Seroprevalance of Batai virus in ruminants from East Germany

Batai virus (BATV), a mosquito-transmitted Orthobunyavirus, was first detected in Southwest Germany in anopheline and culicine mosquitoes in 2009. However, little is known about the exposure to BATV infections for farm animals and humans in Germany as almost no systematic surveillance or infection studies have been carried out to date. This may explain why clinical symptoms in animals or humans have not been reported so far. Therefore and since BATV has meanwhile been detected repeatedly in different mosquito species in several regions of Germany, we performed a surveillance study by assaying more than 1300 blood samples from ruminants (goats, bovines, sheep) from six different federal states covering the years 2013 to 2016. Samples were investigated by BATV-specific real-time polymerase chain reaction as well as by virus neutralisation test. BATV-specific RNA was not detected, whereas BATV-specific antibodies were found in livestock from various geographic regions. We have determined the seroprevalence of 38.8% for goats, 44.7% for sheep and 36.4% for bovines in Saxony-Anhalt. The seroprevalence of goats from Brandenburg was 38.6% and of goats from Saxony 28.4%. These results confirm the levels of seroprevalence to BATV, suggesting endemic circulation, in different regions and indicate that ruminants are potential hosts of BATV in East Germany. Furthermore, the role of BATV as segment donor in disease emergence events should not be overlooked.