Endoparasite infestation of roe deer from a hunting ground in Lower Austria Introduction Infections with endoparasites are very common in roe deer populations and can cause reduced body mass, disease and even death. Therefore it is of great importance for hunters to minimize the parasite burden in their hunting grounds. It is known that fawns are more prone to parasite infections and their consequences than adult animals. Infected fawns frequently excrete parasites, thus contaminating the environment. The aim of this study was to examine 40 intestinal tracts and 44 lungs from roe deer for endoparasites and to determine the parasite species found. Furthermore the species of lungworm found in Austrian roe deer was to be defined. Materials and methods Samples were collected once in October 2006 (n=20) and once in October 2007 (n=20). In total, 19 does, 11 female fawns and 10 male fawns were available. Additionally, lungs were available from 2 other hunting grounds for lungworm identification. Faecal samples were examined for parasite stages by flotation and the number of oocysts and eggs per gramme of faeces was counted by the McMaster technique. Intestinal tracts were examined for occurrence and infestation degree of nematodes. The lungs were dissected and recovered adult lung-worms were characterised by ITS2-PCR and sequencing. Statistical analysis was done by using the program SPSS 13.0. Results All 5 Eimeria species described in Austria were identified after faecal flotation. In total 14 nematode species were found: Ostertagia leptospicularis with the highest prevalence (90 %) and Trichostrongylus colubriformis with the lowest prevalence (5 %). Statistical analysis showed that fawns excreted significantly more oocysts of coccidia and nematode eggs than does. In the same way fawns were significantly higher infected with H. contortus, O. leptospicularis und Tr. capreoli. Furthermore, fawns were significantly more infected with Dictyocaulus spec. than does. There was no correlation between body mass and parasite infestation. Biomolecular characterization of the found specimens of lungworms with ITS2-PCR followed by sequencing showed that the investigated examples at least are Dictyocaulus capreolus. Conclusion Endoparasites such as coccidia, lungworms and nematodes can cause severe infections in roe deer, especially in fawns. So, high parasite burdens can indicate bad environmental conditions, too high population density or lack of food. Thus for hunters parasite infestations should be a sign for intervention, e.g. population control. The Eimeria species of roe deer are host specific and E. ponderosa is considered to be most pathogenic under roe deer coccidia. Furthermore these pathogenic species could be found predominantly in fawns, possibly because young animals are more susceptible to infections due to the need to undergo primary infection for the development of protective immunity. Fawns were more intensely and more frequently infected with some nematodes and coccidia than does. Furthermore excretion of nematode eggs was significantly higher in fawns than in adult roe deer. Consequently infected fawns facilitate environmental contamination. The taxonomic classification of Dictyocaulus from roe deer has previously led to different descriptions in literature. Latest biomolecular investigations identified D. capreolus as a new species and genetic sequencing showed that in animals of this study also D. capreolus was found. Summing up, fawns infected with endoparasites are contaminating their habitat. Therefore recognition and hunting of infected animals has to be justified for a healthy and stable population. Hence hunters play a main role in maintaining health of their wildlife stock.