In contrast to HPS-causing hantaviruses, exposure of hamsters to HFRS-causing hantaviruses such as HTNV, PUUV, Dobrava (DOBV) and Seoul (SEOV) leads to asymptomatic infection, despite viral dissemination, even when immunosuppressed (Hooper Lab, unpublished data) [8] [9] [10] [11] .