Rodents (Order Rodentia) are usually small-sized mammals with a worldwide distribution, accounting for over 40% of all mammal species. Rodents are both widespread and abundant, as are their associated ticks. Thus, mainly from a human health perspective, the rodent-tick associations have a huge importance in most ecosystems . Besides their role as tick hosts, rodents serve as reservoirs of tick-borne pathogens, hence increasing their importance in the eco-epidemiology of diseases like Lyme borreliosis, rickettsiosis, babesiosis, ehrlichiosis or tularaemia [1–3].
Most of the hard ticks feeding on rodents follow a three-host life cycle (i.e. each of the active stages - larva, nymph and adult - feeds on a different host individual). Usually, these ticks feed on a variety of progressively larger hosts, meaning that a large number of small mammal species typically harbour the immature stages . On the other hand, there are certain Ixodidae that characteristically attack micromammals also during their adult stage. One of the most comprehensive reviews on micromammal-tick associations  lists 14 species of adult Ixodidae parasitic on rodents (Anomalohimalaya cricetuli, A. lama, A. lotozskyi, Haemaphysalis verticalis, Ixodes angustus, I. apronophorus, I. crenulatus, I. laguri, I. nipponensis, I. occultus, I. pomerantzevi, I. redikorzevi, I. trianguliceps, Rhipicephalus fulvus). However, the variety of species parasitizing rodents as immature stages is much higher .
The importance of hard-ticks in the epidemiology of several human vector-borne infections has received considerable attention in recent years and will certainly offer an opportunity for new studies in the years to come. The ecology of tick-borne infections is a popular field in parasitology and besides the research focused on the molecular epidemiology of tick-borne pathogens, studies on host preferences, seasonal variation and community structure are nevertheless important. From their reservoir-host perspective, rodents are known to act as key ecological links in the very complex transmission chains of tick-borne diseases as Lyme borreliosis or viral encephalitis [1, 4].
Romania has an outstanding position in terms of biodiversity, being the only European country with five ecoregions on its territory . This unique situation created a wide range of habitats and is mirrored by the number of mammal species present (112 species) . Moreover, Romania not only holds this high biodiversity (especially among rodents ), but has nearly half of its human population living and working in rural areas and maintaining close contacts with nature , creating an interesting situation for epidemiological processes. Thirty-two species of wild rodents are known to occur in Romania . Both this habitat variety and available host diversity  account for relatively high tick species diversity in Romania (25 species) , as compared to neighbouring countries . However, micromammal-tick associations have been poorly studied in Romania despite the importance of each in the ecology of public pathogens. In this context, our manuscript shows the results of a study of tick infestation epidemiology in rodents from Romania.