This notifiable disease is actually caused by a collection of related viruses that are all carried in rodents and cause infections with severities that range from mild to fatal. Hantavirus can result in two different kinds of syndromes with vastly different risk for death: hantavirus pulmonary syndrome, which occurs in infections from viruses in the Americas, has a fatality rate of 40-60%, whereas hemorrhagic fever with renal syndrome, which occurs from viruses in Asia and Europe, only causes death in about 15% of cases for two of the viruses.
This study provides a comprehensive list of all known hantaviruses and their origin and host species, and this selected list also includes the associated disease fatality rates. While rats, mice, and other rodents are the natural reservoirs for hantaviruses and the primary source of human infections, human-to-human transmission has been documented in one of the viruses. It remains a rare occurrence.