CD8+ T-cell Exhaustion Phenotype in Human Asymptomatic and Ocular Toxoplasmosis.

This work analyzed exhaustion markers in CD8+ T-cell subpopulations in 21 samples of peripheral blood mononuclear cells (PBMCs) from individuals with ocular toxoplasmosis (n = 9), chronic asymptomatic toxoplasmosis (n = 7), and non-infected people (n = 5) by using RT-qPCR and flow cytometry techniques. The study found that gene expression of PD-1 and CD244, but not LAG-3, was higher in individuals with ocular toxoplasmosis versus individuals with asymptomatic infection or uninfected. Expression of PD1 in CD8+ central memory (CM) cells was higher in nine individuals with toxoplasmosis versus five uninfected individuals (p = .003). After ex vivo stimulation, an inverse correlation was found between the exhaustion markers and quantitative clinical characteristics (lesion size, recurrence index, and number of lesions). A total exhaustion phenotype was found in 55.5% (5/9) of individuals with ocular toxoplasmosis. Our results suggest that the CD8+ exhaustion phenotype is involved in the pathogenesis of ocular toxoplasmosis.

Identification of Toxoplasma gondii adhesins through a machine learning approach.

Toxoplasma gondii, as other apicomplexa, employs adhesins transmembrane proteins for binding and invasion to host cells. Search and characterization of adhesins is pivotal in understanding Apicomplexa invasion mechanisms and targeting new druggable candidates. This work developed a machine learning software called ApiPredictor UniQE V2.0, based on two approaches: support vector machines and multilayer perceptron, to predict adhesins proteins from amino acid sequences. By using ApiPredictor UniQE V2.0, five SAG-Related Sequences (SRSs) were identified within the Toxoplasma gondii proteome. One of those candidates, TgSRS12B, was cloned in plasmid pEXP5-CT/TOPO and expressed in E. coli BL21 DE3. The resulting recombinant protein was purified via affinity chromatography. Co-precipitation assays in CaCo and Muller cells showed interactions between TgSRS12B-His-tagged and the membrane fractions from both human cell lines. In conclusion, we demonstrated that ApiPredictor UniQE V2.0, a bioinformatic free software, was able to identify TgSRS12B as a new adhesin protein.

Conocimientos, actitudes y prácticas sobre toxoplasmosis en dos comunas de Armenia, Quindío, con alta prevalencia de la infección / Knowledge, attitudes, and practices related to toxoplasmosis in two districts of high prevalence in Armenia, Quindío / Conhecimentos, atitudes e práticas sobre toxoplasmose em duas comunas de Armenia, Quindío, com alta prevalência de infecção

Resumen Objetivo: Describir los conocimientos, las actitudes y las prácticas acerca de la toxoplasmosis en dos comunas de Armenia, Quindío, con alta prevalencia de la infección. Metodología: Estudio descriptivo con población de dos comunas de Armenia, Quindío. Se aplicó un cuestionario autodiligenciado tipo conocimientos, actitudes y prácticas. Esta herramienta incluyó elementos sobre el parásito Toxoplasma gondii, sus vías de transmisión, aspectos clínicos, diagnósticos y de tratamiento generales, así como prácticas para evitar la infección. El instrumento se aplicó antes y después de una intervención educativa. Se describieron las frecuencias en el número de respuestas correctas antes y después de la intervención para cada comuna. Resultados: Participaron 27 personas, con una media de edad de 57 años. El 59 % fueron mujeres. El 48% había completado la educación media y el 40,7 % la primaria. El conocimiento del agente causal antes de la intervención fue del 22 %, mientras que posterior a la intervención fue del 92,3 % en la comuna 1 y del 81,8 % en la comuna 6. Posterior a la intervención, cerca del 90 % de los encuestados reconoció la retina como la principal estructura afectada y todos los encuestados reconocieron el consumo de agua hervida como factor protector. Conclusión: Los conocimientos sobre la toxoplasmosis en las dos comunas eran limitados. Luego de la intervención educativa, se evidenció un aumento en el porcentaje de respuestas correctas en la mayoría de las preguntas. Se recomienda realizar nuevas intervenciones educativas y en salud pública, para evaluar los efectos de estas a largo plazo.

Abstract Objective: To describe knowledge, attitudes and practices related to toxoplasmosis in two districts of high prevalence in Armenia, Quindío. Methodology: descriptive study; the population of two districts of Armenia, Quindío were engaged. A self-administered questionnaire regarding knowledge, attitudes, and practices was applied. This tool included elements related to Toxoplasma gondii, its transmission pathways, general clinical, diagnostic and treatment aspects, as well as practices to prevent infection. The instrument was applied before and after an educational intervention. Frequencies were described as the number of correct answers before and after the intervention for each district. Results: 27 people participated, with an average age of 57 years. 59 % were women; 48 % had completed high school and 40.7 % had completed elementary school. Before the intervention, the knowledge of the causal agent was 22 %, while after the intervention, it was 92.3 % in district 1 and 81.8 % in district 6. After the intervention, about 90 % of participants recognized the retina as the main compromised structure and all participants recognized the consumption of boiled water as a protective factor. Conclusion: The knowledge regarding toxoplasmosis in the two districts was limited. After the educational intervention, there was an increase in the percentage of correct answers in most of the questions. New educational and public health interventions are recommended to assess the long-term effects of these interventions.

Resumo Objetivos: O objetivo deste estudo é descrever os problemas, as ações e as práticas sobre a toxoplasmose nas comunidades da Armênia, Quindío, onde se nota alta prevalência da infecção. Metodologia: Este é um estudo descritivo que abrange uma população de duas comunas na Armênia, Quindío. Foi implementada uma ferramenta, que consiste em questionários destinados àquela população e aplicáveis pelos seus próprios membros, que correspondem a conhecimentos, atitudes e práticas. Essa ferramenta inclui elementos sobre o parasito Toxoplasma gondii, suas vias de transmissão, aspectos clínicos gerais, diagnósticos e tratamento, e práticas de prevenção. O instrumento foi aplicado antes e após uma intervenção educativa exata. Foram descritas as frequências do número de acertos, antes e depois da intervenção para cada comuna. Resultados: participaram 27 pessoas, com média de idade de 57 anos, das quais 59 % eram mulheres e 48 % tinham ensino médio completo e 40,7 % ensino primário. O conhecimento do agente causal antes da intervenção havia em 22 %, enquanto que após a intervenção, passou para 92,3 % na comuna 1, e 81,8 % na comuna 6. Após a intervenção, cerca de 90 % dos entrevistados reconheceram a retina como a estrutura mais afetada e todos os entrevistados reconheceram que o consumo de água fervida é um fator de proteção. Conclusão: Desconhecimento sobre a toxoplasmose nas duas comunas. Após a intervenção educativa, houve evidência de aumento do percentual de acertos na maioria das questões. Recomenda-se a realização de novas intervenções educacionais e de saúde pública, para avaliar os efeitos destas a longo prazo na populacão.

High frequency of ocular toxoplasmosis in Quindío, Colombia and risk factors related to the infection.

OBJECTIVES: To determine the frequency of retinochoroidal lesions by ocular toxoplasmosis and their relationships with risk factors, in residents of two districts with high exposure to Toxoplasma, in Armenia-Quindío, Colombia. METHODS: Cross-sectional analyses of fundoscopy screening, serological tests, and questionnaires were performed to determine risk factors associated with ocular toxoplasmosis retinochoroidal lesions. Differences in proportions were analyzed using the chi-squared test. RESULTS: Of 161 individuals examined, 17 (10.5%) exhibited retinochoroidal scars suggestive of old inactive Toxoplasma gondii infection. All 17 individuals were seropositive for T. gondii antibodies. Consumption of bottled water was protective against T. gondii infection among individuals in this study. There were no specific epidemiological risk factors associated with ocular toxoplasmosis retinochoroidal lesions. CONCLUSION: Ocular toxoplasmosis is an important cause of visual impairment in Armenia-Quindío, Colombia. The consumption of boiled or bottled water is a major preventive public health measure to reduce infection by T. gondii and the subsequent onset of OT.