Transmission of agents of the porcine respiratory disease complex (PRDC) between swine herds: a review. Part 2--Pathogen transmission via semen, air and living/nonliving vectors

The transmission of PRDC-pathogens (PRRSV, influenza virus A, PCV2, M. hyopneumoniae, A. pleuropneumoniae) between swine herds, which was summarized in the first part of the review, mainly occurs via pig movement. The risk of pathogen transmission by insemination with contaminated semen plays only a relevant role in the infection with PRRSV and PCV2. A risk of the aerogen transmission of pathogens between herds within a distance of 2 to 3 km is described for M. hyopneumoniae and PRRSV. Evidence for the other pathogens is not investigated. The PRDC-pathogens are frequently detected in wild boar populations. Therefore, the transmission between wild boars and domestic pigs seems possible by close contacts. PRRSV and M. hyopneumoniae can be transmitted by contaminated clothes and boots, but the use of sanitation protocols appears to limit their spread. Live vectors like rodents or birds seemed to have no special importance for the transmission of PRDC-pathogens.     

Endothelial–platelet interactions in influenza-induced pneumonia: A potential therapeutic target

Every year, influenza viruses spread around the world, infecting the respiratory systems of countless humans and animals, causing illness and even death. Severe influenza infection is associated with pulmonary epithelial damage and endothelial dysfunction leading to acute lung injury (ALI). There is evidence that an aggressive cytokine storm and cell damage in lung capillaries as well as endothelial/platelet interactions contribute to vascular leakage, pro-thrombotic milieu and infiltration of immune effector cells. To date, treatments for ALI caused by influenza are limited to antiviral drugs, active ventilation or further symptomatic treatments. In this review, we summarize the mechanisms of influenza-mediated pathogenesis, permissive animal models and histopathological changes of lung tissue in both mice and men and compare it with histological and electron microscopic data from our own group. We highlight the molecular and cellular interactions between pulmonary endothelium and platelets in homeostasis and influenza-induced pathogenesis. Finally, we discuss novel therapeutic targets on platelets/endothelial interaction to reduce or resolve ALI.     

Tree species admixture increases ecosystem service provision in simulated spruce- and beech-dominated stands

European Journal of Forest Research - Climate-adaptive forest management aims to sustain the provision of multiple forest ecosystem services and biodiversity (ESB). However, it remains largely...     

Schmallenberg virus—Two years of experiences

In autumn 2011, a novel species of the genus Orthobunyavirus of the Simbu serogroup was discovered close to the German/Dutch border and named Schmallenberg virus (SBV). Since then, SBV has caused a large epidemic in European livestock. Like other viruses of the Simbu serogroup, SBV is transmitted by insect vectors. Adult ruminants may show a mild transient disease, while an infection during a critical period of pregnancy can lead to severe congenital malformation, premature birth or stillbirth. The current knowledge about the virus, its diagnosis, the spread of the epidemic, the impact and the possibilities for preventing infections with SBV is described and discussed.     

Sublethal effects of ammonia in soft water on Atlantic salmon smolts at a low temperature

Atlantic salmon (Salmo salar L.) smolts were exposed to ammonia at 4 °C in an open flow system. The concentrations of un-ionized ammonia nitrogen (NH₃-N) and total ammonia nitrogen (TAN) were increased abruptly twice during a period of 28 days. For concentrations in the range 1–15 µgl^–1 un-ionized ammonia nitrogen (4.3–21.1 mgl^–1 TAN), no effects were observed on the smolts. However, plasma glucose was not measured in this range. The observed results for higher concentrations may be divided into two categories of sublethal effects. (1) In smolts exposed to the concentration range 19–37 µgl^–1 NH₃-N (average 26 µgl^–1 NH₃-N; 34.9–50.5 mgl^–1 TAN), the mean plasma glucose concentration was 1.3 times the mean of the control group. No other measured parameters were significantly altered. (2) For smolts exposed to 37–65 µgl^–1 NH₃-N (average 47 µgl^–1 NH₃-N; 57.7–84.5 mgl^–1 TAN), the mean plasma glucose concentration was increased to 2.3 times, the mean plasma chloride level was reduced to 0.9 times, and mean haematocrit was increased to 1.1 times the control values. Histological examination of the gill tissue revealed extensive lamellar hypertrophy. Weight, length, condition factor and ventilation frequency were not significantly affected and no mortality took place during the exposure period (1–65 µgl^–1 NH₃-N; 4.3–84.5 mgl^–1 TAN). Plasma glucose seemed to be the most sensitive parameter in detecting the sublethal stress response, and this investigation may thus demonstrate the importance of measuring plasma glucose in experiments concerning safe levels for ammonia.     

The importance of soil microbial activity for the supply of iron to sorghum and rape

It is generally accepted that soil microorganisms play an important role in producing siderophores which enhance the availability of soil Fe to higher plants. There is not much direct experimental evidence to support this supposition, however, because it is difficult to grow plants under sterile conditions over long periods. The object of this investigation was to test whether a sterile soil medium impairs Fe translocation from the soil to plant roots. The plant species selected are of agronomical importance, namely rape (Brassica napus L.) and sorghum (Sorghum bicolor L.). The latter a graminaceous species which is able to excrete phytosiderophores from the roots into the soil which allows Fe to be mobilized and transported to plant roots. Sorghum and rape were grown for 18 and 21 days, respectively, in a non-sterile soil (control) and in the same soil which was sterilized before plant cultivation. In a further treatment, the sterile grown rape plants were supplied with Fe EDDHA 1 week before harvest in order to test whether a poor growth of plants grown in the sterile soil was caused by an insufficient Fe supply. Plants cultivated on the sterile soil were significantly retarded in root and shoot growth. This was especially true for rape which produced very small leaves. Plants responded immediately to the Fe addition which induced a vigorous growth. This clearly shows that the poor growth in the sterile soil was caused at least in part by an insufficient Fe supply. In neither plant species was yellowing of young leaves observed as a symptom typical of insufficient Fe supply. From this follows that retardation of plant growth is a more sensitive indicator of an insufficient Fe supply than is yellowing of young leaves at least for rape and sorghum. This finding is of agronomical importance since a reduced growth because of insufficient Fe supply is much more difficult to identify as Fe deficieny than Fe chlorosis (yellow leaves). Iron concentrations in roots and leaves of the sterile grown plants were significantly lower than the corresponding concentrations in the non-sterile grown plants. From these findings it can be concluded that soil microbial activity is essential for Fe acquisition by soil-grown rape. Similarily, sorghum which is able to release siderophores from the roots, requires soil microbial activity to ensure satisfactory Fe supply.     

Pea starch meal as a substitute for cereal grain in diets for lactating sows: The effect on sow and litter performance

The major by-product from the production of pea protein concentrate is pea starch, and this starch can be an alternative source of starch compared to for instance starch from wheat in diets for pigs. However, differences in energy utilization between pea starch and cereal starch could affect the animals' production performance. In this study data from 100 Norwegian Landrace x Yorkshire sows was collected to investigate if inclusion of 20% pea starch meal (Pisum sativum L) in diets for lactating sows affected sow and litter performance. Two cereal grain based diets were formulated, but in one of the diets part of the wheat inclusion was replaced with pea starch meal. Data collection included registrations of sow daily feed consumption, individual weight and backfat measures, litter weights, measurement of blood glucose level after feeding and reproductive performance. Sows offered the pea diet had a higher average daily (P<0.0001), weekly (P<0.01) and total feed consumption (P<0.0001) during lactation. They also had a lower weight loss during the first three weeks of lactation (P<0.001). During the last two weeks of lactation sows in both groups were on average gaining weight, but the sows offered the control diet had the highest gain in this period (P<0.05). There was a tendency for a higher backfat loss in the pea group during the first three weeks of lactation (P=0.10), but no difference was found in overall backfat loss between treatments (P>0.05). Dietary treatment did not affect litter performance during lactation (P>0.05). The weaning-to-service interval was higher among the first parity sows offered the pea diet compared to the first parity sows offered the control diet (P<0.05). Blood glucose was not affected by dietary treatment within the chosen timeframe of this study (P>0.05). This study shows that pea starch meal can be used as an alternative source of starch in diets for lactating sows. The sows offered the pea diet had the highest feed consumption during lactation, and although this was not reflected in higher weaning weights, it was reflected in an improved body condition at weaning.     

Sensitivity of ecosystem goods and services projections of a forest landscape model to initialization data

Projections of indicators of forest ecosystem goods and services (EGS) based on process-based landscape models are critical for adapting forest management to climate change. However, the scarcity of fine-grained, spatially explicit forest data means that initializing these models is both a challenge and a source of uncertainty. To test how different initialization approaches influence the simulation of forest dynamics and EGS indicators we initialized the forest landscape model LandClim with fine resolution empirical data, coarse empirical data, and simulation-derived data, and evaluated the results at three spatial scales (stand, management area and landscape). Simulations were performed for a spruce (Picea abies) dominated landscape in the Black Forest, Germany, under current climate and a climate change scenario. We found that long-term (>150 years) projections are robust to initialization uncertainty. In contrast, shorter-term projections are sensitive to initialization uncertainty, with sensitivity increasing when EGS are assessed at smaller spatial scales, and when the EGS indicators depend on the spatial distribution of individual species. EGS dynamics are strongly influenced by interactions between the density, species composition, and age structure of initialized forests and simulated forest management. If EGS dynamics are strongly influenced by climate change, such as when climate change induces mortality in drought-sensitive species, some of the initialization uncertainty can be masked. We advocate for initializing landscape models with fine-grained data in applications that focus on spatial management problems in heterogeneous landscapes, and stress that the scale of analysis must be in accordance with the accuracy that is warranted by the initialization data.     

Effect of temperature on the life of soap bubbles, and their solidification at low temperature

Soap bubbles (also films on wire frames) have been solidified at low temperatures. At~-30 degrees C the bubbles still behave normally, that is, they can be expanded by blowing air into them and contract when the air is let out. At ~ -80 degrees C they become glassy, have very little surface tension, and cannot be blown up any more. At ~-120 degrees C they become completely solid. No further change is observed by cooling them to 90 degrees or 77 degrees K.