Immune response against toxoplasmosis-some recent updates RH: Toxoplasma gondii immune response.

AIMS: Cytokines, soluble mediators of immunity, are key factors of the innate and adaptive immune system. They are secreted from and interact with various types of immune cells to manipulate host body's immune cell physiology for a counter-attack on the foreign body. A study was designed to explore the mechanism of Toxoplasma gondii (T. gondii) resistance from host immune response. METHODS AND RESULTS: The published data on aspect of host (murine and human) immune response against T. gondii was taken from Google scholar and PubMed. Most relevant literature was included in this study. The basic mechanism of immune response starts from the interactions of antigens with host immune cells to trigger the production of cytokines (pro-inflammatory and anti-inflammatory) which then act by forming a cytokinome (network of cytokine). Their secretory equilibrium is essential for endowing resistance to the host against infectious diseases, particularly toxoplasmosis. A narrow balance lying between Th1, Th2, and Th17 cytokines (as demonstrated until now) is essential for the development of resistance against T. gondii as well as for the survival of host. Excessive production of pro-inflammatory cytokines leads to tissue damage resulting in the production of anti-inflammatory cytokines which enhances the proliferation of Toxoplasma. Stress and other infectious diseases (human immunodeficiency virus (HIV)) that weaken the host immunity particularly the cellular component, make the host susceptible to toxoplasmosis especially in pregnant women. CONCLUSION: The current review findings state that in vitro harvesting of IL12 from DCs, Np and MΦ upon exposure with T. gondii might be a source for therapeutic use in toxoplasmosis. Current review also suggests that therapeutic interventions leading to up-regulation/supplementation of SOCS-3, IL12, and IFNγ to the infected host could be a solution to sterile immunity against T. gondii infection. This would be of interest particularly in patients passing through immunosuppression owing to any reason like the ones receiving anti-cancer therapy, the ones undergoing immunosuppressive therapy for graft/transplantation, the ones suffering from immunodeficiency virus (HIV) or having AIDS. Another imortant suggestion is to launch the efforts for a vaccine based on GRA6Nt or other similar antigens of T. gondii as a probable tool to destroy tissue cysts.

Ciencia, salud pública y toma de decisiones: [Editorial] / Science, public health and decision making: [Editorial]

La pandemia por COVID-19 ha obligado a los gobiernos de todo el mundo a la toma de decisiones con información preliminar, insuficiente o discutible en argumentos científicos, algo que como académicos debemos entender y acompañar y se convierte en un reto mayor: ¿cómo dar recomendaciones con información limitada y reducir las incertidumbres? Para ello, primero que todo, se debe reconocer que estos procesos están sometidos a cambios según la evolución del conocimiento y la comunicación de la información se vuelve crucial para evitar minar la confianza pública ante los cambios. Es así como muchas recomendaciones para el manejo de COVID 19 han venido evolucionando a medida que se conoce mejor la patogénesis, sus mecanismos de transmisión y las particularidades en la respuesta inmune y, por ejemplo, pasamos de una recomendación inicial de medidas de prevención que incluía limpieza de superficies a una en la cual el énfasis es la limitación en número de personas en reunión. La Asociación Colombiana de infectología junto con otras 27 sociedades científicas lleva tres diferentes actualizaciones de recomendaciones basadas en evidencia en los primeros 12 meses de pandemia, es decir cada tres meses se han venido revisando las más de 250 recomendaciones, lo cual ha significado un trabajo enorme de revisión, discusión y presentación final las cuales, afortunadamente, han sido acogidas y tomadas como base de las decisiones gubernamentales.

The COVID-19 pandemic has forced governments around the world to take decisions on preliminary, insufficient The COVID-19 pandemic has forced governments around the world to make decisions with preliminary, insufficient or debatable information on scientific grounds, something that as academics we must understand and accompany and which becomes a major challenge: how to give recommendations with limited information and reduce uncertainties? To do this, first of all, it must be recognised that these processes are subject to change as knowledge evolves and the communication of information becomes crucial to avoid undermining public confidence in the face of change. Thus, many recommendations for the management of COVID 19 have evolved as the pathogenesis, transmission mechanisms and particularities of the immune response have become better understood and, for example, we have gone from an initial recommendation of measures to be taken in response to COVID 19 to a recommendation of measures to be taken in response to COVID 19, we have moved from an initial recommendation for prevention measures that included surface cleaning to one in which the emphasis is on limiting the number of people at a meeting. The Colombian Association of Infectious Diseases, together with 27 other scientific societies, has scientific societies has three different updates of evidence-based evidence-based recommendations in the first 12 months of a pandemic, i.e. every months of the pandemic, i.e. every three months, the more than 250 recommendations have been This has meant an enormous work of review, discussion and final presentation which, fortunately, have been accepted and taken as a basis for governmental decisions. and taken as a basis for governmental decisions.

Vacunas para COVID19: las lecciones de un triunfo de la ciencia biomédica: [Editorial] / Vaccines for COVID19: lessons from the triumph of the biomedical science: [Editorial]

Frente al escepticismo de encontrar una vacuna para COVID19, los resultados de los ensayos clínicos de Fase III dieron la sentencia: se lograron vacunas con alto grado de eficacia que llega al 70% a 95%. Al momento de escribir esta editorial, dos de ellas ya tienen autorización para uso de emergencia por el FDA. La OMS realiza un seguimiento cotidiano a los avances de candidatos vacunales, el reporte para el 22 de Diciembre encontraba 57 en fases de evaluación clínica (entre estas 11 en fase III) y 166 en fase preclínica.

In the face of skepticism about finding a vaccine for COVID19 , the results of the Phase III clinical trials were conclusive: vaccines with a high degree of efficacy of 70% to 95% were achieved. At the time of writing this editorial, two of them have already been authorized for emergency use by the FDA. The WHO monitors the progress of vaccine candidates on a daily basis; the report as of December 22nd found 57 in clinical evaluation phases (including 11 in Phase III) and 166 in preclinical phase.

Evaluación de la prueba de avidez para el seguimiento de niños tratados por toxoplasmosis congénita durante el primer año de vida / Evaluation of the avidity test for the follow up on children treated for congenital toxoplasmosis during the first year of life

RESUMEN Objetivos: determinar la utilidad de la prueba de avidez en el seguimiento de los pacientes diagnosticados con toxoplasmosis congénita a través de la evaluación de su comportamiento en el tiempo. Metodología: estudio retrospectivo a partir de los datos en historias clínicas de niños que tuvieron confirmación diagnóstica y tratamiento para toxoplasmosis congénita, realizado en consulta de toxoplasmosis, tercer nivel de referencia en el centro de salud de la Universidad del Quindío. Se estudiaron 21 niños que fueron seleccionados de una cohorte inicial de 168 pacientes, reclutados en los programas de tamizaje prenatal y los programas de prevención o niños que acudieron para el diagnóstico neonatal. Resultados: no se encontró relación estadísticamente significativa entre el porcentaje de avidez baja en el primer mes y haber recibido tratamiento prenatal (p = 0,47). Tampoco entre la primera y los niveles de IgG o los meses de vida, a pesar de haber recibido tratamiento posnatal. Sin embargo, al estudiar específicamente el grupo de niños de 5 meses de edad, se encontró una correlación significativa con los niveles de IgG anti-Toxoplasma (p = 0,01). Conclusión: en esta cohorte de niños colombianos con toxoplasmosis congénita se encontraron los mismos resultados reportados en series previas con un mayor número de casos en Italia. La avidez no mostró ser útil para el seguimiento de los niños con toxoplasmosis congénita.

SUMMARY Objectives: To determine the use of avidity testing in the follow up of patients diagnosed with congenital toxoplasmosis, through the observation of its behavior in time. Methods: Retrospective study from clinical records of children with confirmed diagnosis and treatment for congenital toxoplasmosis, which took place on atoxoplasmosis consultation in the third reference level University of Quindío clinic. A total of 21 children were selected among an initial cohort of 168 patients, recruited during prenatal screening, neonatal screening or children that attended for neonatal diagnosis. Results: There was no statistical significance found between low avidity during the first month and having received prenatal treatment (p=0,47). There was no statistical relationship either between the percentage of avidity and the levels of IgG or the months of age, despite having received postnatal treatment. Nevertheless, when studying specifically the group of children > 5 months of age a significant correlation was found with levels of IgG (p=0,01). Conclusion: In this cohort of Colombian children with congenital toxoplasmosis, the same results were found comparing with those reported in series with greater number of cases. Avidity testing did not prove to be useful for the follow up of children with congenital toxoplasmosis.

Autonomía farmacéutica y biotecnológica frente a emergencias sanitarias / Autonomous pharmaceutical and biotechnological capabilities during sanitary emergencies

La pandemia de COVID 19, ha puesto de presente la necesidad de contar con políticas de autonomía farmacéutica y biotecnológica para cada país. Esta autonomía es necesaria porque en eventos ocasionados por agentes de riesgo biológico, la afectación masiva de la población mundial hace imposible que se cubran las necesidades para todos los países. Muchos medicamentos de interés en salud pública no son producidos por la industria farmacéutica privada dado que los márgenes de ganancia no son importantes para ellos y se encuentran situaciones de desabastecimiento ante brotes de infecciones inusitados.

The COVID 19 pandemic has highlighted the need for pharmaceutical and biotechnology autonomy policies for each country. This autonomy is necessary because in events caused by biological risk agents, the massive involvement of the world population makes it impossible to cover the needs of all countries. Many drugs of public health interest are not produced by the private pharmaceutical industry because the profit margins are not important for them and there are situations of shortages in the event of outbreaks of unusual infections.

El proceso de validación del conocimiento: el indispensable valor de la revista científica: [Editorial] / The knowledge validation process: the fundamental value of the scientific journal: [Editorial]

Esta pandemia ha dejado grandes lecciones sobre la literatura científica y la evaluación crítica del conocimiento. Aunque grandes revistas, egidas del rigor para validar conocimiento, tuvieron errores estrepitosos, la lección final es que la revisión por pares es el mejor sistema, y hasta ahora el único, que puede garantizar que un trabajo de investigación se ha realizado dentro de las exigencias de la ciencia formal y como se escribe habitualmente, es el menos malo de todos los otros sistemas de evaluación del trabajo científico. En medicina esto es crítico por su implicación en vidas humanas, pero nunca se debe esperar que este proceso esté exento de equivocaciones, la revista JAMA al respecto tuvo una editorial con un título muy diciente: "errar es humano y corregirlo es divino"

This pandemic has left us great lessons regarding scientific literature and the critical evaluation of knowledge. Although important journals that are rigorous when validating knowledge, had resounding errors, the ultimate lesson is that peer review is the best system, and until now the only one, that can ensure that a research work has been carried following scientific requirements, and as it is usually stated, it is the least worse scientific work evaluation systems when compared to others3­5. In medicine, this is critical given the way it affects human lives, but one should never expect this process to be error-free; JAMA journal had an editorial with a very telling title in this regard: "To err is human and to correct it is divine".

Consenso de grupo Ad-hoc sobre recomendaciones para la evaluación y controles de calidad para el diagnóstico molecular y serológico de la infección humana por SARS CoV-2 / Ad-hoc group consensus recommendations on the evaluation and quality control of molecular and serological diagnostics tests for SARS CoV-2 human infection

Se formulan recomendaciones de un grupo de consenso de expertos sobre los criterios para evaluar el desempeño diagnóstico (tamaño y selección de muestras para sensibilidad y especificidad analíticas, criterios para establecer límites de detección, criterios para establecer el estándar de oro para las serologías) que deberían ser tenidos en cuenta al evaluar y validar las pruebas diagnósticas para SARS CoV-2. Con el propósito de asegurar la calidad de las pruebas serológicas a utilizar en el país, se recomienda la participación en un programa de control de calidad externo, que garantice la idoneidad y desempeño en la realización de las pruebas diagnósticas serológicas y moleculares durante esta pandemia, ya que su uso tiene profundas implicaciones para las medidas de intervención clínicas individuales y de seguimiento y control en salud pública.

We formulate recommendations from a consensus working group on the criteria to evaluate the diagnostic performance (size and criteria of selection of samples to determine sensitivity, analytical specificity, criteria for limit of detection, criteria for gold standard to evaluate serological assays) that should be taken into account during the evaluation and validation/verification of diagnostic tests for SARS CoV-2 infection. A national external quality control program should be established to guarantee the suitability and performance of these diagnostic serological and molecular tests during this pandemic, that will have deep implications for decisions on clinical and public health.

Pandemia COVID-19: Reflexiones sobre su impacto para la preparación en el control de enfermedades infecciosas en Colombia: [Editorial] / Pandemic COVID-19: A reflection on the impact for preparedness on the control of infectious diseases in Colombia: [Editorial]

La Organización Mundial de la Salud finalmente declaró al brote por el coronavirus SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) como una pandemia el 11 de marzo de 2020 . Al momento de escribir este editorial (Abril 4 de 2020) el mundo sobrepasó el millón de infectados y el número de muertes registraba cerca de 70 mil, con múltiples países sufriendo más de mil muertes diarias . Las características propias de este coronavirus, a pesar de ser similar a otros, como el SARS y el MERS, hace que existan interrogantes sobre su impacto en países de regiones y condiciones socioeconómicas y culturales diferentes.

The World Health Organization finally declared the SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) outbreak a pandemic on March 11, 2020 . At the time of writing this editorial (April 4, 2020) the world surpassed one million infected and the number of deaths was close to 70,000, with multiple countries suffering more than one thousand deaths per day. The specific characteristics of this coronavirus, despite being similar to others, such as SARS and MERS, raise questions about its impact in countries of different regions and socioeconomic and cultural conditions.

Foodborne parasites in Colombia: [Editorial] / Parásitos transmitidos por alimentos en Colombia: [Editorial]

This number of Infectio includes the first report of Anisakis in edible fish in the Colombian pacific coast. Anisakidiasis has become an increasing threat given the extensive consumption of Sushi and raw fish worldwide as consequence of a global fad food. This report of Anisakis in 42% of the most popular fish specimens consumed in the country, call the attention also about the new health risks present in food, particularly parasites. The Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) established a ranking of the top foodborne parasites for control priority in 2014. This was the first expert meeting that established which were the most important parasites to be included in risk analysis of food. The consequences are important, not only for the health sector, but also for the agriculture export market of developing countries. As free trade agreements have become a rule for the commercial exchange between countries, the only way to limit the entry of food products in the developed world are the sanitary controls. CODEX Alimentarius Commission (CAC) is the international organism that define the sanitary code and rules for quality and risk analysis in food. The economic importance of the rules defined by this commission is evident and discussions about inclusion of new controls for new risks are intense and a particularly though task inside this commission.

Este número de Infectio incluye el primer reporte de Anisakis en pescado comestible en la costa pacífica colombiana. La anisakidiasis se ha convertido en una amenaza creciente dado el amplio consumo de sushi y pescado crudo en el mundo como consecuencia de una moda alimentaria mundial. Este reporte de Anisakis en el 42% de los ejemplares de pescado más consumidos en el país, llama la atención también sobre los nuevos riesgos para la salud presentes en los alimentos, particularmente los parásitos. La Organización de las Naciones Unidas para la Agricultura y la Alimentación (FAO) y la Organización Mundial de la Salud (OMS) establecieron en 2014 una clasificación de los principales parásitos transmitidos por los alimentos para su control prioritario. Esta fue la primera reunión de expertos que estableció cuáles eran los parásitos más importantes a incluir en el análisis de riesgo de los alimentos. Las consecuencias son importantes, no solo para el sector sanitario, sino también para el mercado de exportación agrícola de los países en desarrollo. Como los acuerdos de libre comercio se han convertido en una norma para el intercambio comercial entre países, la única forma de limitar la entrada de productos alimentarios en el mundo desarrollado son los controles sanitarios. La Comisión del CODEX Alimentarius (CAC) es el organismo internacional que define el código sanitario y las normas de calidad y análisis de riesgo en los alimentos. La importancia económica de las normas definidas por esta comisión es evidente y las discusiones sobre la inclusión de nuevos controles para nuevos riesgos son intensas y una tarea especialmente ardua dentro de esta comisión.

Evidence based guidelines for congenital Chagas: [Editorial] / Guias basadas en evidencia para Chagas congénito: [Editorial]

In this issue of Infectiowe present the version in English language of the Colombian guidelines for congenital Chagas. This guideline was published in Spanish inInfectioin April 20141. This guideline was a consensus report developed by the Colombian task force, that was integrated by experts in the field and financed by the Ministry of Health, Colciencias (Red Chagas Program Cont. Colciencias 080-2011) and the Pan American Health Organization.

En este número de Infectio presentamos la versión en idioma inglés de la guía colombiana para el Chagas congénito. Esta guía fue publicada en español en Infectio en abril de 2014. Esta guía fue un informe de consenso desarrollado por el grupo de trabajo colombiano, que fue integrado por expertos en el tema y financiado por el Ministerio de Salud, Colciencias (Programa Red Chagas Cont. Colciencias 080-2011) y la Organización Panamericana de la Salud.

Evidence based guideline for toxoplasmosis during pregnancy: [Editorial]

Colombia fue el primer país del mundo en desarrollar una guía basada en la evidencia para la toxoplasmosis. El proyecto se presentó en 2010, se inició en 2011 y se publicó en español en Infectio en diciembre de 20121. Esta guía forma parte de las guías basadas en la evidencia para la complicación infecciosa y hemorrágica del embarazo desarrolladas por el Ministerio de Salud y Colciencias: http://gpc.minsalud.gov.co/gpc_sites/Repositorio/Conv_500/GPC_embarazo/gpc_embarazo.aspx.

Colombia was the first country in the world in to develop one evidence based guideline for toxoplasmosis. The project was presented in 2010, begun in 2011 and it was published in Spanish in Infectio in December 20121. This guideline was part of the evidence based guidelines for infectious and hemorrhagic complication of the pregnancy developed by the ministry of Health and Colciencias: http://gpc.minsalud.gov.co/gpc_sites/Repositorio/Conv_500/GPC_embarazo/gpc_embarazo.aspx.

Detection of protozoa in water samples by formalin/ether concentration method.

Methods to detect protozoa in water samples are expensive and laborious. We evaluated the formalin/ether concentration method to detect Giardia sp., Cryptosporidium sp. and Toxoplasma in water. In order to test the properties of the method, we spiked water samples with different amounts of each protozoa (0, 10 and 50 cysts or oocysts) in a volume of 10 L of water. Immunofluorescence assay was used for detection of Giardia and Cryptosporidium. Toxoplasma oocysts were identified by morphology. The mean percent of recovery in 10 repetitions of the entire method, in 10 samples spiked with ten parasites and read by three different observers, were for Cryptosporidium 71.3 ± 12, for Giardia 63 ± 10 and for Toxoplasma 91.6 ± 9 and the relative standard deviation of the method was of 17.5, 17.2 and 9.8, respectively. Intraobserver variation as measured by intraclass correlation coefficient, was fair for Toxoplasma, moderate for Cryptosporidium and almost perfect for Giardia. The method was then applied in 77 samples of raw and drinkable water in three different plant of water treatment. Cryptosporidium was found in 28 of 77 samples (36%) and Giardia in 31 of 77 samples (40%). Theses results identified significant differences in treatment process to reduce the presence of Giardia and Cryptosporidium. In conclusion, the formalin ether method to concentrate protozoa in water is a new alternative for low resources countries, where is urgently need to monitor and follow the presence of theses protozoa in drinkable water.

A rational approach to select immunogenic peptides that induce IFN-γ response against Toxoplasma gondii in human leukocytes.

The ideal vaccine to prevent toxoplasmosis in humans would comprise antigens that elicit a protective T cell type 1 response with high IFN-γ production. Here, we report the use of a bioinformatics pipeline to discover peptides based on biochemical characteristics that predict strong IFN-γ response by human leukocytes. We selected peptide sequences that previously were reported to induce IFN-γ to identify the biophysical characteristics that will predict HLA-A*02 high-affinity epitopes. We found that the protein motif pattern FL...L..[VL] was common in previously reported highly immunogenic sequences. We have selected new peptides with a length of 9 residues with affinities from 2 to 21 nM with peptide signal and transmembrane domains and predicted to be cleaved at the proteasome to perform ELISPOT assays with human leukocytes. Within 9 peptides with the highest scores for IFN-γ production, four peptides elicited IFN-γ levels in a range from 252 to 1763 SFC/1e6. Our pipeline uncovered Toxoplasma proteins with peptides that are processed by MHC class 1 in humans. Our results suggest that our rational strategy for the selection of immunogenic epitopes could be used to select peptides as candidates for inclusion in epitope-based vaccines.

Ocular cytokinome is linked to clinical characteristics in ocular toxoplasmosis.

PURPOSE: To determine the cytokine levels in aqueous humor (AH) of Colombian patients with active ocular toxoplasmosis (OT), and to correlate them with their clinical characteristics. METHODS: 27 Cytokines/chemokines were assayed in 15 AH samples (nine patients with diagnosis of OT biologically-confirmed and six controls that underwent cataract surgery). Correlations were assessed between cytokine/chemokine levels, type of inflammatory response (Th1, Th2, Th17, Treg), and clinical characteristics. RESULTS: Th2 predominant response was related to more severe clinical features. The presence of VEGF and IL-5 was related to higher number of recurrences. Growth factors (VEGF, FGF, PDGF-ß), were related to higher number of lesions. Patients infected by type-I/III strains had a particular intraocular cytokine-pattern. CONCLUSIONS: Th2 response was related to more severe clinical characteristics in patients infected by Type I/III strains. IL-5 and VEGF were associated with recurrences. We correlate for the first time, specific cytokine-patterns with clinical characteristics and with the infecting Toxoplasma strain.

Gestational and congenital toxoplasmosis in two hospitals in Bogota, Colombia / Toxoplasmosis gestacionaly congénita en dos hospitales de Bogotá, Colombia

Background. Gestational toxoplasmosis is acquired during pregnancy and involves a risk of the parasite crossing the placenta, thereby leading to foetal infection, which can lead to serious sequelae in children, mainly chorioretinitis, cerebral calcification, hydrocephalus and intellectual disability. Objective. Determining the prevalence of maternal and neonatal toxoplasmosis in women attending the Engativa and La Victoria hospitals in Bogota, Colombia, for delivery. Correlating the results with those of a national multicentre study. Determining IgM and IgA anti-toxoplasma prevalence in newborn (NB) umbilical cord blood. Materials and methods. This was a cohort study, which was approved by the participating institutions' ethics committees. The patients signed informed consent forms and filled out a survey requesting demographic and prenatal care data. A blood sample was taken from the umbilical cord on delivery for determining anti-toxoplasma IgM. Anti-toxoplasma IgA was also measured in a subset of patients. Children suspected of having either clinical or serological congenital toxoplasmosis were followed-up for 12 months. Results. The study involved taking 3,224 NB umbilical cord blood samples between April 1st 2009 and July 16th 2010. Positive anti-toxoplasma IgG was found in 28.2% of pregnant women (26.1-29.8 95%CI). Anti-toxoplasma IgM was determined in 558 pregnant women and found positive in 34 patients (i.e. 1.1 per 100 NB gestational toxoplasmosis incidence). Nine blood samples were positive (7 for IgM and 2 for IgA). Five of the NB studied (0.15%) were positive for IgG after 12 months' follow-up, thereby confirming a diagnosis of congenital toxoplasmosis accounting for 1 in every 645 live births. Conclusion. This study showed that 70% of the pregnant women were not infected with T. gondii in the chosen hospitals in Bogotá. Gestational toxoplasmosis frequency was around 1% and 0.6% for congenital toxoplasmosis.

Antecedentes. La toxoplasmosis gestacional es la adquisición de la enfermedad durante la gestación, con el riesgo de que el parásito atraviese la placenta and produzca una infección fetal, que puede llevar a importantes secuelas en el niño, principalmente coroidoretinitis, calcificaciones cerebrales, hidrocefalia and retardo mental. Objetivo. Conocer la prevalencia de la toxoplasmosis materna and neonatal, de las mujeres que asistieron para la atención del parto, en los Hospitales Engativá and La Victoria, de Bogotá, Colombia y correlacionar los resultados con los del estudio multicéntrico nacional. Determinar la prevalencia de IgM and IgA en sangre de cordón umbilical de los recién nacidos (RN). Materiales and métodos. Estudio de cohorte. El estudio fue aprobado por los comités de ética de las instituciones. Las pacientes firmaron el consentimiento informado y, posteriormente, se les diligenció el formato de recolección de datos, para conocer las características demográficas and los datos del control prenatal. En el parto, después del pinzamiento del cordón, se tomó una muestra de sangre de este, para determinar IgM antitoxoplasma y en un subgrupo de pacientes también se midió la IgA antitoxoplasma. Los niños con datos clínicos o serológicos sospechosos de toxoplasmosis congénita, se siguieron hasta los 12 meses. Resultados. Se tomaron muestras de 3.224 RN, entre el 1 de abril de 2009 y el 16 de julio de 2010. En las gestantes se encontró IgG anti-Toxoplasma positiva en 28,2% (IC95% 26,1-29,8). Se determinó la IgM anti-Toxoplasma en 558 gestantes encontrando 34 positivas, calculando una incidencia de toxoplasmosis gestacional de 1,1 por cada 100 RN. Se estudiaron 3215 muestras de cordón umbilical y se encontraron nueve casos positivos (siete con IgM y dos con IgA). De los RN estudiados, cinco (0,15%) tuvieron resultado positivo de IgG al año de edad, con lo cual se confirmó el diagnostico de toxoplasmosis congénita; esto equivale a un diagnóstico de toxoplasmosis congénita en 1 de cada 645 nacidos vivos. Conclusión. En este estudio se encontró que, en los hospitales de Bogotá estudiados, aproximadamente el 70% de las mujeres al momento de la gestación no se han infectado con el T gondii. La frecuencia de la toxoplasmosis gestacional es de aproximadamente 1% y la de toxoplasmosis congénita de 0,6%.

Severe South American ocular toxoplasmosis is associated with decreased Ifn-γ/Il-17a and increased Il-6/Il-13 intraocular levels.

In a cross sectional study, 19 French and 23 Colombian cases of confirmed active ocular toxoplasmosis (OT) were evaluated. The objective was to compare clinical, parasitological and immunological responses and relate them to the infecting strains. A complete ocular examination was performed in each patient. The infecting strain was characterized by genotyping when intraocular Toxoplasma DNA was detectable, as well as by peptide-specific serotyping for each patient. To characterize the immune response, we assessed Toxoplasma protein recognition patterns by intraocular antibodies and the intraocular profile of cytokines, chemokines and growth factors. Significant differences were found for size of active lesions, unilateral macular involvement, unilateral visual impairment, vitreous inflammation, synechiae, and vasculitis, with higher values observed throughout for Colombian patients. Multilocus PCR-DNA sequence genotyping was only successful in three Colombian patients revealing one type I and two atypical strains. The Colombian OT patients possessed heterogeneous atypical serotypes whereas the French were uniformly reactive to type II strain peptides. The protein patterns recognized by intraocular antibodies and the cytokine patterns were strikingly different between the two populations. Intraocular IFN-γ and IL-17 expression was lower, while higher levels of IL-13 and IL-6 were detected in aqueous humor of Colombian patients. Our results are consistent with the hypothesis that South American strains may cause more severe OT due to an inhibition of the protective effect of IFN-γ.

Cluster analysis identifies aminoacid compositional features that indicate Toxoplasma gondii adhesin proteins.

Toxoplasma gondii invade host cells using a multi-step process that depends on the regulated secretion of adhesions. To identify key primary sequence features of adhesins in this parasite, we analyze the relative frequency of individual amino acids, their dipeptide frequencies, and the polarity, polarizability and Van der Waals volume of the individual amino acids by using cluster analysis. This method identified cysteine as a key amino acid in the Toxoplasma adhesin group. The best vector algorithm of non-concatenated features was for 2 attributes: the single amino acid relative frequency and the dipeptide frequency. Polarity, polarizability and Van der Waals volume were not good classificatory attributes. Single amino acid attributes clustered unambiguously 67 apicomplexan hypothetical adhesins. This algorithm was also useful for clustering hypothetical Toxoplasma target host receptors. All of the cluster performances had over 70% sensitivity and 80% specificity. Compositional aminoacid data can be useful for improving machine learning-based prediction software when homology and structural data are not sufficient.

Diagnosis of pulmonary and extrapulmonary tuberculosis using an in-house PCR method in clinical samples from a middle-income resource setting / Diagnóstico de tuberculosis pulmonar y extrapulmonar mediante un método de PCR casera en muestras clínicas de una región de desarrollo intermedio

Introduction: PCR detection offers a good opportunity to obtain fast results which is a priority in tuberculosis control programs. Objectives: We assayed an in-house PCR method based on the detection of mycobaterial IS6110 gene in clinical samples of patients with pulmonary and extrapulmonary tuberculosis to demonstrate its usefulness and reliability in the setting of a middle-resource region with high tuberculosis prevalence. Materials and methods: Pulmonary (n=317) and extrapulmonary (n=41) samples were collected from 358 patients with clinical suspicion of tuberculosis. All samples were processed to detect acid-fast bacilli by microscopy, culture on solid media and PCR. To remove PCR inhibitors, three washing steps of the decontaminated pellet were included before mycobacterial cell lysis. Results: The overall sensitivity was 96% in clinical samples, and specificity was 100% for our in-house method in pulmonary and extrapulmonary samples. No inhibition was found among samples that were PCR negative, but culture positive for Mycobacterium tuberculosis. No false positives were found. Conclusions: In-house PCR in a middle-income setting region, with simple and strictly controlled methods, could efficiently complement conventional bacteriological tools for the rapid diagnosis of tuberculosis, especially in paucibacillary and extrapulmonary samples.

Introducción. La prueba de PCR ofrece la posibilidad de obtener resultados rápidos, una prioridad para los programas de control de la tuberculosis. Objetivos.Evaluar el método de PCR basado en la detección del gen IS6110 de las micobacterias en muestras clínicas de pacientes con tuberculosis pulmonar y extrapulmonar, para demostrar su utilidad y confiabilidad en un sitio de desarrollo medio con alta prevalencia de tuberculosis. Materiales y métodos. Se recolectaron 317 muestras pulmonares y 41 de origen extrapulmonar, de 358 pacientes con sospecha clínica de tuberculosis. Todas las muestras se procesaron para detectar bacilos ácido-alcohol resistentes por microscopía, cultivo en medio sólido y PCR. Para eliminar los inhibidores de la PCR se lavaron tres veces antes de realizar la lisis de la pared de la micobacteria. Resultados. La sensibilidad total fue de 96% y la especificidad de 100% para este método "casero" en muestras pulmonares y extrapulmonares. No se encontró inhibición entre las muestras que fueron negativas por PCR pero con cultivo positivo para Mycobacterium tuberculosis. No se hallaron falsos positivos. Conclusiones. La implementación de la PCR "casera" en regiones de desarrollo intermedio como método simple y estrictamente controlado, podría complementar eficientemente las herramientas bacteriológicas tradicionales para el diagnóstico rápido de la tuberculosis, especialmente en muestras paucibacilares y de origen extrapulmonar.

Prevalencia de tuberculosis infantil en Armenia, Colombia / Prevalence of childhood tuberculosis in Armenia, Colombia

Objetivo Determinar la prevalencia de tuberculosis (TB) infantil y los factores socio-demográficos asociados a esta población en el municipio de Armenia (Colombia). Metodología Se realizó un estudio descriptivo-retrospectivo en el cual se incluyeron pacientes con diagnóstico de TB menores de 14 años que fueron notificados al programa de TB en el municipio de Armenia y que iniciaron esquema de Tratamiento Acortado Estrictamente Supervisado (TAES) entre el 2000-2009. Resultados Se notificaron un total de 58 casos de TB, el mayor número de casos ocurrió en el 2009 (12 casos) seguido del 2008 (8 casos) y 2006 (7 casos) respectivamente, representando una elevada tasa de prevalencia (16,6 casos/100 000 habitantes). Las formas pulmonares tuvieron mayor proporción con 74 por ciento, de las cuales 34 por ciento fueron positivas a la baciloscopia (BK). El nexo epidemiológico se configuró en el 21 por ciento de los enfermos. En cuanto al egreso del programa de control de la TB el 5 por ciento de los pacientes finalizó con criterio de curado, 17 por ciento terminado, 4 por ciento transferidos, 7 por ciento fallecidos y en el 67 por ciento de los casos se desconoció el resultado del tratamiento. Conclusión La TB representa en la actualidad una causa importante de morbilidad y mortalidad infantil. Dada la buena cobertura de vacunación con BCG y que la mayoría de casos son pulmonares en este municipio, la alta tasa de casos de TB infantil estaría indicando fallas en la oportunidad para interrumpir transmisión reciente a partir de casos bacilíferos.

Objective To determine the childhood tuberculosis prevalence and its socio-demographics factors associated to this population in Armenia (Colombia). Methodology A retrospective-descriptive study was carried out; TB patients under the age of 14 years were included and notified to the TB control program in Armenia, those who started a Directly Observed Treatment Supervised (DOTS) scheme among from 2000 to 2009 years. Results 58 TB cases were described, most cases have occurred in 2009 (12 cases) followed by the 2008 (8 cases) and 2006 (7 cases) respectively. Thus, Armenia has a high rate of prevalence (16.6 cases/100 000 inhabitants). Pulmonary forms had greater proportion with 74 percent, of which 34 percent were positive to sputum examination revealed Acid-fast bacilli (AFB). Epidemiological link allowed confirmation of 21 percent of cases. TB treatment cohort revealed that 5 percent of patients were cured, finished 17 percent, transferred 4 percent, dead 7 percent and in 67 percent of cases the results were not documented. Conclusion Nowadays TB still an important cause of childhood morbidity and mortality. The good BCG vaccine covertures and the high prevalence of pulmonary forms in childhood TB indicates that the most plausible explanation for this high prevalence is a failure in early detection of bacilli positive patients to cut recent transmission in this municipality.