Novel Flavi-like virus in ixodid ticks and patients in Russia

Novel Haseki tick virus (HSTV) was detected in ixodid ticks and patients in the Asian part of Russia. Sequencing of the genome fragments corresponding whole polyprotein and viral RdRp demonstrated that HSTV is genetically close to unclassified Flavi-like viruses. Phylogenetic analysis of HSTV sequences showed that these viruses were close to Bole tick virus 4 (BLTV 4), which was detected early in Asia, Europe, Africa and the Caribbean region. The organization of the genome predicts that HSTV and BLTV 4 may also be classified as putative new genera within Flaviviridae with enlarged Flavi-like positive-sense ssRNA viral genomes. Cases of HSTV putative human incidents after Ixodes persulcatus attack were discovered in hospital patients with tick-borne infections in Vladivostok (Russia). The illness was associated with 3–5 days of fever, accompanied by acute respiratory lesions. Mixed human tick-borne infections (TBIs) were also detected for these patients as dual or triple coinfections for tick-borne encephalitis virus, Borrelia spp., Anaplasma spp., and HSTV. Thus, it is necessary to study HSTV antibody tests, virus isolation, and surveillance for HSTV sequences in different species of ticks, different geographical regions and patients after tick attacks.