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Influenza D virus (IDV) has first been identified in 2011 in the USA and was shown to mainly circulate in cattle. While IDV is associated with mild respiratory signs, its prevalence is still unknown. In the present study we show that IDV has been circulating throughout France in cattle and small ruminants, with 47.2% and 1.5% seropositivity, respectively. The high prevalence and moderate pathogenicity of IDV in cattle suggest that it may play an initiating role in the bovine respiratory disease complex.

A study was carried out to assess the efficacy of vaccination, using a phase I Coxiella burnetii-inactivated vaccine (Coxevac®; CEVA), within three goat herds experiencing Q fever abortions waves. The stratification of the population (n = 905) was based on parity and on infection status related to both serological and qPCR vaginal shedding results. Control (n = 443) and vaccinated (n = 462) groups were established in each farm. Vaccination was administered to does before mating and to kids after active immunity acquisition (at least 3–4 months old). The vaccine effectiveness was analyzed at subsequent farrowing on both clinical incidence and vaginal shedding at the delivery day. Among the 231 animals considered as susceptible, that is, seronegative nonshedders, about 90% were infected whatever the group, showing that vaccination did not prevent infection under high infection exposure. Fortunately, vaccination induced an overall decrease in shedding levels. A significant average difference between groups was estimated to 1.16 log(10) bacteria per swab for primiparous and even higher (1.81 log(10)) for initially susceptible ones. Thus, in a clinical context, vaccination should be implemented first in renewal animals. Indeed, young animals are those which best respond to vaccination by significantly reducing C. burnetii burden and, conversely, which excrete bacteria most massively if not vaccinated.

This study, carried out in three goat herds, was aimed at describing individual responses to Q fever infection in an abortive context, focusing on both antibody and shedding levels. Seroprevalence of Coxiella burnetii (Cb) infection and vaginal shedding of 1083 goats were investigated using ELISA and realtime qPCR assays, respectively. At the end of the outbreaks, a seroprevalence of 45.0% was found, and vaginal shedding appeared massive with levels above 10(4) Cb per swab in 42.3% of the whole population and above 10(6) Cb per swab for 90.9% of aborted goats. Susceptible animals (i.e. seronegative nonshedders) were unfrequent (31.2%), most of them being kids (94.7%). Seronegative females were predominant among nonshedders and conversely seropositive ones, predominant among high shedders (above 10(6) Cb per swab). Nevertheless, at least 43.3% of seronegative goats shed bacteria confirming the need of interpreting serology on a herd scale. The subsequent farrowing period was characterized by a significant reduction in the number of clinical cases. Females that had already aborted were more often involved than others. Shedding quantities remained high, particularly for primiparous does, mainly when facing infection for the first time. Thus, Q fever control must be based on both preventive measures directed to the preherd and environmental precautions.

A study was carried out, from 2012 to 2015, in 10 French départements to estimate the serological prevalence of Q fever and the frequency of abortive episodes potentially related to Coxiella burnetii in a large sample of cattle, sheep and goat herds. The serological survey covered 731 cattle, 522 sheep and 349 goat herds, randomly sampled. The frequency of abortive episodes potentially related to C. burnetii was estimated by investigating series of abortions in 2695 cattle, 658 sheep and 105 goat herds using quantitative polymerase chain reaction analyses and complementary serological results when needed. The average between-herd seroprevalence was significantly lower for cattle (36·0%) than for sheep (55·7%) and goats (61·0%) and significantly higher for dairy herds (64·9% for cattle and 75·6% for sheep) than for meat herds (18·9% for cattle and 39·8% for sheep). Within-herd seroprevalence was also significantly higher for goats (41·5%) than for cattle (22·2%) and sheep (25·7%). During the study period, we estimated that 2·7% (n = 90), 6·2% (n = 48) and 16·7% (n = 19) of the abortive episodes investigated could be 'potentially related to C. burnetii'in cattle, sheep and goat herds, respectively. Overall, strong variability was observed between départements and species, suggesting that risk factors such as herd density and farming practices play a role in disease transmission and maintenance.

La fièvre Q est une zoonose provoquée par la bactérie intracellulaire Coxiella burnetii, transmise à l'homme par inhalation de poussières ou d'aérosols contaminés. Les ongulés domestiques (chèvres, moutons, bovins) représentent le principal réservoir de C. burnetii, même si d'autres mammifères tels que les chiens, les chats et les lapins sauvages ont pu être impliqués dans la transmission de la bactérie. Chez les espèces de ruminants, l'avortement est la principale manifestation clinique, d'où une surveillance importante de cette maladie par le laboratoire vétérinaire départemental, parallèlement à la surveillance des avortements d'origine brucellique. L'épidémio-surveillance de la fièvre Q, à laquelle participent officiellement les collectivités territoriales par l'intermédiaire des laboratoires départementaux, s'exerce soit par recherche indirecte de l'infection, le plus souvent par la méthode ELISA, soit de plus en plus souvent, par sa mise en évidence directe, notamment par l'usage de la PCR. Le personnel des laboratoires départementaux, comme tous les professionnels des filières agricoles et vétérinaires, doivent prendre la mesure des précautions à mettre en oeuvre pour éviter toute contamination humaine lors de l'exposition à des échantillons de diagnostic parfois fortement contaminés.

No abstract

Les laboratoires départementaux d'analyses ont été créés pour répondre prioritairement aux contrôles officiels commandés par l'État. Transférés aux conseils départementaux (ex -généraux), ils assurent aujourd'hui une large mission d'épidémiosurveillance sur le territoire français dans les domaines de la santé animale, hygiène alimentaire, santé des végétaux et surveillance sanitaire des produits de la mer. Leur indépendance, leur répartition sur l'ensemble du territoire, et leur haut niveau d'expertise analytique sont des garanties de réactivité et d'expertise en matière de sécurité sanitaire. À ce titre, ils contribuent largement au maillage sanitaire français dont bénéficient les acteurs des filières de production, grâce au soutien financier des collectivités locales qui assurent ainsi leurs missions d'épi-démiosurveillance. Afin de pérenniser ce réseau remarquable, il conviendrait de définir le périmètre d'activités de service public des laboratoires départementaux dans un Service d'Intérêt Économique Général (SIEG) établi à partir d'une commande mixte État -Collectivités. Mots