Viral genome diversity in Swiss ticks

Ticks are a group of blood-feeding arthropods, classified in the order Ixodida with approx. 900 species worldwide. Ixodida can be divided into three families, Argasidae, Ixodidae, and Nuttalliellidae. Along with mosquitoes they are the main arthropod vectors of disease agents to humans, domestic animals, and wildlife.

As ticks play a role as a reservoir for a great variety of pathogenic organisms (e.g., viruses, bacteria, protozoa, and certain helminths) and often may be co-infected with different causative agents, being inoculated with more than one pathogen by a single tick bite is at high risk. Ixodes ricinus, the most frequent tick species in Europe, is known to be the principal vector of tick-borne encephalitis virus (TBEV), Borrelia and Babesia spp.

Environmental changes and human activities affect the geographical distribution and population densities of tick species and therefore lead to emerging and re-emerging diseases. The increasing incidences of tick-borne diseases highlight the importance of research on arthropod vector and pathogen relationship. While previous studies have assessed the prevalence of specific pathogens by polymerase chain reaction (PCR), this study aims to determine the global virome composition of ticks collected in Switzerland by using Next Generation Sequencing (NGS) and to investigate the prevalence and genetic dynamics of specific viruses (e.g.TBEV) over two consecutive years. Furthermore, as the incidence of Lyme Disease in Switzerland is high, the study will also assess the presence of selected bacteria (e.g., Borrelia spp.) as well as important protozoic pathogens (e.g., Babesia spp.).