The "Friedrich-Loeffler-Institut": past, present and future of research in infectious diseases of animals

The Friedrich-Loeffler-Institut, founded in 1910 by Friedrich Loeffler, the discoverer of the first animal virus, foot-and-mouth disease virus, is the oldest virological research facility in the world. Beyond viruses, its area of competence has significantly expanded since its foundation and now also covers bacterial, parasitic and prion diseases of livestock, poultry and aquatic animals. Presently located at four sites within Germany (Insel Riems, Jena,Tübingen,Wusterhausen) the tasks of the institute as delineated in the Animal Disease Act encompass research on infectious animal diseases including zoonoses, import/export examinations, epidemiological studies in case of outbreaks of notifiable animal diseases, acting as reference laboratory for notifiable animal diseases and nationwide quality management of diagnosis of notifiable animal diseases. It is obliged to publish and maintain up-to-date diagnostic regimes for notifiable animal diseases, and it publishes a yearly report on animal health in Germany. With the increasing importance of infectious diseases of animals, in particular those potentially harmful to man (zoonoses), the Friedrich-Loeffler-Institut will be moving into new facilities including laboratories and animal facilities up to the highest biosafety level at its main site Insel Riems on the occasion of its 100th anniversary.     

Evaluation of the effectiveness of selected measures against bovine spongiform encephalopathy (BSE) in Switzerland by use of the basic reproduction ratio R0

The effectiveness of two measures against Bovine Spongiform Encephalopathy (BSE), the compulsory processing of animal by products to meat and bone meal (MBM) at 133 degrees C under 3 bars of pressure for 20 minutes in February 1993 and the exclusion of fallen stock, heads with eyes and spinal cord of cattle older than 30 month from MBM production in April 1996, was evaluated in a process model. The transmission of BSE by calculation of the basic reproduction ratio R0 was modelled.The results were verified by use of a cohort model, based on observed surveillance data. Prior to 1990, before the ban of feeding MBM to ruminants, R0, as calculated in the process model, was above 1, coherent with a slowly progressing BSE epidemic. Since 1991, values of R0 were low at 0.06.The corresponding R0 values derived from the cohort model were higher, the lowest value 0.13 calculated for 1996. Given such low R0 values, the epidemic should have died out. Additionally, no influence of the two measures was obvious at that time given the low level of R0. The discrepancy between the results of the two models is evidence for a dependency of the BSE epidemic from an infection source not considered in the process model. This infection source is most likely importation of feed ingredients and MBM.     

Physiological and biochemical parameters for egg quality determination in lake trout,Salmo trutta lacustris

The present study investigated the relationships between egg viability and ovarian fluid composition, egg physiology and egg metabolism in lake trout, Salmo trutta lacustris, to obtain biomarkers for egg quality determination. The ovarian fluid pH, protein levels and activities of aspartate aminotransferase and -d-glucuronidase were significantly correlated with egg viability expressed as the number of eyed stage embryos. Regression models demonstrated that an ovarian fluid pH between 8.44 and 8.57, protein levels below 235.56 mg 100 ml^–1ovarian fluid, aspartate aminotransferase activity below 31.65 m min^–1 l^–1ovarian fluid and -d-glucuronidase activity below 8.62 m min^–1 l^–1 ovarian fluid characterized egg batches with high viability (80%).The increase in the egg wet weight during water hardening was also significantly correlated with the number of eyed stage embryos, and egg batches with high egg viability (80%) increased in wet weight by 13% during water hardening.From the investigated metabolic parameters the number of eyed stage embryos was significantly correlated with activities of NADP-dependent isocitrate dehydrogenase (egg viability 80% at 2.07 nM min^–1 mg^–1 protein) and NAD-dependent malate dehydrogenase (egg viability 80% at 47.25 nM min^–1 mg^–1 protein), with the respiration rate (egg viability 80% at 8.71 nM min^–1 mg^–1 protein), with the ratio of NADH to NAD levels (egg viability 80% 0.872), with the levels of free, non-esterified fatty acids (egg viability 80% 72.34 g mg^–1 protein), and the ratio of non esterified to esterified fatty acids (egg viability 80% at 0.749). Also, subjective and visual control methods were described to distinguish between batches with viable and non viable eggs.     

Root growth and N‐uptake activity of oilseed rape (Brassica napus L.) cultivars differing in nitrogen efficiency

Nitrate‐N uptake from soil depends on root growth and uptake activity. However, under field conditions N‐uptake activity is difficult to estimate from soil‐N depletion due to different loss pathways. We modified the current mesh‐bag method to estimate nitrate‐N‐uptake activity and root growth of two oilseed‐rape cultivars differing in N‐uptake efficiency. N‐efficient cultivar (cv.) ‘Apex' and N‐inefficient cv. ‘Capitol' were grown in a field experiment on a silty clayey gleyic fluvisol near Göttingen, northern Germany, and fertilized with 0 (N₀) and 227 (N₂₂₇) kg N ha^–1. In February 2002, PVC tubes with a diameter of 50 mm were installed between plant rows at 0–0.3 and 0–0.6 m soil depth with an angle of 45°. At the beginning of shooting, beginning of flowering, and at seed filling, the PVC tubes were substituted by PVC tubes (compartments) of the same diameter, but with an open window at the upper side either at a soil depth of 0–0.3 or 0.3–0.6 m allowing roots to grow into the tubes. Anion‐exchange resin at the bottom of the compartment allowed estimation of nitrate leaching. The compartments were then filled with root‐free soil which was amended with or without 90 mg N (kg soil)^–1. The newly developed roots and nitrate‐N depletion were estimated in the compartments after the installing period (21 d at shooting stage and 16 d both at flowering and grain‐filling stages). Nitrate‐N depletion was estimated from the difference between NO ‐N contents of compartments containing roots and control compartments (windows closed with a membrane) containing no roots. The amount of nitrate leached from the compartments was quantified from the resin and has been taken into consideration in the calculation of the N depletion. The amount of N depleted from the compartments significantly correlated with root‐length density. Suboptimal N application to the crop reduced total biomass and seed‐yield formation substantially (24% and 38% for ‘Apex’ and ‘Capitol’, respectively). At the shooting stage, there were no differences in root production and N depletion from the compartments by the two cultivars between N₀ and N₂₂₇. But at flowering and seed‐filling stages, higher root production and accordingly higher N depletion was observed at N₀ compared to N₂₂₇. Towards later growth stages, the newly developed roots were characterized by a reduction of root diameter and a shift towards the deeper soil layer (0.3–0.6m). At low but not at high N supply, the N‐efficient cv. ‘Apex’ exhibited higher root growth and accordingly depleted nitrate‐N more effectively than the N‐inefficient cv. ‘Capitol’, especially during the reproductive growth phase. The calculated nitrate‐N‐uptake rate per unit root length was maximal at flowering (for the low N supply) but showed no difference between the two cultivars. This indicated that the higher N‐uptake efficiency of cv. ‘Apex’ was due to higher root growth rather than higher uptake per unit of root length.     

Effects of transdermal lidocaine or lidocaine with prilocaine or tetracaine on mechanical superficial sensation and nociceptive thermal thresholds in horses

Objective

To evaluate the transdermal local anaesthetic effect of lidocaine or lidocaine combined with prilocaine or tetracaine in horses.

Zur räumlichen Verteilung und Gestaltung von Erholungswäldern

Summary One of the essential aims of land planning is to satisfy the people's need for recreation. For this purpose it seems to be efficient to differentiate between “local” recreation and “long-distance” recreation areas and to consider them separatly in regional planning. To determine the location of recreational forests we need appropriate aids for decision making. Therefore activities that bring about deterioration of natural conditions, e.g. water pollution, soil erosion etc., as well as injuries to the optical value of the landscape, are not allowed in natural recreational areas. On the other hand it is possible to delimit forests after an analysis of stand composition and also by interpretation of maps giving the physiological effects of the climate. Above all the habits of the people are of importance, especially when they are based on irrational motives. These factores are of great importance in addition to the sociological conditions of an area and therefore do not allow the organization of long-distance recreation areas from simply a regional point of view. In the case of areas designed for local recreation, however, it might be sufficient to appraise the demands of the people through a regional analysis.

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Herrn Professor Dr. Dr. h. c.Julius Speer zum 65. Geburtstag gewidmet.     

Rundschau

Ohne Zusammenfassung     

Elektronische Datenverarbeitung in der Forstwissenschaft

Zusammenfassung In der Forstwissenschaft gewinnen neben der herk?mmlichen elektronischen Datenverarbeitung die zahlreichen Formen fortentwickelter automatisierter Datenverarbeitung zunehmende Bedeutung. Wichtigste Voraussetzung für ihre Anwendung ist, da? Rechenanlagen mit ausreichender Maschinenkonfiguration und leistungsf?higem Betriebssystem zur Verfügung stehen und eine angemessene Programmversorgung gew?hrleistet ist, was heute i. d. R. vorausgesetzt werden kann. Daneben mu? eine Reihe personeller und finanzieller Mindestvoraussetzungen geschaffen sein. Die Programmversorgung für die Datenverarbeitung in der Forstwissenschaft der Bundesrepublik stützt sich im wesentlichen auf Programm-Bibliotheken der internationalen EDV-Benutzungsorganisationen und auf Programmquellen aus dem engeren Bereich der mathematischen Statistik, in jüngster Zeit auch zunehmend auf Programmbest?nde forstlicher Fachinstitute des Auslandes und auf eigene Programmentwicklungen. Die vielf?ltigen Einsatzm?glichkeiten der elektronischen Datenverarbeitung in der Forstwissenschaft werden an Beispielen aus der Holzvorratsinventur und Stichprobensimulation, der Ertragstafelforschung, Planungs- und Optimierungstechnik sowie am Beispiel eines neuen ?kologischen Forschungsprojektes dargestellt. Abschlie?end wird auf einige Aussagegrenzen hingewiesen, die bei Auswertung und Interpretation von Datenverarbeitungsergebnissen zu beachten sind. Herrn Professor Dr.E. Assmann zu seinem 65. Geburtstag in Verehrung gewidmet.