HFRS and hantaviruses in the Balkans/South-East Europe

Hemorrhagic fever with renal syndrome is endemic in the Balkans with epidemic outbreaks and sporadic cases that have been recorded yearly since the disease was first recognized. The incidence of Balkan HFRS is modest, with approximately one hundred cases reported in most years. Seroepidemiological investigations conducted in several Balkan countries revealed an overall seroprevalence of 6% in Bosnia and Herzegovina, 1.6% in Croatia, 4% in Greece and 1.7% in Slovenia, respectively. The complex ecology of the Balkan Peninsula supports the existence of diverse rodent and insectivore species which harbor several pathogenic and non-pathogenic hantaviruses. Among them only Dobrava (DOBV) and Puumala (PUUV) viruses are associated with disease in humans. Comprehensive clinical studies compared clinical signs and symptoms between patients infected with either virus. A spectrum of clinical picture of the disease ranges from mild illness typical of PUUV infections to a severe form with fulminant hemorrhagic fever and an overall mortality rate of 9.8% among DOBV infected patients. While severe DOBV cases are recognized from Slovenia in the North to Greece in the South, PUUV infections are more frequent in northern part of the area. Balkans represent an area with a potential need for hantavirus vaccines, but due to co-existence of DOBV and PUUV causing HFRS in the same region, a universal vaccine is required.