Ticks are vectors for a number of infectious diseases, and an understanding of their ecology is valuable for minimising the risk of human and livestock infections. The aim of this study was to identify the previous hosts of questing ticks, and to investigate the pathogen prevalence of ticks in the south-east of Norway. A new method of analysing tick bloodmeals for the study of vector-host ecology has been developed, based on a reamplified real-time qPCR protocol targeting the cytochrome b region of the mitochondrial genome of vertebrates. The use of this method allowed for the identification of the previous bloodmeal hosts of 49% of 91 nymphal and adult Ixodes ricinus collected from vegetation and from hosts between 2010 and 2012. This is the first analysis of bloodmeals for questing ticks to have results confirmed by sequencing. Borrelia burgdorferi sensu lato infection was not detected in ticks collected from vegetation at Tomb (Østfold, Norway) and a 2% Borrelia afzelii prevalence was found in ticks from Nesodden (Akershus, Norway). Ticks collected at Tomb and Nesodden, as well as ticks from some other sources were also tested for presence of Babesia spp. infections; infections of Babesia microti (0.9%) and a Babesia venatorum/capreoli/divergens cluster (5%) were detected.The reamplified real-time qPCR bloodmeal analysis method described in this thesis allows for an accurate estimation of host importance. The further use and development of this method will allow for the identification of additional tick hosts, which will give increasing insights into the ecology of this disease vector. Understanding the epidemiology of tick-borne diseases can contribute to the development of disease control measures, making the study of vector-host ecology an important tool in the prevention of infectious diseases.