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Volume 16, Number 10–October 2010
Dispatch
Mortality Rate Patterns for Hemorrhagic Fever with Renal Syndrome Caused by Puumala Virus

Marika Hjertqvist, Sabra L. Klein, Clas Ahlm, and Jonas Klingström Comments to Author
Author affiliations: Swedish Institute for Infectious Disease Control, Solna, Sweden (M. Hjertqvist, J. Klingström); The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA (S.L. Klein); Umeå University, Umeå, Sweden (C. Ahlm, J. Klingström); and Karolinska Institutet, Stockholm, Sweden (J. Klingström)

Suggested citation for this article

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.

Hantaviruses cause 2 severe emerging zoonotic diseases: hemorrhagic fever with renal syndrome (HFRS) in Eurasia and hantavirus cardiopulmonary syndrome (HCPS) in the Americas. These diseases have a case-fatality rate ≤40% depending on the specific hantavirus (1,2). Hantaviruses are primarily maintained in the environment by rodents, with humans serving as incidental hosts who are typically infected by inhalation of virus-contaminated rodent excreta (1,2). In parts of Europe, including Sweden, Puumala virus (PUUV) causes nephropathia epidemica (NE), a relatively mild form of HFRS with case-fatality rates of 0.1%–1% (1–4).

For many infectious diseases, frequency of infection is generally higher, and the clinical outcome often worse, in male patients (5–8). The reported male:female ratio for NE cases varies from 2 to 5:1 (1,3). Male-biased rates of infection have also been reported for other hantaviruses (1,9). However, in northern Sweden, seroprevalence does not differ by patient sex, which suggests the same number of persons of either sex might be infected with PUUV (10). Why males are overrepresented for diagnosed NE cases is not known.

We recently reported sex differences in cytokine responses during acute NE (11). Whether sexually dimorphic immune responses during hantavirus infection cause differences in the severity of disease between men and women has not been investigated. Furthermore, whether age is a risk factor in outcome of HFRS/HCPS is unknown. To investigate NE in Sweden during 1997–2007, we determined case-fatality rates for 5,282 patients with this disease.

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Mortality Rate Patterns for HFRS | CDC EID

Suggested Citation for this Article

Hjertqvist M, Klein SL, Ahlm C, Klingström J. Mortality rate patterns for hemorrhagic fever with renal syndrome caused by Puumala virus. Emerg Infect Dis [serial on the Internet]. 2010 Oct [date cited].
http://www.cdc.gov/EID/content/16/10/1584.htm

DOI: 10.3201/eid1610.100242

Comments to the Authors

Please use the form below to submit correspondence to the authors or contact them at the following address:

Address for correspondence: Jonas Klingström, Centre for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden; email: jonas.klingstrom@smi.se