Investigation and Spatial Distribution of Hard Ticks by Geographical Information System (GIS) in the Region of  
Istria, Croatia  
[PERSON]  
1 Faculty of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; [EMAIL_ADDRESS] (M.C. ); [EMAIL_ADDRESS] (D.P) Teaching Institute of Public Health of the Region of Istria, Nazororova 23, 52100 Pula, Croatia; [EMAIL_ADDRESS] (I.K. ); [EMAIL_ADDRESS] (N.L. ); [EMAIL_ADDRESS] (A.S.) Department for Medical Chemistry, Biochemistry and Clinical Chemistry, Faculty of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; [EMAIL_ADDRESS]  
Geogrupa Ltd. Pula, Epulonova 21, 52100 Pula, Croatia; boris. transmitted by ticks, such as bacteria, viruses, rickettsia, and protozoa, cause most vector-borne diseases, such as tick-borne encephalitis (TBE), anaplasmosis, babesiosis, rickettsiosis, borreliosis, and ehrlichiosis. These diseases are often reported in different regions of Europe [3]. In recent years, the spread of tick-borne diseases has been expanding, posing a potential risk to natural ecosystems [4]. The increased occurrences of some diseases have been highly connected with climate change and human behaviour [5; 6]. Therefore, animal reservoirs play an important role in public health and reinforce the urgent need for a global One Health approach to prevent and adequately address many complex problems at the human-animal-environment interface [7]. Ticks that transmit diseases within the Republic of Croatia belong to the _Ixodidae_ family, with a high predominance of the ordinary tick or _Ixodes ricinus_ (Acari: Ixodidae) and the brown dog tick or _Rhipiccephalus sanguineus_ (Ixodida: Ixodidae) [8]. They are effective transmitters of pathogenic organisms due to the relatively slow feeding process of the host, which enables them to suck up a large number of pathogenic organisms through the blood. Blood feeding at least once during each development stage allows them to acquire and transmit various tick-borne diseases. Besides the high reproductive potential, they also show high degrees of survival [9]. _Ixodes ricinus_ is commonly known as the castor bean tick or sheep tick. It is widely distributed across Europe and is the most widespread tick species in the Republic of Croatia. Its population is often present in northern parts of Croatia [8]. Its life cycle lasts two to four years, and it undergoes incomplete transformation, which includes four stages (egg, six-legged larva, eight-legged larva, and adult form) [10]. Immature forms are present on small rodents, while adult forms attack larger mammals (sheep, cows, and humans). _Ixodes ricinus_ is known to be the primary vector for several diseases in humans, including Lyme disease (LD) and tick-borne meningoencephalitis (TBM) [11]. It is typically found in wooded areas and grasslands [1]. _Rhipiccephalus sanguineus_ (Ixodida: Ixodidae) or the brown dog tick, prevails in the coastal areas of Croatia. However, it also occurs in urban environments, preferring warmer and more humid areas [12]. It is a specific ectoparasite of dogs but can also parasitize other mammals. It is a vector of various diseases, such as canine ehrlichiosis, babesiosis, and Mediterranean spotted fever (MSF) [13]. _Hyalomma margintum_ (Ixodida: Ixodidae) is a species of tick commonly referred to as the ornate cow tick or the marginate tick. It is known for its distinct ornate appearance and is typically found in grasslands and open habitats [1]. These tick species are associated with the transmission of various diseases, including Crimean-Congo haemorrhagic fever [14]. Understanding the spatial distribution of ticks in a specific region is crucial for assessing the risk of tick-borne diseases. In addition, a well-posed research question can provide insight into the ecological impact of tick populations within Istria County. Examining the spatial distribution of ticks according to gender and developmental stage can reveal patterns in tick life cycles, feeding preferences, and host interactions.