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

BACKGROUND: Toxoplasmosis is a parasitic infection caused by Toxoplasma gondii and is responsible for gestational and congenital infections worldwide. The current standard therapy is based on the administration of Spiramycin to prevent trans-placental transmission. Other therapies are being studied to reduce the rates of foetal transmission and symptomatic congenital infection. OBJECTIVES: We report our long-standing experience in maternal toxoplasmosis infection treatment using a combination of Spiramycin-Cotrimoxazole, assessing its effectiveness in preventing vertical transmission compared to the expected incidence of congenital infection. METHODS: We retrospectively collected cases of pregnant women referred to our centre for suspected toxoplasmosis infection according to Lebech criteria, treated with Spiramycin-Cotrimoxazole. RESULTS: Of 1364 women referred to our centre, postnatal follow-up of primary toxoplasmosis was available in 562 cases (73.9%). The overall vertical transmission rate was 3.4% in women treated immediately with Spiramycin-Cotrimoxazole after the diagnosis of infection. In comparison, it was 7.7% in women undergoing the same therapy but late or with poor compliance. The foetal transmission rate was 71.4% in untreated cases. All the infected newborns of mother treated adequately with Spiramycin-Cotrimoxazole were asymptomatic afterbirth, while 6/21 infected infants of the inadequate Spiramycin-Cotrimoxazole therapy group had postnatal sequelae (28.5%). The incidence of transmission after appropriate Spiramycin-Cotrimoxazole therapy was significantly lower than the expected rate reported in literature. CONCLUSIONS: A combination of Spiramycin and Cotrimoxazole is safe and effective in preventing foetal congenital toxoplasmosis and reducing sequelae in case of in-utero infection. The timing and adherence to the therapy are crucial to lowering the risk of congenital infection and neonatal morbidity.

Congenital Toxoplasmosis and Long-term Outcomes

Objective: Congenital toxoplasmosis (CT) can have severe early and late sequelae in children. In this study, we aimed to evaluate the demographic, clinical, treatment characteristics of patients diagnosed with congenital Toxoplasma infection and to highlight the long-term complications of the patients. Methods: Patients with CT were included in this study who were followed between 2010 and 2022 in Cukurova University Medical Faculty Hospital. Demographic, clinical and treatment characteristics were searched retrospectively. In the diagnosis of maternal and CT, Toxoplasma IgM, IgG, IgG avidity, T. gondii polymerase chain reaction tests were used along with clinical and symptoms. Results: Eighteen children (two twins) with CT and their mothers (n=16) were included in the study. Median age was 1 month. Ten (55.5%) of the children were male. CT diagnosis was made during pregnancy in 7 mothers (resulting in 8 babies) and postnatally in 9 mothers (resulting in 10 babies). The mothers of 5 (31.1%) babies with CT received spiramycin treatment during pregnancy. Three (60%) of 5 pregnant women who received spiramycin were diagnosed in the first trimester, 4 (80%) of the babies did not have any sequale and only 1 (20%) had microphthalmia. Ocular involvement was the most common presentation of the disease occured in 10 patients (55.5%), hydrocephalus and intracranial calcification developed in five patients (27.7%). Hearing loss developed in 2 (11.1%) patients. During the follow-up period, seizures developed in 3 patients (16.6%), microcephaly in 2 patients (11.1%), and neurodevolopmental retardation in 7 patients (38.8%), two of the patients had severe mental retardation. One (5.5%) patient with hydrocephalus died at 36 months of age due to complications after ventriculoperitoneal shunt application. Conclusion: In our study, we observed severe sequelae in vision, hearing, and neurodevelopmental aspects in children diagnosed with CT at birth and during follow-ups. Early diagnosis and treatment of infants, along with the detection of Toxoplasma infection during pregnancy, are essential in preventing severe sequelae that may arise due to CT.

Long-term Ocular Outcomes in Congenital Toxoplasmosis Treated Perinatally.

BACKGROUND: Congenital toxoplasmosis (CT) can be accompanied by serious organ manifestations, particularly retinochoroiditis, and may occur throughout life. We aimed to monitor long-term ocular prognosis in a large French cohort of patients with CT and its changes over time in the context of mandatory prenatal screening (since 1992) and incidence decrease since 2008. METHODS: Patients with CT diagnosed between 1987 and 2021 were prospectively included and followed for up to 35 years. The effect of the period of conception on the risk of first retinochoroiditis has been tested using a flexible extension of the Cox model. Incidence rates of retinochoroiditis were estimated. RESULTS: A total of 646 infected live born children were followed for a median of 12 years (range, 0.5-35); 187 patients (29%) had at least 1 ocular lesion (first at a median age of 5 years; range, 0-26 years) with peaks at 7 and 12 years. Early maternal infection and the presence of nonocular signs at birth were associated with a higher risk of retinochoroiditis, whereas delayed diagnosis of CT (after birth versus before or at birth) was associated with a lower risk (13% decrease for each additional month after birth; P = .01). A period effect for the risk of developing retinochoroiditis in patients born after 2008 was not detected. CONCLUSIONS: Despite prenatal screening and prolonged perinatal treatment, retinochoroiditis is not a rare event in French patients with CT and can occur well into adulthood, with peak incidences at 7 and 12 years of age. It rarely causes severe damage but warrants regular follow-up into adulthood.

An Early Treatment With BKI-1748 Exhibits Full Protection Against Abortion and Congenital Infection in Sheep Experimentally Infected With Toxoplasma gondii.

Congenital toxoplasmosis in humans and in other mammalian species, such as small ruminants, is a well-known cause of abortion and fetal malformations. The calcium-dependent protein kinase 1 (CDPK1) inhibitor BKI-1748 has shown a promising safety profile for its use in humans and a good efficacy against Toxoplasma gondii infection in vitro and in mouse models. Ten doses of BKI-1748 given every other day orally in sheep at 15 mg/kg did not show systemic or pregnancy-related toxicity. In sheep experimentally infected at 90 days of pregnancy with 1000 TgShSp1 oocysts, the BKI-1748 treatment administered from 48 hours after infection led to complete protection against abortion and congenital infection. In addition, compared to infected/untreated sheep, treated sheep showed a drastically lower rectal temperature increase and none showed IgG seroconversion throughout the study. In conclusion, BKI-1748 treatment in pregnant sheep starting at 48 hours after infection was fully effective against congenital toxoplasmosis.

Gestational toxoplasmosis treatment changes the child's prognosis: A cohort study in southern Brazil.

BACKGROUND: We evaluate the drug treatment for pregnant women with acute toxoplasmosis to reduce the risk of congenital infection, side effects (prenatal and postnatal treatment in children) and the hazard of discontinuing the infant's medication. METHODS: We conducted a prospective cohort study to assess the risks of congenital toxoplasmosis among children born to acutely infected women with and without treatment. We examined the relationship between "exposed" and "infected children", "number of infant neutrophils", "prenatal" and "postnatal treatment". Factor analysis of mixed data (FAMD) was used to analyze the data. All children started treatment at the hospital. FINDINGS: Between 2017 and 2021, 233 pregnant women were evaluated at the University Hospital of Maringá; ninety-four met criteria for acute gestational toxoplasmosis. We followed up 61 children; eleven (18%) had the infection confirmed and 50 (82%) were free of toxoplasmosis (exposed). Children born to untreated mothers have 6.5-times higher risk of being infected; the transmission rate among untreated mothers was 50% versus 8.3% among treated ones. Three decreasing values of immunoglobulin G were a security parameter for stopping the child's medication in the exposed group (50/61). Neutropenia was the leading side effect among children and the infected had a 2.7 times higher risk. There was no correlation between maternal use of pyrimethamine and children's neutropenia. INTERPRETATION: The follow-up of women with acute T. gondii infection and their children, through a multidisciplinary team, availability of anti-T. gondii serology and pre- and post-natal treatments reduced the risk of toxoplasmosis transmission.

Unspecific congenital toxoplasmosis in a two-month-old baby.

A two-month-old baby boy diagnosed with unspecific congenital toxoplasmosis was referred by a pediatrician to the Clinical Parasitology referral center at the Faculty of Medicine, Universitas Indonesia. Baby was post-hospitalized in the NICU and required ventilation support for one month. Furthermore, there was history of from various medical conditions, such as intracranial bleeding, convulsion, hypertrophic cardiomyopathy, retinopathy, and renal failure. After two month, there was no significant weight gain, anti-Toxoplasma IgM showed positive results, and anti-Toxoplasma IgM and IgG of the mother were also positive. Baby and mother were successfully treated with pyrimethamine, cotrimoxazole, and folinic acid for one month. At 2 years, there signs of normal motoric, eye, and hearing development with underdeveloped kidneys. Therefore, pre-pregnancy counseling and education aimed at preventing toxoplasmosis during pregnancy should be increased and conducted routinely by health workers or trained cadres to reduce the risk of fetal defects.

Comparison of adverse reactions of spiramycin versus pyrimethamine/sulfadiazine treatment of toxoplasmosis in pregnancy: is spiramycin really the drug of choice for unproven infection of the fetus?

BACKGROUND: Therapeutic regimens for the treatment of toxoplasmosis are not standardized. Treatment strategy mainly at the end of the second and the beginning of the third trimester, especially in cases of negative prenatal diagnosis, is the least uniform. In some situations, the choice of treatment may be ambiguous, and adverse drug reactions of the therapy should be taken into consideration. METHODS: Adverse drug reactions of anti-toxoplasma therapy with spiramycin (n = 77) versus pyrimethamine/sulfadiazine (n = 35) were compared in 112 pregnant women. RESULTS: Up to 36.6% of women reported adverse reactions to the treatment overall (n = 41). Out of those 38.9% (n = 30) were treated with spiramycin and 31.4% (n = 11) with pyrimethamine/sulfadiazine. Toxic allergic reactions were the only indication for discontinuation of treatment in 8.9% of patients (n = 10), where 9.1% (n = 7) were reported in spiramycin and 8.6% (n = 3) in pyrimethamine/sulfadiazine cohort. Neurotoxic complications (acral paraesthesia) were significantly more frequent during the therapy with spiramycine in 19.5% (n = 15) compared to no cases in pyrimethamine/sulfadiazine group (p = .003). Other adverse drug reactions, such as gastrointestinal discomfort, nephrotoxicity, vaginal discomfort were reported, but the differences between the cohorts were not significant. CONCLUSIONS: The superiority of one of the therapeutic regimens was not statistically demonstrated, since the differences in overall toxicity or incidence of toxic allergic reactions between the cohorts were not confirmed (p = .53 and p = 1.00, respectively). However, although the isolated neurotoxicity of spiramycin was the only significant adverse reaction demonstrated in this study, pyrimethamine/sulfadiazine therapy should be preferred, because it is known to be more effective and with limited adverse reactions.

Stability of sulfadiazine sugar-free oral suspensions for the treatment of congenital toxoplasmosis

Abstract This study aimed to develop and evaluate the stability of sulfadiazine sugar-free extemporaneous oral suspensions, focusing on treating congenital toxoplasmosis. The excipients were carefully chosen to obtain safe products for the pediatric population. Sulfadiazine suspensions (100 mg/ mL) were prepared from the raw material or tablets, stored in amber glass bottles at 5±3ºC, and evaluated at 0, 14, and 30 days. An ultra-performance liquid chromatographic method was developed and validated to assay the drug. The particle size ranged from 29.3 to 50.6 µm, with some variation over the study; pH values around 7.0 and non-Newtonian behavior were observed without modification in the period. Formulations showed a fast dissolution rate (>80% in 15 minutes) without variation over the study. The drug assay was about 100% of the label claimed throughout the study, demonstrating the chemical stability and the preparations' dose homogeneity. The microbiological investigation indicated that both preparations met the requirements for the microbial count and absence of pathogens. In conclusion, the developed formulations can be used for 30 days when stored under refrigeration. The oral suspensions produced are easy to prepare and contain safe components, providing an alternative for congenital toxoplasmosis treatment in children

Spyramicine and Trimethoprim-Sulfamethoxazole Combination to Prevent Mother-To-Fetus Transmission of Toxoplasma gondii Infection in Pregnant Women: A 28-Years Single-center Experience.

BACKGROUND: There is weak evidence on the best treatment of pregnant women with Toxoplasma gondii infection to prevent the vertical transmission to the fetus. METHODS: We conducted a 28-year retrospective study aiming to compare the efficacy of three therapeutic regimens [Spiramicyn alone (Spy) vs. Pyrimethamine-Sulfadiazine (P/S) vs. Spiramicyn with Trimethoprim-Sulfamethoxazole (Spy+TMP-SMX)] for the prevention of mother-to-fetus transmission of T. gondii infection. RESULTS: 170 women were included: 58 (34.1%) had certain congenital toxoplasmosis (CT), 61 (35.9%) a probable infection and 41 (24.1%) possible infection. In total 97 mothers (57.1%) were treated with the Spy+TMP-SMX combination, 64 mothers (37.6%) were treated with Spy only and 8 mothers (4.7%) with P/S. Infected infants were 20/170 (11.7%). However, 8.2% (8/97) of infants born to mothers treated with Spy+TMP-SMX were infected, 20% (11/55) of infants born to women treated with Spy and 12.5% (1/8) of infants born to mothers treated with P/S were infected. Logistic regression analysis demonstrated that Spy treatment alone was associated with an increased risk of CT compared to the Spy+TMP-SMX combination (OR, 2.78, 95% CI 1.04-7.41, P value 0.041). No difference was observed when the Spy+TMP-SMX was compared with the P/S combination (OR 1.59; 95% CI 0.17 - 14.58; P value 0.682). Results were confirmed when the analyses were corrected by trimester of infection and by type of maternal treatment (OR 7.72; 95% CI 3.40-17.53, P value <0.001). CONCLUSIONS: The combination of Spy+TMP-SMX may be more effective in reducing the risk of maternal-fetal transmission of Toxoplasmosis compared to Spy alone; furthermore, this combination is not inferior to P/S, the current international standard-of-care maternal treatment for the prevention of CT. A prospective trial comparing the combination Spy+TMP-SMX with P/S would be necessary to provide definitive evidence on the best regimen for pregnant women with T. gondii infection.

Long-term impact of congenital toxoplasmosis on phenotypic and functional features of circulating leukocytes from infants one year after treatment onset.

Changes in immune response of children with congenital toxoplasmosis (CT) regarding infection evolution and therapeutic intervention was addressed. Infants with CT presented increased counts of monocytes, CD3-CD16-CD56High, CD3+CD56+ and CD4+ T-cells 1-year after treatment onset (TOXO1-yearAT). Smaller numbers of CD3-CD16-CD56+ and TCRγδ+ T-cells were specifically observed in infants with retinochoroidal lesions (L(+)). When infants were classified based on the baseline status, expansion of CD3-CD16-CD56High and CD4+ T-cells were observed in L(+) who had active, active/cicatricial or cicatricial lesions. Infants who had active or active/cicatricial lesions display augmented numbers of monocytes, CD3-CD16+CD56+, CD3+CD56+, CD8+DR+ and TCRγδ+ T-cells and those with active/cicatricial or cicatricial at baseline displayed increase in CD14+CD64+ monocytes. Moreover, all L(+) had increased IFN-γ+ and IL-10+ CD4+ T-cells, while L(-) had increased ratios of TNF+, IFN-γ+ and IL-4+ NK-cells upon antigen-specific stimulation. Persistent alterations in leukocytes in TOXO1-yearAT suggest long-term sequels in the immune system of infants with CT.

One severe case of congenital toxoplasmosis in China with good response to azithromycin.

BACKGROUND: Most infants infected with Toxoplasma gondii are completely asymptomatic at birth, yet they may develop ocular and neurological sequelae in the first few months of life. Cases of congenital toxoplasmosis with severe jaundice early after birth combined with pancytopenia and splenomegaly are extremely rare. Here, we report on a rare case of congenital toxoplasmosis presenting with severe jaundice and hemolysis early after birth combined with pancytopenia and splenomegaly. CASE PRESENTATION: A male preterm infant with severe jaundice and splenomegaly was admitted to our department. Laboratory examinations revealed severe hyperbilirubinemia, increased reticulocytes, and pancytopenia. After comprehensive analysis and examination, the final diagnosis was congenital toxoplasmosis, and the infant was treated with azithromycin and subsequently trimethoprim-sulfamethoxazole. Regular follow-up revealed congenital toxoplasmosis in both eyes, which was surgically treated, while neurofunctional assessment results were unremarkable. In this case of congenital toxoplasmosis combined with severe jaundice, we treated the infant with two courses of azithromycin, followed by trimethoprim-sulfamethoxazole after the jaundice resolved. Clinical follow-up indicated that this treatment was effective with few side effects; thus, this report may serve as a valuable clinical reference. CONCLUSIONS: Timely diagnosis and adequate treatment are closely associated with congenital toxoplasmosis-related prognosis. Infants with congenital toxoplasmosis require long-term follow-up, focusing on nervous system development and ophthalmology.

Congenital toxoplasmosis after adalimumab treatment before pregnancy.

We present a case of congenital toxoplasmosis (TXP) in a woman with Toxoplasma gondii infection more than 6 months before conception. The woman has been treated with adalimumab for ankylosing spondylitis for 4 years until 5 months before conception. TXP serology at the first trimester was compatible with infection prior pregnancy. An ultrasound performed at 26 weeks gestation (WG) showed cerebral echogenic lesions compatible with intrauterine infection. Amniocentesis was performed which confirmed TXP fetal infection. Termination of the pregnancy was performed upon parent's requests and the fetal autopsy confirmed the diagnosis. Here, we discuss the potential role of immunosuppressive treatments, such as adalimumab, in the risk of congenital toxoplasmosis and the importance of counseling before pregnancy.

The Term Newborn: Congenital Infections.

Maternal pathogens can be transmitted to the fetus resulting in congenital infection with sequelae ranging from asymptomatic infection to severe debilitating disease and still birth. The TORCH pneumonic (toxoplasmosis, rubella, cytomegalovirus, and herpes simplex virus) is used widely, but it provides a limited description of the expanding list of pathogens associated with congenital infection. This article focuses on the evaluation and management of infants with common congenital infections such as cytomegalovirus, and infections that warrant early diagnosis and treatment to prevent serious complications, such as toxoplasmosis, human immunodeficiency virus, and syphilis. Zika virus and Chagas disease remain uncommon.

[Congenital toxoplasmosis: the importance of adherence to guidelines and clinical implications in Colombia.] / Toxoplasmosis congénita: la importancia de la adherencia a las guías y las implicaciones clínicas en Colombia.

INTRODUCCIÓN: La toxoplasmosis congénita continúa siendo un problema de salud pública. Aun cuando existen guías plenamente divulgadas y conocidas, se observa poca implementación de ellas en algunas instituciones de salud y una inadecuada interpretación de las pruebas serológicas en las gestantes. Esto puede generar falta de captación y tratamiento en embarazadas con primoinfección por Toxoplasma gondii. CASOS CLÍNICOS: Se reportan dos casos de toxoplasmosis congénita, uno de ellos con desenlace fatal. En ambos no se siguieron las guías de práctica clínica, lo cual conllevó un diagnóstico tardío y, en consecuencia, un manejo en condiciones inapropiadas con daños graves. CONCLUSIONES: La toxoplasmosis es una infección congénita aún prevalente en algunos países, con secuelas graves, discapacidad neurológica y riesgo de daño ocular, incluso tardío. Además, existen algunas variedades de cepas de T. gondii con un comportamiento más agresivo en Latinoamérica, lo cual empeora la presentación de los casos e incluye mayor riesgo de muerte. BACKGROUND: Congenital toxoplasmosis continues to be a public health problem. Although clinical guidelines have been divulgated and are well known, they are not implemented in some health institutions, in addition of an inappropriate interpretation of the serological tests in pregnant women. This situation can lead to lack of screening and treatment in pregnant women with primary Toxoplasma gondii infection. CASE REPORTS: We report two cases of congenital toxoplasmosis, one with a fatal outcome. In both cases, the clinical guidelines were not initially followed, leading to a delayed diagnosis and, consequently, an inappropriate management in conditions with severe damage. CONCLUSIONS: Toxoplasmosis is a congenital infection still prevalent in some countries, with severe sequelae, neurological disability, and even late risk of ocular damage. ­Additionally, some varieties of the T. gondii strains have a more aggressive pattern in Latin America, worsening the clinical presentation of cases and including a high risk of death.

Acute Toxoplasmosis During Pregnancy: A Hard Call

Toxoplasma gondii is an obligate intracellular parasite that infects all animals, including humans, and causes toxoplasmosis. If toxoplasmosis occurs during pregnancy, it may affect the foetus owing to transplacental transmission. Such transmission may lead to foetal complications, some of which can be very serious, e.g. hydrocephaly and chorioretinitis; however, not all cases of acute toxoplasmosis during pregnancy result in foetal complications. The decision whether to continue or terminate the pregnancy is a difficult problem for families as well as healthcare professionals, thus making it important. Here we present a case of acute toxoplasmosis at 6 weeks of pregnancy. The patient was directly advised to terminate the pregnancy. However, with detailed laboratory analyses, close follow-up and treatment to prevent transplacental transmission, she successfully completed the pregnancy and eventually delivered a healthy baby. By presenting this case, we aimed to review acute toxoplasmosis during pregnancy.

Toxoplasma gondii in South America: a differentiated pattern of spread, population structure and clinical manifestations.

Toxoplasma gondii is an obligate intracellular parasite belonging to the phylum Apicomplexa. It has a worldwide distribution and can infect a wide variety of intermediate hosts, including humans. In South America, toxoplasmosis shows high health impacts, and the incidence of the disease is frequently reported and more severe than in other regions, such as Europe. Although most T. gondii infections are asymptomatic, severe manifestations can occur in cases of congenital toxoplasmosis and immunocompromised individuals. In South America, the ocular disease in immunocompetent individuals is also frequently reported. Treatment for any clinical manifestation of toxoplasmosis consists of the combination of sulfadiazine (SDZ) and pyrimethamine (PYR). However, failures in the treatment of toxoplasmosis have been reported, especially in South America, suggesting the acquisition of resistance against SDZ and PYR. Another paradigm present in the literature is that once infected with T. gondii, the host is immunologically protected from further reinfections. However, some studies indicate cases of congenital transmission of T. gondii from immunocompetent pregnant women with chronic infection, suggesting the possibility of reinfection in humans. Thus, in this review, we will cover several aspects of South American T. gondii isolates, such as genetic characterization, disease manifestation, host reinfection and drug resistance.

Consenso Argentino de toxoplasmosis congénita 2020 / Argentine Consensus of congenital toxoplasmosis

Resumen La transmisión vertical de la infección por Toxoplasma gondii ocurre cuando la madre se infecta por primera vez en el transcurso del embarazo. El diagnóstico de la infección materna y la del re cién nacido se logra con el conjunto de pruebas serológicas, hallazgos clínicos y ecográficos. El reconocimiento temprano de la infección materna permite un tratamiento que reduce la tasa de transmisión y el riesgo de daño en el producto de la concepción. El objetivo de este consenso de expertos fue revisar la literatura científica para actualizar las recomendaciones de práctica clínica respecto de la prevención, el diagnóstico y el tratamiento de la toxoplasmosis congénita en nuestro país.

Abstract Mother-to-child transmission in Toxoplasma gondii infection occurs only when the infection is acquired for the first time during pregnancy. Diag nosis of maternal infection and the newborn is achieved by a combination of serological tests, clinical features and ultrasound images. An early diagnosis of maternal infection allows treatment that offers a reduction both in transmission rate and risk of congenital damage. The aim of this expert consensus was to review the scientific literature which would enable an update of the clinical practice guideline of prevention, diagnosis and treatment of congenital toxoplasmosis in our country.

[Argentine consensus of congenital toxoplasmosis]. / Consenso argentino de toxoplasmosis congénita 2020.

Mother-to-child transmission in Toxoplasma gondii infection occurs only when the infection is acquired for the first time during pregnancy. Diagnosis of maternal infection and the newborn is achieved by a combination of serological tests, clinical features and ultrasound images. An early diagnosis of maternal infection allows treatment that offers a reduction both in transmission rate and risk of congenital damage. The aim of this expert consensus was to review the scientific literature which would enable an update of the clinical practice guideline of prevention, diagnosis and treatment of congenital toxoplasmosis in our country.

La transmisión vertical de la infección por Toxoplasma gondii ocurre cuando la madre se infecta por primera vez en el transcurso del embarazo. El diagnóstico de la infección materna y la del recién nacido se logra con el conjunto de pruebas serológicas, hallazgos clínicos y ecográficos. El reconocimiento temprano de la infección materna permite un tratamiento que reduce la tasa de transmisión y el riesgo de daño en el producto de la concepción. El objetivo de este consenso de expertos fue revisar la literatura científica para actualizar las recomendaciones de práctica clínica respecto de la prevención, el diagnóstico y el tratamiento de la toxoplasmosis congénita en nuestro país.

Engineering and Functional Evaluation of Neutralizing Antibody Fragments Against Congenital Toxoplasmosis.

Maternal-fetal transmission of Toxoplasma gondii tachyzoites acquired during pregnancy has potentially dramatic consequences for the fetus. Current reference-standard treatments are not specific to the parasite and can induce severe side effects. In order to provide treatments with a higher specificity against toxoplasmosis, we developed antibody fragments-single-chain fragment variable (scFv) and scFv fused with mouse immunoglobulin G2a crystallizable fragment (scFv-Fc)-directed against the major surface protein SAG1. After validating their capacity to inhibit T. gondii proliferation in vitro, the antibody fragments' biological activity was assessed in vivo using a congenital toxoplasmosis mouse model. Dams were treated by systemic administration of antibody fragments and with prevention of maternal-fetal transmission being used as the parameter of efficacy. We observed that both antibody fragments prevented T. gondii dissemination and protected neonates, with the scFv-Fc format having better efficacy. These data provide a proof of concept for the use of antibody fragments as effective and specific treatment against congenital toxoplasmosis and provide promising leads.