Hantaviruses are RNA viruses of the Bunyaviridae family, represented in the Czech Republic by three genospecies: Dobrava-Belgrade, Puumala and Tula. They persist in natural foci of infection. In 2004 to 2009, a local outbreak with 18 reported cases of nephropathia epidemica caused by Puumala hantavirus occurred in the Sumava mountains and foothills and was spacially associated with another outbreak in Lower Bavaria, Germany. In the Jeleni locality in the Sumava mountains at 880 m above sea level, we identified a natural focus of infection suspected to be the source of hantavirus infection in forest workers. The focus was characterized geobotanically as a montane mixed forest with the predominance of beeches within the association Dentario enneaphylli-Fagetum, alliance Fagion, sub-alliance Eu-Fagenion, in a cold climate region with a podzolic soil. The biocenoses where hantaviruses are circulating typically show higher microclimate humidity. Their characteristization can be helpful in predicting where hantaviruses are likely to circulate.