Hantavirus pulmonary syndrome (HPS) is an emerging disease caused by an increasing number of distinct hantavirus serotypes found worldwide. It is also a very severe immune disease. It progresses quickly and is associated with a high mortality rate. At the prodrome phase, hantavirosis symptoms can resemble those of other infectious diseases such as leptospirosis and influenza. Thus, prognosis could be improved by developing a rapid and sensitive diagnostic test for hantavirus infection, and by improving knowledge about clinical aspects of this disease. This study describes clinical features and laboratory parameters throughout the course of HPS in 98 patients. We report the seasonality and regional distribution of this disease in Paraná State, Brazil during the last seven years. In addition, we evaluated a specific molecular diagnostic test based on a nested reverse transcriptase-polymerase chain reaction for the detection of hantaviruses circulating in Brazil.