Outbreak of Puumala Virus Infection in Sweden
Author Information
Author(s): Pettersson Lisa, Boman Jens, Juto Per, Evander Magnus, Ahlm Clas
Primary Institution: Umeå University
Hypothesis
What factors contributed to the unexpected outbreak of Puumala virus infection in Sweden?
Conclusion
The outbreak of Puumala virus infection in Sweden was likely influenced by an increase in the rodent population and unusual climate conditions.
Supporting Evidence
- The incidence of nephropathia epidemica in Västerbotten County was 313 cases per 100,000 persons in 2007.
- During the outbreak, 30% of NE patients required hospitalization.
- Two deaths were recorded during the first three months of 2007, resulting in a case-fatality rate of 0.25%.
- An increase in the bank vole population was reported in the fall of 2006, coinciding with the outbreak.
Takeaway
A lot of people in Sweden got sick from a virus that comes from rodents, and it happened because there were more rodents and the weather was warmer than usual.
Methodology
The study used immunofluorescence assays and real-time reverse transcription–PCR to diagnose NE in patients.
Limitations
The study did not have access to rodent samples during the outbreak period to confirm the hypothesis about rodent population dynamics.
Participant Demographics
The majority of NE cases were among men (58%) and most cases (72%) were in individuals aged 35-74 years.
Digital Object Identifier (DOI)
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