OR 0.35, 95% CI 0.19-0.65; p=0.001)., Conclusions: A lack or incomplete prenatal treatment was identified as an important risk factor for CT in this study. The proportions of non-classified mothers and children with no prenatal treatment reflect the need to improve prenatal care in Brazil., (Copyright © 2012. Published by Elsevier Ltd.)

Reinfection with Toxoplasma gondii is exceptional but can lead to transmission to the fetus when it occurs during pregnancy. We present a case of congenital toxoplasmosis in a young baby born to an immunocompetent mother who had been immunized against toxoplasmosis before pregnancy. The presence of residual IgG-specific antibodies does not always mean an absolute protection against a new toxoplasma infection. During the pregnancy, the patient was advised to follow the hygienic and dietary preventive measures even though the previous test results were consistent with past toxoplasma infection., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Monthly serological screening of non immune pregnant women is recommended for prevention of congenital toxoplasmosis. However, this screening is often interrupted before delivery. We report a case of congenital toxoplasmosis following infection occurring late in pregnancy. This documented case highlights the need for a final routine serological test, 2-3 weeks post-partum for all seronegative pregnant women. In fact, the screening of congenital toxoplasmosis cases allows the early administration of specific treatment that avoids later severe complications such as chorioretinitis., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Toxoplasma gondii is a parasite of birds and mammals. Cats are the only definitive host and thus the only source of infective oocysts, but other mammals and birds can develop tissue cysts. Although feline infections are typically asymptomatic, infection during human pregnancy can cause severe disease in the fetus. Cat owners can reduce their pets' exposure risk by keeping all cats indoors and not feeding them raw meat. Humans usually become infected through ingestion of oocyst-contaminated soil and water, tissue cysts in undercooked meat, or congenitally. Because of their fastidious nature, the passing of non-infective oocysts, and the short duration of oocyst shedding, direct contact with cats is not thought to be a primary risk for human infection., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

Toxoplasma gondii is a highly ubiquitous and prevalent parasite. Despite the cat being the only definitive host, it is found in almost all geographical areas and warm blooded animals. Three routes of transmission are recognised: ingestion of oocysts shed by the cat, carnivory and congenital transmission. In natural populations, it is difficult to establish the relative importance of these routes. This paper reviews recent work in our laboratory which suggests that congenital transmission may be much more important than previously thought. Using PCR detection of the parasite, studies in sheep show that congenital transmission may occur in as many as 66% of pregnancies. Furthermore, in families of sheep on the same farm, exposed to the same sources of oocysts, significant divergent prevalences of Toxoplasma infection and abortion are found between different families. The data suggest that breeding from infected ewes increases the risk of subsequent abortion and infection in lambs. Congenital transmission rates in a natural population of mice were found to be 75%. Interestingly, congenital transmission rates in humans were measured at 19.8%. The results presented in these studies differ from those of other published studies and suggest that vertical transmission may be much more important than previously thought.

Untreated acute toxoplasmosis among pregnant women can lead to serious sequelae among newborns, including neurological impairment and blindness. In Brazil, the risk of congenital toxoplasmosis (CTox) has not been fully evaluated. Our aim was to evaluate trends in acute toxoplasmosis prevalence from 1998-2005, the incidence of CTox and the rate of mother-to-child transmission (MTCT). A cross-sectional study was undertaken to dentify patients who fit the criteria for acute toxoplasmosis during pregnancy. Exposed newborns were included in a historical cohort, with a median follow-up time of 11 months, to establish definite diagnosis of CTox. Diagnoses for acute infection in pregnancy and CTox were based on European Research Network on Congenital Toxoplasmosis criteria. In 41,112 pregnant women, the prevalence of acute toxoplasmosis was 4.8/1,000 women. The birth prevalence of CTox was 0.6/1,000 newborns [95% confidence interval (CI): 0.4-0.9]. During the follow-up study, 12 additional cases were detected, increasing the CTox rate to 0.9/1,000 newborns (95% CI: 0.6-1.3). Among the 200 newborns exposed to Toxoplasma gondii,there were 37 babies presenting diagnostic criteria of CTox, leading to an MTCT rate of 18.5% (95% CI: 13.4-24.6%). The additional cases identified during follow-up reinforce the need for serological monitoring during the first year of life, even in the absence of evidence of congenital infection at birth.

This paper reviews clinical and asymptomatic Toxoplasma gondii infection in humans and other animals in the USA. Seroprevalence of T. gondii in humans and pigs is declining. Modes of transmission, epidemiology and environmental contamination with oocysts on land and sea are discussed.

Toxoplasmosis in pregnancy is usually subclinic or associated with non specific symptoms. Diagnosis and timing of infection are usually based on serological tests. In this short review we tried to summarize the serological patterns we can encounter and to discuss the interpretation of test results.

Various critical issues still surround the management of toxoplasmosis in pregnant women and neonates. Although the study of specific antibodies remains an essential parameter for diagnosing materno-fetal infection and establishing time of infection, the method needs to be carefully and critically reviewed due to the distinctive immunological sensitivity of the neonate. We began a retrospective epidemiological study of the pre-natal management of Toxoplasma gondii (TG) infection to evaluate the incidence of congenital toxoplasmosis in children in a southern Italian area (Sicily). 230 children born between 1999 and 2005 to mothers with TG infection during pregnancy enrolled in the G. Di Cristina Children's Hospital of Palermo. Retrospective analysis of the maternal sample established that 150 (65%) of the 230 infants enrolled in the study were born to a mother with probable infection, while the remaining 80 (35%) were born to a mother with definite infection. To date, the results of the neonatal follow-up programme have confirmed the diagnosis of congenital infection in 16 infants (7%); for 43%, diagnosis was made early due to the presence, at birth or in the first month of life, of specific anti-TG IgM. Sequelae were observed in 8/16 infected infants. Sequelae in infected born to mothers with infection in the third trimester opens up the problematic issue of which therapeutic approach to adopt for these women: even without consensus support, a combined regimen of Pyrimethamine-Sulfadiazine could be advocated, even in the absence of prenatal diagnosis. Currently, the best diagnostic strategy involves the sequential or contemporaneous combination of more than one of the currently available methods, as no method on its own can ensure an appropriate level of accuracy.

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.

Toxoplasma gondii (T. gondii) is the cause of toxoplasmosis. Primary infection in an immunocompetent person is usually asymptomatic. Serological surveys demonstrate that world-wide exposure to T. gondii is high (30% in US and 50-80% in Europe). Vertical transmission from a recently infected pregnant woman to her fetus may lead to congenital toxoplasmosis. The risk of such transmission increases as primary maternal infection occurs later in pregnancy. However, consequences for the fetus are more severe with transmission closer to conception. The timing of maternal primary infection is, therefore, critically linked to the clinical manifestations of the infection. Fetal infection may result in natural abortion. Often, no apparent symptoms are observed at birth and complications develop only later in life. The laboratory methods of assessing fetal risk of T. gondii infection are serology and direct tests. Screening programs for women at childbearing age or of the newborn, as well as education of the public regarding infection prevention, proved to be cost-effective and reduce the rate of infection. The impact of antiparasytic therapy on vertical transmission from mother to fetus is still controversial. However, specific therapy is recommended to be initiated as soon as infection is diagnosed.

Unlabelled: The clinical management of perinatal toxoplasmosis involves a gynaecologist during pregnancy and a neonatologist after delivery. Then, in the absence of a uniform approach, early evaluation of infected infants requires a thorough long-term follow-up also in asymptomatic children, who have to be observed for at least one year due to unpredictable sequelae in later life. We retrospectively analyzed pregnancy management of 54 women with certain infection from Toxoplasma gondii (TG) and prospectively enrolled their infants to compare prenatal management with postnatal clinical outcome. All mothers with seroconversion for TG infection were from the Palermo area and were retrospectively analyzed, whereas their newborns referred to G. Di Cristina Children Clinical Hospital between 1999-2004 were prospectively enrolled in a 48-month follow-up. Timing of infection was dated for 24 women (45%) to the first trimester, 18 (33%) to the second and 12 (22%) the third. The maternal-fetal transmission rate was 17.2%. Prenatal diagnosis from amniotic fluid was performed in 25/54 pregnant subjects and showed positive results in 6. Despite diagnosis of TG infection, 9 women were untreated and only 2 with positive amniocentesis received combined therapy. 10/55 enrolled infants were infected and half of them were preterm and/or SGA at birth. None showed peculiar signs of TG at birth but 4 had abnormalities during the follow-up. 9/10 infected children were born to mothers who had undergone neither amniocentesis nor combined therapy., Conclusions: Our work confirms the difficulty of applying standardized therapeutic protocol for TG infection during pregnancy. The asymptomatic course of TG infection at birth confirms the importance of an instrumental long-term follow-up to identify typical TG lesion to prevent sequelae.

Objective: To assess the consequences for the fetus of maternal toxoplasma infection acquired during the first 8 weeks of gestation and to set guidelines on how to manage these maternal infections., Methods: Data were prospectively analyzed on 360 pregnancies followed-up in our department due to a toxoplasma infection during the 8 first weeks of pregnancy. Estimates of the risk of fetal infection were based on all cases, including those which could not be followed up until infection was ruled out or confirmed. Severity of infection was estimated based on ultrasound findings during pregnancy, neonatal and long-term postnatal clinical, neurological and ophthalmologic work up., Results: Out of the 360 included women, 336 gave birth to a live born child: 7 (2%) were infected, 302 (90%) were free of infection and follow-up was insufficient to conclude about the 27 (8%) remaining infants. The estimated risk of fetal infection ranged between 2 and 10% based on live born children and between 3 and 14% when the 24 interrupted pregnancies were included. At their last clinical evaluation at 70 months of age, all 7 children, including the 2 who had inactive peripheral eye lesions and the one who had a unique intracranial calcification were free of any ophthalmologic or neurological impairment., Conclusion: Our study confirms that in the event of a maternal infection during the first 8 weeks of pregnancy the risk of fetal infection is low and results mainly in a spontaneous termination of pregnancy. Future parents should be assured that conversely to a common opinion, the prognosis of congenital toxoplasmosis in live-born children is good. For these early maternal infections as for those acquired later, we recommend immediate treatment with spiramycin, monthly ultrasound surveillance, amniocentesis and treatment with pyrimethamine and sulphamides if the PCR is positive. Abortion should be restricted to cases with ultrasound lesions

Background: Women who acquire toxoplasmosis infection during pregnancy (in most cases detected through serological screening) require counselling about the risk of congenital infection and its clinical sequelae. Reliable estimates of risk are not currently available. We undertook an analysis of data from women referred to the toxoplasmosis reference laboratory, Lyon, France, between 1987 and 1995., Methods: Information was collected from clinical notes kept at the laboratory and, where necessary, from the relevant obstetrician or paediatrician via telephone. Methods were developed to derive estimates of the risk of congenital toxoplasmosis by exact duration of gestation at maternal seroconversion., Findings: We analysed obstetric and paediatric data on 603 confirmed maternal toxoplasmosis infections. At least 564 women received antiparasitic drugs according to a standard protocol. Congenital infection status was ascertained in 554 cases, and infected children were followed-up for a median of 54 months. The overall maternal-fetal transmission rate was 29% (95% CI 25-33), which masked a sharp increase in risk with duration of gestation from 6% at 13 weeks to 72% at 36 weeks. However, fetuses infected in early pregnancy were much more likely to show clinical signs of infection. These effects counterbalance, and women who seroconverted at 24-30 weeks of gestation carried the highest risk (10%) of having a congenitally infected child with early clinical signs who was thus at risk of long-term complications., Interpretation: This information will assist the clinical counselling of pregnant women diagnosed with acute toxoplasmosis and may guide individual decisions on investigative and therapeutic options. Further studies are required to determine the long-term risks of clinical symptoms and disability due to congenital toxoplasmosis.

Objective: Toxoplasmosis during pregnancy can cause fetal infection, with unpredictable sequelae in later life. We measured the effects of prenatal antibiotic therapy on the fetomaternal transmission of Toxoplasma gondii and on the appearance of sequelae in the congenitally infected child at age 1 year., Study Design: In a multicenter study we investigated consecutive women with Toxoplasma seroconversion during pregnancy. Data were obtained from 144 women recruited in 5 different Toxoplasma reference centers. Through multivariate analysis we assessed the association between transmission and appearance of sequelae as a function of the following parameters: estimated gestational age at infection, administration of antibiotic therapy, duration of antibiotic therapy, and time lapse between infection and the start of antibiotic therapy., Results: Sixty-four of the 144 women (44%) gave birth to a congenitally infected infant. Multivariate analysis showed that transmission was predicted neither by whether antibiotics had been administered nor by the time lapse between infection and the start of antibiotic therapy, but only by the gestational age at which maternal infection occurred (P <.0001). Sequelae were found in 19 children (13%), 9 of whom (6%) had severe sequelae. Administration of antibiotics was predictive of the absence of sequelae (P =.026, odds ratio 0.30, 95% confidence interval 0.104-0.863), in particular the absence of severe sequelae (P =.007, odds ratio 0.14, 95% confidence interval 0.036-0.584). The sooner antibiotics were given after the infection, the less frequently sequelae were seen (P =. 021)., Conclusion: Prenatal antibiotic therapy after toxoplasmosis during pregnancy had no impact on the fetomaternal transmission rate but reduced the rate of sequelae among the infected infants. The early start of treatment resulted in a significant reduction in the number of severely affected infants.

The clinical sequelae of acute and congenital toxoplasmosis are well established, but that of chronic toxoplasma infection remains uncertain. In rodents, chronic toxoplasma infection is associated with altered behaviour leading to an enhanced risk of feline predation and a putative selective advantage to the parasite. It is proposed that neurotropic cysts of toxoplasma exert an effect on animal behaviour, either directly or via the release of metabolic products. Long-standing toxoplasma infection in humans has been linked to cerebral tumour formation and personality shift. In view of the vast population with chronic toxoplasma infection, further studies of the clinical sequelae of this condition are required.

An infection with Toxoplasma gondii during pregnancy means that the unborn baby may be infected as well. In addition to the risk that the baby may be born dead, central chorioretinitis could also occur. Pregnant women with primary infection were treated with spiramycin or a combination of pyrimethamine and sulfadiacine. A total of 153 children (1 month-1 year) were examined twice with particular attention to the macula region. Only two cases showed central retinochoroiditis. In one case the treatment was insufficient, and in the other the time between the serological examinations was too long. None of the other children showed any central pathological changes within the follow-up period. Screening methods, the appropriate treatment and the results are presented.

Enzyme immunoassay was used in screening for toxoplasmosis of 500 residents of the town of Ghulistan and of 1074 residents of the town of Shavat in the Khorezm district of Uzbekistan. All the examinees were aged 15 to 40. The share of seropositive subjects in Ghulistan was 24.6%, that in Shavat 14.6%, the toxoplasmosis loimopotentials were 0.87 and 0.62%, respectively. The predicted parameters were as follows: new cases of toxoplasmosis among pregnant women were 4.9% in Ghulistan and 3.9% in Shavat, the incidence of congenital condition 1.7 and 1.3%, respectively, the incidence of manifest congenital toxoplasmosis 0.6 and 0.4%, respectively. The presence of a cat in the house was associated with higher share of seropositive subjects in the town of Shavat as against Ghulistan. An urban focus (Ghulistan) appeared more intensive as against a rural type focus (Shavat) at the expense of a higher intensity of the xenotropic route of the agent transmission.

Toxoplasma gondii, the causal agent of toxoplasmosis, is a ubiquitous protozoan parasite which has the potential to infect man and all warm-blooded animals. It has as its definitive host the cat. Infections acquired by the human adult are generally subclinical. However, if acquired for the first time during pregnancy, the parasite can invade the developing foetus. Under these circumstances infection can result in abortion, stillbirth or production of live-born offspring with severe multiple organ involvement. Alternatively, offspring can be symptomless at birth but may manifest neurological and ocular sequelae of toxoplasmosis in later life. The degree of clinical involvement is thought to be dependent upon the time of acquisition of infection by the pregnant female. Recent investigations have been concerned with behavioural aspects of predator-prey relationships between cats and rodents. Since these aspects affect the spread of toxoplasmosis in the environment, they have strong epidemiological and ecological implications. Toxoplasma infection in the environment, they have strong epidemiological and ecological implications. Toxoplasma infection in mice is associated with subtle alterations in exploratory behaviour which are almost certainly maladaptive, rendering infected mice more susceptible to predation by cats. Consequently the behavioural abnormalities in mice associated with Toxoplasma infection would be of major importance for the continuation of the life-cycle of the parasite. Ingestion of Toxoplasma-infected mice leads to oocyst production in cats and this opens up the well-known pathway whereby Toxoplasma infection reaches the human species.

Infection with T. gondii can have devastating effects on the development of the unborn human fetus. As veterinarians or physicians, we should be able to accurately assess the true risk of exposure of a person to meat-borne tissue cysts or to oocysts based on the age, health, roaming and feeding habits of their cats, and the occupational or recreational activities of the individual. When time precludes an in-depth discussion of preventive measures to decrease exposure to the parasite, the whole client education program can be neatly summarized in the admonition, "When pregnant, wash your hands thoroughly before eating or touching your face, and cook your meat thoroughly." In this way, the risk of exposure to toxoplasmosis and all other meat- or soil-borne diseases is greatly reduced.

Recent advances in the epidemiology and life cycle of toxoplasmosis are reviewed. Cats play a key role. Toxoplasma has a coccidian-type entero-epithelial cycle with oocyst prodlction in the feline host. An extra-intestinal cycle occurs in both feline and non-feline hosts. The worldwide distribution and the public health significance of toxoplasmosis as a zoonosis is discussed, with particular reference to available data regarding Southern Africa.