With the arrival of coronavirus disease 2019 (COVID‐19) in Brazil in February 2020, several preventive measures were taken by the population aiming to avoid severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection including the use of masks, social distancing, and frequent hand washing then, these measures may have contributed to preventing infection also by other respiratory viruses. Our goal was to determine the frequencies of Influenza A and B viruses (FLUAV/FLUBV), human mastadenovirus C (HAdV‐C), Enterovirus 68 (EV‐68), and rhinovirus (RV) besides SARS‐CoV‐2 among hospitalized patients suspect of COVID‐19 with cases of acute respiratory disease syndrome (ARDS) in the period of March to December 2020 and to detect possible coinfections among them. Nucleic acid detection was performed using reverse‐transcription quantitative polymerase chain reaction (RT‐qPCR) in respiratory samples using naso‐oropharyngeal swabs and bronchoalveolar lavage. A total of 418 samples of the 987 analyzed (42.3%) were positive for SARS‐CoV‐2, 16 (1.62%) samples were positive for FLUAV, no sample was positive for FLUBV or EV‐68, 67 (6.78%) samples were positive for HAdV‐C, 55 samples were positive for RV 1/2 (26.3%) and 37 for RV 2/2 (13.6%). Coinfections were also detected, including a triple coinfection with SARS‐CoV‐2, FLUAV, and HAdV‐C. In the present work, a very low frequency of FLUV was reported among hospitalized patients with ARDS compared to the past years, probably due to preventive measures taken to avoid COVID‐19 and the high influenza vaccination coverage in the region in which this study was performed.

COVID-19 (Coronavirus Disease 2019) outbreak was declared a pandemic, by World Health Organization, on March 11, 2020. Viral detection using RT-qPCR has been among the most important factors helping to control local spread of SARS-CoV-2 and it is considered the “gold standard” for diagnosis. Nevertheless, the RNA extraction step is both laborious and expensive, thus hampering the diagnosis in many places where there are not laboratory staff of funds enough to contribute for diagnosis efforts. Thus, the need to simplify procedures, reduce costs of the techniques used, and expand the capacity of the number of diagnostics of COVID-19 is imperative. In this study, detection of SARS-CoV-2 in the absence of RNA extraction has been successfully achieved through pre-treatment of the clinical sample with Proteinase K. The results show that only the use of proteinase K, without the need to perform the whole standard protocol for sample extraction and purification, can be an efficient technique for the diagnosis of COVID-19, since 91% of the samples matched the results with the standard procedure, with an average increase of 5.64 CT in the RT-qPCR.

December 2019 marked the begining of the greatest pandemic since Spanish Flu, the disease named Covid-19 that cause severe pneumonia. Until May 19, 2020 more than 4 million and 700 thousand cases were oficially notified with about 316 thousand deaths. Etiological agent of the disease was identified as being a new coronavirus, Severe acute respiratory syndrome-related coronavirus (SARS-CoV-2). In this study we compared four different manual methods for RNA isolation and purification for detection of SARS-CoV-2 through qRT-PCR, as well as the extraction quality itself through detection of RNAse P. Magnetic beads-based (MagMax™) and silica column-based (Biopur ^® ) methods presented the better performances. Concerning to the mean delay in CT values when compared to MagMax™, TRIzol™, Biopur ^® and EasyExtract presented 0,39, 0,95 and 5,23 respectively. Agreement between positive and negative results of different methods when compared with the one with better performance MagMax™ was 94,44% for silica column-based method (Biopur®), 88,89% for phenol-chroloform-based method (TRIzol™) and 77,78% for EasyExtract. We aimed to evaluate how reliable each method is for diagnostic purposes and to propose alternatives when usual methods are not available. In this regard, magnectic beads and silica column-based methods are convenient and reliable choices and phenol-chloroform-based method could also be chosen as an alternative.

In this study, serial dilutions of SARS-CoV 2 RNA extract were tested using RT-dPCR using three different primer-probe assays aiming SARS-CoV 2 nucleocapsid coding region. Narrower confidence intervals, indicating high quantification precision were obtained in 100 and 1000-fold serial dilution and RT-dPCR results were equivalent between different assays in the same dilution. High accuracy of this test allowed conclusions regarding the ability of this technique to evaluate precisely the amount of genomic copies present in a sample. We believe that this fast and safe method can assist other researchers in titration of SARS-CoV2 controls used in RT-qPCR without the need of virus isolation.

Emergence of novel SARS-CoV-2 lineages are under the spotlight of the media, scientific community and governments. Recent reports of novel variants in the United Kingdom, South Africa and Brazil (B.1.1.28-E484K) have raised intense interest because of a possible higher transmission rate or resistance to the novel vaccines. Nevertheless, the spread of B.1.1.28 (E484K) and other variants in Brazil is still unknown. In this work, we investigated the population structure and genomic complexity of SARS-CoV-2 in Rio Grande do Sul, the southernmost state in Brazil. Most samples sequenced belonged to the B.1.1.28 (E484K) lineage, demonstrating its widespread dispersion. We were the first to identify two independent events of co-infection caused by the occurrence of B.1.1.28 (E484K) with either B.1.1.248 or B.1.91 lineages. Also, clustering analysis revealed the occurrence of a novel cluster of samples circulating in the state (named VUI-NP13L) characterized by 12 lineage-defining mutations. In light of the evidence for E484K dispersion, co-infection and emergence of VUI-NP13L in Rio Grande do Sul, we reaffirm the importance of establishing strict and effective social distancing measures to counter the spread of potentially more hazardous SARS-CoV-2 strains. Highlights The novel variant B.1.1.28 (E484K) previously described in Rio de Janeiro is currently spread across the southernmost state of Brazil; The novel variant VUI-NP13L was also identified by causing a local outbreak in Rio Grande do Sul; B.1.1.28 (E484K) is able to establish successful coinfection events co-occurring simultaneously with different lineages of SARS-CoV-2.

The main goal of this study was to apply magnetic bead surface functionalization in the form of immunomagnetic separation (IMS) combined with real-time polymerase chain reaction (qPCR) (IMS-qPCR) to detect Human mastadenovirus species C (HAdV-C) and F (HAdV-F) in water samples. The technique efficiency was compared to a nonfunctionalized method (ultracentrifugation) followed by laboratory detection. Tests were carried out to standardize IMS parameters followed by tests on 15 water samples concentrated by IMS and ultracentrifugation. Microscopic analyses detected a successful beads–antibody attachment. HAdV was detected up to dilutions of 10⁻⁶ by IMS-qPCR, and samples concentrated by IMS were able to infect cell cultures. In water samples, HAdV-C was detected in 60% (monoclonal) and 47% (polyclonal) by IMS-qPCR, while 13% of samples concentrated by ultracentrifugation gave a positive result. HAdV-F was positive in 27% of samples by IMS-qPCR (polyclonal) and ultracentrifugation and 20% by IMS-qPCR (monoclonal). The rate of detection varied from 4.55 × 10² to 5.83 × 10⁶ genomic copies/L for IMS-qPCR and from 2.00 × 10² to 2.11 × 10³ GC/L for ultracentrifugation. IMS showed to be a more effective concentration technique for HAdV than ultracentrifugation, improving the assessment of infectious HAdV in water resources.