Physiological and proteomic responses to single and repeated hypoxia in juvenile Eurasian perch under domestication - clues to physiological acclimatation and humoral immune modulations.

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Sensitivity and permissivity of Cyprinus carpio to cyprinid herpesvirus 3 during the early stages of its development: importance of the epidermal mucus as an innate immune barrier

International audienceCyprinid herpesvirus 3 (CyHV-3) causes a lethal disease in common and koi carp (Cyprinus carpio). The present study investigated the ability of CyHV-3 to infect common carp during the early stages of its development (from embryos to fingerlings) after inoculation by immersion in water containing the virus. Fish were inoculated at different times after hatching with a pathogenic recombinant CyHV-3 strain expressing luciferase. The sensitivity and permissivity of carp to CyHV-3 were investigated using in vivo bioluminescence imaging. The susceptibility of carp to CyHV-3 disease was investigated by measuring the survival rate. Carp were sensitive and permissive to CyHV-3 infection and susceptible to CyHV-3 disease at all stages of development, but the sensitivity of the two early developmental stages (embryo and larval stages) was limited compared to later stages. The lower sensitivity observed for the early developmental stages was due to stronger inhibition of viral entry into the host by epidermal mucus. In addition, independent of the developmental stage at which inoculation was performed, the localization of light emission suggested that the skin is the portal of CyHV-3 entry. Taken together, the results of the present study demonstrate that carp are sensitive and permissive to CyHV-3 at all stages of development and confirm that the skin is the major portal of entry after inoculation by immersion in infectious water. The results also stress the role of epidermal mucus as an innate immune barrier against pathogens even and especially at the early stages of development

Virus influenza aviaire hautement pathogène H5N8: particularités et implications pour la surveillance en Belgique

Given the introduction of highly pathogenic avian influenza virus (HPAI) H5N8 in Europe in 2014, the probability of new introductions, circulation and establishment of the virus in Belgium has been evaluated, and the peculiarities of this H5N8 virus compared to other HPAI viruses, including H5N1, have been highlighted. A warning system based on a routine analysis of the epidemiological situation along the migration routes of wild birds towards Belgium is proposed. This alert system should make it possible to define a level of "risk" of introduction of HPAI viruses in Belgium via wild bird migration at all times in a sustainable manner. A distinction is made between three "risk" levels: basic vigilance, increase alertness and increased risk. In order to be proactive in taking preventive measures to prevent the introduction of HPAI viruses in holdings, specific biosecurity measure were associated with these different "risk" levels. As the H5N8 virus is less pathogenic for wild birds than the H5N1 virus, the probability of circulation and of establishment of the H5N8 virus in the wild fauna in Belgium is believed to be higher. The H5N8 virus is a reassortant sharing many genes with the H5N1 virus and has been circulating enzootically in South-east Asia and some other parts of the world (Egypt, Bangladesh .) for over 10 years. As long as this situation persists, the "risk" of introduction of HPAI viruses, possibly with modified properties, by wild birds in Europe will remain. Therefore, surveillance in wild birds appears more than ever necessary for the early detection of HPAI viruses.SCOPUS: cp.jinfo:eu-repo/semantics/publishe