Spatiotemporal dynamics of Puumala hantavirus associated with its rodent host, Myodes glareolus.

Vanessa Weber De Melo,Rainer G Ulrich,Gerald Heckel,Hanan Sheikh Ali,Stephan Drewes,Konrad M Wanka,Denise Kühnert,Marc Mertens,Sandra Essbauer,Jona Freise

doi:10.1111/eva.12263

Abstract

Many viruses significantly impact human and animal health. Understanding the population dynamics of these viruses and their hosts can provide important insights for epidemiology and virus evolution. Puumala virus (PUUV) is a European hantavirus that may cause regional outbreaks of hemorrhagic fever with renal syndrome in humans. Here, we analyzed the spatiotemporal dynamics of PUUV circulating in local populations of its rodent reservoir host, the bank vole (Myodes glareolus) during eight years. Phylogenetic and population genetic analyses of all three genome segments of PUUV showed strong geographical structuring at a very local scale. There was a high temporal turnover of virus strains in the local bank vole populations, but several virus strains persisted through multiple years. Phylodynamic analyses showed no significant changes in the local effective population sizes of PUUV, although vole numbers and virus prevalence fluctuated widely. Microsatellite data demonstrated also a temporally persisting subdivision between local vole populations, but these groups did not correspond to the subdivision in the virus strains. We conclude that restricted transmission between vole populations and genetic drift play important roles in shaping the genetic structure and temporal dynamics of PUUV in its natural host which has several implications for zoonotic risks of the human population.

Highlights

The evolution of pathogens is profoundly influenced by the evolutionary history and geographical distribution of their hosts
Emerging infectious diseases may be examples where pathogens escape the evolutionary constraints of particular hosts and enter different evolutionary backgrounds (Cox-Singh 2012; Morse et al 2012)
There were large differences in the prevalence between bank vole populations and sampling years, ranging from 0% to 100% for localities with at least ten voles trapped per year and a maximum of 89% Puumala virus (PUUV)-infected voles (n = 47) across all localities in 2010 (Table 1, Fig. 2)

Summary

Introduction

The evolution of pathogens is profoundly influenced by the evolutionary history and geographical distribution of their hosts. Connectivity between host populations and their local sizes determine to a large extent the transmission and infection rates and geographical distribution of a pathogen. Pathogens may evolve specific strategies or use windows of opportunity to overcome the limitations of particular host species, resulting in host-switch events and the (re-)emergence of infectious diseases (e.g., malaria, influenza, AIDS, and Ebola). Emerging infectious diseases may be examples where pathogens escape the evolutionary constraints of particular hosts and enter different evolutionary backgrounds (Cox-Singh 2012; Morse et al 2012). A large proportion of the emerging diseases represent zoonoses caused by RNA viruses that are transmitted to humans from their natural reservoir species (Cleaveland et al 2001; Holmes 2009). Understanding the population dynamics and interactions between viruses and their natural hosts is essential for resolving epidemiological processes and their evolutionary trajectories (Gire et al 2014)

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