Novel transcription and replication-competent virus-like particles system modelling the Nipah virus life cycle.

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.

Molecular Markers and Mechanisms of Influenza A Virus Cross-Species Transmission and New Host Adaptation.

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.

Applying improved ddPCR to reliable quantification of MPXV in clinical settings.

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.

RNA binding motif 4 inhibits the replication of ebolavirus by directly targeting 3'-leader region of genomic RNA.

Ebola virus (EBOV) belongs to Filoviridae family possessing single-stranded negative-sense RNA genome, which is a serious threat to human health. Nowadays, no therapeutics have been proven to be successful in efficiently decreasing the mortality rate. RNA binding proteins (RBPs) are reported to participate in maintaining cell integrity and regulation of viral replication. However, little is known about whether and how RBPs participate in regulating the life cycle of EBOV. In our study, we found that RNA binding motif protein 4 (RBM4) inhibited the replication of EBOV in HEK293T and Huh-7 cells by suppressing viral mRNA production. Such inhibition resulted from the direct interaction between the RRM1 domain of RBM4 and the "CU" enrichment elements located in the PE1 and TSS of the 3'-leader region within the viral genome. Simultaneously, RBM4 could upregulate the expression of some cytokines involved in the host innate immune responses to synergistically exert its antiviral function. The findings therefore suggest that RBM4 might serve as a novel target of anti-EBOV strategy.

Case Report: First case of HIV, hepatitis B, hepatitis C, and Vibrio vulnificus coinfection.

Our patient, a 48-year-old man from Guangdong's coastal region, worked selling and processing oysters and other seafood. He started experiencing swelling and pain in his left knee on October 4, 2022, and they got worse over time. The findings of mNGS test showed Vibrio vulnificus infection. The patient had AIDS, hepatitis A and hepatitis B concurrently. He was admitted to the hospital's intensive care unit (ICU) for treatment as his symptoms worsened. We refrained from performing an amputation because the family members expressed a desire to keep the limb. The limb was managed with regular dressing changes, thorough debridement, wound closure, ongoing VSD drainage, and local antibiotic irrigation. The patient's organ function eventually returned to normal, and the systemic infection got better. On November 1, the wound's new granulation tissue had grown well and had gradually crept to cover 80% of the wound. The tissue's blood flow had also improved, indicating a trend of growth and healing.

Biological characteristics, biosafety prevention and control strategies for the 2022 multi-country outbreak of monkeypox.

Monkeypox is a zoonotic disease caused by the monkeypox virus (MPXV), which is a potential biological warfare agent of bioterrorism and poses the greatest threat to the world's public biosafety and health after variola virus (VARV). While the coronavirus disease 2019 (COVID-19) pandemic has not ended yet, monkeypox is spreading menacingly. The first case of monkeypox in a nonendemic country was confirmed on May 6th, 2022, while the first imported case from Asia was found on June 21st. There were more than 16 thousand reported cases as of July 23rd, the day the World Health Organization (WHO) declared the global monkeypox outbreak a public health emergency of international concern (PHEIC) at the same level as smallpox and COVID-19; while there were more than 53 thousand cases as of September 1st. Therefore, we will propose relevant biosafety prevention and control strategies after analyzing the etiology of the 2022 multi-country monkeypox outbreak from the biological feature, transmissibility, epidemic, and variability of MPXV.