Molecular identification of novel phlebovirus sequences in European ticks

In recent years the number of newly described tick-borne phleboviruses has been steadily growing. Some of these novel viruses are highly pathogenic in humans, e.g. the Heartland and severe fever with thrombocytopenia syndrome virus. We aimed to analyse ticks sampled across Europe to investigate the diversity of phleboviruses using a comprehensive PCR-based screening approach. A total of 4387 ticks were collected from the vegetation in regions of France, Belgium, Germany, Sweden, and Estonia, respectively. Ticks were pooled and 22/979 pools tested positive using a PCR targeting the large (L) segment of phleboviruses. Phylogenetic analysis of a 500-bp fragment of the L segment showed a distinct novel clade provisionally named Glabbeek/Osterholz group (Belgium and Germany). In addition, sequences from ticks sampled in France clustered together with the recently described Antigone virus from Greece and AnLuc from Portugal. Our results extend the current diversity of phleboviruses in Europe. Future research should address the ecological processes driving the occurrence of phleboviruses and the impact of these novel phleboviruses for public health.