A long-term serological survey on Aujeszky's disease virus infections in wild boar in East Germany.

Between 1985 and 2008, a total of 102,387 wild boar sera originating from Eastern Germany covering an area of 108 589 km2 were tested for the presence of Aujeszky's disease virus (ADV)-specific antibodies. From 1985 until 1991 and from 1992 until 2008, wild boar sera were exclusively investigated using either conventional seroneutralization assays (n=39 621) or commercial gB and full antigen ELISAs (n=62,766), respectively. Spatial-temporal analysis revealed an increasing ADV seroprevalence from 0·4% to 15·9%, on average, during the 24-year observation period that went along with a continuous spread of the infection in a western direction. During 2006 and 2008, 18% of the 66 affected districts had ADV seroprevalences >30%. There was a significant correlation between ADV seroprevalence and the hunting index of population density (HIPD) of wild boar in the entire study area, although this did not hold true for some regions. Seroprevalences did not differ between sexes but were age-dependent. East Germany has been officially free of Aujeszky's disease (pseudorabies) in domestic pigs since 1985. Although a risk for domestic pigs cannot be completely ruled out, experience has shown that ADV in domestic pigs could be eliminated although the virus was present in the wild boar population. Despite increasing ADV seroprevalence in the East German wild boar population no spillover infections from wild boar to domestic pigs have been reported. To further trace ADV infections in the wild boar population in Germany, a nationwide serological monitoring programme should be implemented.

Retrospective serological survey on selected viral pathogens in wild boar populations in Germany.

The objective of this study was to retrospectively evaluate the occurrence of porcine parvovirus (PPV), Aujeszky's disease virus (ADV), transmissible gastroenteritis virus (TGEV), porcine respiratory coronavirus (PRCV), porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV) in selected wild boar populations in Germany (n = 1,221). Commercial enzyme linked immunosorbent assay and hemagglutination inhibition tests were used for serological monitoring. The serosurvey revealed seroprevalence rates of 64.28%, 11.26%, 7.87%, 7.84%, 3.82% and 1.59% for PPV, ADV, PRCV, SIV, PRRSV and TGEV, respectively. The seroprevalence rates differed between populations and age classes with the highest number of antibody-positive wild boars in older animals (>1 year old). No antibodies to TGEV were found in Baden-Wuerttemberg and in Mecklenburg-Western Pomerania (investigation period 1997/1998). In addition, sera collected in Mecklenburg-Western Pomerania in 1997/1998 were negative for SIV. Even though the seroprevalence rates established for these viruses, except for PPV, were relatively low, wild boars may act as a reservoir for pathogens and a source of infection for domestic pigs and humans. Based on the epidemiological situation, no risk of a spread of these viruses should emanate from wild boars, neither for wildlife nor for livestock. However, effective and science-based disease monitoring programmes should continuously be carried out in wild boar populations.

Diagnostic procedures after completion of oral immunisation against classical swine fever in wild boar.

The purpose of this paper is to define diagnostic procedures for wild boar after the completion of oral immunisation against classical swine fever (CSF). Epidemiological analysis of CSF in wild boar in Germany demonstrated that it is vital to carry out virological investigations on all animals found dead, sick or involved in traffic accidents. In principle, this should ensure an effective and prompt diagnosis of CSF. In addition, a defined number of wild boar, especially young animals < or = 6 months old, should also be tested for CSF virus to guarantee a high confidence level in the virological monitoring. Which animals should be examined serologically depends on the age class investigated, the season in which vaccination was stopped and the period of time since completion of vaccination. Therefore, different serological procedures have been defined for different situations during the first three years after completion of oral immunisation.

Monoamine abnormalities in the brain of scrapie-infected rats.

The effects of the scrapie agent on the levels of monoamines and their metabolites, and on choline acetyltransferase (CAT) activity have been investigated in discrete brain areas in the rat. Two strains of scrapie (8745 from sheep brain and C506 M3 from mice brain) were inoculated. Scrapie-infected rats showed a reduction in the levels of serotonin (prefrontal cortex, hippocampus, striatum) and dopamine (striatum) and an elevation of 5-HIAA levels (cerebral cortex, striatum, thalamus). Noradrenaline levels were decreased only in the cerebral cortex and cerebellum of rats infected with the scrapie strain C506 M3. CAT activity remained unchanged. These data suggest that the scrapie agent causes a derangement of noradrenergic, serotonergic and dopaminergic systems in the rat brain.

Alterations of noradrenaline and serotonin uptake and metabolism in chronic cobalt-induced epilepsy in the rat.

The high affinity uptake of noradrenaline and serotonin, and the concentrations of these monoamines and their metabolites, have been measured in the perifocal cortical area at various stages of the evolution of cobalt-induced epilepsy in the rat. Noradrenaline uptake was maximally reduced at days 8-10 after cortical cobalt application, a time corresponding to the onset of epileptic discharges; it remained diminished during the spiking activity period of the focus (days 14-20) and was back to normal values at day 40, at which time the epileptic syndrome had disappeared. Serotonin uptake was also diminished at days 8-10 but to a lesser extent than was noradrenaline uptake. In the homotopic cerebral cortex contralateral to cobalt application, noradrenaline uptake was reduced at day 10 only and to a lesser extent than in the perifocal area, whereas serotonin uptake was unaffected. Kinetic analysis of the cobalt-induced monoamine uptake alterations at day 10 revealed a diminution of the maximal velocity with no change in the Km. Noradrenaline and dihydroxyphenylethyleneglycol concentrations in the perifocal area were also maximally reduced at days 8-10 but were unaffected at day 2 and day 40 post cobalt application. A reduction of serotonin levels in the perifocal area was observed only at days 8-10 while 5-hydroxyindoleacetic acid remained unaffected throughout the time period studied. The levels of these monoamines and their metabolites were unchanged in the homotopic contralateral cortex 2-40 days after cobalt application. These results indicate that cortical cobalt application induces alterations of the biochemical indices of the density of noradrenaline-containing terminals that closely parallel the evolution of the epileptic syndrome. These data further emphasize the important role of the cortical noradrenergic system in cobalt-induced epilepsy.

Regional effects of neuroleptics on dopamine metabolism and dopamine-sensitive adenylate cyclase activity.

The effect of haloperidol, chlorpromazine, thioridazine and sulpride on the levels of DOPAC and HVA, as an index of DA turnover, and on the activity of DA-stimulated adenylate cyclase was investigated inthe striatum, the nucleus accumbens and the tuberculum olfactorium of the rat brain. Haloperidol, chlorpromazine and thioridazine caused a more marked increase in DA turnover in the striatum than in the mesolimbic areas, while the reverse was true for sulpiride. In contrast, although the relative potency of these compounds varied greatly, the Ki of each drug for the DA-sensitive adenylate cyclase was similar in three structures of rat brain. The results indicate that in the three brain structures investigated there was no correlation between the differential effects of neuroleptics on dopamine turnover in vivo and the blockade by these drug of the DA-sensitive adenylate cyclase activity in vitro.

Regional 5-HT analysis in Roman high- and low-avoidance rats following MAO inhibition.

5-HT and 5-HIAA levels were investigated in three brain regions of Roman high- and low-avoidance rats, following 10, 30 and 60 min of MAO inhibition (pargyline injection). Higher levels of 5-HT in the cortex at 30 and 60 min, as well as a higher disappearance rate of 5-HIAA in the midbrain/medulla region were exhibited by Roman high-avoidance rats, thus further characterizing the differences previously observed in whole brain 5-HT synthesis between these selected rat lines.

Noradrenergic neurotransmission in the brain of a convulsive mutant mouse, differences between the cerebral cortex and the brain stem.

The Quaking mouse is a genetically determined model of convulsive disorders. We investigated the modulation of noradrenergic neurotransmission through alpha 2-adrenoceptors in the occipital cortex and the brain stem of this mutant. The endogenous levels of noradrenaline were similar in the cerebral cortex of the Quaking mice and their corresponding controls, while a significant increase of endogenous noradrenaline was found in the brain stem of the mutants. The rate of disappearance of noradrenaline in the cerebral cortex and the brain stem after injection of FLA 63 was identical in control and Quaking mice. The calcium-dependent electrically evoked overflow of 3H-noradrenaline from slices of occipital cortex was inhibited by clonidine and enhanced by yohimbine in Quaking as well as in normal mice. The negative feed-back mechanism mediated by presynaptic alpha 2-adrenoceptors operates to a similar extent in both strains of mice. In contrast to the occipital cortex, in the brain stem, the amount of neurotransmitter released by electrical stimulation was significantly increased in Quaking mice when compared with controls. However, in the brain stem, the negative feed-back regulation of noradrenaline release operates to a similar extent in both strains of mice. When the endogenous levels of MOPEG were determined in the brain stem, they were found to be significantly higher in the Quaking mice when compared to the controls. The results suggest that an increase in noradrenergic neurotransmission in the brain stem, rather than in the cerebral cortex, could contribute to the behavioural abnormalities exhibited by the Quaking mice.

Two-way avoidance and acute shock stress induced alterations of regional noradrenergic, dopaminergic and serotonergic activity in Roman high- and low-avoidance rats.

Various brain regions of male RHA/Verh and RLA/Verh rats were dissected out and deep-frozen immediately after 30 min in a shuttle box involving a) no shock (control), b) 40 inescapable shocks or c) 40 avoidable shocks. The RHA/Verh rats used in the "c" category exhibited about 80-85% learned avoidance. 5-HT, 5-HIAA, NA, MHPG-SO4, DA, DOPAC and HVA levels were subsequently measured in selected regions. NA levels were considerably reduced in the hypothalamus and pons/medulla of both selected lines of rats after acute shock stress, supporting the results of numerous studies which have indicated that NA turnover is nonspecifically increased by all types of stress, at least in those regions. An increase in cortical MHPG-SO4 and a reduction in hypothalamic 5-HT seen after avoidance learning also occurred after shock stress in RHA/Verh rats. Whereas RLA/Verh rats showed an increased metabolism of 5-HT in the hypothalamus and pons/medulla after shock stress, RHA/Verh rats showed the opposite response in the hypothalamus after the same treatment. A reduction in 5-HT metabolism was also evident in RHA/Verh rats, after avoidance learning, in the cortex, hippocampus and hypothalamus. These results indicated, pending further studies regarding, for example, possible genetic differences in tryptophan uptake and utilization, that 5-HT probably plays at least a modulatory role in the reaction to stress, and in avoidance behavior. That role may be either active or passive, depending upon the emotional status of the subjects. In regard to the DA responses measured in striatum and hypothalamus of the two rat lines, some divergent inter-treatment tendencies, as well as some similarities, were seen in DA metabolism in both regions, but almost none of the differences were significant.

Epizootiological investigations of canine distemper virus in free-ranging carnivores from Germany.

Canine distemper virus (CDV) infects a broad range of carnivores. To assess whether wild carnivores may play a role in the epidemiology of CDV in domestic dogs in Germany, the seroprevalence of CDV was determined. In sera from red foxes (30 of 591 (5%)) and stone martens (2 of 10 (20%)) antiviral antibodies were detected using a neutralization assay, whereas sera of raccoons, two mink, one pine marten and one raccoon dog were negative. In foxes, there was a significantly higher prevalence in urban and suburban compared to rural regions. When testing lung and spleen tissue samples (fox, badger, stone marten, polecat, raccoon dog) 13 of 253 (5.1%) foxes, 2 of 13 (15.4%) stone martens and 2 of 6 (33%) badgers were virus positive using RT-PCR. Phylogenetic analysis based on partial sequences of the F gene revealed a distinct relatedness to canine CDV isolates. Together, the data support the concept of transmission of CDV between domestic dogs and wild carnivores.

Portacaval anastomosis in rats: effects on behavior and brain serotonin metabolism.

The behavior of male rats with chronic end-to-side portacaval shunts or control surgery were evaluated in a complex enclosed maze, an open-field arena, and a swim canal. Subsequently, serotonin and 5-hydroxyindoleacetic acid levels were measured for hypothalamus, striatum, hippocampus, and midbrain-medulla. Chronic portacaval anastomosis did not significantly alter any of the behavioral parameters evaluated in the diverse test situations studied, despite a significant elevation of 5-hydroxyindoleacetic acid levels in all brain regions analyzed and the elevation of serotonin levels in hypothalamus and midbrain-medulla.

Antibodies against rabbit hemorrhagic disease virus in free-ranging red foxes from Germany.

Antibodies against rabbit hemorrhagic disease virus (RHDV) from 352 red fox (Vulpes vulpes) sera collected in Germany (Mecklenburg-Vorpommern) in 1993 were tested by a blocking enzyme-linked immunosorbent assay (ELISA) test kit. Ninety samples with positive or suspected results also were analyzed by the hemagglutination inhibition test (HIT). Eighteen serum samples (5%) were positive with the blocking ELISA and eight of these also were positive with HIT. The 18 positive sera also were tested by blocking ELISA for antibodies against European brown hare syndrome virus (EBHSV) and by sandwich ELISA to detect for antibodies against RHDV and EBHSV antigen. Antibodies were not found against EBHSV using the blocking ELISA. With the sandwich ELISA, six samples were positive against RHDV and also against EBHSV, indicating cross-reactivity between determinants of both viruses. However, antibody titers against RHDV were higher than against EBHSV in five samples, and in one animal titers were similar. In addition, two positive samples were investigated by Western blot immunoassay which showed clear positive reactions with the two main peptide bands of EBHSV and RHDV. Comparison of the areas below the peaks of the bands after immunoblotting indicated that there was a stronger reaction with the two main polypeptides of RHDV than with the two main peptides of EBHSV. This is the first report of calicivirus antibodies in free-ranging red foxes. Based on the specificity of the tests, the antibodies detected against caliciviruses may be induced by RHDV. There is a potential link for RHDV between free-ranging rabbits and foxes.

[Serologic investigations on the occurrence of Maedi-Visna antibodies in game ruminants]. / Serologische Untersuchungen zum Vorkommen von Maedi-Visna-Virusantikörpern bei Wildwiederkäuern.

The lentiviruses of small domestic ruminants (maedi-visna and caprine arthritis-encephalitis virus) have been shown to be infective for each other. There are only few investigations of virus susceptibility of other species of animals. The aim of our study reported here was to evaluate sera of wild animal species for lentivirus antibodies. 344 sera of Capreolus capreolus, Cervus elaphus and Dama dama from a territory with known sheep populations prevalence were tested in the agar gel immunodiffusion test using MVV-p28 and -gp 135 antigens. While about 27% of sheep herds have been shown to be MVV positive, no wild animal serum has been reacted with any of the antigens.