About
Ticks are hematophagous arthropods responsible for major human and animal diseases. They carry microbial communities that include symbionts, commensals and pathogens. The geographical distribu-tion of ticks is expanding worldwide, leading to the appearance of risks of emergence of tick-borne diseases in naïve areas. Tick dispersal over long distances occurs concomitantly to vertebrate move-ments, for example migratory birds. In Eastern Europe, the Danube Delta constitutes an important wetland area for birds that perform migrations between Europe and Africa, favoring the emergence of pathogens through animal/arthropod exchanges.
The project aimed at investigating the interrelationships between tick, avian, rodent and livestock viruses in the Danube Delta biosphere, a hub for exchanges of ticks and associated pathogens among migratory birds and small mammals. With the identification of known, rare or novel putative tick-borne arboviruses and their vertebrate hosts in this area, we deciphered the ecological cycle of tick-borne viruses at the vector and vertebrate reservoir levels and evaluate the risk of importation of tick-borne arboviruses to new areas via migratory birds. The determination of the host spectrum of tick-borne viruses and the identification of genomic signatures of viruses either able to infect multiple hosts or restricted to ticks is key for improving targeted surveillance of tick-borne arboviruses.
To achieve this objective, we combined state-of-the-art high-throughput sequencing and serological techniques to characterize the virome of different life stages of ticks and to search for infection by candidate arboviruses in wild and domestic animals exposed to ticks. The project was divided into three specific aims: 1) updating the description of tick species that infest the Danube Delta ecosystem and identifying the introduction of exotic species (possibly introduced through bird migration); 2) characterizing the viral communities infesting larvae, nymphs and adult ticks in the Danube Delta; 3) searching for trace of tick-borne viral infection in domestic and wild vertebrate animals exposed to tick bites.
