Tracking WNV transmission with a combined dog and wild boar surveillance system.

West Nile virus (WNV) is a mosquito-borne flavivirus mainly circulating in eastern Germany, causing annually reoccurring epizootics in the avifauna as well as sporadic infections in humans and horses. WNV is closely-related to Usutu virus (USUV) and tick-borne encephalitis virus (TBEV) and co-infections thereof are becoming more frequent. To not solely be dependent on the monitoring of wild birds and horses the availability of alternative sentinel species is advantageous. The study examined the seroprevalence of WNV antibodies (Abs) in eastern Germany in readily available species: dogs, wild boars, sheep, and goats. An NS1-ELISA was implemented to ease future differentiation of cross-reacting flavivirus Abs with a sensitivity of 92.3 and 90.9% for dog and wild boar sera, respectively. Flavivirus seroprevalences were the highest in wild boars with 42.03%, followed by dogs with 7.86%, and small ruminants with 1.57%. In the wild boars and dogs, WNV Abs were most frequent (17.64 and 3.90%, respectively) while seroprevalences in small ruminants and of USUV were lower. The NS1-ELISA is cost-efficient and reliable in monitoring WNV Abs in dogs as well as wild boars and the combined testing thereof could be ideal in detecting semi-urban transmission events prior to wildlife-human spill overs.