Seroprevalence of tick-borne encephalitis (TBE) in naturally exposed monkeys ( Macaca sylvanus) and sheep and prevalence of TBE virus in ticks in a TBE endemic area in Germany

Abstract

In a recently published study, a clinical case of severe tick-borne encephalitis (TBE) in a monkey ( Macaca sylvanus) was described after natural exposure (tick bite) in a TBE endemic area in Germany, and from the tissue of this monkey the strain ‘Salem’, closely related to the strain ‘Neudoerfl’, was isolated and characterized. In this study, it was our aim to test all the available data for characterizing a TBE endemic area like TBE cases in humans and animals, TBE virus (TBEV) in ticks, and TBE-positive sera from animals. Sera from 283 monkeys and 100 sheep as well as 294 unfed ticks were collected at the monkey mountain Salem and its surroundings. A seroprevalence of 2.6% in monkeys and 9% in sheep were found. Furthermore, a new real-time RT-PCR method was established and used, in combination with an already published RT-qPCR, for TBEV genome detection in field-collected ticks, but no TBEV could be detected in the ticks tested.