Home/ Glossary/ Aerosol Aerosol A suspension of fine particles in air, small enough to be inhaled deep into the lungs. N95 respirators block the relevant aerosol size range; surgical masks are inadequate. Related glossary terms Hantavirus A genus of rodent-borne RNA viruses that cause severe diseas… Hantavirus pulmonary syndrome (HPS) A severe, often fatal lung disease caused by New World hanta… Hemorrhagic fever with renal syndrome (HFRS) A severe kidney-and-bleeding disease caused by Old World han… Case-fatality ratio (CFR) The proportion of confirmed cases of a disease that result i… Reservoir host A species in which a pathogen circulates persistently and as…