Multiple orthonairoviruses including Crimean-Congo hemorrhagic fever virus, Tamdy virus and the novel Meram virus in Anatolia.

We conducted orthonairovirus RNA screening of 7043 tick specimens-representing 16 species-collected from various regions of Anatolia. In 602 pools, Crimean-Congo hemorrhagic fever virus (CCHFV) Europe 1 and 2 lineages were detected in seven pools (1.1 %) comprising Hyalomma marginatum, Hyalomma scupense, Rhipicephalus bursa, Rhipicephalus sanguineus sensu lato and Rhipicephalus turanicus ticks. In pools of Hyalomma aegyptium, we detected Tamdy virus (TAMV) and an unclassified nairovirus sequence. Next-generation sequencing revealed complete coding regions of three CCHFV Europe 2 (AP92-like) viruses, TAMV and the novel orthonairovirus, tentatively named herein as Meram virus. We further performed in silico functional analysis of all available CCHFV Europe 2, TAMV, Meram and related virus genomes. The CCHFV Europe 2 viruses possessed several conserved motifs, including those with OTU-like cysteine protease activity. Probable recombinations were identified in L genome segments of CCHFV and TAMV. Through phylogeny reconstruction using individual genome segments, Meram virus emerged as a distinct virus among species within the Orthonairovirus genus. It further exhibited conserved motifs associated with RNA binding, encapsidation, signal peptidase cleavage, post-translational modification, RNA-dependent RNA polymerase and OTU-like activities. Bole tick virus 3 was also detected in two pools with CCHFV reactivity. Hereby, we describe a novel tick-associated orthonairovirus, in a CCHFV-endemic region with confirmed TAMV activity. Human and animal health impact of these viruses need to be addressed.