Annual Review of Virology最新文献

A common cause of acute hepatitis in humans, hepatitis A virus (HAV) replicates within hepatocytes without inducing cytopathology. Virus is released from infected cells in the absence of cell lysis as quasi-enveloped HAV (eHAV) virions cloaked in host membranes. These virions circulate in blood when exported across the basolateral membrane of hepatocytes but are stripped of their membranes by bile salts when exported across the apical membrane into the biliary system resulting in fecal shedding of abundant naked, nonenveloped virus. This review summarizes the composition and structure of these two distinct types of infectious extracellular hepatovirus virions and outlines the evidence for specific signals within HAV capsid proteins that mediate interactions with the endosomal sorting complexes required for transport (ESCRT). Capsid protein interactions with the ESCRT-associated proteins ALIX and HD-PTP play a crucial role in the budding of newly assembled capsids into multivesicular endosomes, the first step in nonlytic release of quasi-enveloped virions from infected cells. This review also considers how eHAV virions enter naïve cells to establish infection in the absence of a virally encoded protein on their surface and compares the role played by quasi-envelopment in the hepatovirus life cycle with the nonlytic release of other types of viruses in extracellular vesicles.

Environmental surveillance, including wastewater and air sampling, has emerged as a powerful complement to traditional clinical surveillance for monitoring viral circulation. Advances in sampling and detection technologies, many spurred by the COVID-19 pandemic, have enabled more sensitive and comprehensive characterization of viruses in diverse types of commingled samples from multiple individuals. Expanding environmental monitoring globally presents challenges and opportunities, particularly in low- and middle-income countries where centralized sewage infrastructure may be limited. Ethical implementation will require balancing privacy and transparency through community engagement. Future directions include using environmental surveillance to detect emerging zoonoses, fill gaps when clinical testing wanes, and inform public health actions. While logistical, regulatory, and ethical challenges remain, coordination across scientific and public health stakeholders can enable environmental monitoring to transform epidemic intelligence. This review summarizes recent developments in environmental surveillance systems and discusses how they can mitigate the introduction and spread of viruses in communities.

The evolution of pathogen virulence is a central question in evolutionary epidemiology. This review examines the development of these ideas over the last 75 years from an ecological perspective using a mixture of theoretical and empirical studies. I begin with Fenner's work on myxomatosis, which led to the key concept that trade-offs exist between transmission and virulence in pathogen life histories. I then consider how models of Fenner's study gradually developed into a major area of theoretical epidemiology. The emerging concepts were constantly challenged by new empirical studies that illustrated how virulence may be modified by culling, vaccination, and different forms of heterogeneity within and between species and spatial heterogeneity. The emerging field of phylodynamics has provided multiple new tools to analyze and visualize the evolution of virulence and a much broader perspective on the diversity of viruses and their hosts. I conclude with a brief discussion of possible future directions of study.

Infection by neurovirulent pathogens in utero and during the neonatal period can lead to fetal and neonatal mortality as well as neurological morbidity with lifelong consequences. Fortunately, maternal antibodies (Abs) serve as a means to protect humans as their immune system forms and matures. For some of the particularly consequential viral infections of early life, preclinical and clinical evidence demonstrate an unambiguously protective role of maternal Abs; for others, maternal Abs also have the potential to contribute to disease pathology. Here, we discuss how maternal Abs are temporarily inherited and distributed in fetal tissue. We focus on how this transgenerational form of immunity influences mortality and neurological morbidity as a result of herpes simplex virus, human cytomegalovirus, and flavivirus infections in early life.

The recent global spread of mpox virus, facilitated by a newly established human-to-human transmission mode, has rekindled interest in poxviruses and the molecular factors defining their host range. Poxviruses employ host-range factors, a subset of their immune evasion proteins, to overcome cell-intrinsic defenses in specific cell types or host species. Over the past decade, investigations of these factors have revealed previously unrecognized antiviral mechanisms and expanded our understanding of innate immunity. Among the key developments are the discovery of novel restriction factors, including SAMD9 and SAMD9L (SAMD9/9L), and expanded roles for established antiviral proteins such as IFITs, FAM111A, and ZAP. These advances not only clarify how poxvirus host range is determined but also offer valuable insights into the complexity and evolution of mammalian innate immunity. Here, I highlight new findings on poxvirus host-range determinants, with a particular focus on SAMD9/9L and the three distinct classes of poxvirus host-range factors that antagonize them.

The aphid holobiont includes the aphid host and aphid-associated microorganisms, including pathogenic plant viruses. The polerovirus potato leafroll virus (PLRV) is transmitted exclusively by aphids and is one of the most economically significant viruses infecting potatoes. In potato plants, PLRV infection results in stunting, leaf rolling, and net necrosis on tubers. PLRV threatens global potato cultivation, especially in regions where vector management options are limited. In this review, we describe the effect of PLRV on the aphid holobiont and highlight studies of the evolutionary and mechanistic ways in which PLRV influences the aphid holobiont during plant infection. We explore ideas to address the pressing need for aphid and PLRV management strategies by targeting interactions within the holobiont. Approaching PLRV-aphid interactions research through the lens of the holobiont allows a systems-level analysis of host, plant, and microbial effects that influence virus transmission. In turn, this knowledge can be leveraged to develop new virus management strategies.

Mitochondria play a vital role in cellular metabolism, energy production, and immune signaling, making them key targets for viral manipulation. Viruses exploit mitochondrial functions to enhance replication and evade immune responses. They also disrupt mitochondrial dynamics by altering fission/fusion balance and modulating mitophagy, which is essential for mitochondrial quality control. Additionally, they reprogram mitochondrial metabolism, affecting pathways such as oxidative phosphorylation and glycolysis to support replication. Viruses regulate apoptosis, either inhibiting or activating mitochondria-mediated apoptosis to prolong host cell survival or facilitate viral spread. Viral infections also induce oxidative stress through reactive oxygen species generation, affecting cellular integrity. Furthermore, viruses manipulate mitochondrial antiviral immunity by degrading mitochondrial antiviral signaling protein and triggering the release of mitochondrial DNA, modulating immune responses. Understanding these interactions offers valuable insights into viral pathogenesis and presents therapeutic opportunities. Targeting mitochondrial dysfunction and enhancing antiviral immunity could provide new strategies to mitigate viral damage and enhance cellular resilience.

Plant viruses, which can cause devastating plant diseases, are obligate intracellular pathogens that replicate their genomes inside cells and spread infection by cell-to-cell movement through cell wall nanochannels called plasmodesmata (PD). Double-stranded RNA, which occurs as a replication intermediate of RNA viruses, triggers adaptive and innate host defense responses that are controlled by virus-encoded effector proteins. These defenses include RNA silencing and RNA decay, which target viral RNA and inhibit virus accumulation, and pattern-triggered immunity (PTI), which targets PD and inhibits virus movement. This review discusses the role of RNA silencing, RNA decay, PTI, and effector-triggered immunity as antiviral defense mechanisms, how they are interrelated, and how viruses interact with these mechanisms to ensure their successful replication and spread throughout the plant organism.

Restriction factors serve as innate host defenses against viruses and act as critical barriers to cross-species transmission. In response, viruses have evolved accessory proteins to counteract restriction factors, enabling evasion of innate immune responses. The interplay between primate APOBEC3G (A3G) and lentiviral virion infectivity factor (Vif) exemplifies a molecular arms race between a restriction factor and its viral antagonist. This review integrates evolutionary and functional analyses of this system, showing how genetic signatures of molecular arms races map onto high-resolution cryo-electron microscopy structures. However, A3G's interaction with Vif is not limited to the evolutionary dynamic interface, characterized by rapidly evolving residues under selective pressure, but also involves a conserved interface mediated by RNA binding that positions A3G for antagonism by Vif. These findings propose a model wherein Vif and potentially other viral antagonists target functional complexes using a dual strategy: leveraging both adaptive interfaces subject to evolutionary pressures and conserved interfaces that constrain host escape mechanisms.