Emergence of hantavirus in South Germany: rodents, climate and human infections

Abstract

Human hantavirus (serotype Puumala) infections are prevalent throughout Europe. The bank vole is the main reservoir of the Puumala virus (PUUV). Between 2001 and 2006, the annual incidences in Germany ranged from 0.1 to 0.5 per 100,000 inhabitants. About half of the cases were reported from the state of Baden-Württemberg (BW) in southwest Germany. In 2007, 1,089 PUUV infections were reported from BW. This reflects an incidence of 10.1:100,000, which is more than 11 times higher than the mean incidence of the previous 6 years. Spatial analysis highlights incidences up to 90:100,000 in the most affected district. The winter season 2006/2007 showed an all time high in reported mean temperature. The previous summer and autumn led to a beech mast year, resulting in favourable feed conditions for bank voles in the winter season 2006/2007. The causes of the observed increase in PUUV infections in 2007 cannot be restricted to known cycles in the bank vole population. Favourable feed conditions, a mild winter and an early onset of spring may have influenced bank vole population size as well as human exposure to infectious rodent excretions. Further epidemiologic studies are necessary to better understand the interaction between environmental factors, occurrence of Puumala virus in bank voles and the risk for human disease.

Survey and case-control study during epidemics of Puumala virus infection

“…In summary, the reasons for the PUUV epidemic in Baden-Wuerttemberg in 2007 were probably multifactorial. Favourable feeding and climatic conditions led to an increase in the bank-vole population with a higher PUUV infestation, and thus to an increase of PUUV dispersion into the environment [38]. In addition, the dry, warm weather conditions probably resulted in more human contacts with contaminated environments.…”

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

“…In contrast to France, and apparently even more pronounced than in Belgium, it witnessed heavy beech masting in autumn 2006, leading to a record 1,623 NE cases in 2007. This record year was preceded by the mildest winter ever recorded in Germany, a very warm spring 2007, and confirmed by a noticeable increase in local bank vole population begin 2007 (Piechotowski et al, 2008). Of note, the Netherlands witnessed in 2007 also their highest NE peak (27 cases).…”

“…Its population (10.7 million) is comparable to that of Belgium (11 million), but the 2007 NE incidence was 3.6 times higher (10.1/10 5 ) than the record 2005 incidence (2.8/10 5 ) for Belgium. (Piechotowski et al, 2008) (Schwarz et al, 2009). It is striking that in Baden-Württemberg, districts with the highest beech forest cover (15% or more) correlate significantly with the highest district NE incidences (50/10 5 ).…”

Hantaviruses—Infections, Epidemiology and Hosts

“…In France, most human infections are reported during late spring and summer Sauvage et al 2002). In contrast, in Belgium and Germany seasonal peaks are quite variable: some years exclusively show summer peaks, but in other years also winter peaks occur Essbauer et al 2013;Faber et al 2010;Piechotowski et al 2008). So far the seasonal pattern of hantavirus cases in Germany and also neighbouring countries seems unpredictable.…”