Distribution of dirofilariasis in Omsk region

Abstract

Background. Recently, in the Russian Federation, there has been a tendency to an increase in the number of registered cases of dirofilariasis among residents living in a temperate climate zone, including in Western Siberia. The species Dirofilaria repens and Dirofilaria immitis are of clinical importance for humans. Dirofilariae are characterized by migration into the subcutaneous tissue, mucous membranes, organs of vision, internal organs. In the Omsk region, there is an increase in cases of dirofilariasis, including among children.The aim. To assess endemicity of the territory of the Omsk region in relation to pathogens of dirofilariasis.Materials and methods. The maps of the epidemiological survey of persons infected with dirofilariae for the period 2013–2020 were analyzed, parasitological and molecular biological methods examined 1155 blood samples of dogs, 2488 samples female blood-sucking mosquitoes, 26 samples of dirofilaria helminths removed from residents of the Omsk region.Results. In 18 people, the infection was regarded as local, since the infected persons had not left the Omsk region for the previous three years. Local infections are reported annually. Infection of the final owners – dogs – with dirofilaria ranges from 0.6 to 4.8 % in different years. On average, the extensiveness of the invasion was 3.0 ± 0.6 %; and the intensity of microfilaremia was 1277.68 ± 395.87 specimens/ml of blood. On the territory of Omsk and the Omsk region, 11 species of mosquitoes belonging to the genus Aedes, Ochlerotatus, Culex, Anopheles, Coquillettidia were identified. The estimated individual infection of mosquitoes of different species ranged from 0.6 % (O. flavescens) to 9.8 % (An. messeae). The total infection of vectors was 3.4 %. All positive samples were found to contain DNA of D. repens.Conclusion. The territory of the Omsk region is endemic for pathogens of dirofilariasis, in particular, D. repens. Further studies are needed to study the prevalence and species diversity of pathogens of dirofilariasis in Western Siberia, to identify the most dangerous from an epidemiological point of view, species of vectors.