Orthohantaviruses in Reservoir and Atypical Hosts in the Czech Republic: Spillover Infection and Indication of Virus-Specific Tissue Tropism.

Orthohantaviruses (genus Orthohantavirus) are a diverse group of viruses that are closely associated with their natural hosts (rodents, shrews, and moles). Several orthohantaviruses cause severe disease in humans. Central and western Europe are areas with emerging orthohantavirus occurrences. In our study, several orthohantaviruses, including the pathogenic Kurkino virus (KURV), were detected in their natural hosts trapped at several study sites in the Czech Republic. KURV was detected mainly in its typical host, the striped field mouse (Apodemus agrarius). Nevertheless, spillover infections were also detected in wood mice (Apodemus sylvaticus) and common voles (Microtus arvalis). Similarly, Tula virus (TULV) was found primarily in common voles, and events of spillover to rodents of other host species, including Apodemus spp., were recorded. In addition, unlike most previous studies, different tissues were sampled and compared to assess their suitability for orthohantavirus screening and possible tissue tropism. Our data suggest possible virus-specific tissue tropism in rodent hosts. TULV was most commonly detected in the lung tissue, whereas KURV was more common in the liver, spleen, and brain. Moreover, Seewis and Asikkala viruses were detected in randomly found common shrews (Sorex araneus). In conclusion, we have demonstrated the presence of human-pathogenic KURV and the potentially pathogenic TULV in their typical hosts as well as their spillover to atypical host species belonging to another family. Furthermore, we suggest the possibility of virus-specific tissue tropism of orthohantaviruses in their natural hosts. IMPORTANCE Orthohantaviruses (genus Orthohantavirus, family Hantaviridae) are a diverse group of globally distributed viruses that are closely associated with their natural hosts. Some orthohantaviruses are capable of infecting humans and causing severe disease. Orthohantaviruses are considered emerging pathogens due to their ever-increasing diversity and increasing numbers of disease cases. We report the detection of four different orthohantaviruses in rodents and shrews in the Czech Republic. Most viruses were found in their typical hosts, Kurkino virus (KURV) in striped field mice (Apodemus agrarius), Tula virus (TULV) in common voles (Microtus arvalis), and Seewis virus in common shrews (Sorex araneus). Nevertheless, spillover infections of atypical host species were also recorded for KURV, TULV, and another shrew-borne orthohantavirus, Asikkala virus. In addition, indications of virus-specific patterns of tissue tropism were observed. Our results highlight the circulation of several orthohantaviruses, including KURV, which is pathogenic to humans, among rodents and shrews in the Czech Republic.

Detection of shrew-borne hantavirus in Eurasian pygmy shrew (Sorex minutus) in Central Europe.

Recently, it was found that not only rodents but also shrews are reservoir hosts of hantaviruses. In Central Europe, only Seewis virus, associated with the Eurasian common shrew (Sorex araneus), has been recognized until now. In the present report, tissue samples from shrews belonging to Crocidurinae and Soricinae subfamilies, trapped in Czech Republic, Germany, and Slovakia, were screened for the presence of novel hantaviruses. Three new hantavirus partial L-segment sequences were obtained from pygmy shrews (Sorex minutus) trapped in Czech Republic and Germany. Complete nucleocapsid protein- and glycoprotein precursor-coding S- and M-segment sequences were then determined for the newly recognized hantavirus strains, CZ/Beskydy/412/2010/Sm, CZ/Drahany/420/2010/Sm, and DE/Dürrbach/1912/2009/Sm. Phylogenetic analyses showed that they represent strains of Asikkala virus (ASIV), a novel hantavirus also found in pygmy shrews from Finland. Our study reveals a broad geographic distribution of ASIV across Europe and indicates pygmy shrew as the primary reservoir host. Future studies will have to determine the pathogenic relevance of ASIV.