Thrombocytopenia, neutrophilia with left shift, atypical lymphocytes and hemoconcentration are common. There is acute renal failure, but the precise pathophysiologic lesion producing renal failure is uncertain. Mortality is usually from shock or hemorrhage. Isolation attempts had been unsuccessful. Despite extensive study, no arthropod vector has been implicated in the transmission of any hantavirus.
Infected rodents appear to be persistently infected and viruric.
HTN seroprevalence among mice in endemic areas, as assessed by seroreactivity to culture-adapted Hantaan virus, fluctuates in a biphasic manner. The incidence of HFRS among humans follows a similar trend, but the curve slightly trails the seroprevalence curve among A. agrarius populations. A conference was assembled among local physicians and state and federal health authorities, even as additional cases began to be recognized. The common clinical features among the case-patients included a prodromal illness of fever, chills, and myalgia. The prodrome was followed by dyspnea, cough, thrombocytopenia, severe hemodynamic instability, neutrophilia with immature forms, atypical lymphocytes, elevated serum levels of lactate dehydrogenase.