Respuesta inmunitaria al SARS-CoV-2 previa a la vacunación en personal de salud de Alto Paraná, Paraguay, un estudio seroepidemiológico / Immune response to SARS-CoV-2 prior to vaccination among healthcare workers from Alto Paraná, Paraguay, a seroepidemiological study

INTRODUCCIÓN: La comprensión del comportamiento de la respuesta humoral en COVID-19 continúa siendo un desafío para la producción de vacunas que proporcionen inmunidad más duradera. OBJETIVO: Describir la respuesta humoral natural inducida por SARS- CoV-2 en personal de salud con base en el perfil epidemiológico y clínico. MATERIALES Y MÉTODOS: Estudio transversal en personal de salud de hospitales públicos de referencia del Departamento de Alto Paraná, Paraguay. Se incluyeron 962 participantes, mediante muestreo no probabilístico de tipo consecutivo, aplicación de cuestionario y toma de muestras sanguíneas. Se buscaron anticuerpos por ensayo inmunocromatográfico para detección de IgM e IgG contra SARS- CoV-2 y por el método ELISA de captura de IgG específicos contra la proteína spike (SARS-CoV-2) y se evaluaron factores asociados a la seropositividad. RESULTADOS: La seroprevalencia global fue 36,5% (IC 95%: 33,4 - 39,5); 59,3% (n: 571) de los encuestados refirió haber tenido síntomas compatibles al COVID-19 entre el inicio de la pandemia y la fecha de toma de muestra, de estos 44% (n: 251) resultó seropositivo; 10,4% (n: 100) manifestó no haber tenido síntomas en el periodo estudiado, pero tuvo un resultado positivo. Los factores asociados a la seropositividad fueron: presencia de síntomas (p 90 días). CONCLUSIONES: Las características clínicas fueron mayormente asociadas con la seropositividad y la seropreva- lencia en los sintomáticos varió de acuerdo con el tiempo transcurrido desde el inicio de los síntomas y la serología.

BACKGROUND: Understanding the behavior of humoral response in COVID-19 continues to be a challenge to produce vaccines that provide long-lasting immunity. AIM: To describe the natural humoral response induced by SARS-CoV-2 among healthcare workers based on epidemiological and clinical profiles. METHODS: Cross-sectional study in healthcare workers from public hospitals in the Department of Alto Paraná, Paraguay, 962 participants were recruited through consecutive sampling, using a questionnaire and blood sampling. Antibodies were determined by immunochromatography assay for detection of IgM and IgG and by SARS-CoV-2 IgG anti-spike capture ELISA method and factors associated with seropositivity were evaluated. RESULTS: The overall seropositivity was 36.5% (95% CI: 33.4 - 39.5); 59.3% (n: 571) of respondents reported symptoms compatible with COVID-19 since the start of the pandemic and the date of blood draw, 44% (n: 251) of them tested positive; 10.4% (n: 100) who reported no history of symptoms tested positive. The factors associated with seropositivity were the presence of symptoms (p 90 days). CONCLUSIONS: Clinical characteristics were mostly associated with seropositivity and sero prevalence in symptomatic participants varied according to the time elapsed from the onset of symptoms to serology.

Predictores de gravedad en pacientes hospitalizados por COVID-19 en el Hospital Integrado Respiratorio del Alto Paraná, 2021 / Predictors of severity in patients hospitalized for COVID-19 at the Alto Paraná Integrated Respiratory Hospital, 2021

RESUMEN Introducción. La gravedad de los pacientes internados por COVID-19 puede ser determinada por sus características sociodemográficas y las enfermedades de base, así como la alteración de los síntomas y resultados de laboratorios. Objetivo. analizar predictores de gravedad en los pacientes internados por COVID-19 en el Hospital Integrado Respiratorio de Alto Paraná. Metodología. Estudio observacional retrospectivo de corte transversal. Se realizó una revisión retrospectiva de las fichas clínicas de los pacientes internados entre enero a marzo del año 2021. Se analizaron características sociodemográficas, clínicas y factores de riesgo de gravedad. Resultados. De los 137 pacientes estudiados, el 62,0% (n=85) era del sexo masculino. La mortalidad fue del 43,8% (n=60), similar en menores y mayores de 60 años. El ingreso a UTI estuvo asociado a mayor mortalidad 69,4% (n=43) (p<0,001). Los principales síntomas fueron disnea 63,5% (n=87), tos seca 55,47% (n=76) y fiebre 54,0% (n=74), únicamente la disnea se asoció (p<0,05) a óbito. Las enfermedades de base más frecuentes y asociadas a mayor riesgo de muerte (p<0,001) fueron la Hipertensión arterial, Diabetes mellitus y obesidad. Los parámetros laboratoriales alterados en mayor frecuencia fueron leucocitosis, neutrofilia, linfopenia, AST, Dímero D, ferritina y glicemia, pero los marcadores asociados (p<0,05) con óbito fueron linfopenia, AST y glicemia. Conclusión. Se identificaron algunos parámetros de gravedad que contribuyeron al monitoreo de la evolución del paciente, los cuales pueden ser útiles como predictores en las decisiones de los profesionales de la salud para el tratamiento.

ABSTRACT Introduction. The severity of patients hospitalized for COVID-19 can be determined by its sociodemographic characteristics and underlying diseases, as well as changes in symptoms and laboratory results. Objective. to analyze severity predictors in patients hospitalized for COVID-19 at the Alto Paraná Respiratory Integrated Hospital. Methodology. Observational cros-sectional, retrospective study. Clinical charts of patients hospitalized between January and March of 2021 were retrospectively reviewed. Sociodemographic and clinical characteristics and severity risk factors were analyzed. Results. Of the 137 patients studied, 62.0% (n=85) were male. Mortality was 43.8% (n=60), similar in those under and over 60 years old. ICU admission was associated with higher mortality 69.4% (n=43) (p<0.001). The main symptoms were dyspnea 63.5% (n=87), dry cough 55.47% (n=76) and fever 54.0% (n=74), only dyspnea was associated (p<0.05) to death. The most frequent underlying diseases associated with a higher risk of death (p<0.001) were arterial hypertension, diabetes mellitus and obesity. The most frequently altered laboratory parameters were leukocytosis, neutrophilia, lymphopenia, AST, D-dimer, ferritin and glycemia, but the markers associated (p<0.05) with death were lymphopenia, AST and glycemia. Conclusion. Some severity parameters were identified that contributed to the monitoring of the patient's evolution, which can be useful as predictors in the decisions of health professionals for treatment.

Analysis of Multi-Pesticide Residues and Dietary Risk Assessment in Fresh Tomatoes (Lycopersicum esculentum) from Local Supermarkets of the Metropolitan Region, Chile.

In recent years, the official authorities in Chile have reported transgressions in the maximum residue levels of pesticides in fresh vegetables. There is no official information about traceability, pesticide levels, and potential health risks. The aim of this study was to analyse pesticide residues and their corresponding dietary risk assessments in tomatoes from supermarkets in the Metropolitan Region. Pesticides were extracted using the Quick, Easy, Cheap, Effective, Rugged and Safe, QuEChERS method, and their concentrations were determined by using chromatography with HPLC-FL/UV and GC-MS/ECD/NPD, following the Analytical Quality Control and Method Validation Procedures for Pesticides Residues Analysis in Food and Feed, SANTE guide and ISO 17025:2017 standard. In addition, a dietary risk assessment was carried out by comparing Chilean data to international references. The results reported that 9% of the samples had pesticide residue levels above the maximum residue levels permitted in Chile. All the scenarios evaluated revealed the highest estimated daily intake and hazard quotients for methamidophos and chlorpyrifos. Both the active substances used were acetylcholinesterase inhibitors and were neurotoxic under chronic risk assessment. The results showed the highest chronic hazard index in the Chilean scenario for all age groups and genders. The evidence obtained revealed that methamidophos, methomyl, and chlorpyrifos should be restricted for their use in Chilean agriculture.

Pesticide Residues and Health Risk Assessment in Tomatoes and Lettuces from Farms of Metropolitan Region Chile.

Over the last years, the detection of pesticide residues in the official food surveillance programs of Chile has been increased, mainly in fresh vegetables such as tomatoes and lettuces. The Metropolitana Region of Chile presents the highest detections in the country. The lack of evaluations of toxicological risks in human health have increased uncertainty of the potential effects of pesticides exposures in the Chilean population. This research aims to determinate health risks assessment of pesticide residues associated to tomatoes and lettuces produced in Metropolitana Region. The findings of this study reveal that tomatoes and lettuces cultivated in the MR show more than 50% of samples with one or multiple pesticides residues. From the total samples, 16% were over the Chilean Maximum Residue Levels (MRLs). The main pesticides detected in tomatoes and lettuces were methamidophos, methomyl, difenoconazole, cyprodinil and boscalid. The results obtained using the official data of the Ministry of Health of Chile (MINSAL) compared to the World Health Organization (WHO), describe relevant risks through the Estimated Daily Intakes (EDI), Hazard Quotients (HQ) and Hazard Index (HI) for the Chilean population due to high concentrations of methamidophos, methomyl and cyprodinil. More restrictions for the use of methamidophos, methomyl, difenoconazole, cyprodinil and boscalid and effective control programs should be implemented in order to mitigate the impacts on the Chilean population.

Pesticide residues in ready-to-eat leafy vegetables from markets of Santiago, Chile, and consumer's risk.

The detection of pesticide residues in leafy vegetables has been a relevant concern in Chile over the last years. There is also a priority at the national level to propose a methodology to assess health risks. The aim of this study was to evaluate the presence of pesticide residues in ready-to-eat leafy vegetables in order to evaluate different models for health risk assessment. The models considered data of the World Health Organization (WHO) and the Ministry of Health of Chile (MINSAL). The Hazard Quotients and Hazard Indexes for the pesticides evaluated in all models decreased in the following order: methamidophos>lambda-cyhalothrin> chlorpyrifos. From a food safety perspective, the investigated samples suggest the presence of a greater health risk to consumers when compared using the official data of MINSAL, which needs appropriate attention.

Atrazine, chlorpyrifos, and iprodione effect on the biodiversity of bacteria, actinomycetes, and fungi in a pilot biopurification system with a green cover.

The use of biopurification systems can mitigate the effects of pesticide contamination on farms. The primary aim of this study was to evaluate the effect of pesticide dissipation on microbial communities in a pilot biopurification system. The pesticide dissipation of atrazine, chlorpyrifos and iprodione (35 mg kg-1 active ingredient [a.i.]) and biological activity were determined for 40 days. The microbial communities (bacteria, actinomycetes and fungi) were analyzed using denaturing gradient gel electrophoresis (DGGE). In general, pesticide dissipation was the highest by day 5 and reached 95%. The pesticides did not affect biological activity during the experiment. The structure of the actinomycete and bacterial communities in the rhizosphere was more stable during the evaluation than that in the communities in the control without pesticides. The rhizosphere fungal communities, detected using DGGE, showed small and transitory shifts with time. To conclude, rhizosphere microbial communities were not affected during pesticide dissipation in a pilot biopurification system.

Pesticide residues in leafy vegetables and human health risk assessment in North Central agricultural areas of Chile.

To investigate pesticide residue concentrations and potential human health risk, a study was conducted in 118 leafy vegetable samples collected in 2014-2015 from the North Central agricultural areas of Chile. The pesticide residues were determined using the multiresidue QuEChERS method by gas chromatography as well as high-performance liquid chromatography. The results indicated that 27% of the total samples contained pesticide residues above the maximum residue limits of each active ingredient. The maximum estimated daily intake obtained for carbon disulphide (CS2), methamidophos, azoxystrobin and cypermethrin were 0.57, 0.07, 0.06 and 0.05 mg kg-1, respectively, which was higher than their acceptable daily intake. It is concluded that inhabitants of the North Central agricultural area of Chile are not exposed to health risks through the consumption of leafy vegetables with the exception of methamidophos. Nevertheless, the high levels of methamidophos detected in leafy vegetables could be considered a potential chronic health risk.

Dengue Virus Directly Stimulates Polyclonal B Cell Activation.

Dengue infection is associated to vigorous inflammatory response, to a high frequency of activated B cells, and to increased levels of circulating cross-reactive antibodies. We investigated whether direct infection of B cells would promote activation by culturing primary human B lymphocytes from healthy donors with DENV in vitro. B cells were susceptible, but poorly permissive to infection. Even though, primary B cells cultured with DENV induced substantial IgM secretion, which is a hallmark of polyclonal B cell activation. Notably, DENV induced the activation of B cells obtained from either DENV immune or DENV naïve donors, suggesting that it was not dependent on DENV-specific secondary/memory response. B cell stimulation was dependent on activation of MAPK and CD81. B cells cultured with DENV also secreted IL-6 and presented increased expression of CD86 and HLA-DR, which might contribute to B lymphocyte co-stimulatory function. Indeed, PBMCs, but not isolated B cells, secreted high amounts of IgG upon DENV culture, suggesting that interaction with other cell types in vivo might promote Ig isotype switching and IgG secretion from different B cell clones. These findings suggest that activation signaling pathways triggered by DENV interaction with non-specific receptors on B cells might contribute to the exacerbated response observed in dengue patients.