Background Diarrheal diseases are an important cause of morbidity and mortality among children in developing countries. We aimed to study the etiology and severity of diarrhea in children living in the low-income semiarid region of Brazil. Methodology This is a cross-sectional, age-matched case-control study of diarrhea in children aged 2–36 months from six cities in Brazil’s semiarid region. Clinical, epidemiological, and anthropometric data were matched with fecal samples collected for the identification of enteropathogens. Results We enrolled 1,200 children, 596 cases and 604 controls. By univariate analysis, eight enteropathogens were associated with diarrhea: Norovirus GII (OR 5.08, 95% CI 2.10, 12.30), Adenovirus (OR 3.79, 95% CI 1.41, 10.23), typical enteropathogenic Escherichia coli (tEPEC), (OR 3.28, 95% CI 1.39, 7.73), enterotoxigenic E . coli (ETEC LT and ST producing toxins), (OR 2.58, 95% CI 0.99, 6.69), rotavirus (OR 1.91, 95% CI 1.20, 3.02), shiga toxin-producing E . coli ( STEC ; OR 1.77, 95% CI 1.16, 2.69), enteroaggregative E . coli (EAEC), (OR 1.45, 95% CI 1.16, 1.83) and Giardia spp. (OR 1.39, 95% CI 1.05, 1.84). By logistic regression of all enteropathogens, the best predictors of diarrhea were norovirus, adenovirus, rotavirus, STEC, Giardia spp. and EAEC. A high diarrhea severity score was associated with EAEC. Conclusions Six enteropathogens: Norovirus, Adenovirus, Rotavirus, STEC, Giardia spp., and EAEC were associated with diarrhea in children from Brazil’s semiarid region. EAEC was associated with increased diarrhea severity.

Several biomarkers have been evaluated as predictors of severity or in directing the treatment of COVID-19, however there are no conclusive results with prediction of the pathobiology of the infection. In this study, we evaluated serum levels of cytokines, chemokines, and cell growth factors in association with the pathobiology of mild to moderate SARS-CoV-2 infection. Those markers may act as immuno-inflammatory biomarkers in adults with mild to moderate flu syndrome who sought care at health units. Serum levels of SARS-CoV-2 infected patients (n=113) and flu symptoms individuals negative for SARS-CoV-2 (n=58), tested by the RT-qPCR test - nasal swab were compared to healthy controls (n=53). Participants who were symptomatic but negative for SARS-CoV-2 were tested for Influenza A/B and Respiratory Syncytial Virus (RSV). Results showed that the pro-inflammatory cytokines IL-1β, MCP-3, TNF-α and G-CSF were increased in symptomatic patients and the cytokines IL-6 and IL-10 were associated with patients positive for SARS-CoV-2 when compared to healthy controls. Symptoms associated with COVID-19 were fever, anosmia, ageusia and myalgia. For patients without SARS-CoV-2 infection their major symptom was sore throat. Five percent (4/83) of SARS-CoV-2 negative patients were positive for RSV. The pathobiology of mild to moderate SARS-CoV-2 infection was associated with increasing pro-inflammatory cytokines and also a pleiotropic IL-6 and anti-inflammatory IL-10 cytokines compared to healthy controls.

Background: Rotavirus A (RVA) is one of the leading causes of acute gastroenteritis worldwide; however, few studies assessed RVA genetics with community surveillance. Objectives: This study aimed to investigate clinical data, genetic diversity, and coinfection patterns of RVA infections in children from 2 to 36 months old with or without community childhood diarrhea in the Brazilian semiarid region during postvaccination era. Methods: We enrolled and collected socioeconomic/clinical information using a standardized questionnaire and fecal samples from 291 children. Viral RNA samples were extracted and analyzed using quantitative reverse transcription polymerase chain reaction to establish the diagnosis of RVA. Sequencing of VP7 and VP4 (VP8∗) regions and phylogenetic analysis were performed. Results: RVA-negative diagnosis was associated with children 24 to 36 months old with complete vaccination schedule. Genotype G1P[8] was the most prevalent (57%), whereas unusual genotypes including G1P[4], G2P[8], and G3P[9] were also detected. G1- and P[8]-positive samples showed high degrees of similarity with the vaccine strain. RVA coinfections were frequently observed, and enteroaggregative Escherichia coli was the most prevalent copathogen. Conclusions: These results demonstrate that genotype G1P[8] is the most prevalent strain. VP7 and/or VP8∗ gene segments arising from RV1 vaccine strain were documented in these children, suggesting shedding or herd vaccination. Moreover, our study indicates full vaccination is important for protection against RVA infections.

Lactulose and mannitol have been used to assess intestinal permeability and several methodologies have been used. Objectives: This study aimed to validate the high-performance liquid chromatography method coupled with tandem mass spectrometry to measure mannitol and lactulose sugars. Material and Methods: We used a high-performance liquid chromatography (HPLC) system coupled to an ABsciex Q-TRAP 5500 triple quadrupole mass spectrometer (MS/MS) with an ABSciex Electro Nebulization Interface (ESI) (Framingham, MA, USA). For the separation of lactulose and mannitol compounds in the HLPC, the analytical column HILIC-ZIC from ES Industries (West Berlin, USA) was used. The parameters analyzed for analytical validation were specificity/selectivity, linearity, LD, LQ accuracy, precision (repeatability and intermediate precision) and matrix effect. Results: The accuracy was demonstrated from the recovery at three concentration levels (100, 500 and 1000 ng/mL) and in triplicate, which showed recovery values above the recommended (>120%). Intermediate precision was determined at 24-hour intervals and the coefficients of variation found were less than 8.7%. The matrix effect was measured through the retention times in the standard samples and in the samples of the spiked standards in dilutions with urine samples, which varied between 99.3% and 100.3%. Urine samples from malnourished and healthy children were analyzed. The L:M ratio was considerably lower in the control group compared to the MN group (p<0.0001) and the mannitol excretion rate was higher (p<0.0001). Conclusions: The results showed that the HPLC-MS/MS method was sensitive, specific, and accurate for the determination of molecular biomarkers of lactulose and mannitol. In addition, the L:M test is a functional test capable of determining with high sensitivity the barrier function damage of the intestinal epithelium in children with malnutrition compared to health control children.

We adopted the reverse transcriptase - loop mediated isothermal amplification (RT-LAMP) to detect SARS-Cov-2 in patient samples. Two primer sets for genes N and Orf1ab were designed to detect SARS-CoV-2, and one primer set was designed to detect the human gene Actin. We collected prospective 138 nasopharyngeal swabs, 70 oropharyngeal swabs, 69 saliva, and 68 mouth saline wash samples from patients suspected to have severe acute respiratory syndrome (SARS) caused by SARS-CoV-2 to test the RT-LAMP in comparison with the golden standard technique RT-qPCR. Accuracy of diagnosis using both primers, N5 and Orf9, was evaluated. Sensitivity and specificity for diagnosis was 96% (95% CI 87-99) and 85% (95% CI 76-91) in 138 samples, respectively. Accurate diagnosis results were obtained only in nasopharyngeal swab processed via extraction kit. Accurate and rapid diagnosis could aid COVID-19 pandemic management by identifying, isolating, and treating patients rapidly.