The Central Upper-Rhine (Baden-Württemberg, Germany) is one of the warmest regions in Germany and also harbours abundant numbers of mosquitoes. Case reports on presumably autochthonous occurrence of Dirofilaria spp. were reported previously and were a reason for a further investigation into the occurrence of vector-borne pathogens. For this purpose, 44 hunting dogs from the Central Upper-Rhine region were tested between 4(th) and 29(th) June 2007. The blood samples were tested using the Knott's test and IDEXX SNAP 4Dx test. The Knott's test revealed unsheathed microfilaria identified as Dirofilaria repens by PCR in 3 dogs with no history of travelling (6.8%; 95% CI: 2.4-18.2%). The seroprevalence for Anaplasma phagocytophilum was 43.2% (95% CI: 29.7-57.8%), but only 4.5% (95% CI: 1.3-15.1%) for antibodies to Borrelia C6 peptide. Dirofilaria immitis antigen was not detected in any of the samples. A further 288 blood samples from non-hunting companion dogs of the Central Upper-Rhine region were tested negative for heartworm antigen between February and August 2007.

In this work, we have introduced a novel process, referred to as magnetic gelation, to produce porous polymeric monoliths with controlled anisotropic structure. Magnetite polymer composite nanoparticles have been prepared by dispersing hydrophobic magnetite nanocrystals in an organic monomer phase, followed by its miniemulsification in water in the presence of a polymerizable surfactant, and finally by polymerizing the resulting droplets into solid nanoparticles. The electrostatically charged nanoparticles, after being swollen with additional monomer, are destabilized and gelled by increasing the ionic strength of the suspension using an enzyme catalyzed reaction that decomposes urea and produces ions. During the gelation process, a magnetic field is applied. The resulting gel phase is hardened by polymerizing the added monomer, thus chemically crosslinking the nanoparticles together. The process combines a conventional reaction-limited aggregation process, which leads to disordered fractal porous structures, with magnetically-induced self-assembly, which aligns nanoparticles into strings of particles parallel to the direction of the applied field. By tuning the strength of dipole-dipole interactions among the nanoparticles, which has been achieved by changing the amount of magnetic material encapsulated in each nanoparticle and by varying the intensity of the applied magnetic field, the anisotropy of the final monoliths has been controlled. The extent of material anisotropy has been quantified by performing magnetic torque measurements. Additionally, Brownian Dynamics simulations have been performed and found to reproduce qualitatively and semiquantitatively the most important features of the magnetic gelation process.

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