Multiple synchronous outbreaks of Puumala virus, Germany, 2010

Abstract

To investigate 2,017 cases of hantavirus disease in Germany, we compared 38 new patient-derived Puumala virus RNA sequences identified in 2010 with bank vole-derived small segment RNA sequences. The epidemic process was driven by outbreaks of 6 Puumala virus clades comprising strains of human and vole origin. Each clade corresponded to a different outbreak region.

Figure 1

Distribution of investigated Puumala virus infections in Germany. Black dots indicate sequences obtained from patient samples in 2010; gray dots indicate sequences obtained from patient samples in 2007; diamonds indicate sequences obtained from rodent (Myodes glareolus) samples. Areas surrounded by lines indicate outbreak regions (numbered 1–6) where Puumala virus nucleotide sequences of human and vole origin have been analyzed. Numbers of the outbreak regions/virus clades and designations of local virus strains are also used in Figure 2. Arrows in outbreak region no. 2 indicate trapping sites of rodents from which strains 10 MuEb14v and 10 MuEb51 were obtained, which originated from localities 25 km apart.

Figure 2

Neighbor-joining phylogenetic tree (TN93 evolutionary model) of Puumala virus (PUUV) strains constructed on the basis of partial sequences of the small segment (504-nt sequence, nt positions 392–894). Bootstrap values >70%, calculated from 10,000 replicates, are shown at the tree branches. Analysis was performed by using MEGA5 software (www.megasoftware.net). PUUV-like sequences from Japan (JPN) were used as outgroup. Numbers from 04 to 11 in front of the sample names indicate the year (2004–2011) when the sample was collected. Black dots indicate human samples from 2010, gray dots indicate human samples from 2007, and diamonds indicate rodent samples. Novel sequences from this study are indicated by the symbol #. For numbers (1–6) of PUUV clades that correspond to the 6 defined outbreak regions, see Figure 1. Phylogenetic clades are shown in parentheses followed by names and numbers. For clarity, previously characterized PUUV clades from other parts of Europe are shown in simplified form. BEL, Belgium; BAL, Balkan; AUT, Austrian; SSCA, South Scandinavian; NSCA, North Scandinavian; RUS, Russian; BALT, Baltic; OMSK, Russian from Omsk region; FIN, Finnish; DAN, Danish.