Vector-borne transmitted helminthic zoonosis affects the health and economy of both developing and developed countries. The concept of episystem includes the set of biological, environmental, and epidemiological elements of these diseases in defined geographic and temporal scales. Dirofilariasis caused by different species of the genusDirofilariais a disease affecting domestic and wild canines and felines and man, transmitted by different species of culicid mosquitoes. This complexity is increased becauseDirofilariaspecies harbor intracellular symbiontWolbachiabacteriae, which play a key role in the embryogenesis and development of dirofilariae and in the inflammatory pathology of the disease. In addition, the vector transmission makes the dirofilariasis susceptible to the influence of the climate and its variations. The present review addresses the analysis of dirofilariasis from the point of view of the episystem, analyzing the complex network of interactions established between biological components, climate, and factors related to human activity, as well as the different problems they pose. The progress of knowledge on human and animal dirofilariasis is largely due to the multidisciplinary approach. Nevertheless, different aspects of the disease need to continue being investigated and cooperation between countries and specialists involved should be intensified.

We report 14 cases of human subcutaneous dirofilariasis caused by Dirofilaria repens, diagnosed from February 2003 through July 2004, in patients from Rostov-on-Don, Russia. Serologic analysis showed evidence of high risk of exposure to D. repens. Surveillance studies on prevalence and prevention effectiveness of canine infection are needed to control this emerging zoonosis.

We analyze through a climatic model the influence of regional warming on the geographical spreading and potential risk of infection of human dirofilariosis in Russia, Ukraine, and other post-Soviet states from 1981 to 2011 and estimate the situation by 2030. The model correctly predicts the spatiotemporal location of 97.10% of 2154 clinical cases reported in the area during the studied period, identified by a retrospective review of the literature. There exists also a significant correlation between annual predictedDirofilariagenerations and calculated morbidity. The model states the progressive increase of 14.8% in the potential transmission area, up to latitude 64°N, and 14.7% in population exposure. By 2030 an increase of 18.5% in transmission area and 10.8% in population exposure is expected. These findings strongly suggest the influence of global warming in both geographical spreading and increase in the number ofDirofilariagenerations. The results should alert about the epidemiological behavior of dirofilariosis and other mosquito-borne diseases in these and other countries with similar climatic characteristics.

Epidemiological data on canine and human dirofilariosis in the Rostov Region (Southern Russia) are presented. Prevalence ofDirofilariaspp. infections in 795 autochthonous dogs, assessed by the Knott test, was 20.25%. The highest prevalence was found in Novocherkassk (38.3%) and Rostov-on-Don (18.5%), while prevalences were lower in other points of the region. Prevalence ofD. repenswas 44.7%, prevalence ofD. immitiswas 30.3%, and coinfections were observed in 25.0% of the dog population. A case finding study carried out during 9 years (2000–2009) revealed 131 cases of human dirofilariosis in the Rostov Region, 129 of subcutaneous dirofilariosis and 2 of pulmonary dirofilariosis. Seroprevalence among 317 healthy blood donors from the Rostov Region was 10.4%, while seroprevalence in policemen living in Rostov city and working in training dogs was 19%. These data show high infection rates ofDirofilariaspp. in both human and dog populations of Rostov, probably because of the existence of favorable conditions for the transmission in this region.