Epidemiological consequences of host specificity of ticks (Ixodida).

Arthropod-borne diseases still pose a serious health problem worldwide. Epidemiological consequences result from various environmental connections and interaction between parasites and their host, including host specificity of parasites and transmitted pathogens. The ixodid ticks (Ixodida) occupy a prominent position within the group of parasites as being vectors on the northern hemisphere in temperate climate zone. They are blood-feeding ectoparasites with different host specificity and capacity to transmit various pathogens. Feeding on many mammals (including humans), birds, reptiles and amphibians they present a great medical problem. For example, Ixodes ricinus can infest several hundred species of animals. It is a vector of pathogenic viral, bacterial and protozoal organisms, including Borrelia burgdorferi sensu lato complex which is the etiological agent of Lyme borreliosis. The competent reservoir hosts of Borrelia include many common species of small and medium-sized rodents as well as several bird species. Epidemiological consequences are complicated by the fact that specific Borrelia genospecies are associated with particular reservoir hosts. Thus, detailed analysis of epidemiological consequences requires a comprehensive knowledge of the biology and ecology of vectors, pathogens and their reservoirs including host specificity of ticks. Spatial modelling tick-borne risk in time and space is made possible by the use of remote sensing and techniques of geographical information system (GIS).