An outbreak of sheep-associated malignant catarrhal fever in sows

his paper describes a case of malignant catarrhal fever in a sow herd in Belgium caused by infection with ovine herpesvirus-2 (OHV-2). The 11 affected sows had high fever and 10 of them died within 3 days after the onset of clinical disease. The most prominent macroscopic lesion was a hemorrhagic to pseudo-membranous gastritis. Histopathology revealed severe infiltration and necrosis of the gastric mucosa. Neither antimicrobial treatment nor injection with anti-inflammatory drugs ameliorated the severity of the disease. As the sows and sheep were housed in the same building with the possibility of having direct nose-to-nose contact, and as PCR testing showed that the virus found in the sows was identical to that found in the sheep, it is very likely that the infection was transmitted from the subclinically infected sheep to the sows. The present case showed that OHV-2 infection should be included in the differential diagnosis when facing problems of fever followed by death, especially when pigs are housed in close contact with sheep

Detection of hepatitis e virus (HEV) antibiodies in swine herds in Québec, Canada

Hepatitis E virus (HEV) has a zoonotic potential and pork products have been identified as possible human infection sources. Swine HEV infection in pigs have now been reported in pigs in many countries and generally occurs at about 2-3 months of age. Data from USA indicated that about 80-100% of pigs in commercial farms are infected. The objective of this study was to estimate prevalence of HEV in selected Canadian herds by serology using the PrioCHECK HEV Ab porcine-ELISA kit

Observability of dynamical networks from graphic and symbolic approaches

A dynamical network, a graph whose nodes are dynamical systems, is usually characterized by a large dimensional space which is not always accesible due to the impossibility of measuring all the variables spanning the state space. Therefore, it is of the utmost importance to determine a reduced set of variables providing all the required information for non-ambiguously distinguish its different states. Inherited from control theory, one possible approach is based on the use of the observability matrix defined as the Jacobian matrix of the change of coordinates between the original state space and the space reconstructed from the measured variables. The observability of a given system can be accurately assessed by symbolically computing the complexity of the determinant of the observability matrix and quantified by symbolic observability coefficients. In this work, we extend the symbolic observability, previously developed for dynamical systems, to networks made of coupled $d$-dimensional node dynamics ($d>1$). From the observability of the node dynamics, the coupling function between the nodes, and the adjacency matrix, it is indeed possible to construct the observability of a large network with an arbitrary topology.Comment: 12 pages, 4 figures made from 12 eps file

Survival in water of Campylobacter jejuni strains isolated from the slaughterhouse

Campylobacter jejuni cause gastroenteritis in humans. The main transmission vector is the consumption or handling of contaminated chicken meat, since chicken can be colonized asymptomatically by C. jejuni. However, water has been implicated as the transmission vector in a few outbreaks. One possibility is the contamination of water effluent by C. jejuni originating from chicken farm. The ability of C. jejuni to be transmitted by water would be closely associated to its ability to survive in water. Therefore, in this study, we have evaluated the ability of reference strains and chickenisolated strains to survive in water. Defined water media were used, since the composition of tap water is variable. We showed that some isolates survive better than others in defined freshwater (Fraquil) and that the survival was affected by temperature and the concentration of NaCl. By comparing the ability of C. jejuni to survive in water with other phenotypic properties previously tested, we showed that the ability to survive in water was negatively correlated with autoagglutination. Our data showed that not all chicken isolates have the same ability to survive in water, which is probably due to difference in genetic content

Evolution of Salmonella excretion by sows during gestation in link with the faecal microbiome

Pork meat is estimated to be responsible of 10 to 20% of human salmonellosis cases. Control strategies at the farm could reduce contamination at the slaughterhouse. One of the targeted sector of the production is the maternity, where sows could be Salmonella reservoirs. The aim of this study was to characterize the faecal microbiome of sows excreting or not Salmonella during gestation phases. A total of 76 sows were selected and fecal matters were analysed at the beginning or the end of gestation period. Salmonella detection was conducted using a method including two selective enrichment media (MSRV and TBG). Nine (9) isolates per positive samples were collected. Among the 76 sows tested, 31 were shedding Salmonella. The sows in the first third of their gestation shed significantly more frequently Salmonella (22/29) than those in the last third (9/47) (χ² P \u3c 0.05). The shedding status of 19 of the sows that were previously sampled in the first third of their gestation was followed, this time in the last third, confirming reduction of the shedding. Association between changes in the intestinal microbiome and this evolution of Salmonella shedding will be explored. MiSeq sequencing is currently being conducted on the feces to identify shifts in the composition or diversity in the microbial community that could be associated to these variations. A large number of Salmonella isolates that were collected were genotyped by a high resolution melt (HRM) technique. These results showed the presence of a major HRM profile (136 isolates / 169) and two minor profiles (24 and 9 /169)

Feed size and texture influence propionic and butyric acid concentrations and Escherichia coli populations in the pig gastrointestinal tract

Natural approaches are now being considered to replace antimicrobials to reduce the risk of antimicrobial resistance development. This has put the new emphasis on using diet to control bacterial infections in pigs, some of which having recently demonstrated a zoonotic disease potential

Residual contamination detection and serovar distribution of Listeria monocytogenes isolates in pork slaughterhouse and cutting facilities in province of Quebec

L. monocytogenes (L. mono) is recognised as a zoonotic foodborne pathogen. Its control is focused on the “Readyto Eat” food production level. Recently, Health Canada had reinforced its “Policy on L. mono in Ready-to-Eat Foods”, highlighting environmental surveillance and control of meat processing facilities as important risk reduction tools. The industry wants to improve its management of L. mono risk, taking into account previous steps of meat production. Nowadays, few information are available on the presence, distribution and types of strains in the environments concerning this pathogen in pork slaughterhouses and cutting facilities in Canada. Our objective was to detect and described residual L. mono contamination and analyse serovars distribution in different areas in the pork production continuum in and between slaughterhouses and cutting facilities in province of Quebec, during a one year period. Such data are a pre-requisite to achieve the optimization of the management measures by the industrials

Digestive microbiota changes during application of an effective, feed presentation based, mitigation option against Salmonella shedding in pigs

If some studies have attempted to mitigate the Salmonella spp. excretion in pigs by feed related interventions, none clearly demonstrated the impact of the presentation (mash or pellet and particular size). Thus this study aimed to determine if the modification of the pigs feed presentation alone can lower the Salmonella spp. excretion

Molecular serotyping and virulence potential of Listeria monocytogenes isolated from bovine, swine and human in the province of Quebec

Listeria monocytogenes (L mono) cause rare but critical diseases, particularly for at risk population that include pregnant women. Food-borne origin of listeriosis is clearly recognised only since 1984. Since then, a great number of grouped cases occurred and milk or meat products, particularly pork meat, were implicated. Management of this zoonotic pathogen considers all strains as at equal risk. Recently a new perspective for characterisation of strain virulence was allowed since unaltered sequence of InlA was recognised as a key for strain virulence

Source-Term and building-Wake Consequence Modeling for the Godiva IV Reactor at Los Alamos National Laboratory

The objectives of this work were to evaluate the consequences of a postulated accident to onsite security personnel stationed near the facility during operations of the Godiva IV critical assembly and to identify controls needed to protect these personnel in case of an extreme criticality excursion equivalent to the design-basis accident (DBA). This paper presents the methodology and results of the source-term calculations, building ventilation rates, air concentrations, and consequence calculations that were performed using a multidisciplinary approach with several phenomenology models. Identification of controls needed to mitigate the consequences to near-field receptors is discussed