New Allele-Specific Oligonucleotide (ASO) amplifications for Toxoplasma gondii rop18 allele typing: Analysis of 86 human congenital infections in Brazil.

This study aimed to detect and differentiate Toxoplasma gondii by the allele typing of its polymorphic rop18 gene. For this purpose, a novel genotyping system using allele-specific oligonucleotides (ASOs) was designed, consisting of three ASO pairs. The first and third pairs specifically amplify rop18 allele I and allele III, while the second pair amplify both allele I and II.

Toxoplasma gondii SAG2, SAG3 and GRA6 alleles and single nucleotide polymorphism in congenital infections with known parasite load and clinical outcome.

Amniotic fluid DNA samples were genotyped by multilocus-nested-PCR-RFLP, but only three of 11 markers amplified 113 of 122 (92.6%) samples, resulting in 12 untyped and 101 partial non-archetypal genotypes. The 101 typed samples were subdivided into four groups: G1 with 73 samples (5'and 3' SAG2 allele I + SAG3 allele III + GRA6 allele III), 53 had parasite load ≤ 102 parasites/mL (43 asymptomatic, 10 mild infections), 17 had load > 102 and ≤ 103 (one mild, 13 moderate and three severe), and three had load > 103 parasites/mL (three severe); G2 with 22 samples (5'and 3' SAG2 allele I + SAG3 allele III), all parasite load levels ≤ 102 parasites/mL (18 asymptomatic and four mild); G3 with five samples (5' and 3' SAG2 allele I + SAG3 allele II), parasite load ≤ 102 parasites/mL (three asymptomatic and two mild); G4 with one sample (5' and 3' SAG2 allele II + SAG3 allele II + GRA6 allele I), a parasite load < 102 parasites/mL in an asymptomatic infant.

Technical performance of a lateral flow immunoassay for detection of anti-SARS-CoV-2 IgG in the outpatient follow-up of non-severe cases and at different times after vaccination: comparison with enzyme and chemiluminescent immunoassays.

This study assessed the technical performance of a rapid lateral flow immunochromatographic assay (LFIA) for the detection of anti-SARS-CoV-2 IgG and compared LFIA results with chemiluminescent immunoassay (CLIA) results and an in-house enzyme immunoassay (EIA). To this end, a total of 216 whole blood or serum samples from three groups were analyzed: the first group was composed of 68 true negative cases corresponding to blood bank donors, healthy young volunteers, and eight pediatric patients diagnosed with other coronavirus infections. The serum samples from these participants were obtained and stored in a pre-COVID-19 period, thus they were not expected to have COVID-19.

SARS-CoV-2 and rhinovirus infections: are there differences in clinical presentation, laboratory abnormalities, and outcomes in the pediatric population?

This study aims to assess COVID-19 and other respiratory viruses in pediatric patients. Between April 17 and September 30, 2020, we collected 1,566 respiratory samples from 1,044 symptomatic patients who were younger than 18 years old to assess SARS-CoV-2 infection. Of these, 919 were analyzed for other respiratory pathogens (ORP).

Silent circulation of Chikungunya virus among pregnant women and newborns in the Western Brazilian Amazon before the first outbreak of chikungunya fever.

The prevalence of immunity to Chikungunya virus (CHIKV) in pregnant women and newborns in the Western Brazilian Amazon was assessed at a time when previous studies did not report chikungunya fever in the area. In 435 asymptomatic pregnant women and 642 healthy unrelated newborns, the presence of IgM and IgG antibodies to CHIKV were determined by a commercial ELISA. All participants were negative to IgM anti-CHIKV.

Single-round multiplex PCR with species-specific mitochondrial primers of P. falciparum, P. vivax/P. simium and P. malariae/P. brasilianum: Comparison with standard techniques.

A single-round multiplex PCR (mPCR) with species-specific primers (SSP) of three mitochondrial genes of Plasmodium, namely COX I, COX III and CYT B, was compared to microscopy and 18S rRNA semi-nested PCR, nested-PCR and Real Time PCRs (*PCRs). Each parasite has between 20 and 150 mitochondria and each mitochondria has one copy of each target gene, while 18S rRNA gene is repeated 4 to 8 times. The specificity of mPCR was assessed by testing Plasmodium from rodents and birds, parasites responsible for other endemic diseases in the country such as schistosomiasis, Chagas disease and leishmaniasis in addition to microorganisms that, like Plasmodium, can cause anemia (Bartonella henselae, Babesia vogeli, Rickettsia vini).

Nucleoprotein-based ELISA for detection of SARS-COV-2 IgG antibodies: Could an old assay be suitable for serodiagnosis of the new coronavirus?

Objectives: We evaluated the performance of a nucleoprotein-based enzyme-linked immunosorbent assay (ELISA) for detection of IgG antibodies to SARS-CoV-2.

Methods: The ELISA was based on serum IgG reactivity to a 46-kDa protein derived from the recombinant SARS-CoV2 nucleoprotein. Assay sensitivity was assessed using serum samples from 134 COVID-19 confirmed cases obtained > 15 days after symptom onset.

A sensitive and reliable quantitative immunohistochemistry technique to evaluate the percentage of Trypanosoma cruzi-infected tissue area.

Quantification of parasites in the context of Chagas disease is required to monitor the treatment with benznidazole, disease-associated cardiomyopathies and graft rejection after heart transplantation. As parasitological exams lack sensitivity, Real Time Polymerase Chain Reaction (rt-PCR) has emerged to evaluate the parasite load in blood samples and cardiac biopsies. However, despite its higher sensitivity, rt-PCR does not provide information on the location and distribution of amastigote nests within infected tissues, the characterization of inflammatory infiltrates or changes to tissue architecture.

SARS-CoV-2 infections with emphasis on pediatric patients: a narrative review.

This narrative review summarizes the main aspects underlying the new coronavirus SARS-CoV-2, its epidemiology, pathophysiology, pointing to differences of SARS-CoV-2 main receptors ACE2, in terms of expression and the amount of soluble ACE2 in the circulation of children, men and women, and also in those with risk factors such as the smokers and pregnant women or presenting with comorbidities (diabetes, obesity, hypertension and other cardiovascular diseases, renal and CNS pre-existing diseases). Clinical manifestations in adults and children were also described, emphasizing the particularities already seen in children, regarding signs, symptoms, viral excretion time and the involvement of all organs and systems. The COVID-19 in the pediatric population was divided into two sections: one dedicated to previously healthy children and adolescents with COVID-19, and the other to those who live with comorbidities and acquired COVID-19.

Severe clinical spectrum with high mortality in pediatric patients with COVID-19 and multisystem inflammatory syndrome.

Objectives: To assess the outcomes of pediatric patients with laboratory-confirmed coronavirus disease (COVID-19) with or without multisystem inflammatory syndrome in children (MIS-C).

Methods: This cross-sectional study included 471 samples collected from 371 patients (age<18 years) suspected of having severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The study group comprised 66/371 (18%) laboratory-confirmed pediatric COVID-19 patients: 61 (92.

A new Real Time PCR with species-specific primers from Plasmodium malariae/P. brasilianum mitochondrial cytochrome b gene.

Plasmodium malariae mainly causes asymptomatic submicroscopic parasitemia in the endemic Amazon and non-endemic Atlantic Forest, where the number of cases and transmission of malaria through blood transfusion has increased. This study developed a P. malariae/P.

Performance of a Multiplex Nested Polymerase Chain Reaction in Detecting 7 Pathogens Containing DNA in Their Genomes Associated With Congenital Infections.

Context.—: Infections are the leading cause of perinatal and infant mortality in low-income and low-resource countries, which have a higher prevalence of infections. Definitive diagnosis of congenital and perinatal infections is largely dependent upon the results of laboratory tests.

Mitochondrial and satellite real time-PCR for detecting T. cruzi DTU II strain in blood and organs of experimentally infected mice presenting different levels of parasite load.

The choice of cost-effective molecular methods for diagnosing and monitoring of Chagas disease before and after treatment is crucial in endemic countries with high patients' demand and limited financial resources. To this end, a kDNA was compared to a satellite real-time quantitative PCR (sat-qPCR), both amplifications using Sybr Green instead of Taqman hydrolysis probes. Non-isogenic Swiss albino mice were infected with a small inoculum of the highly virulent and partially resistant to benznidazole Y strain, belonging to T.

Assessment and comparison of bacterial load levels determined by quantitative amplifications in blood culture-positive and negative neonatal sepsis.

Bacterial sepsis remains a major cause of mortality and blood cultures are the gold standard of laboratory diagnosis even though they lack sensitivity in neonates. Culturenegative sepsis, also known as clinical sepsis, has long been considered a diagnosis in neonatal intensive care units because, as well as culture-positive infants, culture-negative neonates have worse prognosis in comparison with non-infected ones. Quantitative amplifications are used to detect bacterial infections in neonates but results are considered only in a qualitative way (positive or negative).

Association of Parasite Load Levels in Amniotic Fluid With Clinical Outcome in Congenital Toxoplasmosis.

Objective: To correlate neonatal and infant clinical outcome with parasite load in amniotic fluid (AF).

Methods: We conducted a retrospective cohort study of 122 children whose mothers had toxoplasmosis during pregnancy. The children were monitored from birth to 12 months old.

PRELIMINARY REPORT ON THE PUTATIVE ASSOCIATION OF IL10 -3575 T/A GENETIC POLYMORPHISM WITH MALARIA SYMPTOMS.

Only a small percentage of individuals living in endemic areas develop severe malaria suggesting that host genetic factors may play a key role. This study has determined the frequency of single nucleotide polymorphisms (SNPs) in some pro and anti-inflammatory cytokine gene sequences: IL6 (-174; rs1800795), IL12p40 (+1188; rs3212227), IL4 (+33; rs2070874), IL10 (-3575; rs1800890) and TGFb1 (+869; rs1800470), by means of PCR-RFLP. Blood samples were collected from 104 symptomatic and 37 asymptomatic subjects.

HLA-DQA1/B1 alleles as putative susceptibility markers in congenital toxoplasmosis.

Host and parasite genotypes are among the factors associated with congenital toxoplasmosis pathogenesis. As HLA class II molecules play a key role in the immune system regulation, the aim of this study was to investigate whether HLA-DQA1/B1 alleles are associated with susceptibility or protection to congenital toxoplasmosis. One hundred and twenty-two fetuses with and 103 without toxoplasmosis were studied.

Usefulness of a 16S rDNA real-time PCR to monitor neonatal sepsis and to assist in medical decision to discontinue antibiotics.

Objective: To monitor the bacterial load in newborns with proven infections on the day of admission, 48 h and 7 days after treatment.

Methods: Real-time PCR (qPCR) targeting the 16S rDNA.

Results: The study recruited 17 newborns and the bacterial load was in general low (<50 CFU/mL).

The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples.

Introduction: Toxoplasmosis may be life-threatening in fetuses and in immune-deficient patients. Conventional laboratory diagnosis of toxoplasmosis is based on the presence of IgM and IgG anti-Toxoplasma gondii antibodies; however, molecular techniques have emerged as alternative tools due to their increased sensitivity. The aim of this study was to compare the performance of 4 PCR-based methods for the laboratory diagnosis of toxoplasmosis.

Anti-leishmania infantum IgG antibody avidity in visceral leishmaniasis.

IgG avidity tests are used to discriminate acute from chronic infections. There are few reports on the IgG avidity profile of patients with visceral leishmaniasis (VL). This study investigated the anti-Leishmania IgG avidity in patients with classic VL (n = 10), patients showing clinical cure after treatment (n = 18), and asymptomatic subjects with at least one positive Leishmania test (n = 20).

A study of IgA antibody response to different mycobacterium tuberculosis antigens in the diagnosis and monitoring of pulmonary tuberculosis.

We evaluated the performance of the ELISA technique in the detection of IgA antibodies against different Mycobacterium tuberculosis antigenic preparations in serum samples from 49 patients with pulmonary tuberculosis collected before and after the start of specific treatment. The controls consisted of serum samples from healthy patients without any prior contact with the bacteria and serum samples from patients with other pneumopathies. Glycolipid antigen gave the best diagnostic performance, with a sensitivity of 88% and specificities varying from 88 to 100% in the control groups.

Enhancement of diagnostic efficiency by a gamma interferon release assay for pulmonary tuberculosis.

This study was designed to examine the use of the QuantiFERON-TB Gold assay as an aid in the diagnosis of active pulmonary tuberculosis (TB) in Brazilian patients. Using the receiver operating characteristic curve, the cutoff was adjusted to >or=0.20 IU/ml.

Differential recognition of Plasmodium falciparum merozoite surface protein 2 variants by antibodies from malaria patients in Brazil.

Four variants of merozoite surface protein 2 (MSP-2) of Plasmodium falciparum were used in serology to examine whether changes in repeat units affect its recognition by antibodies during infection with parasites of known MSP-2 types. The results indicate that variation in MSP-2 repeats may represent a mechanism for parasite immune evasion.