Goats and sheep as sentinels for tick-borne encephalitis (TBE) virus--epidemiological studies in areas endemic and non-endemic for TBE virus in Germany.

The aim of the study was to examine grazing goats and sheep as specific sentinels for characterization of the tick-borne encephalitis virus (TBEV)-related risk in an area by means of serosurveillance tests in the German federal states Baden-Wuerttemberg, Bavaria, Thuringia, North Rhine-Westphalia, Lower Saxony, Schleswig-Holstein, and Mecklenburg-West Pomerania. A total of 3590 sheep sera and 3793 goat sera was collected in 2003 and 2006-2009 and were examined by ELISA screening and confirmed by serum neutralization test. Considerable differences in seroprevalence were seen between single flocks in districts in Baden-Wuerttemberg, Bavaria, and Thuringia with values between 0 and 43% which confirmed the patchy pattern of TBEV foci that can range in size from very small to large. The here described serological screening may be a helpful tool for an early warning system of a potential TBEV risk. Testing of 1700 ticks by real-time RT-PCR in two districts in Baden-Wuerttemberg revealed only one positive tick, thus illustrating the problems of expensive and time-consuming tick collection.