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The importance of bank vole density and rainy winters in predicting nephropathia epidemica incidence in Northern Sweden.

Khalil H, Olsson G, Ecke F, Evander M, Hjertqvist M, Magnusson M, Löfvenius MO, Hörnfeldt B - PLoS ONE (2014)

Bottom Line: Adding the number of rainy winter days improved the model (R2 = 84%, p<0.05).In a rainy winter scenario, we predicted 812 NE cases in boreal Sweden, triple the number of cases predicted in a rain-free winter in 2013/2014.Our model enables identification of high risk years when preparedness in the public health sector is crucial, as a rainy winter would accentuate risk.

View Article: PubMed Central - PubMed

Affiliation: Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden.

ABSTRACT
Pathogenic hantaviruses (family Bunyaviridae, genus Hantavirus) are rodent-borne viruses causing hemorrhagic fever with renal syndrome (HFRS) in Eurasia. In Europe, there are more than 10,000 yearly cases of nephropathia epidemica (NE), a mild form of HFRS caused by Puumala virus (PUUV). The common and widely distributed bank vole (Myodes glareolus) is the host of PUUV. In this study, we aim to explain and predict NE incidence in boreal Sweden using bank vole densities. We tested whether the number of rainy days in winter contributed to variation in NE incidence. We forecast NE incidence in July 2013-June 2014 using projected autumn vole density, and then considering two climatic scenarios: 1) rain-free winter and 2) winter with many rainy days. Autumn vole density was a strong explanatory variable of NE incidence in boreal Sweden in 1990-2012 (R2 = 79%, p<0.001). Adding the number of rainy winter days improved the model (R2 = 84%, p<0.05). We report for the first time that risk of NE is higher in winters with many rainy days. Rain on snow and ground icing may block vole access to subnivean space. Seeking refuge from adverse conditions and shelter from predators, voles may infest buildings, increasing infection risk. In a rainy winter scenario, we predicted 812 NE cases in boreal Sweden, triple the number of cases predicted in a rain-free winter in 2013/2014. Our model enables identification of high risk years when preparedness in the public health sector is crucial, as a rainy winter would accentuate risk.

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The relationship between proportion of occupied 1-ha plots (arcsine-transformed) (total number  = 58) and autumn bank vole density (number of trapped individuals per 100 trap nights) (arcsine-transformed) in 1971–2012 during the four phases of the vole cycle.
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pone-0111663-g002: The relationship between proportion of occupied 1-ha plots (arcsine-transformed) (total number  = 58) and autumn bank vole density (number of trapped individuals per 100 trap nights) (arcsine-transformed) in 1971–2012 during the four phases of the vole cycle.

Mentions: Bank vole landscape occupancy in 1971–2012 increased with density (Pearson correlation, r = 0.94, p<0.001, df = 40, Fig.2). Mean occupancy during high-density years was 82%, significantly higher than the 54% mean occupancy during low-density years (t-test, df = 29, p<0.001). Bank vole autumn densities in both low and high years in 1990–2012 were significantly related to NE incidence (p<0.05 and p<0.001 for low and high density years, respectively); however, during low density years only 37% of variation in NE incidence was explained, compared to 71% in high density years (Fig 3). The standard error around the slope was higher for the low density years model (slope (SE): 10.3 (3.9)) compared to the high density years model (slope (SE): 11.4 (2.1)).


The importance of bank vole density and rainy winters in predicting nephropathia epidemica incidence in Northern Sweden.

Khalil H, Olsson G, Ecke F, Evander M, Hjertqvist M, Magnusson M, Löfvenius MO, Hörnfeldt B - PLoS ONE (2014)

The relationship between proportion of occupied 1-ha plots (arcsine-transformed) (total number  = 58) and autumn bank vole density (number of trapped individuals per 100 trap nights) (arcsine-transformed) in 1971–2012 during the four phases of the vole cycle.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4229113&req=5

pone-0111663-g002: The relationship between proportion of occupied 1-ha plots (arcsine-transformed) (total number  = 58) and autumn bank vole density (number of trapped individuals per 100 trap nights) (arcsine-transformed) in 1971–2012 during the four phases of the vole cycle.
Mentions: Bank vole landscape occupancy in 1971–2012 increased with density (Pearson correlation, r = 0.94, p<0.001, df = 40, Fig.2). Mean occupancy during high-density years was 82%, significantly higher than the 54% mean occupancy during low-density years (t-test, df = 29, p<0.001). Bank vole autumn densities in both low and high years in 1990–2012 were significantly related to NE incidence (p<0.05 and p<0.001 for low and high density years, respectively); however, during low density years only 37% of variation in NE incidence was explained, compared to 71% in high density years (Fig 3). The standard error around the slope was higher for the low density years model (slope (SE): 10.3 (3.9)) compared to the high density years model (slope (SE): 11.4 (2.1)).

Bottom Line: Adding the number of rainy winter days improved the model (R2 = 84%, p<0.05).In a rainy winter scenario, we predicted 812 NE cases in boreal Sweden, triple the number of cases predicted in a rain-free winter in 2013/2014.Our model enables identification of high risk years when preparedness in the public health sector is crucial, as a rainy winter would accentuate risk.

View Article: PubMed Central - PubMed

Affiliation: Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden.

ABSTRACT
Pathogenic hantaviruses (family Bunyaviridae, genus Hantavirus) are rodent-borne viruses causing hemorrhagic fever with renal syndrome (HFRS) in Eurasia. In Europe, there are more than 10,000 yearly cases of nephropathia epidemica (NE), a mild form of HFRS caused by Puumala virus (PUUV). The common and widely distributed bank vole (Myodes glareolus) is the host of PUUV. In this study, we aim to explain and predict NE incidence in boreal Sweden using bank vole densities. We tested whether the number of rainy days in winter contributed to variation in NE incidence. We forecast NE incidence in July 2013-June 2014 using projected autumn vole density, and then considering two climatic scenarios: 1) rain-free winter and 2) winter with many rainy days. Autumn vole density was a strong explanatory variable of NE incidence in boreal Sweden in 1990-2012 (R2 = 79%, p<0.001). Adding the number of rainy winter days improved the model (R2 = 84%, p<0.05). We report for the first time that risk of NE is higher in winters with many rainy days. Rain on snow and ground icing may block vole access to subnivean space. Seeking refuge from adverse conditions and shelter from predators, voles may infest buildings, increasing infection risk. In a rainy winter scenario, we predicted 812 NE cases in boreal Sweden, triple the number of cases predicted in a rain-free winter in 2013/2014. Our model enables identification of high risk years when preparedness in the public health sector is crucial, as a rainy winter would accentuate risk.

Show MeSH
Related in: MedlinePlus