Predicting High Risk for Human Hantavirus Infections, Sweden

Abstract

An increased risk for hemorrhagic fever with renal syndrome caused by Puumala hantavirus was forecast for Sweden in 2007. The forecast was based on a predicted increase in the number of Myodes glareolus rodents (reservoir hosts). Despite raised awareness and preparedness, the number of human cases during July 2007–June 2008 was 1,483, a new high.

Serological Survey of Rodent-Borne Viruses in Finnish Field Voles

“…Of taxonomic groups, rodents are considered one of the largest sources of zoonotic agents (Luis et al 2013). In northern Europe, rodent populations display multiannual, high-amplitude, cyclic density fluctuations (Hansson and Henttonen 1985, Norrdahl 1995, Korpela et al 2013, which can be correlated with the human incidence of zoonotic diseases they spread (for example, Kallio et al 2009, Olsson et al 2009). During density peaks, field voles (Microtus agrestis) become one of the most abundant rodent species in northern Europe (Hanski and Henttonen 1996), yet very little is known of the viruses they carry.…”

Global Warming and Epidemic Trends of an Emerging Viral Disease in Western-Europe: The Nephropathia Epidemica Case

“…However, cyclic NE peaks have also been noted during a 1973-2002 study period, linked to cyclic peaks in local bank vole populations every 2-4 years (mostly 3 years). These "mice years" started with higher reproduction of voles under the snow during winter, and were correlated (R= 0.86) with abundant linden harvest during previous autumn (Olsson et al, 2009). Winter NE peaks are characteristic for Fenno-Scandia, in contrast to the summer peaks in W.-Europe.…”

“…Global warming during wintertime has been incriminated somewhat paradoxically for an increased contact between humans and voles, since the decreased protective snow cover in Fenno-Scandia is supposed to favour bank voles' entry into human dwellings, in search for food and shelter. Overall, the 3-yearly NE peaks in Fenno-Scandia are ascribed to predator-prey cycles, a mechanism very different from the one operative in temperate Europe (Olsson et al, 2009). Indeed, the vegetation type that covers most of Norway, Sweden and Finland is another difference, since the boreal forest or taiga consists mainly of pine trees, in contrast to the temperate forest in the rest of Europe, wherein deciduous broad-leaf trees predominate.…”

“…This seems now somewhat in contradiction with the fact that the record 2010 peak was preceded in Germany by a harsh 2009-2010 winter, as in many other European countries. Thus, the impact of low winter temperatures as a separate NE risk factor needs further study, the more so since it is known from Scandinavian countries that a constant winter cover with snow can have a rather protective effect on vole populations (Olsson et al, 2009 France, a significant increase of the forest "length of the growing season" was observed, most pronounced in the densely forested areas, being also NE hot foci (Barrios et al, 2010). Moreover, a mathematical so-called multiple input-single output (MISO) model was developed, in which the inputs were average measured monthly precipitation and temperature in Belgium, as well as the estimated "vole carrying capacity", expressed as number of voles per hectare, and based mainly on the yearly mast production.…”

Serologic Investigation of Hantavirus Infection in Patients with Previous Thrombocytopenia, and Elevated Urea and Creatinine Levels in an Epidemic Region of Turkey

“…In line with previous work, we found that most cases were seen in autumn and winter (Table 3). It is also known that the number of reported HFRS cases increase after a hot summer has led to a rich seed season for beech and oak trees (47,48). In the Bartin region, 2008 and 2009 were significantly wetter than previous years, leading to particularly rich seed seasons.…”