Species

Puumala virus (PUUV)

The bank-vole hantavirus of Northern and Central Europe. Causes the mild form of HFRS known as nephropathia epidemica (NE). It is by far the most common hantavirus in Europe — and the least lethal.

Symptoms — nephropathia epidemica

• Abrupt fever, severe headache, back/flank pain.
• Blurred vision ("Puumala myopia") in many patients.
• Transient kidney injury — low urine output, then a diuretic phase.
• Mild bleeding tendency (rarely severe hemorrhage).
• Recovery in 2–6 weeks; long-term sequelae are uncommon.

Vole cycles

Bank-vole populations boom and crash on a 3–4 year cycle tied to seed-mast years (good acorn/spruce-cone harvests). NE incidence tracks the cycle — Finland and Germany see large multi-thousand-case waves in peak years.

Diagnosis & treatment

Diagnosis is by Puumala-specific IgM ELISA; RT-PCR on serum during early illness. Treatment is supportive — most patients do not require dialysis. No specific antiviral. There is no licensed Puumala vaccine; the US Army DNA vaccine includes a Puumala component in trials.

Geography

Puumala is the dominant hantavirus across the bank-vole range. Finland's annual incidence reaches up to ~60 per 100,000 in vole-peak years — making it one of the highest hantavirus incidences anywhere in the world, even though severity is mild.

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