engleski

Detection and genetic characterization of tick-borne encephalitis virus (TBEV) derived from ticks removed from red foxes (Vulpes vulpes) and isolated from spleen samples of red deer (Cervus elaphus) in Croatia

Tick-borne encephalitis (TBE) is a growing public health concern in central and northern European countries. Even though TBE is a notifiable disease in Croatia, a significant lack of information in regards to tick identification, distribution as well as TBE virus prevalence in ticks or animals, and host specificity, is present. The aim of our study was to identify and investigate the viral prevalence of TBE in ticks removed from red fox (Vulpes vulpes) carcasses, hunted in endemic areas in northern Croatia, and to gain a better insight in the role of wild ungulates, the red deer (Cervus elaphus) in the persistence of TBE virus. We have identified five tick species removed from red foxes. However, TBE virus has been isolated only from adult Ixodes ricinus and Ixodes hexagonus ticks showing a viral prevalence higher than reported in endemic areas of European countries (6, 1%). Furthermore, positive spleen samples from red deer (1, 1%) were found, indicating a possible viraemia. Therefore, the role of the red deer in the ecology and epidemiology of TBE in Croatia may be more important than currently thought. Croatian TBE virus isolates were genetically analysed and they were shown to be closely related, all belonging to the European TBE virus subgroup. However, on the basis of nucleotide and amino acid sequence analysis, two clusters have been identified. Our results show that further investigation is needed to understand the clustering of isolates, tick ecology and recognize the most common transmission hosts in Croatia. Sentinel surveys based on wild animal species could be considered as appropriate and would give a better insight in defining TBEV endemic and possible risk areas in Croatia.

tick-borne encephalitis virus; ticks; red fox; red deer; genetic characterization; Croatia

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