1. Hantaviruses in Microtus voles
Petra Straková1,2,3, Sabrina Schmidt1, Moritz Saxenhofer4,8, Chao Wen1, Laima Balčiauskienė5, Linas Balčiauskas5, Marta Heroldová2, Olivia Beerli6, Philippe Marianneau7, Gerald Heckel4,8, Rainer G. Ulrich1
1 Friedrich-Loeffler-Institut, Institute for Novel and Emerging Infectious Diseases, Greifswald - Insel Riems, Germany, 2 Institute of Vertebrate Biology v.v.i., Academy of Sciences, Brno, Czech Republic; 3 Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic; 4 Computational and Molecular Population Genetics (CMPG), Institute of Ecology and Evolution, University of Bern, Bern, Switzerland; 4 Nature Research Centre, Vilnius, Lithuania; 6 Institute of Parasitology, University of Zurich, Zurich, Switzerland; 7French Agency for Food, Environmental and Occupational Health and Safety (ANSES), Virology Unit, Laboratory of Lyon, Lyon, France; 8 Swiss Institute of Bioinformatics, Genopode, Lausanne, Switzerland
Introduction
In North America and Asia, different hantaviruses were found to be associated with the meadow vole (Microtus pennsylvanicus), the North American California vole (Microtus californicus), the Maximowicz´s vole (Microtus maximowiczii), the reed vole (Microtus fortis) or the root vole (Microtus oeconomus) (Plyusnin and Morzunov 2001). Tula virus (TULV) is widely distributed through Europe and has been detected in several vole species – the common vole (Microtus arvalis), the East European vole (Microtus levis), the field vole (Microtus agrestis), the European pine vole (Microtus subterraneus) and the water vole (Arvicola spp.) (Fig. 1). In addition, two TULV-related strains were described – Adler virus in Russia (in the common vole) and Tatenale virus in the UK (in the field vole).
Results
Here, we present a study of more than 1,000 voles (M. arvalis, M. agrestis, M. oeconomus) from Germany, France, Luxembourg, the Czech Republic and Lithuania. Blood samples were investigated by in-house ELISA using recombinant nucleocapsid protein of TULV strain Moravia. For detection of viral RNA, lung samples were screened by RT-PCR targeting S segment (Tab. 1). A phylogenetic tree was generated for partial S segment sequences with novel sequences from Germany, France, the Czech Republic and Lithuania being labeled (Fig. 2). To evaluate the relations of hantavirus and vole reservoir phylogenies, a phylogenetic tree based on the complete cytochrome b coding sequence of different Microtus species was created (Fig. 3). A B
Fig.1: The two main TULV hosts in Europe: A – the common vole (Microtus arvalis), and B – the field vole (Microtus agrestis). These voles are distributed widely through Europe.
Tab.1: Results of ELISA and RT-PCR investigations of Microtus voles in Germany, France, the Czech Republic, Luxembourg
and Lithuania. N.d.: not determined. C
all Microtus arvalis
Brno, Czech Republic
Isla Vista virus
Bloodland Lake virus
Prospect Hill virus
TULV
all Microtus arvalis
Rutesheim, BW, Germany
Adler virus
TULV
both Microtus arvalis
Amplepuis, France
Vladivostok virus
Microtus arvalis, Jeeser, MWP, Germany
Microtus agrestis, Jeeser, MWP, Germany ?
Microtus agrestis, Gotha, Thuringia, Germany
Microtus oeconomus, Rusné, Lithuania
Khabarovsk virus
Vladivostok virus
Yuanjiang virus
Khabarovsk virus
Fig. 2: Phylogenetic tree based on sequences of TULV RT-PCR positive animals from Germany, France, the Czech Republic and Lithuania (Maximum Likelihood Tree, Jukes-Cantor model, bootstrap value 1000). For this tree, sequences of 340 bp were used. Identical sequences are not included.
Fig. 3: Phylogenetic tree based on sequences of the complete coding region of cytochrome b gene (Maximum Likelihood Tree, Jukes-Cantor model, bootstrap value 1000). For this tree, sequences of 1140 bp were used.
Conclusion and Outlook
Our investigations confirmed a broad geographical distribution of TULV in different parts of Central Europe with varying prevalences (Tab. 1). Phylogenetic analyses demonstrated a strong genetic structuring of TULV sequences according to geography but indepentent on rodent host species (see Schmidt et al. 2016). The RNA prevalence was higher in common voles than in the other vole species, indicating the common vole as the preferential host with spillover infections in co-occurring field voles .
The initial finding of large-scale associations of some TULV clades with different evolutionary lineages of common voles indicates the need for future studies of potential (co-) evolutionary processes and the role of reservoir species barriers for TULV infection.
Acknowledgement
This study was performed within the network „Rodent-borne pathogens“ and supported by the Deutsche Forschungsgemeinschaft (SPP 1596 „Ecology and Species Barriers in Emerging Viral Diseases“, UL 405/1-1 to RGU) and by the EMIDA ERA-NET project APHAEA (grant no. 2811ERA117). We would also like to thank to ERASMUS+ for financial support to Petra Straková.
References
Plyusnin A., Morzunov S.P. (2001): Virus evolution and genetic diversity of hantaviruses and their rodent hosts. Curr Top Microbiol Immunol 256:47–75.
Schmidt et al. (2016): High genetic structuring of Tula hantavirus. Arch Virol 161: