Classical swine fever and avian influenza epidemics: lessons learned

Experience with recent large-scale epidemics of Classical Swine Fever and Avian Influenza--among others in the Netherlands--have teached us several lessons that should prepare us better for future outbreaks. Among others, improving early detection of outbreaks--by using syndrome surveillance systems--is a key factor, in which farmers and veterinary practitioners have an imminent role. A major step in this respect is facilitation of the use of exclusion diagnostics without closing down the farm in clinical situations with non-specific clinical signs observed in sick animals. The hesitance of farmers and veterinary practitioners to report a suspect clinical situation on a livestock farm and how to facilitate that process is another major issue. Furthermore, the importance of communication between the field and the laboratory with respect to post mortem examination will be highlighted, and the need for outbreak simulation exercises with neighbouring countries in order to be better prepared, will be discussed.     

Apatite Control of Phosphorus Release to Runoff from Soils of Phosphate Mine Reclamation Areas

This study was initiated to explore the effects of ozone (O₃) exposure on potted wheat roots and soil microbial community function. Three treatments were performed: (1) Air with daily averaged O₃ concentration of 4–10 ppb (control situation, CK), (2) Air plus 8 h averaged O₃ concentration of 76.1 ppb (O₃-1), and (3) Air plus 8 h averaged O₃ concentration of 118.8 ppb (O₃-2). In treatments with elevated O₃ concentration (O₃-1 and O₃-2), the root and shoot biomass were reduced by 25% and 18%, respectively, compared to the control treatment (CK). On the other hand, root activity was significantly reduced by 58% and 90.8% in the O₃-1 and O₃-2 treatments, respectively, compared to CK. The soil microbial biomass was significantly reduced only in the highest O₃ concentration (O₃-2 treatment) in the rhizosphere soil. Soil microbial community composition was assessed under O₃ stress based on the changes in the sole carbon source utilization profiles of soil microbial communities using the Biolog? system. Principal component analysis showed that there was significant discrimination in the sole-carbon source utilization pattern of soil microbial communities among the O₃ treatments in rhizosphere soil; however, there was none in the bulk soil. In rhizosphere soil, the functional richness of the soil microbial community was reduced by 27% and 38% in O₃-1 and O₃-2 treatments, respectively, compared to CK. O₃-2 treatment remarkably decreased the Shannon diversity index of soil microbial community function in rhizosphere soil, but the O₃-1 treatment did not. In the dominant microorganisms using carbon sources of carbohydrates and amino acids groups were significantly reduced by an elevated O₃ concentration in the rhizosphere soil. Our study shows that the elevated ozone levels may alter microbial community function in rhizosphere soil but not in the bulk soil. Hence, this suggests that O₃ effects on soil microbes are caused by O₃ detriments on the plant, but not by the O₃ direct effects on the soil microbes.     

Carbon,iron, and aluminum responses to controlled water table fluctuations in sandy soil material

Purpose

Seasonal fluctuating water tables are common in sandy coastal plain soils, but their role in soil organic carbon dynamics is uncertain. Seasonal saturation influences biogeochemical processes that affect fate of organic matter and metals. A column study was conducted to test hypotheses that shallow water table (SWT) fluctuations reduce CO₂ loss (H1), increase leaching of dissolved organic C (DOC) and metals (Al and Fe) (H2), and result in greater net soil C storage (H3).

Materials and methods

The A- and E-horizon material of moderately well-drained sandy soils from five sites was collected for the study. Ten columns (two per site) of 90-cm height were packed to a thickness of 60 cm with E-horizon material, above which was packed 15 cm of A-horizon material from the same soil. Five columns were subjected to SWT treatments and five to deep water table (DWT) treatments. Upward CO₂ flux was measured using a NaOH (1 M) trap. Metal and DOC-C concentrations in leachates and in water sampled at the surface of columns were measured. Soil samples from the columns were collected by depth at 5–6-cm increments and tested for total and organic C, metals, and <50-μm material distribution by WT treatment.

Results and discussion

Upward flux of CO₂ was significantly less for SWT treatment. Higher DOC (for all events) and Fe concentrations (for first 18 days) were measured in SWT leachates as compared to DWT. Metal- and C concentrations were correlated (P?<?0.0001) for surface pore water samples of SWT but not for DWT. Net loss of C was significantly less under SWT condition. Results indicate significant water-table effects on magnitude and direction of C flux (solution or gaseous) and <50-μm particle distribution for sandy coastal plain soils materials.

Conclusions

Changes in water table depth can potentially alter not only net soil C storage but also the proportion of C converted to CO₂ versus DOC. Differences in the proportion would have consequences for C dynamics in ecosystems dominated by soils with fluctuating water tables such as occur extensively in the coastal plain of the SE USA and elsewhere.

     

Scanning electron microscopic study of the dentinal tubules in dog canine teeth

Dentin adhesive restorative techniques are regularly used in veterinary dentistry. Knowledge of the microanatomic structure and properties of dentin is essential to ensure success in restorative procedures. The aim of this study was to describe the density and diameter of dentinal tubules in dog canine teeth using recently described standardized scanning electron microscopy techniques. The results showed dentin of dog canine teeth to be more oval-shaped with a higher tubular density and slightly larger tubular diameters compared with human teeth. These features suggest dog canine teeth have less intertubular dentin compared with human teeth, which may theoretically result in lower resin-dentin shear bond strengths.     

Creating wetland islands to enhance shoreline habitat for fish recruitment in a modified shallow lake

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Detection and quantification of classical swine fever virus in air samples originating from infected pigs and experimentally produced aerosols

During epidemics of classical swine fever (CSF), neighbourhood infections occurred where none of the 'traditional' routes of transmission like direct animal contact, swill feeding, transport contact or transmission by people could be identified. A hypothesized route of virus introduction for these herds was airborne transmission. In order to better understand this possible transmission route, we developed a method to detect and quantify classical swine fever virus (CSFV) in air samples using gelatine filters. The air samples were collected from CSFV-infected pigs after experimental aerosolization of the virus. Furthermore, we studied the viability of the virus with time in aerosolized state. Three strains of CSFV were aerosolized in an empty isolator and air samples were taken at different time intervals. The virus remained infective in aerosolized state for at least 30 min with half-life time values ranging from 4.5 to 15 min. During animal experiments, concentrations of 10(0.3)-10(1.6)TCID(50)/m(3) CSFV were detected in air samples originating from the air of the pig cages and 10(0.4)-10(4.0)TCID(50)/m(3) from the expired air of infected animals. This is the first study describing the isolation and quantification of CSFV from air samples originating from infected pigs and their cages, supporting previous findings that airborne transmission of CSF is feasible.