As numerous publications attest, knowledge on hantaviruses progressed rapidly since the isolation of the agent of Korean hemorrhagic fever in 1978. This trend was even enhanced after the recognition of a previously unknown hantavirus that caused an outbreak of acute respiratory distress syndromes in the southwestern United States in 1993. Hantaviruses are carried by rodents worldwide and may cause severe diseases in humans. Hantavirus pulmonary syndrome in the New World and hemorrhagic fever with renal syndrome in Asia and Europe are being more and more reported. This could reflect a growing threat to public health as a consequence of behavioural and environmental changes. Though such infections are likely to occur in Switzerland too, prevalence and incidence of hantaviral infections among wild rodents and humans have not been studied yet in this country. The present paper reviews the epidemiology and clinical presentations of hantavirus infections.