Mortality rate patterns for hemorrhagic fever with renal syndrome caused by Puumala virus

Abstract

To investigate nephropathia epidemica in Sweden during 1997-2007, we determined case-fatality rates for 5,282 patients with this disease. Overall, 0.4% died of acute nephropathia epidemica ≤3 months after diagnosis. Case-fatality rates increased with age. Only women showed an increased case-fatality rate during the first year after diagnosis.

Figure 1

Incidence of acute nephropathia epidemica (NE) and case-fatality rates, Sweden, 1997–2007. A) Age distribution for male and female patients with acute NE. B) Age distribution of case-fatality rates for all patients with acute NE. The Swedish Death Register was used to identify all deceased persons with a diagnosis of NE. Numbers of deaths during different periods after diagnoses were 21 (13 male patients and 8 female patients) during the acute phase (<3 months after diagnoses), 7 (5 male patients and 2 female patients) after the acute phase (>3 months after diagnoses) but <1 year later, and 24 (19 male patients and 5 female patients) during the second year after diagnoses.

Figure 2

Overall standardized mortality ratios (SMRs) for male and female patients with a diagnosis of acute nephropathia epidemica (NE) and SMRs 3–12 mo after diagnosis, Sweden, 1997–2007.