Small-molecule antivirals can be used as chemical probes to stabilize transitory conformational stages of viral target proteins, facilitating structural analyses. Here, we evaluate allosteric pneumo- and paramyxovirus polymerase inhibitors that have the potential to serve as chemical probes and aid the structural characterization of short-lived intermediate conformations of the polymerase complex. Of multiple inhibitor classes evaluated, we discuss in-depth distinct scaffolds that were selected based on well-understood structure-activity relationships, insight into resistance profiles, biochemical characterization of the mechanism of action, and photoaffinity-based target mapping. Each class is thought to block structural rearrangements of polymerase domains albeit target sites and docking poses are distinct. This review highlights validated druggable targets in the paramyxo- and pneumovirus polymerase proteins and discusses discrete structural stages of the polymerase complexes required for bioactivity.

In 2023, the EBMT Practice harmonization and Guidelines Committee partnered with the EBMT Infection Diseases Working Party (IDWP) to undertake the task of delivering best practice recommendations, aiming to harmonize by expert consensus, the already existing definitions and future epidemiological and clinical studies among centers of the EBMT network. To attain this objective, a group of experts in the field was convened. The workgroup identified and discussed some critical aspects in definitions of community-acquired respiratory viruses (CARV) and adenovirus (ADV) infections in recipient of hematopoietic cell transplant (HCT). The methodology involved literature review and expert consensus. For CARV, expert consensus focused on defining infection severity, infection duration, and establishing criteria for lower respiratory tract disease (LRTD). For ADV, the expert consensus focused on surveillance methods and the definitions of ADV infection, certainty levels of disease, response to treatment, and attributable mortality. This consensus workshop provided indications to EBMT community aimed at facilitating data collection and consistency in the EBMT registry for respiratory viral infectious complications.

BACKGROUND: Human parainfluenza viruses (HPIVs) commonly cause childhood respiratory illness requiring hospitalization in Taiwan. This study aimed to investigate clinical severity and identify risk factors predisposing to severe disease in hospitalized children with HPIV infection.
METHODS: We included hospitalized patients with lab-confirmed HPIV infection from 2007 to 2018 and collected their demographic and clinical characteristics. Patients with ventilator support, intravenous inotropic agents, and extracorporeal membrane oxygenation were defined as severe cases.
RESULTS: There were 554 children hospitalized for HPIV infection. The median age was 1.2 years; 518 patients had non-severe HPIV infection, whereas 36 patients (6.5%) had severe HPIV infection. 266 (48%) patients had underlying diseases, and 190 patients (34.3%) had bacterial co-detection. Children with severe HPIV infection were more likely to have bacterial co-detection than those without (52.8% vs 33.0%, p = 0.02). Patients with lung patch or consolidation had more invasive bacterial co-infection or co-detection than those without patch or consolidation (43% vs 33%, p = 0.06). Patients with neurological disease (adjusted OR 4.77, 95% CI 1.94-11.68), lung consolidation/patch (adjusted OR 6.64, 95% CI 2.80-15.75), and effusion (adjusted OR 11.59, 95% CI 1.52-88.36) had significantly higher risk to have severe HPIV infection.
CONCLUSIONS: Neurological disease and lung consolidation/patch or effusion were the most significant predictors of severe HPIV infection.

Vectored RNA vaccines offer a variety of possibilities to engineer targeted vaccines. They are cost-effective and safe, but replication competent, activating the humoral as well as the cellular immune system.This chapter focuses on RNA vaccines derived from negative-strand RNA viruses from the order Mononegavirales with special attention to Newcastle disease virus-based vaccines and their generation. It shall provide an overview on the advantages and disadvantages of certain vector platforms as well as their scopes of application, including an additional section on experimental COVID-19 vaccines.

Mononegaviruses are promising tools as oncolytic and transgene vectors for gene therapy and regenerative medicine. However, when mononegaviruses are used for therapeutic applications, the viral activity must be strictly controlled due to concerns about toxicity and severe side effects. With this technology, mononegavirus vectors can be grown where they are intended and can be easily removed when they are no longer needed. In particular, a photoswitch protein called Magnet (consisting of two magnet domains) is incorporated into the hinge region between the connector and methyltransferase domains of the mononegavirus polymerase protein (L protein) to disrupt the L protein functions. Blue light (470 ± 20 nm) irradiation causes the dimerization of the two magnet domains, and the L protein is restored to activity, allowing viral gene expression and virus replication. Since the magnet domains\' dimerization is reversible, viral gene expression and replication cease when blue light irradiation is stopped.

(1) Background: This study investigated the epidemiology and viral connections of Henoch-Schönlein purpura (HSP) using information from the Korea Disease Control and Prevention Agency and the Health Insurance Review and Assessment database. (2) Method: Between 2016 and 2019, a total of 25,443 patients with HSP were identified, with 51.3% of patients under the age of 20 years and the highest incidence in March. (3) Results: The autoregressive integrated moving average model and Granger causality test were used to analyze the association between the virus positivity detection rate and HSP incidence. (4) Conclusions: The incidence of HSP was associated with rotavirus, bocavirus, parainfluenza virus, and respiratory syncytial virus in individuals under 20 years of age, whereas adenovirus, respiratory syncytial virus, and norovirus were associated with individuals above that age.

During the coronavirus disease 2019 (COVID-19) pandemic, outbreaks of parainfluenza virus type 3 (PIV-3) decreased due to infection control measures. However, a post-pandemic resurgence of PIV-3 has recently been observed. Nonetheless, the role of viral genetic epidemiology, possibly influenced by a genetic bottleneck effect, remains unexplored. We investigated the phylogenetic structure of the publicly available PIV-3 whole-genome and hemagglutinin-neuraminidase (HN) gene sequences spanning the last 65 years, including the COVID-19 pandemic. Sequences were retrieved from the nucleotide database of the National Center for Biotechnology Information using the search term \"Human respirovirus 3.\" Sequence subsets covering all six genes of PIV-3 or the HN gene were designated as the whole-genome and HN surveillance data sets, respectively. Using these data sets, we constructed maximum-likelihood phylogenetic trees and performed a time-scaled analysis using a Bayesian SkyGrid coalescent prior. A total of 455 whole-genome and 1,139 HN gene sequences were extracted, revealing 10 and 11 distinct lineages, respectively, with >98% concurrence in lineage assignments. During the 2020 COVID-19 pandemic, only three single-lineage clusters were identified in Japan, Korea, and the USA. The inferred year of origin for PIV-3 was 1938 (1903-1963) for the whole-genome data set and 1955 (1930-1963) for the HN gene data set. Our study suggests that PIV-3 epidemics in the post-COVID era are likely influenced by a pandemic-driven bottleneck phenomenon and supports previous hypotheses suggesting s that PIV-3 originated during the early half of the 20th century.IMPORTANCEUsing publicly available parainfluenza virus type 3 (PIV-3) whole-genome sequences, we estimated that PIV-3 originated during the 1930s, consistent with previous hypotheses. Lineage typing and time-scaled phylogenetic analysis revealed that PIV-3 experienced a bottleneck phenomenon in Korea and the USA during the coronavirus disease 2019 pandemic. We identified the conservative hemagglutinin-neuraminidase gene as a viable alternative marker in long-term epidemiological studies of PIV-3 when whole-genome analysis is limited.

Paramyxoviruses are important pathogens affecting various animals, including humans. In this study, we identified a paramyxovirus in 2004 (180608_2004), isolated from a sample of the femoral marrow bone of a wild boar carcass imported from Australia. Antigenic and morphological characteristics indicated that this virus was similar to members of the family Paramyxoviridae. The complete genome phylogenetic analysis grouped this virus into genotype A of bovine parainfluenza virus type 3 (BPIV-3), recently renamed bovine respirovirus type 3 (BRV3), which also includes two swine paramyxoviruses (SPMV)-Texas-81 and ISU-92-isolated from encephalitic pigs in the United States in 1982 and 1992, respectively. The wild boar 180608_2004 strain was more closely related to both the BRV3 shipping fever (SF) strain and the SPMV Texas-81 strain at the nucleotide and amino acid levels than the SPMV ISU-92 strain. The high sequence identity to BRV3 suggested that this virus can be transferred from cattle to wild boars. The potential for cross-species transmission in the Respirovirus genus makes it essential for intensified genomic surveillance.

To analyze changes in the detection of parainfluenza virus (PIV) in children hospitalized with acute respiratory tract infection (ARTI) during 2014-2022 in Hubei Province, and explore the impact of the universal two-child policy and the public health measures against COVID-19 epidemic on the prevalence of PIV in China. The study was conducted at the Maternal and Child Health Hospital of Hubei Province. Children aged <18 years with ARTI admitted from January 2014 to June 2022 were enrolled. The infection of PIV was confirmed by the direct immunofluorescence method in nasopharyngeal specimens. Adjusted logistic regression models were used to analyze the influence of the universal two-child policy implementation and public health measurements against COVID-19 on PIV detection. Totally 75 128 inpatients meeting the criteria were enrolled in this study from January 2014 to June 2022 with an overall PIV positive rate of 5.5%. The epidemic seasons of PIV prevalence lagged substantially in 2020. A statistically significant higher positive rate of PIV was observed in 2017-2019 compared to that in 2014-2015 (6.12% vs 2.89%, risk ratio = 2.12, p < 0.001) after the implementation of the universal two-child policy in 2016. A steep decline occurred in PIV positive rate during the COVID-19 epidemic in 2020 (0.92% vs 6.92%, p < 0.001) and it rebounded during the regular epidemic prevention and control period in 2021-2022 (6.35%, p = 0.104). In Hubei Province, the implementation of the universal two-child policy might have led to an increase of PIV prevalence, and public health measures during the COVID-19 epidemic might have influenced the fluctuation in PIV detection since 2020.

Ectopic protein overexpression in immortalised cell lines is a commonly used method to screen host factors for their antiviral activity against different viruses. However, the question remains as to what extent such artificial protein overexpression recapitulates endogenous protein function. Previously, we used a doxycycline-inducible overexpression system, in conjunction with approaches to modulate the expression of endogenous protein, to demonstrate the antiviral activity of IFITM1, IFITM2, and IFITM3 against influenza A virus (IAV) but not parainfluenza virus-3 (PIV-3) in A549 cells. We now show that constitutive overexpression of the same IFITM constructs in A549 cells led to a significant restriction of PIV-3 infection by all three IFITM proteins. Variable IFITM mRNA and protein expression levels were detected in A549 cells with constitutive versus inducible overexpression of each IFITM. Our findings show that overexpression approaches can lead to levels of IFITM1, IFITM2, and IFITM3 that significantly exceed those achieved through interferon stimulation of endogenous protein. We propose that exceedingly high levels of overexpressed IFITMs may not accurately reflect the true function of endogenous protein, thus contributing to discrepancies when attributing the antiviral activity of individual IFITM proteins against different viruses. Our findings clearly highlight the caveats associated with overexpression approaches used to screen cellular host proteins for antiviral activity.