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International audience; The presence of pneumoviruses in pigs is extremely poorly documented. To inquire about these viruses in French pig farms, we used the published sequence of the nucleoprotein (N) of the recently identified Swine Orthopneumovirus (SOV) to express and purify SOV N as a recombinant protein in Escherichia coli. Then, SOV N was purified as nanorings and used to set up an enzyme-linked immunosorbent assay (ELISA). Using that ELISA we analysed the presence of anti-SOV N Immunoglobulins G (IgG) in various swine sera to inquire about the circulation of the virus in France. Since the virus has never been isolated, real positive controls were unavailable and negative controls challenging to obtain. Sera collected from specific pathogen free new born piglets before colostrum uptake were used as negative controls. These sera were negative for anti-SOV N IgG while most of the other sera collected in older animals from different pig farms in Brittany (France) were positive at various levels. To further confirm the validity of our ELISA assay cross-reactivity with bovine sera, human respiratory syncytial virus (hRSV) N, and whole inactivated bovine RSV (bRSV) particles were tested. Bovine sera were negative for IgG anti-SOV N and porcine sera did not react with inactivated bRSV. Interestingly, in two pig farms presenting respiratory clinical signs and negative or under control for common respiratory pathogens such as influenza virus and Mycoplasma spp, pigs were detected positive for anti-SOV N IgG. Several field and laboratory studies will be required to further characterize the circulation of the virus amongst pigs, to isolate the circulating virus, and to determine its potential pathogenicity and interactions with the porcine immune system. SOV may prove to be an overlooked actor of the porcine respiratory complex, important on its own or in association with other viral and bacterial micro-organisms.

National audience; In the pig, respiratory co-infections involving multiple pathogens are more frequent than single infections. Amongst porcine respiratory viruses, porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza type A virus (swIAV) are frequently associated. Previously, we performed co-infections and superinfections (maximum 3h of delay between infections) with swIAV and PRRSV in porcine alveolar macrophages (PAM) and precision cut lung slices (PCLS). Interference caused by the first virus on replication of the second virus was observed, though limited. On the host side, additive and synergistic effects were identified. However, the main target cell of swIAV is the epithelial cell, while for PRRSV it is the PAM; it was practically impossible to have co-infections of the same cells. This constraint complicated the study of interference between the two viruses. Consequently, in a second series of experiments we used an epithelial cell line expressing CD163, the main receptor of PRRSV. Results showed that swIAV, as well as PRRSV, were highly interfering with each other when infecting the same cells with consequences for the cellular antiviral response. More recently, we started to perform co-infections as well as superinfections with local strains of PRRSV, swIAV, and Aujeszky disease virus (ADV), as a DNA virus control, but this time with longer delays between infections. Moreover, we initiated preliminary works in order to assess a potential induction of trained immunity. A better understanding of the complex interactions existing between infectious agents in the respiratory tract will enable more rational preventive and therapeutic actions against the porcine respiratory complex

International audience; Cetacean adipose tissues contain an extremely very wide variety of acyl-chains present in triacylglycerols and / or wax esters. In addition, changes in the lipid composition across organs suggest fine stratification. It therefore remains technically challenging to describe precisely the lipid organization of these tissues. In the present study, we used in parallel HR-MAS NMR (High Resolution Magic Angle Spinning Nuclear Magnetic Resonance) and GC (gas-chromatography) to characterize and quantify the lipids and fatty acyl-chains from the blubber and melon of two odontocete species. Both methods generated very similar compositions , but each presented clear advantages. While GC underestimated the amount of short branched fatty acyl-chains, which are specific to cetacean adipose tissues and most probably of primary importance for their functioning, HR-MAS NMR allowed for their exact quantification. Conversely, when HR-MAS NMR could only discriminate a few types of fatty acyl-chain families, GC unambiguously identified and quantified most of them. In addition, this technique allowed for the determination of the wax esters molecular species. Our results further suggest that the stratification of these adipose tissues relies on changes in the tria-cylglycerol to wax ester ratio and in the fatty acyl composition of triacylglycerols, but not on changes in the wax esters composition. Altogether, our data show that the complementari-ties of these two approaches result in lipid analyses of unprecedented precision, paving the way for the detailed description of the fatty acyl composition of cetacean adipose tissues and the understanding of their functioning.

International audience; Viral respiratory diseases are problematic in swine industry. Among viruses, porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV), alone or in combination, are two main known contributors to respiratory infectious diseases. In the field, single viral infection is not frequent and most of the time association of infectious agents is encountered. So far most of the studies focused on single infectious agents ignoring the interactions existing between various pathogens (additive effects, synergism or antagonism) and their consequences for prophylactic treatments. In the current study we used a modified newborn pig trachea (NPTr) cell line expressing CD163, the receptor of PRRSV virus. Using this epithelial cell line allowing co-infections we assessed the impact of single infections compared to co-infections using specific strains and focusing on viral replication and the induction of cellular response, its characterization, and its regulation. One virus could influence the replication of the other, especially when the first virus inoculated to the cell was PRRSV. Regarding the triggering of cellular response the outcome is complex and target dependent. In some cases, co-infection did not lead to any synergism or additive effects while in other situations we observed a clear antagonism. Thus, obvious synergisms between the two viruses were not reported in any situations. In conclusions, using cells that can be infected with both PRRSV and SIV, we did not observe any synergism in the cellular response developed against viruses. On the contrary it appeared that the first virus was negatively influencing the replication of the second and the associated cellular response. Further studies are required to fully decipher the complex interactions occurring between the two viruses in their host

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International audience

International audience; European avian-like swine H1N1 was identified as one major pathogen of the porcine respiratory disease complex (PRDC) together with Mycoplasma hyopneumoniae (Mhp), and experimental pre-infection of pigs with Mhp was shown to increase the severity of a subsequent infection with H1N1. In order to evaluate novel control strategies towards such a multifactorial disease, we studied the impact of a moderate feed restriction on the ability of Mhp/H1N1 co-inoculated animals to resist the infection, as efficiency of inflammatory responses might be influenced by the nutritional status of the animal. Two groups of 8 SPF pigs were intra-tracheally inoculated with Mhp and H1N1 21 days apart. One group was fed ad libitum whereas the other one was applied a 40% feed restriction one week before H1N1 infection. Two similar mock-inoculated groups of 4 pigs each were included. All pigs were fitted with a jugular catheter. Three days post-H1N1 infection, the same amount of a standardized meal was given to all animals and kinetics of blood samples were performed during 4 hours for measuring plasma postprandial nutrient concentrations. Pigs were slaughtered 7 days post-H1N1 infection. Clinical signs were observed throughout the study and pathogens were detected in nasal swabs and lung tissues. Feed restriction had no effect on pathogen excretion and dissemination in infected host or on pulmonary lesions. However, feed- restricted pigs presented a shorter hyperthermia as well as a positive mean weight gain over the 3 first days following H1N1 infection as compared to animals fed ad libitum which lost weight during that period. Both infection and feed restriction modified postprandial kinetics of glucose and amino acid concentrations showing dramatic changes in nutrient metabolism. Our results indicated that feeding practices could be a strategy to prepare animals to overcome an influenza infection, especially in a PRDC context.

International audience

National audience; Emerging infectious diseases are actually of major concern worldwide. Most of them are zoonotic and their epidemiology must consequently be studied conjointly in humans and animals. We present here a long-term research program led in the Camargue. This area situated in the Rhone delta, crossroads of many birds‘ migration routes is a biodiversity hotspot. It appears vulnerable to disease emergence due to its key location and to the common use of wetlands by wild and domestic animals as well as humans. Since 2004, a health ecology program is led in the Camargue mainly focusing on Influenza A viruses. First, pathogen dynamics are studied in their wild reservoir. For example, a seasonal pattern of avian influenza A virus circulation in waterfowl was highlighted, an infection peak being generally observed in early fall, probably due to the massive arrival of young and possibly immunologically naive birds. Seasonality of avian Influenza viruses is currently studied in gulls. Second, pathogen transmission between wild and domestic birds is investigated. Interestingly, no highly pathogenic avian influenza virus was detected in wild birds of the region from 2006 to 2009 suggesting that migrating birds do not play an important role in the transmission of these viruses. On the other hand, the potential impact of domestic duck releases for shooting on avian influenza A viruses dynamics in wild waterfowl is currently studied. Finally, researches are led on pathogen exchanges between wildlife and humans. Antibio-resistant bacteria, similar to those circulating in humans in France, have been detected in gulls showing that they could be contaminated by human pathogens. This multidisciplinary program already proved that animal health, human health and ecology issues can be fruitfully linked to gain insight in the epidemiology of emerging pathogens. Besides, it highlights that long-term studies are needed to be able to face emerging health issues, rather than short-term studies limited to crisis periods that are necessarily insufficient.