As the basis for entomological monitoring, the authors first propose to investigate the structure of a season of D. repens invasion transmission in the carrier in relation to the ambient temperature, such as onset of a transmission season, terminaton of mosquito infection, the number of invasion circulations. A calculating procedure has been developed. It is shown that there is a need for entomological monitoring of each specific area irrespective of the latitude to study a risk for local dirofilariasis cases.