However, clinical SINV infection in humans has almost exclusively been reported in Northern Europe where it is endemic and where large outbreaks occur intermittently.
Sellele vaatamata on inimestel esinevatest SINV-nakkustest teatatud peaaegu erandita Põhja-Euroopas, kus see haigus on endeemiline ja kus aeg-ajalt tekib suuri haiguspuhanguid.