The paper presents the results of clinical, epidemiological, and epizootological analyses of local cases of human dirofilariasis in the Nizhny Novgorod Region, which suggest that natural and climatic changes, namely the abnormally hot summer in 2010-2011 and increasing migratory processes among human beings and animals, open up possibilities for forming foci ofdirofilariasis outside habitats of Dirofilaria repens.