Analysis of caprine IgG1 and IgG2 subclass responses to Chlamydia psittaci infection and vaccination

Enzyme-linked immunosorbent assays (ELISAs) specific for caprine IgG(H+L), IgG1 and IgG2 were developed and evaluated for serodiagnosis of Chlamydia psittaci infections in a Tunisian goat flock with currently occurring chlamydial abortions and a clinically inapparent goat flock of an animal research facility. Additionally, ELISAs were applied to record the IgG1 and IgG2 dynamics of four goats vaccinated with inactivated Chlamydia psittaci and Coxiella burnetii. For screening purposes, the IgG(H+L) ELISA proved to be superior to the complement fixation test because it detected a larger number of chlamydial abortions and was easier to perform and to interpret. Analysis of Chlamydia psittaci-specific IgG1 and IgG2 responses to naturally occurring infections by ELISA revealed high IgG1 levels associated with IgG2 in goats with current abortions, whereas clinically inapparent, but seropositive goats were characterized by significantly lower IgG1 levels only (P less than 0.001). Similarly, the four vaccinated goats responded initially with Chlamydia psittaci-specific IgG1, whereas second and third vaccinations induced (as in goats with chlamydial abortions) predominantly IgG1, but also IgG2. The results indicated that clinically inapparent chlamydial infection may be distinguished from overt disease by analysing specific IgG1 and IgG2 responses. Applying Coxiella burnetii- specific ELISAs on field samples, IgG1 alone could be detected in eight, IgG2 alone in one and IgG1 combined with IgG2 in nine goats. The coxiella-specific antibody response of the four vaccinated goats was--in contrast to the chlamydia-specific response--characterized by IgG2 dominance.     

Isolation of a poxvirus from a sparrow (Passer domesticus)

From liver, lung, and kidney of a dead sparrow with signs of conjunctivitis a cytopathic agent was isolated in chicken embryo cell culture which was identified as a poxvirus by electron microscopy. From its growth characteristics in avian and mammalian cell culture it was concluded to belong to the genus avipox virus.     

Detection of virus in connection with "European brown hare syndrome" in Hesse, F.R.G

Materials from the liver of a wild-living hare (Lepus europeus pallas) which had died from "European Brown Hare Syndrome" (EBHS) and of two hares kept in captivity which had been experimentally infected with the same material and died after two days with the classical signs of EBHS (Eskens and Volmer, 1989) were investigated for the presence of virus particles by electron microscopy using the negative contrast technique. Virus particles of 32 nm in diameter were found in all three samples investigated. The same particles were detected in the filtered inoculum used for experimental infection and in the supernatant of the first three passages of feline embryonic cell cultures. Haemagglutination or haemadsorption could not be achieved with the material investigated.     

Carrot fly (Psila rosae) control in Switzerland – current strategies and prospective developments*

Carrot fly (Psila rosae) control in Switzerland appears not to have been a major problem during the years 1985–2000. However, reports on crop losses due to increased damage, and yield lots not complying with raised quality standards, have become more frequent in recent years. Carrot fly control has clearly become more difficult because the fly’s population dynamics have changed (3 generations instead of 2) and due to changes in the cropping system. Furthermore, some insecticides with high efficacy, such as soil insecticides, are no longer available. Seed treatments with various insecticides were tested as potential alternatives to no longer approved soil insecticides, but these were not efficient enough when infestation pressure was high. Spraying, mainly with pyrethroids against the flies landing on carrot leaves, proved to be successful in some plots if the flight of adult flies was monitored with sticky traps and the timing of the insecticide treatments was adequate. However, in other cases treatment efficacy was low, presumably due to less precise timing of the applications. In conclusion, current experience on supervised chemical control indicates that strategies can be adapted, but Swiss agricultural research stations are not yet able to provide the growers with validated recommendations.     

Get larger or grow longer wings? Impacts of habitat area and habitat amount on orthopteran assemblages and populations in semi-natural grasslands

Landscape Ecology - Habitat loss and fragmentation are major threats to biodiversity and can change community composition, species traits and intraspecific morphology. Calcareous grasslands are...     

Photochemical oxidation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in soils — a tool to assess their degradability?

To determine the degradability of PAHs and PCBs for soil remediation or ecotoxicological risk assessment, a simple method is needed. We tested the suitability of photocatalytic oxidation for this purpose. We determined the concentrations of 20 PAHs and 12 PCBs in four mineral topsoil horizons, six organic horizons, and four particle‐size fractions of each of three soils before and after UV irradiation with TiO₂ as a catalyst in suspension. Preliminary experiments showed that in dry soil no photooxidation occurred, but after 48 h of irradiation in suspension the PCB concentrations decreased by up to 40—50 %, while the PAH concentrations did not change significantly. In contrast to this, 95—100 % of PAH and PCB standards spiked on quartz sand were degraded within 8 h, indicating that sorption to organic matter limited degradation of PAHs and PCBs in soil suspensions. There was no difference in the degradation among different individual PAHs and PCBs, respectively, indicating that the degradation did not occur in dissolved state, but in association with soil organic matter. In all samples except one, the degradation of PCBs (10—80 % loss of initial concentrations) was higher than those of the PAHs (0—40 % loss). This suggests that the accessibility of PCBs for OH· radicals generated during irradiation was higher, or the oxidation of PAHs was limited by the properties of the sorbing organic matter. Thus, the tested method was not suitable to predict biodegradability, because it did not reflect the differences in degradability of individual compounds.