The recently discovered influenza D virus (IDV) of the Orthomyxoviridae family has been detected in swine and ruminants with a worldwide distribution. Cattle are considered to be the primary host and reservoir, and previous studies suggested a tropism of IDV for the upper respiratory tract and a putative role in the bovine respiratory disease complex. This study aimed to characterize the pathogenicity of IDV in naive calves as well as the ability of this virus to transmit by air. Eight naive calves were infected by aerosol with a recent French isolate, D/bovine/France/5920/2014. Results show that IDV replicates not only in the upper respiratory tract but also in the lower respiratory tract (LRT), inducing moderate bronchopneumonia with restricted lesions of interstitial pneumonia. Inoculation was followed by IDV-specific IgG1 production as early as 10 days postchallenge and likely both Th1 and Th2 responses. Study of the innate immune response in the LRT of IDV-infected calves indicated the overexpression of pathogen recognition receptors and of chemokines CCL2, CCL3, and CCL4, but without overexpression of genes involved in the type I interferon pathway. Finally, virological examination of three aerosol-sentinel animals, housed 3 m apart from inoculated calves (and thus subject to infection by aerosol transmission), and IDV detection in air samples collected in different areas showed that IDV can be airborne transmitted and infect naive contact calves on short distances. This study suggests that IDV is a respiratory virus with moderate pathogenicity and probably a high level of transmission. It consequently can be considered predisposing to or a cofactor of respiratory disease. IMPORTANCE Influenza D virus (IDV), a new genus of the Orthomyxoviridae family, has a broad geographical distribution and can infect several animal species. Cattle are so far considered the primary host for IDV, but the pathogenicity and the prevalence of this virus are still unclear. We demonstrated that under experimental conditions (in a controlled environment and in the absence of coinfecting pathogens), IDV is able to cause mild to moderate disease and targets both the upper and lower respiratory tracts. The virus can transmit by direct as well as aerosol contacts. While this study evidenced overexpression of pathogen recognition receptors and chemokines in the lower respiratory tract, IDV-specific IgG1 production as early as 10 days postchallenge, and likely both Th1 and Th2 responses, further studies are warranted to better understand the immune responses triggered by IDV and its role as part of the bovine respiratory disease complex. FIG 1 (A) Experiment timeline and sampling. D0 is the day of inoculation. (B)Fourteen naive calves were allocated to two separated pens, one with 5 mock-infected calves (control group) and the second with 11 calves. In the latter pen, calves were divided into two groups separated by steel panels, 3 m apart. Eight calves (direct-inoculated group) were inoculated at day 0 (D0) with 10 7 TCID 50 of IDV 5...

After fossil fuels, agricultural production and fisheries are industries with the largest impact on the environment in terms of greenhouse gas (GHG) emissions, especially in the production of ruminant meats such as beef, veal or lamb. In order to reduce this environmental impact, consumers can change their food consumption habits to utilize less polluting products such as white meats or vegetable food products. We analyze whether or not a CO 2 equivalent (CO 2-eq) tax policy can change consumer habits with respect to meat and marine purchases, and using different indicators, we examine the effect of such a tax policy on the environment. We also infer the implications of such a tax on nutritional indicators as well as on consumer welfare. First, to evaluate the impact of a variation in the price of meat and marine products on consumption, we estimate a random coefficients logit demand model using purchase data from the French household panel Kantar Worldpanel. We define 28 meat and marine products, and divide them into eight meat and marine product categories. This model allows us to estimate flexible own-and cross-price elasticities of meat and marine products' demand. Results on the consumer purchase behavior model suggest that the demands for these products are fairly inelastic, and substitutions occur both within and between categories for all products. Moreover, using two levels of a CO 2-eq tax (e56 and e200 per tonne of CO 2-eq per kilogram of product) applied to either all meat and marine products, only ruminant meats, or only beef, we show that a tax of e56 leads to a very small change in GHG emissions, even if all meat and marine products are taxed. The most efficient scenario would be to tax only the beef category at a high level since it would allow a 70% reduction in the total variation of GHG emissions, and would be responsible for only 20% of the consumer welfare damages generated when all products are taxed.

No abstract

In Southeast Asia, surveillance at live bird markets (LBMs) has been identified as crucial for detecting avian influenza viruses (AIV) and reducing the risk of human infections. However, the design of effective surveillance systems in LBMs remains complex given the rapid turn-over of poultry. We developed a deterministic transmission model to provide guidance for optimizing AIV surveillance efforts. The model was calibrated to fit one of the largest LBMs in northern Vietnam at high risk of low pathogenic H7N9 virus introduction from China to identify the surveillance strategy that optimizes H7N9 detection. Results show that (i) using a portable diagnostic device would slightly reduce the number of infected birds leaving the LBM before the first detection, as compared to a laboratory-based diagnostic strategy, (ii) H7N9 detection could become more timely by sampling birds staying overnight, just before new susceptible birds are introduced at the beginning of a working day, and (iii) banning birds staying overnight would represent an effective intervention to reduce the risk of H7N9 spread but would decrease the likelihood of virus detection if introduced. These strategies should receive high priority in Vietnam and other Asian countries at risk of H7N9 introduction.