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BACKGROUND Direct-acting oral anticoagulant use for stroke prevention in atrial fibrillation is limited by bleeding concerns. Asundexian, a novel, oral small molecule activated coagulation factor XIa (FXIa) inhibitor, might reduce thrombosis with minimal effect on haemostasis. We aimed to determine the optimal dose of asundexian and to compare the incidence of bleeding with that of apixaban in patients with atrial fibrillation. METHODS In this randomised, double-blind, phase 2 dose-finding study, we compared asundexian 20 mg or 50 mg once daily with apixaban 5 mg twice daily in patients aged 45 years or older with atrial fibrillation, a CHA2DS2-VASc score of at least 2 if male or at least 3 if female, and increased bleeding risk. The study was conducted at 93 sites in 14 countries, including 12 European countries, Canada, and Japan. Participants were randomly assigned (1:1:1) to a treatment group using an interactive web response system, with randomisation stratified by whether patients were receiving a direct-acting oral anticoagulant before the study start. Masking was achieved using a double-dummy design, with participants receiving both the assigned treatment and a placebo that resembled the non-assigned treatment. The primary endpoint was the composite of major or clinically relevant non-major bleeding according to International Society on Thrombosis and Haemostasis criteria, assessed in all patients who took at least one dose of study medication. This trial is registered with ClinicalTrials.gov, NCT04218266, and EudraCT, 2019-002365-35. FINDINGS Between Jan 30, 2020, and June 21, 2021, 862 patients were enrolled. 755 patients were randomly assigned to treatment. Two patients (assigned to asundexian 20 mg) never took any study medication, resulting in 753 patients being included in the analysis (249 received asundexian 20 mg, 254 received asundexian 50 g, and 250 received apixaban). The mean age of participants was 73·7 years (SD 8·3), 309 (41%) were women, 216 (29%) had chronic kidney disease, and mean CHA2DS2-VASc score was 3·9 (1·3). Asundexian 20 mg resulted in 81% inhibition of FXIa activity at trough concentrations and 90% inhibition at peak concentrations; asundexian 50 mg resulted in 92% inhibition at trough concentrations and 94% inhibition at peak concentrations. Ratios of incidence proportions for the primary endpoint were 0·50 (90% CI 0·14-1·68) for asundexian 20 mg (three events), 0·16 (0·01-0·99) for asundexian 50 mg (one event), and 0·33 (0·09-0·97) for pooled asundexian (four events) versus apixaban (six events). The rate of any adverse event occurring was similar in the three treatment groups: 118 (47%) with asundexian 20 mg, 120 (47%) with asundexian 50 mg, and 122 (49%) with apixaban. INTERPRETATION The FXIa inhibitor asundexian at doses of 20 mg and 50 mg once daily resulted in lower rates of bleeding compared with standard dosing of apixaban, with near-complete in-vivo FXIa inhibition, in patients with atrial fibrillation. FUNDING Bayer.

International audience; To limit the use of antibiotics in farmed fish and their potential negative impacts on public health and the environment, an evaluation of “functional alternatives” is required. The availability of effective treatments to control fish diseases is one of the most significant challenges facing aquacultures and veterinarians to reduce consequences of antimicrobial resistance. This paper includes results from in vivo studies in major freshwater-farmed fish species (salmonids, cyprinids, and cichlids), focusing on the efficacy of functional alternatives against Aeromonas spp. infections. It also outlines the recent biocontrol advances and potential alternative treatments in aquaculture. Functional alternative products can increase the resistance against Aeromonas spp. particularly by increasing the immunocompetence of fish. Many diverse alternative products such as probiotics, prebiotics, plants, essential oils, algae phages, minerals, and nanoparticles have been tested, but the diversity of the experimental designs makes it difficult to compare the efficacy of the tested products. It suggests the standardization of investigations on functional feed products for each fish species against a specific pathogen. This review also recommends farm research on functional feed alternatives in natural conditions in order to evaluate the decrease of antibiotic consumption in fish farms.

International audience; AimsThis study aimed to evaluate in vitro efficacy of essential oils (EOs) and their compounds (EOCs) alone or in combination against Aeromonas salmonicida subsp. salmonicida, the causative agent of furunculosis in salmonid fish.Methods and ResultsAntimicrobial activity of 13 EOs and 16 EOCs was investigated for four A. salmonicida subsp. salmonicida strains using broth microdilution. The checkerboard assay was used to evaluate a putative synergy between the most efficient EOs and EOCs against the tested strains. Cinnamon bark, oregano, clove, and thyme oils and their major compounds cinnamaldehyde, eugenol, carvacrol and thymol showed the lower minimum inhibitory concentration and minimum bactericidal concentration values. The association of cinnamaldehyde and eugenol (V/V: 30%/70%) showed a synergistic activity against three tested strains. The combinations of cinnamon with oregano, clove or thyme EOs showed a neutral or additive activity against all the tested strains.ConclusionsCinnamon, oregano, clove and thyme oils and their major phytochemical compounds showed strong activities against A. salmonicida subsp. salmonicida strains.Significance and Impact of the StudyTo reduce the use of antibiotics in aquaculture, phytochemicals such as cinnamaldehyde and eugenol can be tested alone or in combination in in vivo studies as functional feed alternatives.

AIM To assess the arrhythmic determinants and prognosis of patients presenting with myocardial infarction and non-obstructive coronary arteries (MINOCA) with normal ejection fraction (EF). METHODS This is an observational analysis of 131 MINOCA patients with normal EF. Three cardiac magnetic resonance (CMR) diagnosis classes were recognized according to the late gadolinium enhancement (LGE) pattern: Myocardial infarction (MI) (n = 34), myocarditis (n = 47), and “no LGE” (n = 50). Ventricular events occurring during hospitalization were recorded and the entire population was followed-up at 1 year. RESULTS Ventricular arrhythmia was observed in 18 (13.8%) patients during hospitalization. The “no LGE” patients experienced fewer ventricular events than the MI and myocarditis patients [4.0% vs 26.5% and 14.9%, respectively (P = 0.013)]. There was no significant difference between the MI and myocarditis groups. On multivariate analysis, LGE transmural extent [OR = 1.52 (1.08-2.15), P = 0.017] and ST-segment elevation [OR = 4.65 (1.61-13.40), P = 0.004] were independent predictors of ventricular arrhythmic events, irrespective of the diagnosis class. Finally, no patient experienced sudden cardiac death or ventricular arrhythmia recurrence at 1-year. CONCLUSION MINOCA patients with normal EF presented no 1-year cardiovascular events, irrespective of the CMR diagnosis class. LGE transmural extent and ST segment elevation at admission are risk markers of ventricular arrhythmia during hospitalization.

International audience; This report describes a problem-based learning activity concerning antibiotic exposure and bacterial resistance in humanand veterinary medicine. In addition, learning outcomes and satisfaction of students were recorded by the supervisors ofthe activity. The students all participated actively in the group work and considered that the small size of the groupfacilitated interpersonal communication. They believed that working in an interdisciplinary group helped them learn betterthan if they were following specific courses. They also reported that their mid-term meeting with one of the supervisorswas a catalyst for the initiation of a real work group. Concerning the evaluation of the activity itself, the supervisorsconsidered that the group provided a relevant analysis of the issue. These characteristics should encourage teachers to testthis method of learning certain aspects of microbiology and infectious diseases with their students.This report describes a problem-based learning activity concerning antibiotic exposure and bacterial resistance in humanand veterinary medicine. In addition, learning outcomes and satisfaction of students were recorded by the supervisors ofthe activity. The students all participated actively in the group work and considered that the small size of the groupfacilitated interpersonal communication. They believed that working in an interdisciplinary group helped them learn betterthan if they were following specific courses. They also reported that their mid-term meeting with one of the supervisorswas a catalyst for the initiation of a real work group. Concerning the evaluation of the activity itself, the supervisorsconsidered that the group provided a relevant analysis of the issue. These characteristics should encourage teachers to testthis method of learning certain aspects of microbiology and infectious diseases with their students.

International audience; A large fraction of antibacterial agents administered to farmed fish is released into the environment, either in leaching from uneaten medicated pelleted feed, or through urinary, branchial and faecal excretions. Processes such as hydrolysis and photolysis might be important for the elimination of antibacterial agents from water. The aim of the present study was to compare hydrolysis and photolysis of oxytetracycline (OTC), oxolinic acid (OXA), flumequine (FLU) and florfenicol (FLO) in three types of water (deionised water, freshwater and seawater) under abiotic conditions. For each antibacterial agent, a 7-day factorial experiment was designed in order to study the effect of light, pH and dissolved oxygen on hydrolysis and photolysis in deionised water. Furthermore, 14-day kinetics experiments were performed for each antibacterial agent and each type of water. FLO was not degraded by hydrolysis or photolysis phenomena. Hydrolysis phenomena only concerned OTC and were responsible for about 20% of its degradation following a 14-day exposure at a temperature of + 8 °C. Photolysis was responsible for about 70% of the OTC degradation in freshwater and seawater and 10% of the OXA and FLU degradation in seawater following the same exposure. Water pH played a role in OTC hydrolysis and photolysis. There was no close connection between OTC hydrolysis and photolysis and OTC binding to cations and organic matter, but it would be suggested that there was a connection between absence of OXA and FLU photolysis and OXA and FLU binding to organic matter.

Novel procedures for the determination of florfenicol in freshwater, sediments and bryophyte Fontinalis antipyretica, using reversed-phase high-performance liquid chromatography are described. Liquid chromatography was performed on a 5 µm PuroSpher RP-18E® column using methanol and 0.05 M phosphate buffer (18/82 v/v, pH 7.3) as mobile phase (0.8 ml min−1) and fluorescence detection (excitation wavelength 265 nm and emission wavelength 295 nm). Florfenicol was determined in centrifuged freshwater samples. Florfenicol was extracted from sediments and bryophytes samples by using a solid-liquid extraction step followed by a solid phase extraction step. Linearity was confirmed over the concentration range 25–1000 ng mL−1 water and 50-1000 ng g−1 sediment or bryophyte. Limits of detection and quantitation were 8 and 25 ng mL−1 water and 17 and 50 ng g−1 sediment or bryophyte respectively. Mean extraction recoveries of florfenicol from sediments and bryophyte were from 85.9 to 109.1%.

Vanadium was measured by atomic absorption spectrophotometry in the liver and kidney of several oiled seabirds that were stranded on the French Atlantic coasts after the Erika wreck and died in wildlife care Centers. Estimated averages were 30 to 77 ng g−1 wet weight (ww) in the liver and 52 to 72 ng g−1 wet weight in the kidney. These concentrations were not higher in oiled birds than in dead birds found later, without visible traces of petroleum on beaches not affected by the Erika pollution. Vanadium hepatic and renal concentrations do not seem to be appropriate biomarkers for recent exposure to fuel in seabirds.

International audience; In recent years, the fate of pharmacological substances in the aquatic environment have been more and more studied. Oxolinic acid (OA), flumequine (FLU) and oxytetracycline (OTC) are commonly used antibacterial agents. A large amount of these drugs is released into water directly by dissolved fraction and indirectly in urine and feces. Monitoring these compounds in the freshwater environment is difficult because of the lack of suitable indicators. The aim of this work was to evaluate the OA, FLU and OTC bioaccumulation abilities of Fontinalis antipyretica Hedw., known for heavy metal bioaccumulation. The experiment described was decomposed for two times: a 10-days accumulation period during which bryophytes were in contact with antibiotics and a 15-days post-exposure period during which bryophytes were in water with no antibiotic. This experiment showed that this bryophyte strongly accumulates OA, FLU and OTC in freshwater. Bioaccumulation factors (ratio of concentrations in bryophyte and water) ranged between 75 and 450. Moreover, OA, FLU and OTC persisted in the bryophyte for a long time with clearance between 0.19 and 3.04 ng/g/day. Mean residence times ranged between 18 and 59 days. Accumulation and decontamination mechanism models were proposed

International audience; The ability of blue mussel (Mytilus edulis) to act as a potential antibiotic bioindicator in marine waters was experimentally tested by the study of the kinetics of two veterinary antibiotics (oxolinic acid: OA and oxytetracycline: OTC). Antibiotic uptake was fast in the soft parts of the mussels. OA was quickly eliminated while OTC was released more slowly (half-life in VISCERA=3.9 days). OA and OTC were preferentially accumulated in gills and in viscera, respectively. Bio-accumulation factors were low (maximum: 2 for OTC in viscera) in accordance with the low Kows. It was assumed that the higher OTC bioaccumulation pattern was related to its binding to mineral and organic compounds that led to its activity inhibition (62%). The antibiotics were persistent in shells (OTC HALF-LIFE=8.3 days). Most veterinary and human antibiotics such as tetracyclines and sulphonamides have low logKow (

Oxytetracycline (OTC) is one of the major antibacterial agent used in freshwater fish farming. Because of its rapid decomposition rate in sediments, it is difficult to monitor OTC in the freshwater environment. Fontinalis antipyreticais known for its bioaccumulation properties. Determining OTC concentration in F. antipyretica by HPLC was a real challenge because pigments coextracted with OTC. Ion-pairing was used in the clean-up procedure to improve the selectivity of the C18 solid phase extraction. Octanesulfonic acid was used as counter-ion. Tetracycline was used as internal standard. The linearity ranged between 100 and 1000 ng/g and limits of detection and quantitation were 30 and 100 ng/g, respectively. Mean recovery for OTC was 48.2% and the validation procedure demonstrated that the method was selective, reliable and precise enough to allow environmental monitoring. This method was applied to a 25 days experimental study showing the bioaccumulation of OTC by the bryophyte F. antipyretica. © 2002 Elsevier Science B.V. All rights reserved.

A procedure for the determination of oxolinic acid (OA) in faeces and urine of turbot (Scophthalmus maximus), using reversed-phase high-performance liquid chromatography is described. Liquid chromatography was performed on a 5-microm PuroSpher RP-18E cartridge using acetonitrile and 0.001 M aqueous orthophosphoric acid solution as mobile phase, with fluorescence detection. After the addition of an internal standard, oxolinic acid was extracted by using a liquid-liquid extraction procedure. Linearity and precision were checked over the concentration ranges 1.0-1000 microg/g (faeces) and 0.06-10.00 microg/ml (urine). Limits of detection of OA in faeces and urine were 0.20 microg/g and 0.02 microg/ml respectively. Mean extraction recoveries of OA from faeces and urine were 102.0 and 91.6% respectively.

A very specific high-performance liquid chromatography–mass spectrometric method for the determination of natural tetracyclines was developed in order to characterise the degradation products of oxytetracycline in sediments. First, extraction used a clean up step with a Bond Elut Certify® LRC cartridge. A 3 μm Spherisorb® ODS1 column was then used with a methanol, acetonitrile and oxalic acid mobile phase gradient. Chromatographic resolution in these conditions was 3.31 between oxytetracycline and tetracycline. Two liquid chromatography–mass spectrometry methodologies based on a particle beam and a frit fast atom bombardment interface were developed. In the first approach, ionisation was performed in the negative chemical mode using methane as reacting gas. In the other case, glycerol–thioglycerol mixture was used as matrix to ensure good sensitivity. MS–MS experiment was performed to determinate oxytetracycline fragmentation pattern in the perspective of degradation product study.

A simple high performance liquid chromatographic method for the determination of oxolinic acid, a chemotherapeutic agent, in turbot serum has been developed. Nalidixic acid was used as an internal standard. The drugs were separated by using a 5 μm Supelcosil ABZ+Plus® reversed phase cartridge, a mobile phase of acetonitrile, tetrahydrofuran and 0.001 M orthophosphoric acid solution (22:10:68 v/v), pH 3.4 with a fluorescence detection. The sample clean-up was reduced to the use of precipitating agents and centrifugations because the solid-phase extraction procedure was not suited to the analysis of oxolinic acid in turbot serum. Linearity and precision were checked over the concentration range 0.020–2.500 μg/mL. Limits of detection and determination were respectively 0.005 and 0.015 μg/mL. Recoveries of oxolinic acid from turbot serum were between 103.89 and 110.71 %.

A procedure for the determination of warfarin, an anticoagulant rodenticide, in the white and the yolk of hens' eggs, using reversed-phase high-performance liquid chromatography is described. Liquid chromatography was performed on an octadecylsilane cartridge using methanol and ammonium acetate triethylamine buffer as the mobile phase, with UV detection at 281 nm. Samples (5 g) were analysed after liquid-phase extraction using a mixture of acetone and diethyl ether. Linearity, precision and accuracy of the method were determined in the range of 0.5–8.0 μg. Limits of quantitation for warfarin in the white and the yolk were 0.020 and 0.015 μg/g, respectively. Mean recoveries of warfarin from spiked white and yolk samples were 84.6 and 87.4%, respectively. The analytical method was applied to a fourteen-day experimental study conducted in laying hens that had been orally dosed with warfarin.

A reversed-phase high-performance liquid chromatographic method was developed for the analysis of eight anticoagulant rodenticides in animal liver. Coumarinic anticoagulant rodenticides (brodifacoum, bromadiolone, coumachlor, coumatetralyl, difenacoum, and warfarin) were detected by using a gradient elution and a fluorimetric detection. Indanedione anticoagulant rodenticides (chlorophacinone and diphacinone) were detected by using an isocratic elution and an UV detection. Anticoagulants were extracted from liver with mixtures of acetone/diethylether and acetone/chloroform. Extracts were applied to solid-phase extraction cartridges. Linearity was checked over the concentration range 0.1-0.6 microgram/g. Relative standard deviations of within-run and between-run variability were all between 5.7 and 10.3%. Recoveries from spiked liver samples were between 51.7 (difenacoum) and 78.2% (warfarin). Limits of detection were between 0.01 (difenacoum and warfarin) and 0.11 microgram/g (chlorophacinone).

A simple procedure for the determination of oxolinic acid (OA) and oxytetracycline (OTC), two antibacterial agents, in the shell of the blue mussel (Mytilus edulis), using reversed-phase high-performance liquid chromatography is described. Liquid chromatography was performed on a 5-microm LiChroSpher 100 RP-18E column using acetonitrile and a 0.02 M orthophosphoric acid solution as the mobile phase, with ultraviolet detection. After roughly grinding the shell, drugs were extracted using a methanolic oxalic acid solution. Linearity and precision were checked over the concentration range 0.04-0.32 microg/g. Limits of detection of OA and OTC were 0.012 and 0.008 microg/g, respectively. Mean extraction recoveries of OA and OTC from mussel shell were 72.9 and 65.4%, respectively. To demonstrate the usefulness of the analytical procedure, an experimental study was performed in blue mussels exposed to the drugs for eight days.

Oxolinic acid and oxytetracycline are commonly used antibacterial agents for treatment of infectious diseases in marine fish farming and reach sediments. The aim of this study was to describe the sorption of these antibacterial agents to marine sediments (mud, sandy mud and sand) by using batch experiments. Sorption of antibacterial agents increased with the sediment content in mineral and organic matter and in particles of less than 63 μm diameter. Sorption of oxytetracycline to mud and sandy mud was higher than sorption of oxolinic acid. Furthermore, oxytetracycline, but not oxolinic acid, was transformed in sediment probably by both chemical and bacteriological processes.

In many ancient saltmarshes marine fish farms are now being developed. These farms, during their production cycles, use many chemical and veterinary products to prevent or fight disease. Since effluents from the farms are discharged directly into shellfish rearing areas, it is necessary to be aware of how shellfish accumulate such substances. An experimental apparatus allowed the creation of a fish farm effluent containing oxytetracycline (OTC) for a seven day treatment period. This effluent was poured into three test tanks, into which individuals of three edible species of bivalves, Crassostrea gigas, Ruditapes philippinarum and Scrobicularia plana , had previously been placed. The highest concentrations were observed in C. gigas (average 1.42 μg.g −1 wet weight). After treatment, the OTC concentration decrease was gradual and slow in C. gigas , reaching 0.68 μg.g −1 wet weight 14 d after the end of medication. Concentrations were stable in R. philippinarum and S. plana until the end of the experiment. Differences observed in the kinetics and maximal OTC concentration values may be related to the filtering rate of the species and their feeding behaviour. These findings illustrated the long persistence of OTC in shellfish. This may be related to the availability of OTC from sediment, the formation of complexes between OTC and some mineral or organic components of the bivalves, and their low xenobiotic metabolism. Considering the dilution processes of the coastal ecosystem, one might surmise that the influence of such contamination is only restricted to the vicinity of the farms. Nevertheless, special care should be taken in the utilization of such substances, especially in integrated aquaculture systems.

A 44-year-old man was referred to our hospital 3 years after heart transplantation for systematic endo-myocardial biopsies. The initial physical examination and transthoracic echocardiography were normal. The right internal jugular vein was punctured under local anaesthesia. Three heart biopsies of the right ventricular septum were obtained. One hour after this …

International audience; BACKGROUND: The honey bee, Apis mellifera, is frequently used as a sentinel to monitor environmental pollution. In parallel, general weakening and unprecedented colony losses have been reported in Europe and the USA, and many factors are suspected to play a central role in these problems, including infection by pathogens, nutritional stress and pesticide poisoning. Honey bee, honey and pollen samples collected from eighteen apiaries of western France from four different landscape contexts during four different periods in 2008 and in 2009 were analyzed to evaluate the presence of pesticides and veterinary drug residues. METHODOLOGY/FINDINGS: A multi-residue analysis of 80 compounds was performed using a modified QuEChERS method, followed by GC-ToF and LC-MS/MS. The analysis revealed that 95.7%, 72.3% and 58.6% of the honey, honey bee and pollen samples, respectively, were contaminated by at least one compound. The frequency of detection was higher in the honey samples (n = 28) than in the pollen (n = 23) or honey bee (n = 20) samples, but the highest concentrations were found in pollen. Although most compounds were rarely found, some of the contaminants reached high concentrations that might lead to adverse effects on bee health. The three most frequent residues were the widely used fungicide carbendazim and two acaricides, amitraz and coumaphos, that are used by beekeepers to control Varroa destructor. Apiaries in rural-cultivated landscapes were more contaminated than those in other landscape contexts, but the differences were not significant. The contamination of the different matrices was shown to be higher in early spring than in all other periods. CONCLUSIONS/SIGNIFICANCE: Honey bees, honeys and pollens are appropriate sentinels for monitoring pesticide and veterinary drug environmental pollution. This study revealed the widespread occurrence of multiple residues in beehive matrices and suggests a potential issue with the effects of these residues alone or in combination on honey bee health.

International audience; Three beehive matrices, sampled in eighteen apiaries from West France, were analysed for the presence of lead (Pb). Samples were collected during four different periods in both 2008 and 2009. Honey was the matrix the least contaminated by Pb (min = 0.004 μg g(-1); max = 0.378 μg g(-1); mean = 0.047 μg g(-1); sd = 0.057). The contamination of bees (min = 0.001 μg g(-1); max = 1.869 μg g(-1); mean = 0.223 μg g(-1); sd = 0.217) and pollen (min = 0.004 μg g(-1); max = 0.798 μg g(-1); mean = 0.240 μg g(-1); sd = 0.200) showed similar levels and temporal variations but bees seemed to be more sensitive bringing out the peaks of Pb contamination. Apiaries in urban and hedgerow landscapes appeared more contaminated than apiaries in cultivated and island landscapes. Sampling period had a significant effect on Pb contamination with higher Pb concentrations determined in dry seasons.

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International audience; Three beehive matrices, sampled in six different apiaries from West France, were analyzed for the presence of four polycyclic aromatic hydrocarbons (PAH4: benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene and chrysene). Samples were collected during four different periods in both 2008 and 2009. Honey samples showed the lowest levels of PAH4 contamination (min=0.03 μg kg(-1); max=5.80 μg kg(-1); mean=0.82 μg kg(-1); Sd=1.17). Bee samples exhibited higher levels of PAH4 contamination (min=0.32 μg kg(-1); max=73.83 μg kg(-1); mean=7.03 μg kg(-1); Sd=17.83) with a great dispersion of the concentrations due to four main events of high concentrations. Pollen samples showed only one major episode with the highest PAH4 concentration found (min=0.33 μg kg(-1); max=129.41 μg kg(-1); mean=7.10 μg kg(-1); Sd=22.28). The PAH4 concentrations found were significantly influenced by the landscape context for all beehive samples.

A reversed-phase high-performance liquid chromatographic method was developed to detect oxolinic acid in seawater, marine sediment, and japanese oyster (Crassostrea gigas). Seawater was analysed after filtration and centrifugation. Sediment and oyster tissues were respectively analysed after liquid-phase and solid-phase extraction. Linearity and precision were checked over the concentration range 0.05–2.50 μg/mL or μg/g. Limits of detection and determination were respectively 0.01 and 0.04 μg/mL or μg/g. Recoveries of oxolinic acid were 102.1% from seawater, 68.1% from sediment and 88.3% from oyster. Oxolinic acid concentrations in seawater, sediment and oyster spiked at 0.50 μg/mL or μ.g/g were stable at −20°C for 60 days.

International audience; One of the factors that may explain nowadays honeybees' colonies losses is the increasing presence of chemicals in the environment. The aim of this study is to obtain a global view of the presence of environmental contaminants in beehives and, develop a fast, cheap and sensitive tool to analyze environmental contaminants in apiarian matrices. A multi residue analysis was developed to quantify 80 environmental contaminants, pesticides and veterinary drugs, belonging to different chemical classes, in honeys, honeybees and pollens. It consists in a single extraction, based on a modified "QuEChERS method", followed by gas chromatography coupled with Time of Flight mass spectrometry (GC-ToF) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The "QuEChERS method" combines salting-out liquid-liquid extraction with acetonitrile and a dispersive-SPE clean up. It was adjusted to honey and especially to honeybee and pollen, by adding a small fraction of hexane in acetonitrile to eliminate lipids that interfere with mass spectrometry analysis. This method, combined with accurate and sensitive detection, allowed quantification and confirmation at levels as low as 10 ng/g, with recoveries between 60 and 120%. Application to more than 100 samples of each matrix was achieved for a global view of pesticide presence in the honeybee environment. Relatively high percentages of honeys, honeybees and pollens were found to be contaminated by pesticides used to combat varroa but also by fungicides like carbendazim and ubiquitous contaminants.

A rapid procedure for the quantitative determination of oxytetracycline (OTC) in seawater using high performance liquid chromatography is presented. The limits of detection and determination were respectively 0.01 μ g/ml and 0.05 μ g/ml (precision ± 10%) when injecting a 50 μ l sample of seawater. The mean recovery of OTC from the seawater was 91.9%. Also included is an experimental study of the OTC kinetics in seawater. Experimental shellfish farms were polluted by effuents containing OTC coming from an experimental fish farm located in a salt-marsh. The disappearance of OTC from seawater was faster in the fish farm than in the shellfish farms where two kinetic phases were observed; the first one with an average half-life of 30.27 h and the second one with a higher average half-life of 318.57 h. Only the first phase was studied because it was assumed that the second phase would be complicated by the disappearance of OTC occurring simultaneously with diffusion from the sediment and shellfish. The results varied between tanks because of the differences in temperature, light intensity and flow from one tank to another. Fourteen days after the end of the chemotherapy in the experimental fish farm, the average OTC concentration in seawater of the shellfish farms was 0.2 μ g/ml.

Anticoagulant rodenticides are commonly used to control rodent pests all over the world. These pesticides inhibit the vitamin K cycle in the liver, prevent blood clotting and cause death by hemorrhage. Despite the fact that they were intended for the control of commensal rodents, they may affect non target species, either directly by consumption of contaminated cereal-based baits, or indirectly by consumption of contaminated preys (secondary poisoning). Secondary poisoning of non target species by anticoagulant rodenticides has been confirmed in many mammals and birds species, such as mustelids, foxes and birds of prey (Shore et al., 1996; Berny et al., 1997; Birks 1998; Stone et al., 1999; Stone et al., 2003; Harding 2004; Fournier-Chambrillon et al., 2004). Nevertheless, poisoning of non target species by direct consumption of anticoagulant rodenticides in the form of contaminated baits is poorly documented. Loire Atlantique is a French department well known for its wetlands and marshes in which anticoagulant rodenticides are commonly used especially against coypus (Myocastor coypus) because of the damage to cereal fields, rivers and water ponds banks. The aim of this study was to estimate the exposure of raptors and waterbirds to anticoagulant rodenticides in Loire Atlantique.

The consequences of antibiotic use in aquatic integrated systems, which are based on trophic interactions between different cultured organisms and physical continuity through water, need to be examined. In this study, fish reared in a prototype marine integrated system were given an oxolinic acid treatment, during and after which the level of resistance to this quinolone antibiotic was monitored among vibrio populations from the digestive tracts of treated fish, co-cultured bivalves and sediments that were isolated on thiosulfate-citrate-bile-sucrose. Oxolinic acid minimum inhibitory concentration distributions obtained from replica plating of thiosulfate-citrate-bile-sucrose plates indicated that a selection towards oxolinic acid resistance had occurred in the intestines of fish under treatment. In contrast, and despite oxolinic acid concentrations higher than minimum inhibitory concentrations of susceptible bacteria, no clear evolution of resistance levels was detected either in bivalves or in sediments.

A large amount of oxolinic acid administered in freshwater fish farms reaches the environment. In order to allow environmental monitoring, an HPLC method to determine oxolinic acid in the bryophyte Fontinalis antipyretica was developed. Nalidixic acid was used as an internal standard. Oxolinic and nalidixic acids were extracted by cracking the bryophytes in liquid nitrogen with 0.1 M acid oxalic solution in ethyl acetate and a liquid-liquid clean up procedure was then performed. Mobile phase was a 0.02 M orthophosphoric acid aqueous solution-acetonitrile mixture (70:30, v/v). The stationary phase was 5 microm PuroSpher RP18e and quinolones were detected by fluorescence. The linearity, accuracy and precision of this method were demonstrated by a validation assay. The limits of detection and quantitation were 1 and 10 ng/g respectively. The linearity range was 10 to 500 ng/g. This method was applied to a 25 days experimental study performed with the bryophyte Fontinalis antipyretica.

A high-performance liquid chromatographic (HPLC) method for the determination of oxoclinic acid (OA) in the plasma of seabass (Dicentrarchus labrax) anaesthetized with 2-phenoxyethanol is described. The samples were extracted and cleaned up by a solid-phase extraction procedure using C18 extraction cartridges. After the eluent was evaporated, the dry residue was dissolved in 1/15 M phosphate buffer. OA was determined by using an isocratic HPLC method with UV detection at 340 nm. Seabass drug-free plasma samples were spiked with OA at 0.2, 1.0, 5.0 and 25.0 μg/ml. Validation of the method showed good precision and accuracy. The mean recovery was 92.2%, with a relative standard deviation lower than 5%. The quantification limit was 0.2 μg/ml. The method was tested on 300 plasma samples of OA-treated seabass.

Marine fish farms use many antibacterial agents to prevent or fight bacterial diseases. The major part of the orally supplied drugs reach the environment, either directly due to excessive feeding and reduced appetite of the cultured fish, or indirectly after passing through the fish. Some of the drugs entering the environment may be taken up by bivalves. Comparative contamination and decontamination of Japanese oyster Crassostrea gigas and blue mussel Mytilus edulis were studied when these bivalves were kept during 10 d in seawater containing oxytetracycline (OTC) or oxolinic acid (OA) at concentrations of 0.15 and 1.50 mg l(-1). After the 10 d exposure at the seawater concentrations of 0.15 and 1.50 mg l(-1), OTC and OA concentrations in bivalve tissues were respectively 0.09 to 0.16 and 0.70 to 1.40 mg kg(-1). OTC, which is in a large part bound to ions and organic molecules in seawater, was less absorbed by bivalves than OA and therefore contaminated their tissues less than did OA. However, OTC, whose binding to mineral and organic compounds of the bivalve tissues is stronger than OA, was eliminated more slowly from the bivalve tissues than OA. Differences of contamination and decontamination of the bivalve species may be related to some chemical properties of the antibacterial agents and to some anatomical and physiological specificities of the bivalve. The biotransformations of the antibacterials agents by the bivalves did not seem to play a prominent part in the contamination and decontamination of the bivalve tissues.

A reversed-phase high-performance liquid chromatographic method was developed to detect oxytetracycline (OTC) in three species of marine shellfish (Crassostrea gigas, Ruditapes philippinarum and Scrobicularia plana). Shellfish tissues were analysed after solid-phase extraction by using a mobile phase containing acetonitrile and 0.02 M orthophosphoric acid solution. The linearity and precision of the method were checked over the concentration range 0.100-1.500 micrograms/g. The limits of detection and determination of OTC were 0.040 and 0.100 microgram/g, respectively. The recovery of OTC from spiked shellfish tissues was 79.8%. The OTC concentration in oyster (Crassostrea gigas) spiked at 0.500 microgram/g and stored at -20 degrees C was stable for 6 weeks. The method was applied to a 21-day experimental study performed with oysters.

International audience; Oxolinic acid, flumequine, oxytetracycline, and florfenicol are antibiotics commonly used in farming. Because an important percentage of these antibiotics given to fish and cattle ends up, directly or indirectly, in the freshwater environment, suitable tools for the monitoring of these antibiotics are needed. A French river was chosen because of the location of four fish farms and a sewage plant on its main course. First, a passive monitoring program involving water, sediment, and autochthonous bryophytes was performed at 25 sampling sites tested once every three months for one year. Second, an active monitoring method was performed using moss bags for a one-month exposure period, both upstream and downstream of each potential source of antibiotics. Sediment and bryophyte samples, but not water samples, were found to be useful for monitoring environmental contamination by oxolinic acid, flumequine, oxytetracycline, and florfenicol. Sediments and bryophytes also appeared to be complementary media for dating the river's contamination by antibiotics. Data collected by both active and passive monitoring methods confirmed contamination of the river, mainly by flumequine and oxytetracycline, attributable to fish farming but also to terrestrial animal farming and perhaps human pharmaceuticals.

National audience; Emerging infectious diseases are becoming more and more important throughout the world. Emerging or reemerging infectious diseases are characterized by a high and rapid increase of their incidence and by the uncertainty about their exact impact on humans or on animals or on both in the case of zoonoses. In this paper, the conditions or << drivers >> of emergence and reemergence are presented and classifled according to three parameters: the environment, host(s) and pathogen. Two examples of emerging diseases are presented: the first one concerns SARS in humans with the identification of potential animal reservoirs and the second one concerns the bluetongue virus, which has emerged recently in ruminants in Europe. The early identification, control and prevention of emerging and reemerging infectious diseases lies not only with clinicians and public health experts, but importantly with veterinarians, animal scientists and wildlife ecologists; surveillance of perturbations in ecosystems and surveillance of the animal and human health continuum must be done at the local, national and international levels to ensure that we are well prepared for future emerging threats.; Les maladies infectieuses émergentes, qu’elles soient animales, humaines ou zoonotiques, sont devenues une composante essentielle dans le paysage sanitaire mondial. Qu’elles soient inconnues jusqu’alors pour les vraies émergences ou simplement qu’elles réapparaissent après plusieurs années voire des décennies de silence dans le cas des réémergences, les maladies infectieuses émergentes ou réémergentes sont caractérisées par une augmentation brutale de leur incidence et par une incertitude sur l’ampleur du phénomène. Dans cette revue, les conditions de l’émergence sont présentées et hiérarchisées en fonction des connaissances actuelles, selon que ces conditions soient liées à l’environnement, à l’hôte (ou les hôtes) ou à l’agent infectieux lui-même. Deux exemples sont présentés pour illustrer le propos : d’une part une maladie humaine nouvelle, le SRAS avec un ou des réservoirs animaux et une maladie strictement animale, la fièvre catarrhale ovine ou bluetongue apparue récemment en Europe. Face à ces émergences ou réémergences, les différents acteurs, chercheurs et autorités sanitaires, doivent s’organiser y compris au niveau mondial afin de prévenir ou au mieux de bien se préparer à ces émergences de maladies infectieuses.

Le réseau français REPAMO a été créé en 1992 pour répondre aux directives européennes relatives aux conditions de police sanitaire des animaux d’aquaculture et au contrôle de certaines maladies affectant les mollusques bivalves. Ses missions sont : 1) la surveillance des maladies à déclaration obligatoire présentes en France, 2) l’étude des mortalités anormales, 3) la surveillance du statut zoosanitaire des populations de mollusques sauvages ou cultivés. Le réseau REPANUI a été créé plus récemment pour répondre à des buts similaires, en insistant plus particulièrement sur le suivi de la santé des huîtres perlières en appui à la filière d’élevage polynésienne., Created in 1992, the French network REPAMO is in charge of the surveillance and monitoring of the mollusc health status along the French coast according to European legislation. The missions of the network are the following: (1) the surveillance of notifiable diseases present in France, (2) the study of abnormal mortalities, (3) the surveillance of health status of cultivated and natural mollusc populations. The more recent network REPANUI has similar goals mainly focused on the pearl oyster health status to support the oyster farming industry in French Polynesia.

Since the middle of the twentieth century, industrialization, growing urbanization, transports and agricultural practices let to an ecosystem overall contamination and to profound modifications in landscape structure and composition. Those major changes cause physiological and behavioral damages on organisms and have adverse effects on biodiversity. Honey bee (Apis mellifera) is in the central point of this problematic: 1/ bees colonies are recently dramatically declining both in Europe and USA, and 2/ bees are recognized as appropriate sentinels to assess the environmental contamination due to their physiological and biological characteristics. In this context, honeybees, honey and pollen sampled from West France, were analyzed to monitor their contamination and the presence in the environment of polycyclic aromatic hydrocarbons, lead, pesticides and veterinary drugs. Samples were collected in eighteen apiaries from different landscape context (urban, rural-grassland, rural-cultivated and island) during four periods (spring, early summer, middle summer, early autumn) over 2008 and 2009. Toxicological analysis results show different sensitiveness according to the environmental pollutant, the studied matrix, the period and the landscape context. Despite such differences, most often specific to each apiary, our study shows an overall contamination of beehive matrices in all landscapes and during all periods. Even if the measured concentrations are generally low, this xenobiotic pressure is added to, even increases, the effect of many other environmental stressors which threaten the survival of bees in general., Depuis la seconde moitié du XXème siècle, l’industrialisation, l’urbanisation croissante, les transports et les pratiques agricoles ont entraîné une contamination généralisée des écosystèmes et des modifications profondes dans la composition et la structure des paysages. Ces changements majeurs induisent des perturbations physiologiques et comportementales des organismes et ont des effets négatifs sur la biodiversité. L’Abeille mellifère (Apis mellifera) est au coeur de cette problématique : 1/ les colonies d’abeilles déclinent dramatiquement depuis quelques années en Europe et aux Etats-Unis, et 2/ les abeilles sont reconnues comme d’excellentes sentinelles pour évaluer la contamination environnementale grâce à leurs caractéristiques physiologiques et biologiques. C’est dans ce contexte, que des abeilles, du miel et du pollen récoltés dans l’Ouest de la France ont été analysés pour évaluer leurs contaminations et la présence dans l’environnement d’hydrocarbures aromatiques polycycliques, de plomb, de pesticides et de médicaments vétérinaires. Les échantillons ont été prélevés dans 18 ruchers de contextes paysagers différents (ville, bocage, culture et insulaire) sur 4 périodes (printemps, début d’été, milieu d’été et début d’automne) en 2008 et en 2009. Les résultats d’analyses toxicologiques mettent en évidence des sensibilités différentes en fonction du polluant environnemental, de la matrice étudiée, de la période de prélèvements et du contexte paysager. En dépit de ces différences, le plus souvent propres à chaque rucher, notre étude montre une contamination généralisée des matrices apicoles quels que soient le paysage et la période considérés. Même si les concentrations mesurées sont généralement faibles, cette pression par les xénobiotiques s’ajoute à, voire amplifie l’action des nombreux autres stresseurs environnementaux qui menacent la survie des abeilles en général.

Selon l’Office International des Epizooties (OIE) une maladie émergente désigne une maladie grave récemment reconnue, dont la cause peut, ou non, avoir déjà été établie, et qui est susceptible de se propager au sein d’une population ou entre des populations, par exemple à l’occasion d’échanges internationaux d’animaux aquatiques et/ou de produits d’animaux aquatiques. Si les maladies émergentes qui affectent la santé humaine ont été très étudiées, celles qui touchent les organismes marins et les organismes aquacoles d’intérêt économique en particulier sont en revanche peu documentées. C’est en restreignant l’émergence aux seules maladies infectieuses que seront présentés de façon non exhaustive quelques scénarios de l’émergence des maladies chez les organismes d’intérêt aquacole en les illustrant par trois exemples disponibles dans la littérature scientifique : l’un relatif à l’apparition d’un agent pathogène chez un nouvel hôte avec le cas de l’herpesvirus de la carpe Koï, l’autre à l’évolution d’un agent pathogène existant avec le cas de la vibriose à Vibrio nigripulchritudo sévissant dans les élevages de crevettes pénéides de Nouvelle-Calédonie et enfin le dernier lié à l’introduction d’un pathogène préexistant avec le cas de Bonamia ostreae infectant l’huître plate Ostrea edulis. Les causes d’émergence de maladies sont multiples et font intervenir de façon intercurrente l’agent pathogène, l’environnement, l’hôte ou les espèces hôtes et des facteurs anthropiques. Dans le milieu marin, ces causes sont bien souvent méconnues. Dans ce contexte le développement des réseaux de surveillance et des techniques de diagnostic revêtent un intérêt considérable afin d’anticiper, de prévenir et/ou d’intervenir sur l’émergence des maladies en limitant leur conséquences sanitaires, écologiques et politiques., According to the world organisation for animal health (OIE) an emerging disease is defined as a recently admitted serious illness, whose aetiology can, or not, have already been established, and which is likely to be propagated within a population or between populations, for example at the time of international exchanges of aquatic animals and/or products of aquatic animals. Even though the emerging diseases that affect human health have been much studied, those which affect marine organisms and species of aquaculture interest in particular are poorly documented. By restricting emergence to only infectious diseases, we aim at presenting in a non-exhaustive way some scenarios of the emergence of the diseases of aquacultured species by illustrating them with three examples available in the scientific literature: one relating to the appearance of a pathogenic agent in a new host with the case of the herpesvirus of the Koi carp, the other with the evolution of a pre-existing pathogenic agent with the case of shrimp vibriosis due to Vibrio nigripulchritudo in New Caledonia, and the last example relating to the introduction of one pathogenic pre-existing pathogen in an unscathed area with the case of Bonamia ostreae infecting the flat oyster Ostrea edulis. The causes of the emergence of diseases are multiple and implicate in an intercurrent way pathogenic agents, the environment, the host or host species and anthropogenic factors. In the marine environment, these causes are very often ignored. In this context, the development of zoosanitary surveillance networks and diagnostic tools present a considerable interest in order to anticipate, prevent and/or intervene on the emergence of the diseases by limiting their sanitary, ecological and political consequences.

National audience; In the last few years, the global increase of aquatic animal production and farmed species has been associated with an increase in the number and spread of infectious diseases. In 2002-2003, 62 cases of emerging diseases were reported in aquatic animals, two thirds in aquacultured species, mainly in Europe and Northern America. A disease is emerging when its incidence significantly increases in a given time, place and population. To emerge, a disease has to be introduced in a free zone or a free population, and animals must be exposed to favouring transmission factors. The risks of introducing new diseases are mainly associated to movements of infected animals (farmed or feral, dead or alive), contaminated farming gear or transport media, evolution of pathogens, and environmental factors-wild reservoirs, pollutants, climatic changes. Exposition factors allowing the emergence of an introduced disease include farming conditions, epidemiology of the diseases and movements of water and wild animals.; Au cours des dernières années, l’augmentation de la production aquacole et du nombre d’espèces aquatiques élevées au niveau mondial s’est accompagnée d’une augmentation du nombre et de la répartition des maladies infectieuses. En 2002-2003, 62 cas d’émergence de ma-ladies infectieuses chez des animaux aquatiques ont été rapportés, les deux tiers en élevage, principalement en Europe et en Amérique du Nord. Une maladie est dite émergente quand son incidence augmente significativement pour une population, un lieu et une période donnés. Pour émerger, une maladie doit d’abord être introduite dans une zone ou une population indemne, et les animaux être exposés à des facteurs favorisants sa transmission. Les risques d’introduction de nouvelles maladies sont principalement associés aux mouvements d’animaux infectés (sauvage ou d’élevage, vivants ou morts), au matériel d’élevage ou à des milieux de transport contaminés, à l’évolution des agents pathogènes eux-mêmes, et à des facteurs environnementaux : réservoirs sauvages, polluants, changements climatiques. Les facteurs d’exposition permettant l’émergence d’une maladie après son introduction sont liés aux conditions d’élevage, à l’épidémiologie des différentes maladies et aux mouvements d’eau et d’animaux sauvages.

National audience; Created in 1992, the French network REPAMO is in charge of the surveillance and monitoring of the mollusc health status along the French coast according to European legislation. The missions of the network are the following: (1) the surveillance of notifiable diseases present in France, (2) the study of abnormal mortalities, (3) the surveillance of health status of cultivated and natural mollusc populations. The more recent network REPANUI has similar goals mainly focused on the pearl oyster health status to support the oyster farming industry in French Polynesia.; Le réseau français REPAMO a été créé en 1992 pour répondre aux directives européennes relatives aux conditions de police sanitaire des animaux d’aquaculture et au contrôle de certaines maladies affectant les mollusques bivalves. Ses missions sont : 1) la surveillance des maladies à déclaration obligatoire présentes en France, 2) l’étude des mortalités anormales, 3) la surveillance du statut zoosanitaire des populations de mollusques sauvages ou cultivés. Le réseau REPANUI a été créé plus récemment pour répondre à des buts similaires, en insistant plus particulièrement sur le suivi de la santé des huîtres perlières en appui à la filière d’élevage polynésienne.

National audience; Les moteurs de l’évolution des agents pathogènes, qu’il s’agisse des espèces sensibles, des vecteurs animaux ou des effets environnementaux incluant la pollution et le réchauffement climatique sont difficiles à appréhender. Il est donc important de générer des connaissances sur l’épidémiologie des maladies infectieuses aquacoles pour lesquelles il est difficile de contrôler le milieu d’élevage. Les connaissances épidémiologiques ainsi acquises peuvent alimenter des modèles dynamiques de transmission de ces maladies. Un premier article (Renault et al) présente les facteurs de risques d’apparition et d’émergence des maladies en aquaculture. Il souligne l’importance de générer des données pour améliorer la connaissance des facteurs d’épidémiologie descriptive impliqués dans l’apparition et la diffusion de maladies dues à des agents infectieux, en s’intéressant notamment aux interactions entre l’hôte, l’agent pathogène et l’environnement. Dans ce cadre, le développement d’études portant sur les effets de polluants et de facteurs physico-chimiques liés aux changements globaux chez différentes espèces d’intérêt aquacole est considéré comme une priorité. Un second article (Thébault et al) décrit l’intérêt potentiel de la modélisation pour l’étude de maladies infectieuses chez les poissons et les mollusques. La formulation précise des questions posées par une maladie infectieuse ouvre la voie à des formes de modélisation dynamique intégrant les caractéristiques de population de l’agent pathogène et les effets des actions de maîtrise éventuellement mises en oeuvre. Parmi les retombées utiles de la modélisation, figurent l’évaluation anticipée des mesures de contrôle et l’identification en continu des lacunes pouvant subsister dans un corpus de données. Le manque de données issues aussi bien du terrain que de l’expérimentation est le principal frein au développement de tels modèles en infectiologie aquacole. Il ne faut évidemment pas attendre de la modélisation plus qu’elle ne peut donner. Néanmoins, l’expérience des élevages terrestres montre que la modélisation peut parfois contribuer à quelques améliorations, notamment en termes de gestion de la santé des élevages au quotidien ou d’aide à la décision.

L’amélioration de la santé des cheptels est une composante essentielle du développement durable des filières aquacoles. La sélection d’animaux résistants aux différents organismes pathogènes rencontrés en élevage est une des stratégies possibles, complémentaire des approches prophylactiques, médicamenteuses ou vaccinales qui sont parfois difficiles à mettre en œuvre. L’analyse de la littérature scientifique permet en effet de conclure qu’il existe, dans les espèces et populations de mollusques et de poissons, une variabilité génétique de la résistance potentiellement exploitable par sélection. Les conditions d’exploitation de ce potentiel sont analysées. Pour des caractères complexes comme la résistance aux maladies, la mise au point de « marqueurs » susceptibles de fournir de l’information sur la valeur génétique des individus sans recourir à l’épreuve par le pathogène serait une aide précieuse pour mettre la sélection en pratique. Les travaux et perspectives dans ce domaine sont présentés, et leurs répercussions sur les stratégies possibles d’amélioration génétique discutées dans le contexte des filières aquacoles françaises., Controlling health of livestock has become of considerable importance to the aquaculture industry. Selective breeding of animals with increased resistance to pathogens is likely to complete efficiently the use of drugs, vaccines or prophylactic approaches that may be difficult to implement. A review of the scientific literature shows that the prospect of selecting for increased resistance is quite hopeful in both molluscs and fish. Yet, selecting for disease resistance is hampered by the difficulty to measure the resistance of individuals. Prospects for the development of « markers » that would predict the genetic merit of individuals without pathogen challenge are presented. The breeding schemes that may be implemented for fish and molluscs in the French industry are discussed.

Les agents pathogènes présents dans les milieux aquatiques peuvent exercer leurs méfaits dans tous les types d’élevage et sur toutes sortes d’espèces vertébrées ou invertébrées. Leur diagnostic a longtemps été handicapé par le manque de connaissances taxonomiques relatives aux organismes d’intérêt médical ou vétérinaire, mais les progrès accomplis en ce domaine avec le développement des approches génétiques et moléculaires permettent de disposer désormais d’un arsenal de techniques adaptées à toutes les situations. Leur emploi est dicté par le contexte clinique, sanitaire, voire réglementaire dans lequel s’inscrit la demande et par la priorité accordée à l’identification ou à la détection des organismes pathogènes. La revue critique des techniques accessibles aux laboratoires permettra d’aborder les questions posées par l’évolution de la pathologie aquacole et d’envisager quelques réponses qu’il serait possible d’apporter., A great variety of pathogenic organisms present in the water may affect the vertebrate and invertebrate species cultured in different aquatic habitats. Compared to humans and terrestrial species, the diagnostic of aquatic animal diseases has long been hampered by scarce taxonomic knowledge about the relevant pathogens, but advances resulting from genetic and molecular developments has now resulted in a complete panoply of suitable techniques for this purpose. Choosing a diagnostic method should be done according to clinical, sanitary or officially prescribed considerations, and also according to the purpose of the procedure, should it be the correct identification or the detection of a pathogen. A critical overview of the techniques available of common use in diagnostic laboratories is presented. This will permit to discuss emergent problems resulting from the aquaculture transformation and to suggest some appropriate responses to these problems.

National audience; Les réseaux de surveillance des maladies infectieuses aquacoles constituent un excellent outil de gestion de ces maladies. Un premier article (Joly et al) présente la surveillance des maladies des mollusques par le biais de deux réseaux de surveillance, REPAMO (surveillance de l’apparition des maladies chez les coquillages des côtes françaises métropolitaines) et REPANUI (surveillance de l’apparition des maladies de l’huître perlière en Polynésie). De tels réseaux n’existent pas pour les poissons. Etant donné leur intérêt pour la gestion des élevages, l’Agence Française de Sécurité Sanitaire des Aliments (AFSSA) a décidé de mettre en place cette année un réseau de surveillance des maladies des poissons, qui bénéficiera de l’expérience des réseaux mollusques. Parmi les mesures de gestion des maladies infectieuses piscicoles, la vaccination est celle qui séduit le plus les professionnels de terrain. Un deuxième article (Quentel et al) dresse ainsi l’état des lieux des vaccins disponibles en pisciculture. La principale limite de la vaccination tient à la difficulté d’en garantir l’efficacité lors d’administration orale malgré des tentatives d’amélioration par microencapsulation. Par ailleurs, le nombre de vaccins disponibles est très limité en raison des investissements nécessaires pour obtenir une autorisation de mise sur le marché piscicole de taille réduite. Les autovaccins peuvent aussi être utilisés, notamment en situation d’urgence, même si leurs conditions de préparation sont réglementées. La sélection génétique d’animaux résistants est porteuse d’espoir, en particulier pour les animaux destinés à l’exportation. Un troisième article (Quillet et al) présente donc la génétique de la réponse aux pathogènes piscicoles. Néanmoins, cette sélection génétique soulève des questions, d’une part sur les éventuelles corrélations génétiques entre différentes maladies ou entre une maladie et d’autres caractères (par exemple, la résistance à la SHV montre une légère corrélation négative avec la croissance chez la truite), d’autre part sur la possibilité de mutation des agents pathogènes. Les probiotiques, les prébiotiques et les peptides antimicrobiens pourraient à terme et en partie se substituer aux antibiotiques, notamment pour des raisons d’image des élevages et des produits mais aussi par crainte de voir se développer des antibiorésistances dans les élevages. Un dernier article (Nicolas et al) souligne donc la nécessité de soutenir des études sur ce thème dans le double objectif, d’une part d’une meilleure compréhension de leurs effets sur le système immunitaire des animaux aquatiques, d’autre part de la détermination de leur innocuité pour les animaux cibles, le consommateur et l’environnement. Il faut également rappeler la nécessité de poursuivre des études sur l’utilisation raisonnée des antibiotiques, principal moyen thérapeutique à court et moyen terme contre certaines maladies infectieuses aquacoles, émergentes ou non.