Virologica Sinica最新文献

Ephemeroviruses (EVs) are arthropod-borne rhabdoviruses and were isolated exclusively from cattle and haematophagous arthropods until two new ephemeroviruses were first identified from domestic pigs most recently. Here we report the identification of newer EVs in wild boar by meta-transcriptomic (MTT) sequencing. Further screening by specific RT-nPCR of tissue samples of 459 free-ranging wild boars collected between 2018 and 2023 from 26 provinces across China confirmed five positive wild boars in four provinces. Interestingly, two ticks especially collected from two positive wild boars were also EV positive. Finally, four complete genome sequences of wild boar ephemeroviruses (WbEVs) were obtained with two strains belonging to a new EV species and the rest two falling into porcine ephemerovirus 2 (PoEV2) species identified from domestic pigs. Our study has further extended EV host range and demonstrated natural circulations of divergent EVs in wild boars, in which ticks may play roles. Biological implications of EV infection in wild boars should be interesting topics for future investigations.

Zika virus (ZIKV) is a mosquito-borne virus belonging to the genus Orthoflavivirus, and the family Flaviviridae. It commonly presents with febrile-like symptoms, neurological issues, and pregnancy complications in humans. Currently, there is no commercial vaccine or specific treatment available to prevent ZIKV infection. Therefore, controlling the epidemic's spread relies on preventing mosquitoes from transmitting the virus. Although various studies have explored the transmission of ZIKV between mosquitoes and vertebrate hosts, comprehensive research on potential mosquito-to-mosquito transmission of ZIKV remains limited. In this study, we conducted systematic laboratory investigations to assess the ability of ZIKV to spread among mosquitoes, and to evaluate the impact of ZIKV infection on mosquito development. Our findings revealed that ZIKV can be transmitted between Aedes aegypti mosquitoes both vertically and horizontally, through oviposition and contact between mosquitoes of the same or opposite sex. Additionally, we observed that ZIKV infection resulted in a reduction in the number of mosquito eggs but an increase in their size. The widespread distribution of ZIKV in infected mosquitoes and the altered levels of hormone related genes following viral infection were noted, which may contribute to viral transmission among mosquitoes and affect mosquito development. This research provides systematic experimental evidence of ZIKV transmission among mosquitoes, which is crucial for developing novel strategies to disrupt the spread of orthoflaviviruses and other mosquito-borne pathogens.

Respiratory syncytial virus (RSV) is one of the most common viruses leading to lower respiratory tract infections (LRTIs) in children and elderly individuals worldwide. Although significant progress in the prevention and treatment of RSV infection was made in 2023, with two anti-RSV vaccines and one monoclonal antibody approved by the FDA, there is still a lack of postinfection therapeutic drugs in clinical practice, especially for the pediatric population. In recent years, with an increasing understanding of the pathogenic mechanisms of RSV, drugs and drug candidates, have shown great potential for clinical application. In this review, we categorize and discuss promising anti-RSV drug candidates that have been in preclinical or clinical development over the last five years.

A switch from avian-type α-2,3 to human-type α-2,6 receptors is an essential element for the initiation of a pandemic from an avian influenza virus. Some H9N2 viruses exhibit a preference for binding to human-type α-2,6 receptors. This identifies their potential threat to public health. However, our understanding of the molecular basis for the switch of receptor preference is still limited. In this study, we employed the random forest algorithm to identify the potentially key amino acid sites within hemagglutinin (HA), which are associated with the receptor binding ability of H9N2 avian influenza virus (AIV). Subsequently, these sites were further verified by receptor binding assays. A total of 12 substitutions in the HA protein (N158D, N158S, A160 ​N, A160D, A160T, T163I, T163V, V190T, V190A, D193 ​N, D193G, and N231D) were predicted to prefer binding to α-2,6 receptors. Except for the V190T substitution, the other substitutions were demonstrated to display an affinity for preferential binding to α-2,6 receptors by receptor binding assays. Especially, the A160T substitution caused a significant upregulation of immune-response genes and an increased mortality rate in mice. Our findings provide novel insights into understanding the genetic basis of receptor preference of the H9N2 AIV.

The long-term effects of combined antiretroviral therapy (ART) on liver fibrosis patterns in adults living with human immunodeficiency virus (HIV) and chronic hepatitis B virus (HBV) are not well understood. Therefore, this study aimed to investigate the trajectories of liver fibrosis and identify the associations of baseline variables with different patterns of liver fibrosis evolution. A total of 333 individuals with HIV/HBV co-infection and undergoing long-term ART were enrolled in this study. Demographic, clinical, and biochemical data were collected at baseline and during annual visits. Group-based trajectory models (GBTMs) were used to detect the patterns of liver fibrosis evolution based on longitudinal data of fibrosis-4 (Fib-4) and aspartate aminotransferase to platelet ratio index (APRI) scores. Logistic regression analysis was performed to identify baseline predictors of liver fibrosis evolution. The median age of all participants was 33 years. Among them, 89.5% initially received TDF-containing ART. GBTMs identified two distinct patterns of liver fibrosis evolution using either APRI or Fib-4 scores. The majority of individuals (78.5% for APRI and 75.3% for Fib-4; pattern A) showed stable or low fibrosis with no progression, while the remaining participants showed regression from high fibrosis levels (21.5% for APRI and 24.7% for Fib-4; pattern B). Pattern A participants were younger and had higher CD4⁺ cell counts, higher lymphocyte cell counts, higher white blood cell counts, and lower platelet counts at baseline compared to pattern B participants. For HIV/HBV co-infected patients with varying degrees of initial liver fibrosis, long-term ART has shown distinct patterns of alleviating liver fibrosis.

In-utero exposure to Zika virus (ZIKV) could lead to miscarriage, preterm birth and congenital Zika syndrome. This study aimed at estimating the burden of ZIKV and Dengue virus (DENV) infections among pregnant women in Bojude, Nigeria. A total of 200 blood samples were collected from pregnant women between February and April 2022. Using the updated CDC guidelines for the diagnosis of ZIKV infections, including ELISA and microneutralization test (MNT), we found that 16.5% of participants were positive for ZIKV IgM, 10% were positive for IgG, and 23% had nAb in their serum. Among the 46 ZIKV nAb-positive women, 52.2% and 10.9% were recent and previous ZIKV infections, respectively, while 6.5% had previous DENV infections. Although no recent DENV infection was detected, recent and previous ZIKV/DENV co-infections were 13.0% and 17.4%, respectively. Two participants had recent secondary ZIKV infections, while 39.1% had prolonged lifelong immunity. Recent ZIKV infection rates were significantly higher among sexually active females aged 20-29 years than other age groups, with the highest risk observed in the first trimester of pregnancy. In addition, the grand-multiparous women are at higher risk of ZIKV infections than other categories. Monotypic recent, secondary and past ZIKV infections, as well as DENV and ZIKV co-infections, were detected in both the asymptomatic and symptomatic pregnant women. These findings highlight that ZIKV infection is prevalent among pregnant women in Nigeria and underscore the associated risk factors, providing evidence-based information on the burden of ZIKV infections in DENV-endemic region.