Dirofilariosis is an emerging mosquito-borne veterinary and medical problem in the Northern hemisphere. The ecological investigation of 56 canine dirofilariosis cases in new endemic locations was performed in Szeged, Hungary. The aim was to analyse the influence of the spatial patterns of dog abundance and the potential mosquito breeding habitats on the spatial occurrence patterns of dirofilariosis in the city of Szeged. The limnoecological characterisation was based on the fluvial habitat classification of Amoros of natural water bodies; the built environment was evaluated using the UrbanisationScore urbanisation intensity measuring software. Dirofilaria immitis accounted for 51% and D. repens for 34.3% of the dirofilariosis cases, and in 20% of the cases only the Knott's test was positive. It was concluded that most of the cases were related to locations with a medium to high urbanisation index, although the proximity of mosquito-bearing waters also played an important role in the observed spatial infection patterns. We found that the distance from potential mosquito habitats and the urbanisation intensity determine the abundance of dirofilariosis in urban environments. Key words: Dirofilaria immitis, Dirofilaria repens, urbanisation intensity, Amoros classificationDirofilariosis caused by Dirofilaria immitis and D. repens is one of the most important emerging parasitic, mosquito-borne diseases in the oceanic and temperate climate areas of Europe (Raccurt, 1999;

-Dirofi lariasis caused by Dirofi laria immitis (Leidy, 1856) is one of the most important mosquito-transmitted fi larioid infections in the Carpathian Basin and many parts of Europe. It can lead to lethal hearth infection in dogs and can be the source of serious diagnostic problems in humans. In August 2014 an exploratory mosquito collecting was performed for blood-fed mosquitoes in the site of the fi rst known lethal canine dirofi lariasis, Szeged. Th e trapped mosquito material showed 95% dominance of Culex pipiens Linnaeus, 1758. Th e potential vectors of Dirofi laria immitis, Aedes vexans (Meigen, 1830) and Anopheles maculipennis (Meigen, 1818) mosquitoes were also present in the collected material. Ochlerotatus dorsalis (Meigen, 1830), a species associated with the lowland sodium-rich waters was also trapped. With 9 fi gures and 1 table.