Hepatitis E virus (HEV) belongs to the Hepeviridae family, Orthohepevirinae subfamily, Paslahepevirus genus which includes eight genotypes. HEV genotype 1 (HEV-1) and genotype 2 (HEV-2) are specific to humans, while genotype 3 (HEV-3) and genotype 4 (HEV-4) circulate mainly in pigs, wild boars and deer, but have also a zoonotic potential. HEV genotype 5 (HEV-5) and 6 (HEV-6) viruses circulate in wild boars in Japan and genotype 7 (HEV-7) and 8 (HEV-8) viruses circulate in camelids. The worldwide distribution of HEV is influenced by ecological and socioeconomic factors. In developing countries in Africa, transmission of the virus through fecally contaminated water accounts for a high proportion of epidemics. Direct human-to-human transmission is less frequent, although cases of infection through blood transfusion have been reported in several countries. Thanks to the "One Health" approach, zoonotic transmissions of HEV from pig to human have been more recently observed. These zoonotic infections are mainly due to the handling or consumption of pork meat or contact with pig manure, contaminating the environment. They alert on professions or populations at-risk, such as livestock farmers or butchers. In addition, HEV infection is particularly severe in pregnant women, leading to fetal and maternal death due to acute liver failure. Finally, the development and application of serological or molecular detection tests in Africa indicates that HEV can be incriminated in symptoms without etiology or falsely attributed to other hepatic viruses or to the yellow fever virus. This review updates studies on the epidemiology of HEV in Africa, a crucial step to better understand the virus and develop surveillance strategies to prevent and better control epidemics.

Hepatitis E virus (HEV) belongs to the Hepeviridae family, Orthohepevirinae subfamily, Paslahepevirus genus which includes eight genotypes. HEV genotype 1 (HEV-1) and genotype 2 (HEV-2) are specific to humans, while genotype 3 (HEV-3) and genotype 4 (HEV-4) circulate mainly in pigs, wild boars and deer, but have also a zoonotic potential. HEV genotype 5 (HEV-5) and 6 (HEV-6) viruses circulate in wild boars in Japan and genotype 7 (HEV-7) and 8 (HEV-8) viruses circulate in camelids. The worldwide distribution of HEV is influenced by ecological and socioeconomic factors. In developing countries in Africa, transmission of the virus through fecally contaminated water accounts for a high proportion of epidemics. Direct human-to-human transmission is less frequent, although cases of infection through blood transfusion have been reported in several countries. Thanks to the "One Health" approach, zoonotic transmissions of HEV from pig to human have been more recently observed. These zoonotic infections are mainly due to the handling or consumption of pork meat or contact with pig manure, contaminating the environment. They alert on professions or populations at-risk, such as livestock farmers or butchers. In addition, HEV infection is particularly severe in pregnant women, leading to fetal and maternal death due to acute liver failure. Finally, the development and application of serological or molecular detection tests in Africa indicates that HEV can be incriminated in symptoms without etiology or falsely attributed to other hepatic viruses or to the yellow fever virus. This review updates studies on the epidemiology of HEV in Africa, a crucial step to better understand the virus and develop surveillance strategies to prevent and better control epidemics.

Genetic recombination is a key process in the evolution of HIV-1. The co-circulation of genetically divergent variants of groups M and O in the same geographical areas has led to the description of 20 HIV-1/M+O dual infections and 20 unique HIV-1/MO recombinant forms (URF_MO). Their virological and pathophysiological consequences are unknown, but their viability raises questions about the selection process during genesis. Target cells have means to fight HIV, including restriction factors, which are counteracted by viral accessory proteins. This review summarizes the available knowledge on the currently described HIV-1/MO recombinants. Their virological and genetic characteristics were analysed, and the potential impacts of HIV-1/MO recombination on diagnosis, monitoring, treatment, viral counteracting of restriction factors, and fitness were studied. The analysis of this unique series of 20 URF_MO showed that HIV-1/MO recombinant forms are generally isolated from patients from which no parental forms are found. This suggests that the recombinant replicated faster than the parental forms, eventually out-grouping them.

In medicine, virological diagnosis is mainly based on the detection of the viral genome and antigens, or on the identification of specific antibodies produced in response to infection. These strategies are suitable for characterizing an active infection or past contact with an already known virus. The recent development of tests for evaluating the host's cellular immune response opens new perspectives for personalized patient care based on immunomonitoring. The IGRA tests (Interferon Gamma Release Assay), measuring interferon gamma produced by T lymphocytes stimulated in vitro by antigenic peptides specific to infectious agents and the quantification of the blood viral load of Torque teno virus (TTV) thus constitute tools for assessing infectious risk, particularly usable to predict opportunistic viral reactivations in immunocompromised patients. The characterization of the expression profile of interferon stimulated genes (IGS) in a respiratory sample is also likely to provide significant assistance in diagnosis, discriminating a viral infection from a bacterial infection, an acute infection from a persistence of nucleic acids from non-replicating microorganisms or allowing, in case of viral emergence, to quickly identify infected subjects in the absence of specific PCR tests available. All of these new approaches, described in this review, have the potential to considerably improve patient care with the objective to correctly prescribe medical virology tests and anti-infective treatments.

Among the wide range of viruses studied for their possible use as an oncolytic virus, the mammalian reovirus has the particularity of being naturally oncolytic, without requiring prior genetic modification. Since the 1970s, it has been observed that this virus has a propensity to destroy transformed cells in a preferential manner. These preliminary observations were refined at the end of the 1990s, and the idea of using reovirus as an oncolytic virus in anticancer virotherapy quickly took hold. This review briefly describes the main steps of the viral replication cycle pertinent to the oncolytic activity of the virus, as well as possible strategies for better optimization of this activity.

Among the wide range of viruses studied for their possible use as an oncolytic virus, the mammalian reovirus has the particularity of being naturally oncolytic, without requiring prior genetic modification. Since the 1970s, it has been observed that this virus has a propensity to destroy transformed cells in a preferential manner. These preliminary observations were refined at the end of the 1990s, and the idea of using reovirus as an oncolytic virus in anticancer virotherapy quickly took hold. This review briefly describes the main steps of the viral replication cycle pertinent to the oncolytic activity of the virus, as well as possible strategies for better optimization of this activity.

Despite advances in research and clinical practice, pancreatic ductal adenocarcinoma remains a major public health challenge due to the lack of early detection and effective treatments. In this context, oncolytic viruses have emerged as a promising therapeutic alternative. These viruses selectively infect and lyse cancer cells after replication while also having the potential to induce an antitumor immune response. This review explores the fundamental aspects of pancreatic cancer and its management, along with the principles of oncolytic virotherapy, highlighting clinically used viruses before discussing the therapeutic potential of the SG33 myxoma virus strain in pancreatic cancer virotherapy.

Antitumor immuno-virotherapy involves the use of replicating oncolytic viruses capable of selectively infecting and killing tumor cells, with the aim of stimulating an antitumor immune response. Attenuated strains of measles virus (MeV) used as measles vaccines are good candidates. Attenuated MeVs use the CD46 molecule as a tumor cell entry receptor, but also CD150/SLAM and Nectin-4. The CD46 molecule blocks complement-mediated lysis and is frequently overexpressed by many cancer cell types, enabling the attenuated MeV to infect these cells. In addition, MeVs take advantage of defects in the antiviral type I interferon (IFN I) response in tumor cells to replicate, while this antiviral response blocks its replication in healthy cells. Attenuated MeVs display oncolytic properties against numerous cancers in vitro and in mouse models. They induce immunogenic cell death with infiltration of tumors by immune cells, notably T lymphocytes, thus activating the anti-tumor immune response. Several phase I and II clinical trials using different MeVs have been carried out, with encouraging results. Here, we provide an update on this therapeutic approach.

Fanleaf degeneration disease is referred to as "ortiage" in the French literature in 1723. Nowadays it occurs in most vineyards worldwide. Grapevine fanleaf virus (GFLV) is the main causal agent of the disease. It was identified in 1960 following the identification of the ectoparasitic dagger nematode Xiphinema index as its exclusive vector. The expression of the bipartite viral genome has been characterized and functions have been assigned to most viral proteins. Remarkably, the viral RNAs are monouridylated. The virion structure was determined by crystallography and transmission determinants were mapped on the coat protein. Further, viral determinants of symptoms in leaves and roots of plant hosts, three suppressors of RNA silencing, and metabolic pathways dysregulated upon infection were identified. Despite tremendous progress, management responses are limited. Future research will undoubtfully better elucidate the different steps of the infection cycle and provide opportunities to apply transformative GFLV management solutions in the vineyard.

The conference gathered experts from many fields working on various aspects of virus-virus interactions, ranging from mutualistic to parasitic, and harnessing different approaches to studying virus evolution (e.g., molecular biology, theory, mathematical modelling, genomics, phylogenetics, clinical studies, laboratory experiments). Altogether, this allowed the common theme of virus-virus interactions to be addressed from myriad perspectives, by researchers representing the breadth of career stages in academia, including graduate students, postdocs, beginning faculty and established experts. Moreover, some participants represented industry and government agency labs studying translational goals, creating a vibrant conference that spanned basic and applied research on virus-virus interactions, where virus evolution featured prominently.