Horizontal transmission of Mycobacterium avium subsp. paratuberculosis in cattle in an experimental setting: calves can transmit the infection to other calves

In September 2001, two subsequent transmission experiments both lasting 3 months were carried out to study cow-calf transmission of Mycobacterium avium subsp. paratuberculosis (Map) (Period 1), followed by calf-calf transmission of the infection (Period 2). Every 2 weeks, serum, heparinised blood and faecal samples were collected from all animals. After these experiments, the 20 calves were housed individually for more than 3 years to be able to detect the infection status and excretion pattern of each animal. In autumn 2004, the animals were inseminated, to observe a possible increase in faecal excretion of Map shortly before expected calving. One month before the expected calving date in 2005, animals were slaughtered and several tissues per cow and unborn calf were sampled for culture. The results indicate that horizontal cow-calf transmission is readily achieved (Period 1). At the highest infection pressure (six shedding cows of which three high shedders in Period 1) all five calves excreted Map in their faeces during Period 1 (shortly after infection), and four of these calves during Period 2 (when the shedding cows were absent). After that, excretion became less frequently. Horizontal calf-calf transmission did take place (Period 2), as the four donor-calves infected two receiver-calves. Transmission rates during the 3 months periods were quantified as a reproduction ratio R. The R [95% CI] of cow-calf and calf-calf transmission were estimated as 2.7 [1.1, 6.6] and 0.9 [0.1, 3.2] new infections per infectious animal during 3 months.     

The Impact of Atmospheric Deposition of Non-Acidifying Substances on the Quality of European Forest Soils and the North Sea

In the pilot study ESQUAD the impact of atmospheric deposition of three heavy metals (cadmium, copper and lead) and two persistent organic pollutants (benzo(a)-pyrene and lindane) on the quality of European soils and seawater has been calculated. Calculations have been made of atmospheric transport and deposition using a detailed emissions database for Europe. This enabled deposition maps to be produced to a resolution of approximately 50 km. The distribution of pollutant concentrations in forest soils was calculated for each grid cell using a database of soil property parameters in Europe. For the North Sea, a model was used to map long-term concentrations in water and sediment, which are due to atmospheric deposition and other, non-atmospheric sources. The model calculations allowed detailed comparisons of deposition fluxes and concentrations of the substances studied with critical loads and environmental quality threshold values, including critical loads. Although significant uncertainties were identified, the study gives insight in how threshold exceedance rates in Europe relate to pollutant type, threshold type, environmental compartment and chemophysical phase (adsorbed, dissolved). For all pollutants and for all compartments exceedances were calculated for at least some of the quality thresholds that were chosen.     

Use of fiber interface direct mass spectrometry for the determination of volatile flavor release from model food systems.

Described in this paper is a fiber interface direct headspace mass spectrometric system for the real-time measurement of flavor release. The system was optimized for the detection of the garlic aroma volatile, diallyl disulfide, from water. Parameters investigated included interface temperature, flow rate through the fiber, flow rate through the sample vessel, and sample stir rate. The delay time for detection of sample after introduction into the sample vessel was determined as 43 s. The system proved to be reliable and robust with no loss in sensitivity or contamination of the mass spectrometer over a 6 month period. The technique was applied to a homologous series of aliphatic alcohols from C(2) to C(7). Results showed that as polarity decreased with increasing chain length the release of volatile into the headspace was faster and gave a higher maximum intensity. Release of the garlic aroma volatile from different commercial mayonnaise products clearly showed a decrease in the release of diallyl disulfide as fat content increased. These results demonstrate the potential of using this technique as a tool for understanding the complex interactions that occur between flavor compounds and the bulk food matrix.     

Defining output-based standards to achieve and maintain tuberculosis freedom in farmed deer, with reference to member states of the European Union

Within the European Union (EU), detailed legislation has been developed for cattle, but not deer, to minimise disease risks associated with trade in animals and animal products. This legislation is expressed as input-based standards, providing a detailed outline of the activity required (for example, testing of animals and application of defined control measures), on the expectation that an adequate output (for example, confidence in freedom) will be achieved. Input-based standards are at odds with the increasing shift towards output-based standards, particularly in OIE rules governing international trade. In this paper, we define output-based standards to achieve and maintain freedom from tuberculosis (TB) in farmed deer, with reference to EU member states. After considering the probability of freedom achieved for cattle under existing EU legislation, we defined a ‘free farmed deer holding’ as one with a probability of freedom from infection of at least 99%. We then developed an epidemiological model of TB surveillance systems for deer holdings, incorporating different surveillance strategies, including combinations of diagnostic tests, and a variety of different scenarios relating to the potential for introduction of infection. A range of surveillance strategies were identified to achieve and maintain a free farmed deer holding, and worked examples are presented. The surveillance system sensitivity for varying combinations of screening and confirmatory tests in live animals, animals at slaughter and on-farm deaths is also presented. Using a single test at a single point in time, none of the TB tests routinely used in farmed deer is able to achieve an acceptable probability of TB freedom. If repeat testing were undertaken, an acceptable probability of TB freedom could be achieved, with differing combinations of the surveillance system sensitivity, frequency of testing and risk of introduction. The probability of introduction of infection through the importation of infected deer was influenced by the use of a pre-movement test (assumed 90% test sensitivity and negative test results), the TB prevalence in the source herd and the number of animals imported. A surveillance system sensitivity of at least 81% was achieved with different combinations of annual live animal surveillance and surveillance of animals at slaughter or on-farm deaths. This methodology has broad applicability and could also be extended to other diseases in both deer and other species with relevance to trade in animals and animal products.     

An Evaluation of the Loss-on-Ignition Method for Determining the Soil Organic Matter Content of Calcareous Soils

The Loss-on-Ignition (LOI) method is widely employed for measuring the organic matter (OM) content of soil samples. There is a risk of carbonate losses when calcareous soil samples are analyzed through LOI, but this has never been investigated in detail. Moreover, a worldwide standard protocol for determining the carbonate content of soils is not available. The aims of this study were (i) to evaluate two commonly employed carbonate analysis procedures using calcareous and non-calcareous soil samples: the gravimetric method with (GMF) and without (GM) the addition of the antioxidant iron(II) chloride (FeCl₂) and the acetic acid dissolution procedure (AAD); (ii) to evaluate the effect of ignition temperature on losses of pure calcite, calcite-quartz and calcareous soil samples. We found that the average apparent carbonate content of the non-calcareous soils was greatest for the GMF method followed by the AAD procedure. The GM method showed the smallest apparent carbonate contents. For the calcite-quartz sand mixture, ignition losses started at 600°C and increased with temperature in a sigmoidal way. LOI values stabilized at 750°C when 80% of the carbon dioxide was released. We recommend the GM procedure for carbonate analysis because the apparent carbonate contents of the non-calcareous soil samples were smallest. Furthermore, we recommend an LOI temperature of 550°C because at this ignition temperature 99.8% of the total calcite fraction remains in the soil samples.     

Ferric pseudobactin 358 as an iron source for carnation

The influence of the siderophore produced by plant growth‐promoting Pseudomonas putida strain WCS358, pseudobactin 358 (PSB358), on chlorophyll synthesis and iron(III) reduction in carnation cultivars Lena and Pallas grown in hydroponics was studied. Ferric pseudobactin 358 (4 μM) stimulated chlorophyll synthesis in cv. Lena, but not in cv. Pallas. FeEDDHA stimulated chlorophyll synthesis in both cultivars. Differences between the two carnation cultivars in the utilization of FePSB358 as an iron source are correlated with differences in iron efficiency reactions of the two cultivars: Fe‐deficient plants of cv. Lena produced more and longer root hairs than Fe‐deficient plants of cv. Pallas, and the ferric reducing activity of cv. Lena was higher than that of cv. Pallas.