In a prospective study, during the latest hantavirus outbreak in 2007 in the county of Västerbotten, Sweden [17] , HFRS patients with cardiopulmonary failure and need of invasive assisted ventilation, i.e. intubation and mechanical ventilation, were selected. We identified three patients, two of which had fatal outcome and one survived. The two patients who died both underwent autopsy three days post-mortem. Organ samples were investigated using immunohistochemistry to describe the immunological response and detect presence of viral antigen. Quantitative real-time RT-PCR was used to detect viral RNA in organ samples, plasma and bronchoalveolar lavage [18] .