Influenza A viruses continue to be a serious health risk to people and result in a large-scale socio-economic loss. Avian influenza viruses typically do not replicate efficiently in mammals, but through the accumulation of mutations or genetic reassortment, they can overcome interspecies barriers, adapt to new hosts, and spread among them. Zoonotic influenza A viruses sporadically infect humans and exhibit limited human-to-human transmission. However, further adaptation of these viruses to humans may result in airborne transmissible viruses with pandemic potential. Therefore, we are beginning to understand genetic changes and mechanisms that may influence interspecific adaptation, cross-species transmission, and the pandemic potential of influenza A viruses. We also discuss the genetic and phenotypic traits associated with the airborne transmission of influenza A viruses in order to provide theoretical guidance for the surveillance of new strains with pandemic potential and the prevention of pandemics.

Nipah virus (NiV), a highly pathogenic Henipavirus in humans, has been responsible for annual outbreaks in recent years. Experiments involving live NiV are highly restricted to biosafety level 4 (BSL-4) laboratories, which impedes NiV research. In this study, we developed transcription and replication-competent NiV-like particles (trVLP-NiV) lacking N, P, and L genes. This trVLP-NiV exhibited the ability to infect and continuously passage in cells ectopically expressing N, P, and L proteins while maintaining stable genetic characteristics. Moreover, the trVLP-NiV displayed a favourable safety profile in hamsters. Using the system, we found the NiV nucleoprotein residues interacting with viral RNA backbone affected viral replication in opposite patterns. This engineered system was sensitive to well-established antiviral drugs, innate host antiviral factors, and neutralizing antibodies. We then established a high-throughput screening platform utilizing the trVLP-NiV, leading to the identification of tunicamycin as a potential anti-NiV compound. Evidence showed that tunicamycin inhibited NiV replication by decreasing the infectivity of progeny virions. In conclusion, this trVLP-NiV system provided a convenient and versatile molecular tool for investigating NiV molecular biology and conducting antiviral drug screening under BSL-2 conditions. Its application will contribute to the development of medical countermeasures against NiV infections.

Previous studies reported that the association between statins use and influenza infection was contradictory. A systematic review and meta-analysis of longitudinal studies were performed to determine the association between statins use and influenza susceptibility. The literature search was conducted in PubMed, Embase, and Web of Science, from each database’s inception to 21 May 2023. The fixed effect model and random effects model were used for data synthesis. In our study, a total of 1,472,239 statins users and 1,486,881 statins non-users from five articles were included. The pooled risk ratio (RR) of all included participants was 1.05 (95% CI: 1.03–1.07), and there were still significant differences after adjusting for vaccination status. Of note, RR values in statins users were 1.06 (95% CI: 1.03–1.08) in people aged ≥60 years old and 1.05 (95% CI: 1.03–1.07) in participant groups with a higher proportion of females. Administration of statins might be associated with an increased risk of influenza infection, especially among females and elderly people. For those people using statins, we should pay more attention to surveillance of their health conditions and take measures to prevent influenza infection.

Influenza A virus (IAV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and respiratory syncytial virus (RSV) are significant pathogens that induce respiratory symptoms in humans, significantly impacting healthcare systems, economic activities, and human life on a global scale. The clinical manifestations associated with SARS-CoV-2, IAV, and RSV exhibit similarities. Cases of clinical coinfection are prevalent, highlighting the necessity for rapid differential diagnosis to avoid treatment delays. Traditional reverse transcription quantitative polymerase chain reaction (RT-qPCR) methods are often time-consuming and limited to central laboratories, necessitating the development of rapid and in situ screening techniques to accommodate broad and large-scale testing requirements. In light of the possibility of coinfection with multiple viral strains, a multiplex detection method known as triplex reverse transcription recombinase-aided amplification (RT-RAA) has been established to facilitate the simultaneous detection of these three pathogens. The triplex real-time RT-RAA assay operates at a constant temperature of 42°C and achieves detection within 30 minutes.The limits of detection (LOD) for IAV, SARS-CoV-2, and RSV were 138, 198, and 162 copies per reaction, respectively, comparable in order of magnitude to the 100 copies per reaction observed in the triplex RT-qPCR assay. Importantly, no cross-reactivity was observed with other significant viruses. In addition, compared with the triplex RT-qPCR assay, the triplex real-time RT-RAA assay demonstrated a high degree of concordance in the detection of IAV, SARS-CoV-2, and RSV in 58 clinical specimens. Overall, the triplex real-time RT-RAA assay holds considerable promise as a powerful tool for the rapid screening of respiratory diseases, owing to its advantages, including expedited detection, ease of operation, strong specificity, and high sensitivity. IMPORTANCE: It is well established that SARS-CoV-2, IAV, and RSV are significant pathogens that elicit respiratory symptoms in humans. In this study, we successfully developed a triplex real-time RT-RAA assay for the simultaneous rapid detection of SARS-CoV-2, IAV, and RSV. This assay is distinguished by its high specificity, sensitivity, and user-friendliness. It addresses the limitations associated with the necessity of specialized biological laboratories and the time-consuming, complex procedures that impede rapid diagnosis. This assay holds significant importance for the early diagnosis and epidemiological surveillance of respiratory tract infections, providing comprehensive and timely diagnostic information for clinical practice. Furthermore, this assay serves as a valuable tool for facilitating extensive and large-scale screening of SARS-CoV-2, IAV, and RSV.

Monkeypox virus (MPXV) poses a global health threat. Droplet digital PCR (ddPCR) holds potential as an accurate diagnostic tool for clinical microbiology. However, there is limited literature on the applicability of ddPCR in clinical settings. In this study, the clinical features of patients with MPXV during the initial outbreak in China in June 2023 were reviewed, and an optimized ddPCR method with dilution and/or inhibitor removal was developed to enhance MPXV detection efficiency. Eighty-two MPXV samples were tested from nine different clinical specimen types, including feces, urine, pharyngeal swabs, anal swabs, saliva, herpes fluid, crust, and semen, and the viral load of each specimen was quantified. A comparative analysis was performed with qPCR to assess sensitivity and specificity and to investigate the characteristics of MPXV infection by analyzing viral loads in different clinical specimens. Consequently, common pharyngeal and gastrointestinal symptoms were observed in patients with MPXV. The optimized ddPCR method demonstrated relatively high sensitivity for MPXV quantification in the clinical materials, with a limit of detection of 0.1 copies/μL. This was particularly evident in low-concentration samples like whole blood, semen, and urine. The optimized ddPCR demonstrated greater detection accuracy compared with normal ddPCR and qPCR, with an area under the curve (AUC) of 0.939. Except for crust samples, viral loads in the specimens gradually decreased as the disease progressed. Virus levels in feces and anal swabs kept a high detection rate at each stage of post-symptom onset, and feces and anal swabs samples may be suitable for clinical diagnosis and continuous monitoring of MPXV. IMPORTANCE: The ddPCR technique proved to be a sensitive and valuable tool for accurately quantifying MPXV viral loads in various clinical specimen types. The findings provided valuable insights into the necessary pre-treatment protocols for MPXV diagnosis in ddPCR detection and the potentially suitable sample types for collection. Therefore, such results can aid in comprehending the potential characteristics of MPXV infection and the usage of ddPCR in clinical settings.