Resurgence of human respiratory syncytial virus during COVID-19 pandemic in Southern Brazil.

Respiratory Syncytial Virus (RSV) is an important cause of respiratory infection in humans. Severe cases are common in children ≤2 years old, immunocompromised individuals, and the elderly. In 2020, RSV infection reduced in Rio Grande do Sul (RS), southern Brazil; however, in 2021 resurgence of RSV was observed. This study analyzed epidemiological and genetic features of RSV infection cases reported in 2021 in RS. Nasopharyngeal samples collected from individuals with respiratory infection negative for SARS-CoV-2, Influenza A and B viruses were assessed for the presence of RSV by real time RT-qPCR. RSV-A and RSV-B genomic sequencing and phylogenetic reconstructions were performed for genotyping and clade characterization. Among 21,035 respiratory samples analyzed, 2,947 were positive for RSV, 947 of which were hospitalized patients. Positive cases were detected year-round, with the highest number in June-July (winter). Children <1 year comprised 56.28% (n = 533) of the hospitalized patients infected with RSV, whereas 14.46% (n = 137) were individuals >60 years. Of a total of 361 deaths, 14.68% (n = 53) were RSV positive, mostly patients >60 years old (73.58%, n = 39). Chronic kidney disease, cardiopathy, Down syndrome and neurological diseases were associated with RSV infection. RSV-A was identified in 58.5% (n = 117/200) of the patients, and RSV-B in 41.5% (n = 83/200). Of 95 RSV genomes recovered from SARI cases, 66 were RSV-A GA.2.3.5 genotype, while 29 were RSV-B GB.5.0.5a genotype. This study provides epidemiological and molecular data on RSV cases in RS during the COVID-19 pandemic and highlights that investigation of different respiratory viruses is essential for decision-making and disease prevention and control measures.

Tracking the emergence of antigenic variants in influenza A virus epidemics in Brazil.

Influenza A virus (IAV) circulation patterns differ in North America and South America, with influenza seasons often characterized by different subtypes and strains. However, South America is relatively undersampled considering the size of its population. To address this gap, we sequenced the complete genomes of 220 IAVs collected between 2009 and 2016 from hospitalized patients in southern Brazil. New genetic drift variants were introduced into southern Brazil each season from a global gene pool, including four H3N2 clades (3c, 3c2, 3c3, and 3c2a) and five H1N1pdm clades (clades 6, 7, 6b, 6c, and 6b1). In 2016, H1N1pdm viruses belonging to a new 6b1 clade caused a severe influenza epidemic in southern Brazil that arrived early and spread rapidly, peaking mid-autumn. Inhibition assays showed that the A/California/07/2009(H1N1) vaccine strain did not protect well against 6b1 viruses. Phylogenetically, most 6b1 sequences that circulated in southern Brazil belong to a single transmission cluster that rapidly diffused across susceptible populations, leading to the highest levels of influenza hospitalization and mortality seen since the 2009 pandemic. Continuous genomic surveillance is needed to monitor rapidly evolving IAVs for vaccine strain selection and understand their epidemiological impact in understudied regions.

Dual and Triple Infections With Influenza A and B Viruses: A Case-Control Study in Southern Brazil.

Influenza surveillance is important for disease control and should consider possible coinfection with different viruses, which can be associated with disease severity. This study analyzed 34 459 patients with respiratory infection from 2009 to 2018, of whom 8011 were positive for influenza A virus (IAV) or influenza B virus (IBV). We found 18 cases of dual influenza virus infection, including coinfection with 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09) and influenza A(H3N2) virus (1 case), A(H1N1)pdm09 and IBV (6 cases), A(H3N2) and IBV (8 cases), and nonsubtyped IAV and IBV (3 cases); and 1 case of triple infection with A(H3N2), A(H1N1)pdm09, and IBV. Compared with 76 monoinfected patients, coinfection was significantly associated with cardiopathy and death. Besides demographic characteristics and clinical symptoms, we assessed vaccination status, antiviral treatment, timeliness of antiviral use, hospitalization, and intensive care unit admission, but no significant differences were found between coinfected and monoinfected cases. Our findings indicate that influenza virus coinfection occurs more often than previously reported and that it can lead to a worse disease outcome.

Examination of the ligand-binding and enzymatic properties of a bilin-binding protein from the poisonous caterpillar Lonomia obliqua.

The bilin-binding proteins (BBP) from lepidopteran insects are members of the lipocalin family of proteins and play a special role in pigmentation through the binding of biliverdin IXγ. Lopap, a BBP-like protein from the venom of the toxic caterpillar Lonomia obliqua has been reported to act as a serine protease that activates the coagulation proenzyme prothrombin. Here we show that BBPLo, a variant of lopap from the same organism binds biliverdin IXγ, forming a complex that is spectrally identical with previously described BBP proteins. Although BBPLo is nearly identical in sequence to lopap, no prothrombinase activity was detected in our recombinant preparations using reconstituted systems containing coagulation factors Xa and Va, as well as anionic phospholipids. In addition to biliverdin, BBPLo was found to form a 1:1 complex with heme prompting us to examine whether the unusual biliverdin IXγ ligand of BBPs forms as a result of oxidation of bound heme in situ rather than by a conventional heme oxygenase. Using ascorbate or a NADPH(+)-ferredoxin reductase-ferredoxin system as a source of reducing equivalents, spectral changes are seen that suggest an initial reduction of heme to the Fe(II) state and formation of an oxyferrous complex. The complex then disappears and a product identified as a 5-coordinate carbonyl complex of verdoheme, an intermediate in the biosynthesis of biliverdin, is formed. However, further reaction to form biliverdin was not observed, making it unlikely that biliverdin IXγ is formed by this pathway.

Hypercholesterolemia magnitude increases sympathetic modulation and coagulation in LDLr knockout mice.

We investigated the effects of low lipoprotein receptor deficiency in cholesterol blood concentrations, blood pressure, hemostatic factors, and the autonomic nervous system in three groups: control mice fed standard diet (CO, n=9), lipoprotein receptor-deficient mice (LDLr(-/-), n=9) fed standard diet (LDLr-S) or hypercholesterolemic diet (LDLr-H, n=8). Frequency domain analysis of heart rate and blood pressure variability was performed with an autoregressive algorithm. The spectral components were expressed in absolute (s(2) or mmHg(2)) and normalized units. Spontaneous baroreflex sensitivity (BRS) was estimated by alpha index, defined as square root ratio between low frequency power in blood pressure variability and heart rate variability. LDLr/- mice presented a significant increase in the cholesterol blood concentration (mean±SD; mg/dl; LDLr-S=202.01±34.38 and LDLr-H=530.7±75.17) compared to CO (79.2±13.6), p=0.001. The receptor deletion was associated with a heart rate variability reduction (p=0.013). The BRS was reduced (p<0.05) in LDLr-S and LDL-H (mean±SD: 0.96±0.39 and 0.59±0.34, respectively) compared to CO (4.02±1.92). Moreover, hypercholesterolemic diet significantly increased the cardiac sympathetic modulation (0V pattern of symbolic analysis: mean±SD, CO=8.04±4.53; LDLr-S=16.49±4.52 and LDLr-H=21.80±8.24, p=0.006). The 0V pattern was statically correlated to coagulation factor VII (r=0.555, p=0.0208). In LDLr-H, the concentration (interquartile range) of plasmatic fibrinogen and hemostatic factors VII (2.8-3.3) and XII (1.1-1.3) were increased compared to CO (0.9-1.1and 0.9-1.0, respectively) and LDLr-S (0.7-1.0 and 0.8-0.9, respectively) (p<0.004 for FVII and p<0.006 for FXII). Taken together, the results indicate that plasmatic cholesterol magnitude is determinant to increase the coagulation and the sympathetic modulation.

A catalog for the transcripts from the venomous structures of the caterpillar Lonomia obliqua: identification of the proteins potentially involved in the coagulation disorder and hemorrhagic syndrome.

Accidents with the caterpillar Lonomia obliqua are often associated with a coagulation disorder and hemorrhagic syndrome in humans. In the present study, we have constructed cDNA libraries from two venomous structures of the caterpillar, namely the tegument and the bristle. High-throughput sequencing and bioinformatics analyses were performed in parallel. Over one thousand cDNAs were obtained and clustered to produce a database of 538 contigs and singletons (clusters) for the tegument library and 368 for the bristle library. We have thus identified dozens of full-length cDNAs coding for proteins with sequence homology to snake venom prothrombin activator, trypsin-like enzymes, blood coagulation factors and prophenoloxidase cascade activators. We also report cDNA coding for cysteine proteases, Group III phospholipase A2, C-type lectins, lipocalins, in addition to protease inhibitors including serpins, Kazal-type inhibitors, cystatins and trypsin inhibitor-like molecules. Antibacterial proteins and housekeeping genes are also described. A significant number of sequences were devoid of database matches, suggesting that their biologic function remains to be defined. We also report the N-terminus of the most abundant proteins present in the bristle, tegument, hemolymph, and "cryosecretion". Thus, we have created a catalog that contains the predicted molecular weight, isoelectric point, accession number, and putative function for each selected molecule from the venomous structures of L. obliqua. The role of these molecules in the coagulation disorder and hemorrhagic syndrome caused by envenomation with this caterpillar is discussed. All sequence information and the , including figures and tables with hyperlinks to FASTA-formatted files for each contig and the best match to the databases, are available at http://www.ncbi.nih.gov/projects/omes.