Virologie最新文献

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.