Biology session

Small mammals abundant in natural and rural habitats of Hungary are important hosts for nymphs and larvae of ticks. Thus they may play a central role in the maintenance of the tick population in the habitat, and so indirectly in the natural cycle of tick-borne pathogens (e.g. Babesia spp., Hepatozoon spp., Anaplasma spp., Borrelia spp.).

In our research at Gemenc – in the flood-basin of the Danube – we collected small mammals from three areas with modified Sherman traps between 2009 and 2012. After about 2200 trapping nights we managed to trap 7 species (yellow-necked mouse: Apodemus flavicollis, stripped field mouse: A. agrarius, bank vole: Myodes glareolus, common vole: Microtus agrestis, eastern house mouse: Mus musculus, harvest mouse: Micromys minutus, common shrew: Sorex araneus). Following the euthanasia we removed their ectoparasites and took tissue samples from them. We stored the ectoparasites and the small mammals in alcohol, while we stored the tissue samples at -20 °C.

We analysed the tissue samples with molecular methods, amplifying the DNA of the possible pathogens. In May 2012 we began the collection of ticks from the vegetation as well. During this we found the individuals of 4 species (Dermacentor reticulatus male: 18, female: 31; Dermacentor marginatus female: 2; Ixodes ricinus: male: 4, nymph: 20; Haemaphysalis concinna male: 8, female: 11, nymph: 10, larva: 30). We found 206 ticks on small mammals: D. marginatus larvae and nymphs, all three developmental stages of I. acuminatus, H. concinna larvae and nymphs, I. ricinus larvae, nymphs and a male.

In eight of the stained spleen impression smears of M. glareolus we detected Hepatozoon pathogens. For the identification of these protozoa, we isolated the DNA of the infected individuals and amplified the whole 18S rDNA sequence. It showed the highest sequence similarity to an unnamed Hepatozoon species. Our preliminary experiment proved that three species of rodents (M. glareolus, M. arvalis és A. agrarius) consume ticks. This might play a role in the spreading of this parasite.

We extracted DNA from the skin tissue samples and performed polymerase chain reaction using Borrelia-specific primers. The processing of samples and analysis of data is underway.