Tick-borne encephalitis virus in Ixodes ricinus (Acari: Ixodidae) ticks, Tunisia.

Abstract Tick-borne encephalitis virus (TBEV) is the etiologic agent of tick-borne encephalitis (TBE) and transmitted by Ixodes ricinus (Linnaeus, 1758) in Europe. The geographical distribution of I. ricinus in the Palearctic region covers also northern Africa, including northwestern Tunisia. While the eco-epidemiology of TBE in Europe is well documented, no data concerning TBEV form northern Africa are available. We investigated whether TBEV is circulating in Tunisia. A total of 877 adult I. ricinus collected from northwestern Tunisia were examined in pools for the presence of TBEV by nRT-PCR. Viral RNA was detected in one pool of three engorged ticks, yielding a minimum infection rate of 0.11% (1/877). Phylogenetic analysis showed that Tunisian TBEV strain belongs to the European lineage. We report for the first time the presence of TBEV in I. ricinus from northern Africa. These preliminary data led us to suspect the presence of TBE in Tunisia. Therefore, more studies are needed to assess the public health importance of TBEV in northern Africa.