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.

Surveillance of microcephaly and selected brain anomalies in Argentina: Relationship with Zika virus and other congenital infections.

BACKGROUND: Zika virus (ZIKV) vertical transmission may lead to microcephaly and other congenital anomalies. In March and April 2016, the first outbreak of ZIKV occurred in Argentina. The objective was to describe the surveillance of newborns with microcephaly and other selected brain anomalies in Argentina, and evaluation different etiologies. METHODS: Participants were enrolled between April 2016 and March 2017. CASES: newborns from the National Network of Congenital Abnormalities of Argentina (RENAC) with head circumference lower than the 3rd percentile according to gestational age and sex, or selected brain anomalies. Blood and urine samples from cases and their mothers were tested for ZIKV by real-time polymerase chain reaction (RT-PCR), antigen-specific Immunoglobulin M (MAC-ELISA) and plaque-reduction neutralization test (PRNT90 ). Toxoplasmosis, rubella, herpes simplex, syphilis, and cytomegalovirus (CMV) infection were also tested. RESULTS: A total of 104 cases were reported, with a prevalence of 6.9 per 10,000 [95% confidence interval (CI): 5.7-8.4], a significant increase when compared with the data prior to 2016, Prevalence Rate Ratio 1.7 (95% CI 1.2-2.3). In five cases positive serology for ZIKV (IgM and IgG by PRNT) was detected. The five cases presented microcephaly with craniofacial disproportion. We detected four cases of CMV infection, three cases of congenital toxoplasmosis, two cases of herpes simplex infection, and one case of congenital syphilis. CONCLUSION: The prevalence of microcephaly was significantly higher when compared with the previous period. The system had the capacity to detect five cases with congenital ZIKV syndrome in a country with limited viral circulation.

Pulmonary toxoplasmosis in human immunodeficiency virus-infected patients in the era of antiretroviral therapy.

Toxoplasmosis is a severe opportunistic infection in patients infected with the human immunodeficiency virus (HIV). The lung is a major site of infection after the central nervous system. In this report we described two cases of pneumonia due to Toxoplasma gondii infection in HIV patients with antiretroviral therapy. Clinical and radiological abnormalities are not specific. Pulmonary toxoplasmosis should be considered in HIV-infected patients with late stage of HIV, CD4 count less than 100 cells/µl and a poor adherence to HAART.

First report of Cystoisospora belli parasitemia in a patient with acquired immunodeficiency syndrome.

Cystoisospora belli in patients with the acquired immunodeficiency syndrome (AIDS) has been described as cause of chronic diarrhea and disseminated cystoisosporosis. Diagnosis of intestinal cystoisosporosis can be achieved at the tissue level in the villus epithelium of the small bowel. Disseminated cystoisosporosis is diagnosed by microscopy identification of unizoite tissue cysts in the lamina propria of the intestine. We report a case of disseminated cystoisosporosis in a human immunodeficiency virus (HIV)-infected patient with detection of parasitemia. We studied a 39-year old patient with AIDS and chronic diarrhea by analysis of stool and duodenal biopsy samples. Blood samples were also collected and examined by light microscopy and molecular techniques for C. belli DNA detection. The unizoite tissue cyst stages were present in the lamina propria, with unsporulated oocysts in feces. Zoites were present in blood smears and DNA of C. belli was detected in blood samples. Our study identified a new stage in the life cycle of C. belli. Detection of parasitemia is a novel and noninvasive tool for diagnosis of disseminated cystoisosporosis.

[Retrospective study of the implementation of the qualitative PCR technique in biological samples for monitoring toxoplasmosis in pediatric patients receiving hematopoietic stem cell transplantation]. / Estudio retrospectivo de la aplicación de la amplificación génica cualitativa en muestras biológicas para el seguimiento de la toxoplasmosis en pacientes pediátricos receptores de trasplante de células progenitoras hematopoyéticas.

Toxoplasmosis is an opportunistic infection caused by the parasite Toxoplasma gondii. The infection is severe and difficult to diagnose in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Twelve patients receiving HSCT were monitored post-transplant, by qualitative PCR at the Children's Hospital S.A.M.I.C. "Prof. Dr. Juan P. Garrahan". The monitoring of these patients was defined by a history of positive serology for toxoplasmosis in the donor or recipient and because their hematologic condition did not allow the use of trimethoprim-sulfamethoxazole for prophylaxis. During the patients' monitoring, two of them with positive PCR results showed signs of illness by T. gondii and were treated with pyrimethamine-clindamycin. In two other patients, toxoplasmosis was the cause of death and an autopsy finding, showing negative PCR results. Four patients without clinical manifestations received treatment for toxoplasmosis because of positive PCR detection. In four patients there were no signs of toxoplasmosis disease and negative PCR results during follow-up. The qualitative PCR technique proved useful for the detection of toxoplasmosis reactivation in HSCT recipients, but has limitations in monitoring and making clinical decisions due to the persistence of positive PCR over time and manifestations of toxicity caused by the treatment.

Estudio retrospectivo de la aplicación de la amplificación génica cualitativa en muestras biológicas para el seguimiento de la toxoplasmosis en pacientes pediátricos receptores de trasplante de células progenitoras hematopoyéticas / Retrospective study of the implementation of the qualitative PCR technique in biological samples for monitoring toxoplasmosis in pediatric patients receiving hematopoietic stem cell transplantion

La toxoplasmosis es una infección oportunista causada por el parásito Toxoplasma gondii; su infección es grave y de difícil diagnóstico en pacientes que reciben un trasplante alogénico de células progenitoras hematopoyéticas (TCPH). En el Hospital de Pediatría S.A.M.I.C. "Profesor Dr. Juan P. Garrahan" se realizó la vigilancia postrasplante de 12 pacientes receptores de TCPH mediante la técnica de PCR cualitativa. La necesidad de seguimiento de estos pacientes fue definida por el antecedente de serología positiva para toxoplasmosis en el donante o receptor y ante la imposibilidad de iniciar el uso profiláctico de trimetoprima-sulfametoxazol a causa de la condición hematológica. Dos pacientes presentaron signos de enfermedad por T. gondii con resultado de PCR positivo y recibieron tratamiento con pirimetamina-clindamicina. En otros dos, la toxoplasmosis fue causa de muerte y hallazgo de autopsia, con resultado de PCR negativo. Cuatro pacientes recibieron tratamiento contra toxoplasmosis por la detección de una PCR positiva, sin manifestaciones clínicas. En los cuatro pacientes restantes no se detectaron signos de enfermedad por toxoplasmosis, con resultados de PCR negativos durante el seguimiento. La técnica de PCR cualitativa demostró ser útil para detectar la reactivación de la toxoplasmosis en receptores de TCPH, pero tiene limitaciones para el seguimiento y la toma de decisiones clínicas en pacientes con PCR positiva que persiste en el tiempo y manifestaciones de toxicidad por el tratamiento.

Toxoplasmosis is an opportunistic infection caused by the parasite Toxoplasma gondii. The infection is severe and difficult to diagnose in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Twelve patients receiving HSCT were monitored post-transplant, by qualitative PCR at the Children's Hospital S.A.M.I.C. "Prof. Dr. Juan P. Garrahan". The monitoring of these patients was defined by a history of positive serology for toxoplasmosis in the donor or recipient and because their hematologic condition did not allow the use of trimethoprim-sulfamethoxazole for prophylaxis. During the patients' monitoring, two of them with positive PCR results showed signs of illness by T. gondii and were treated with pyrimethamine-clindamycin. In two other patients, toxoplasmosis was the cause of death and an autopsy finding, showing negative PCR results. Four patients without clinical manifestations received treatment for toxoplasmosis because of positive PCR detection. In four patients there were no signs of toxoplasmosis disease and negative PCR results during follow-up. The qualitative PCR technique proved useful for the detection of toxoplasmosis reactivation in HSCT recipients, but has limitations in monitoring and making clinical decisions due to the persistence of positive PCR over time and manifestations of toxicity caused by the treatment.

Estudio retrospectivo de la aplicación de la amplificación génica cualitativa en muestras biológicas para el seguimiento de la toxoplasmosis en pacientes pediátricos receptores de trasplante de células progenitoras hematopoyéticas / Retrospective study of the implementation of the qualitative PCR technique in biological samples for monitoring toxoplasmosis in pediatric patients receiving hematopoietic stem cell transplantion

La toxoplasmosis es una infección oportunista causada por el parásito Toxoplasma gondii; su infección es grave y de difícil diagnóstico en pacientes que reciben un trasplante alogénico de células progenitoras hematopoyéticas (TCPH). En el Hospital de Pediatría S.A.M.I.C. "Profesor Dr. Juan P. Garrahan"Ø se realizó la vigilancia postrasplante de 12 pacientes receptores de TCPH mediante la técnica de PCR cualitativa. La necesidad de seguimiento de estos pacientes fue definida por el antecedente de serología positiva para toxoplasmosis en el donante o receptor y ante la imposibilidad de iniciar el uso profiláctico de trimetoprima-sulfametoxazol a causa de la condición hematológica. Dos pacientes presentaron signos de enfermedad por T. gondii con resultado de PCR positivo y recibieron tratamiento con pirimetamina-clindamicina. En otros dos, la toxoplasmosis fue causa de muerte y hallazgo de autopsia, con resultado de PCR negativo. Cuatro pacientes recibieron tratamiento contra toxoplasmosis por la detección de una PCR positiva, sin manifestaciones clínicas. En los cuatro pacientes restantes no se detectaron signos de enfermedad por toxoplasmosis, con resultados de PCR negativos durante el seguimiento. La técnica de PCR cualitativa demostró ser útil para detectar la reactivación de la toxoplasmosis en receptores de TCPH, pero tiene limitaciones para el seguimiento y la toma de decisiones clínicas en pacientes con PCR positiva que persiste en el tiempo y manifestaciones de toxicidad por el tratamiento.(AU)

Toxoplasmosis is an opportunistic infection caused by the parasite Toxoplasma gondii. The infection is severe and difficult to diagnose in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Twelve patients receiving HSCT were monitored post-transplant, by qualitative PCR at the Childrens Hospital S.A.M.I.C. "Prof. Dr. Juan P. Garrahan"Ø. The monitoring of these patients was defined by a history of positive serology for toxoplasmosis in the donor or recipient and because their hematologic condition did not allow the use of trimethoprim-sulfamethoxazole for prophylaxis. During the patients monitoring, two of them with positive PCR results showed signs of illness by T. gondii and were treated with pyrimethamine-clindamycin. In two other patients, toxoplasmosis was the cause of death and an autopsy finding, showing negative PCR results. Four patients without clinical manifestations received treatment for toxoplasmosis because of positive PCR detection. In four patients there were no signs of toxoplasmosis disease and negative PCR results during follow-up. The qualitative PCR technique proved useful for the detection of toxoplasmosis reactivation in HSCT recipients, but has limitations in monitoring and making clinical decisions due to the persistence of positive PCR over time and manifestations of toxicity caused by the treatment.(AU)

Estudio retrospectivo de la aplicación de la amplificación génica cualitativa en muestras biológicas para el seguimiento de la toxoplasmosis en pacientes pediátricos receptores de trasplante de células progenitoras hematopoyéticas. / [Retrospective study of the implementation of the qualitative PCR technique in biological samples for monitoring toxoplasmosis in pediatric patients receiving hematopoietic stem cell transplantation].

Toxoplasmosis is an opportunistic infection caused by the parasite Toxoplasma gondii. The infection is severe and difficult to diagnose in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Twelve patients receiving HSCT were monitored post-transplant, by qualitative PCR at the Childrens Hospital S.A.M.I.C. "Prof. Dr. Juan P. Garrahan". The monitoring of these patients was defined by a history of positive serology for toxoplasmosis in the donor or recipient and because their hematologic condition did not allow the use of trimethoprim-sulfamethoxazole for prophylaxis. During the patients monitoring, two of them with positive PCR results showed signs of illness by T. gondii and were treated with pyrimethamine-clindamycin. In two other patients, toxoplasmosis was the cause of death and an autopsy finding, showing negative PCR results. Four patients without clinical manifestations received treatment for toxoplasmosis because of positive PCR detection. In four patients there were no signs of toxoplasmosis disease and negative PCR results during follow-up. The qualitative PCR technique proved useful for the detection of toxoplasmosis reactivation in HSCT recipients, but has limitations in monitoring and making clinical decisions due to the persistence of positive PCR over time and manifestations of toxicity caused by the treatment.

Estudio de un nuevo blanco diagnóstico para la detección temprana de la toxoplasmosis mediante PCR en tiempo real / Study on a new diagnostic target for the early detection of toxoplasmosis by real-time PCR

Toxoplasma gondii es un protozoo parásito intracelular obligado que infecta a los vertebrados de sangre caliente. Alrededor de un tercio de la población humana está crónicamente infectado con este parásito, y la infección es causada principalmente por la ingestión de carnes mal cocida que contiene quistes viables de T. gondii u ooquistes de las heces de gatos infectados. Aunque la infección humana con T. gondii suele ser asintomática, la toxoplasmosis ocular y linfadenopatia cervical u occipital se produce en algunos pacientes. La infección congénita o los casos de reactivación en immunodeprimidos pueden conducir a la encefalitis mortal. En este trabajo se analizaron dos marcadores moleculares, denominados B1 y TgIRE para la detección de taquizoítos circulantes de T. gondii, en muestras biológicas mediante la técnica de PCR en tiempo real para el diagnostico precoz de la Toxoplasmosis, utilizando dos sistemas de detección, TaqMan y SYBR Green I. El análisis del estudio comparativo se baso en la diferencia en el número de ciclos necesarios para alcanzar el umbral de detección (Ct) en las distintas cantidades de taquizoítos, donde se evidencio una sensibilidad superior del sistema TaqMan frente al SYBR Green I en ambos marcadores biológicos. El marcador B1 permitió la detección de 10 Tq mediante ambos sistemas; aunque reveló un valor de Ct superior para TaqMan (34.15+-0,99) frente a SYBR Green I (37,51+-1,538) y en un caso TaqMan detecto el ADN correspondiente a solo 1Tq. La diferencia entre los sistemas fue mas evidente en el elemento TgIRE donde el limite de detección para SYBR Green I fue de 1000Tq con valores de la media de Ct de 39,24+-0,39, cercanos al final del ciclo de amplificación, en cambio para el sistema TaqMan fue 100 veces superior, al permitir la detección de 10 tq con valores de Ct promedio de 38,27+-0,71,. Estos valores permitieron observar que B1 denota un límite de detección superior a TgIRE dentro del sistema más sensible. Dado estos resultados se evaluaron distintos fluidos biológicos por el sistema de detección B1-TaqMan, que suministraron los siguientes resultados: en muestras de humor acuosos la detección de la carga parasitaria fue de entre 1000 a 10 tq; en muestras de LCR los valores se situaron cercano al limite de detección de entre 1 y 10 taquizoítos; en mustras de sangre el valor de detección fue inferior a 10 tq; en muestras de tejido la detección fue próximo entre 1000 a 1 taquizoítos y en muestras de liquido amniótico no se ha evidenciado presencia de ADN de T.gondii. Estos resultados permiten proponer al sistema B1-TaqMan como una herramienta valiosa en el diagnostico temprano de la toxoplasmosis humana, en especial en pacientes inmunosuprimidos donde su sistema inmunológico esta deteriorado y los test serológicos utilizados para la detección de anticuerpo anti-T. gondii son de poca utilidad.

Toxoplasma gondii protease inhibitor-1 (TgPI-1) is a novel vaccine candidate against toxoplasmosis.

The Toxoplasma gondii serin protease inhibitor-1 (TgPI-1) is a dense granule antigen that showed to specifically inhibit trypsin, chymotrypsin and neutrophil elastase, suggesting a possible modulatory role during the parasite invasion process and on the development of the innate immune response. To study the immune-protective value of TgPI-1, C3H/HeN mice were immunized with a recombinant form of the antigen rTgPI-1 combined with alum. All immunized mice produced specific anti-rTgPI-1 immunoglobulins, with high IgG antibody titers and a mixed IgG(1)/IgG(2a) response, with predominance of IgG(1) production. The cellular immune response was associated with the production of IFN-gamma and IL-10 cytokines. Vaccinated mice displayed significant protection against an oral challenge either after a lethal infection with Me49 cysts (90% survival vs. 50%) and also after a non-lethal infection (58% reduction in brain parasite load) compared to the non-vaccinated control group. In conclusion, rTgPI-1 elicits a strong specific immune response providing partial protection against both T. gondii acute and chronic infection, so it would be a good candidate in a vaccine against toxoplasmosis, which could be combined with other relevant parasite antigens.

Identification and characterization of serine proteinase inhibitors from Neospora caninum.

Two cDNA clones obtained from the Neospora caninum Expressed Sequence Tag project were selected by their homology with the Toxoplasma gondii serine proteinase inhibitor (serpin) gene, TgPI-1 and TgPI-2. One of them, named NcPI-H, showed several premature stop codons. The other cDNA, named NcPI-S, encoded a 79 amino acid protein containing a putative signal peptide and only one non-classical Kazal domain. Two other N. caninum EST sequences (NcEST1 and NcEST2) and one from Eimeria tenella (EtPI-S) were retrieved from the database. Amino acid sequence analysis suggested that NcEST1 and NcEST2 might be the N. caninum counterparts of TgPI-1 and TgPI-2, respectively. EtEST-S, as NcPI-S, is a single domain serpin. The open reading frame encoding the mature version of NcPI-S was expressed as recombinant protein, fused to a 6 histidine tag in Escherichia coli. Specific rabbit antiserum generated against the recombinant NcPI-S was used in immunoblot assays. Bands of 20, 30, 40, and 66-kDa were detected by SDS-PAGE of whole parasite homogenate. In addition, when an anti-TgPI-1 serum was used, bands of 25 and 35-kDa were detected indicating that there is no cross-reactivity between both serpins, and showing as well, the presence of another putative serpin in N. caninum. The recombinant protein NcPI-S, inhibited bacterial subtilisin completely, and showed lower inhibitory capacity on human neutrophil elastase, animal trypsin, and chymotrypsin, suggesting differences in effectiveness.