Hantavirus research has been stimulated by the recent highly lethal ou
tbreak of an influenzal illness mainly affecting the respiratory syste
m and leading on to hyperpyrexia, hypoxia and hypotension. Genetic cha
racterization of known hantaviruses has emphasized the diagnostic powe
r of polymerase chain reaction. Control of emerging outbreaks of Hanta
virus infection in many countries should be aimed, primarily, at under
standing the rodent vectors.