Low risk of prolonged SARS-CoV-2 shedding and molecular evolution in kidney transplant recipients during the Omicron era: A prospective observational study.

The aim of this prospective study was to assess the duration of culture-viable SARS-CoV-2 and to monitor the emergence of mutations in a cohort of 23 kidney transplant recipients (KTRs) from June 2022 to June 2023. Combined nares/oropharyngeal swabs were collected weekly starting as soon as possible after symptom onset. The time from symptom onset to a negative culture was 11 days (interquartile range, 8-14), while the time to negative reverse transcriptase quantitative polymerase chain reaction was 18 days (interquartile range, 15-30).

Can variants, reinfection, symptoms and test types affect COVID-19 diagnostic performance? A large-scale retrospective study of AG-RDTs during circulation of Delta and Omicron variants, Czechia, December 2021 to February 2022.

BackgroundThe sensitivity and specificity of selected antigen detection rapid diagnostic tests (AG-RDTs) for SARS-CoV-2 were determined in the unvaccinated population when the Delta variant was circulating. Viral loads, dynamics, symptoms and tissue tropism differ between Omicron and Delta.AimWe aimed to compare AG-RDT sensitivity and specificity in selected subgroups during Omicron vs Delta circulation.

New perspectives on respiratory syncytial virus surveillance at the national level: lessons from the COVID-19 pandemic.

https://bit.ly/40TsO0G

Retrospective Analysis Revealed an April Occurrence of Monkeypox in the Czech Republic.

Herein, we present our findings of an early appearance of the Monkeypox virus in Prague, Czech Republic. A retrospective analysis of biological samples, carried out on the 28th of April, revealed a previously unrecognized case of Monkeypox virus (MPxV) infection. Subsequent data analysis confirmed that the virus strain belongs to the ongoing outbreak.

Reverse-zoonotic transmission of SARS-CoV-2 lineage alpha (B.1.1.7) to great apes and exotic felids in a zoo in the Czech Republic.

We report an outbreak of SARS-CoV-2 lineage alpha in gorillas and felid species in a zoo in Prague, Czech Republic. The course of illness and clinical signs are described, as are the results of characterization of these particular SARS-CoV-2 variants by next-generation sequencing and phylogenetic analysis. The putative transmission routes are also discussed.

Multi-branch cooperation on SARS-CoV-2 omicron capture: a case report.

Shortly after the WHOs first notice a suspected case of omicron SARS-CoV-2 was reported in Liberec, Czech Republic. The primary goal of the following actions was to test the presence of the variant and stop the spread of the virus variant. On November 25 a sixty-year-old lady, who had recently returned from Namibia, visited a GP with flu-like symptoms and a rash on her chest.

A universal RT-qPCR assay for "One Health" detection of influenza A viruses.

The mutual dependence of human and animal health is central to the One Health initiative as an integrated strategy for infectious disease control and management. A crucial element of the One Health includes preparation and response to influenza A virus (IAV) threats at the human-animal interface. The IAVs are characterized by extensive genetic variability, they circulate among different hosts and can establish host-specific lineages.

Circulation of influenza A and B in the Czech Republic from 2000-2001 to 2015-2016.

Background: To improve national influenza vaccination recommendations, additional data on influenza A and B virus circulation are needed. Here, we describe the circulation of influenza A and B in the Czech Republic during 16 seasons.

Methods: This was a retrospective analysis of data collected from the 2000-2001 to 2015-2016 influenza seasons by the Czech Republic national influenza surveillance network.

In silico re-assessment of a diagnostic RT-qPCR assay for universal detection of Influenza A viruses.

The ongoing evolution of microbial pathogens represents a significant issue in diagnostic PCR/qPCR. Many assays are burdened with false negativity due to mispriming and/or probe-binding failures. Therefore, PCR/qPCR assays used in the laboratory should be periodically re-assessed in silico on public sequences to evaluate the ability to detect actually circulating strains and to infer potentially escaping variants.

Evaluation of TaqMan qPCR System Integrating Two Identically Labelled Hydrolysis Probes in Single Assay.

Ongoing evolution of viral pathogens is a significant issue in diagnostic virology employing TaqMan qPCR/RT-qPCR. Specific concerns are related to false negativity due to probe binding failure. One option for compensating for such deficiency is to integrate a second identically labelled probe in the assay.

Mumps in the Czech Republic in 2013: Clinical Characteristics, Mumps Virus Genotyping, and Epidemiological Links.

Aim: The aim of the study was to map the incidence of mumps in the Czech Republic in terms of clinical symptoms, epidemiological links, and characteristics of circulating genotypes.

Methods: Patients with suspected mumps examined in the Infectious Diseases Clinic of the Na Bulovce Hospital in 2013 were enrolled in the study. Buccal swab specimens were tested by means of nucleic acid detection (RT-qPCR) and when positive, they were cultured in tissue culture.

MeltMan: Optimization, Evaluation, and Universal Application of a qPCR System Integrating the TaqMan qPCR and Melting Analysis into a Single Assay.

In the present work, we optimised and evaluated a qPCR system integrating 6-FAM (6-carboxyfluorescein)-labelled TaqMan probes and melting analysis using the SYTO 82 (S82) DNA binding dye in a single reaction. We investigated the influence of the S82 on various TaqMan and melting analysis parameters and defined its optimal concentration. In the next step, the method was evaluated in 36 different TaqMan assays with a total of 729 paired reactions using various DNA and RNA templates, including field specimens.

Large-scale nucleotide sequence alignment and sequence variability assessment to identify the evolutionarily highly conserved regions for universal screening PCR assay design: an example of influenza A virus.

The development of a diagnostic polymerase chain reaction (PCR) or quantitative PCR (qPCR) assay for universal detection of highly variable viral genomes is always a difficult task. The purpose of this chapter is to provide a guideline on how to align, process, and evaluate a huge set of homologous nucleotide sequences in order to reveal the evolutionarily most conserved positions suitable for universal qPCR primer and hybridization probe design. Attention is paid to the quantification and clear graphical visualization of the sequence variability at each position of the alignment.

Local-scale diversity and between-year "frozen evolution" of avian influenza A viruses in nature.

Influenza A virus (IAV) in wild bird reservoir hosts is characterized by the perpetuation in a plethora of subtype and genotype constellations. Multiyear monitoring studies carried out during the last two decades worldwide have provided a large body of knowledge regarding the ecology of IAV in wild birds. Nevertheless, other issues of avian IAV evolution have not been fully elucidated, such as the complexity and dynamics of genetic interactions between the co-circulating IAV genomes taking place at a local-scale level or the phenomenon of frozen evolution.

[Phylogenetic analysis and genotyping of A/H3N2 Influenza viruses isolated from patients hospitalised with influenza-like illness symptoms in the na bulovce hospital in the season 2011/2012].

Influenza A virus is an important cause of acute respiratory infections (ARI). Clinical manifestations of ARI vary from mild or moderate to life-threatening conditions requiring intensive care. Given the segmented genome, a large natural reservoir of other influenza virus subtypes, and antibody selection pressure in the population, the virus is variable and genetically unstable.

[Microneutralization assay in the diagnosis of influenza infection].

Serology plays an important role in the diagnosis of influenza, particularly in the detection of post-vaccination and post-infection antibodies. When considering the range of diagnostic options, the serological method should be selected depending on the circumstances - whether single or paired serum samples are tested, whether adequate patient medical history data are available, whether epidemiological links are suspected, and, in particular, to what purpose the result will be used (differential diagnosis, post-infection follow-up, post-vaccination monitoring, etc.).

Development and evaluation of a one-step real-time RT-PCR assay for universal detection of influenza A viruses from avian and mammal species.

The objective of our study was to develop and evaluate a TaqMan real-time RT-PCR (RRT-PCR) assay for universal detection of influenza A (IA) viruses. The primers and LNA-modified octanucleotide probe were selected to correspond to extremely conserved regions of the membrane protein (MP) segment identified by a comprehensive bioinformatics analysis including 10,405 IA viruses MP sequences, i.e.

Challenge of conducting a placebo-controlled randomized efficacy study for influenza vaccine in a season with low attack rate and a mismatched vaccine B strain: a concrete example.

Background: Our aim was to determine the efficacy of a trivalent inactivated split virus influenza vaccine (TIV) against culture-confirmed influenza A and/or B in adults 18 to 64 years of age during the 2005/2006 season in the Czech Republic.

Methods: 6203 subjects were randomized to receive TIV (N = 4137) or placebo (N = 2066). The sample size was based on an assumed attack rate of 4% which provided 90% power to reject the hypothesis that vaccine efficacy (VE) was > or = 45%.