Pig herpesvirose: Aujeszky's disease

Aujeszky's disease, due to Suid herpesvirus 1, is a disease of wild and domestic pigs, which can occasionally infect other mammal species, such as cattle and domestic carnivores. Eradicated or in the process of being eradicated in domestic pig herds in most countries of the European Union and in North America, the disease remains endemic in wild boar populations, with a prevalence varying according to population densities. In domestic pigs, symptoms vary depending on the age of the animals, ranging from severe nervous disorders in piglets to respiratory and reproductive disorders in adults. In other species, the disease causes a fatal meningo-encephalitis. Control programmes usually combine vaccination with marker vaccines and screening with companion diagnostic kits. In countries free from Aujeszky's disease, serological surveillance is supplemented by active surveillance.La maladie d'Aujeszky, due à Suid herpesvirus 1, est une maladie des suidés sauvages et domestiques, qui peut atteindre occasionnellement d'autres espèces de mammifères comme les bovins et les carnivores domestiques. Éradiquée ou en cours d'éradication dans les élevages de porcs domestiques dans la plupart des pays de l'Union européenne et en Amérique du Nord, la maladie demeure endémique dans les populations de suidés sauvages, avec une prévalence qui diffère selon leur densité. Les symptômes varient selon l'âge des porcs, allant des troubles nerveux sévères chez les jeunes aux troubles respiratoires et troubles de la reproduction chez les adultes. Chez les autres espèces, la maladie se traduit par une méningo-encéphalite mortelle. Les plans de lutte associent généralement vaccination par des vaccins marqueurs et dépistage par des kits sérologiques compagnons. Dans les pays où la maladie est éradiquée, la surveillance sérologique active est complétée par la surveillance évènementielle

Acute induction of cell death-related IFN stimulated genes (ISG) differentiates highly from moderately virulent CSFV strains

Classical swine fever (CSF) severity is dependent on the virulence of the CSF virus (CSFV) strain. The earliest event detected following CSFV infection is a decrease in lymphocytes number. With some CSFV strains this leads to lymphopenia, the severity varying according to strain virulence. This lymphocyte depletion is attributed to an induction of apoptosis in non-infected bystander cells. We collected peripheral blood mononuclear cells (PBMC) before and during 3 days post-infection with either a highly or moderately virulent CSFV strain and subjected them to comparative microarray analysis to decipher the transcriptomic modulations induced in these cells in relation to strain virulence. The results revealed that the main difference between strains resided in the kinetics of host response to the infection: strong and immediate with the highly virulent strain, progressive and delayed with the moderately virulent one. Also although cell death/apoptosis-related IFN stimulated genes (ISG) were strongly up-regulated by both strains, significant differences in their regulation were apparent from the observed differences in onset and extent of lymphopenia induced by the two strains. Furthermore, the death receptors apoptotic pathways (TRAIL-DR4, FASL-FAS and TNFa-TNFR1) were also differently regulated. Our results suggest that CSFV strains might exacerbate the interferon alpha response, leading to bystander killing of lymphocytes and lymphopenia, the severity of which might be due to the host’s loss of control of IFN production and downstream effectors regulation

Management of a wild reservoir : Swine fever in European wild boars (sus scrofa)

Classical swine fever (CSF) is a disease affecting wild and domestic Suidae. Wild boars (Sus scrofa) are considered as a reservoir for the disease, as CSF may persist for years in certain wild populations. The presence of this infection is a threat for the pig industry in the European Union where most of the member States are free of CSF.We describe the possible outcomes of an outbreak of CSF in wild animals, as well as the factors likely to influence the virus transmission and persistence. We also detail the management measures that were tested to date to prevent geographical spreading from the infected zones, and to eradicate CSF within the infected areas. The complexity of health measures dealing with an outbreak within natural populations is explained, with further details on the vaccination approach implemented in France since 2004.La peste porcine classique (PPC) est une maladie virale des Suidés domestiques et sauvages. Le sanglier (Sus scrofa) est considéré comme un réservoir de PPC car la maladie peut persister plusieurs années dans certaines populations sauvages. Or la présence de cette infection représente une menace pour la filière porcine de l'union européenne dont la plupart des États membres sont indemnes. Nous présentons ici les évolutions possibles d'un foyer sauvage de PPC en déclinant les facteurs probables de la transmission et de la persistance du virus. Nous abordons ensuite les différents moyens de gestion qui ont été mis en place jusqu'à aujourd'hui pour empêcher l'extension des zones infectées, et permettre l'éradication des foyers au sein des zones infectées. L'accent est mis sur la complexité de la gestion sanitaire d'un foyer en population naturelle. Un développement plus particulier est consacré à la gestion vaccinale qui est mise en oeuvre en France depuis 2004

Adjuvants and delivery systems in veterinary vaccinology: current state and future developments

Modern adjuvants should induce strong and balanced immune responses, and it is often desirable to induce specific types of immunity. As an example, efficient Th1-immunity-inducing adjuvants are highly in demand. Such adjuvants promote good cell-mediated immunity against subunit vaccines that have low immunogenicity themselves. The development of such adjuvants may take advantage of the increased knowledge of the molecular mechanisms and factors controlling these responses. However, knowledge of such molecular details of immune mechanisms is relatively scarce for species other than humans and laboratory rodents, and in addition, there are special considerations pertaining to the use of adjuvants in veterinary animals, such as production and companion animals. With a focus on veterinary animals, this review highlights a number of approaches being pursued, including cytokines, CpG oligonucleotides, microparticles and liposomes. (Résumé d'auteur

Putative role of arthropod vectors in African swine fever virus transmission in relation to their bio-ecological properties

African swine fever (ASF) is one of the most important diseases in Suidae due to its significant health and socioeconomic consequences and represents a major threat to the European pig industry, especially in the absence of any available treatment or vaccine. In fact, with its high mortality rate and the subsequent trade restrictions imposed on affected countries, ASF can dramatically disrupt the pig industry in afflicted countries. In September 2018, ASF was unexpectedly identified in wild boars from southern Belgium in the province of Luxembourg, not far from the Franco-Belgian border. The French authorities rapidly commissioned an expert opinion on the risk of ASF introduction and dissemination into metropolitan France. In Europe, the main transmission routes of the virus comprise direct contact between infected and susceptible animals and indirect transmission through contaminated material or feed. However, the seasonality of the disease in some pig farms in Baltic countries, including outbreaks in farms with high biosecurity levels, have led to questions on the possible involvement of arthropods in the transmission of the virus. This review explores the current body of knowledge on the most common arthropod families present in metropolitan France. We examine their potential role in spreading ASF—by active biological or mechanical transmission or by passive transport or ingestion—in relation to their bio-ecological properties. It also highlights the existence of significant gaps in our knowledge on vector ecology in domestic and wild boar environments and in vector competence for ASFV transmission. Filling these gaps is essential to further understanding ASF transmission in order to thus implement appropriate management measures