Identification and classification of Crimean-Congo hemorrhagic fever virus from Hyalomma asiaticum from southern Mongolia

Crimean-Congo hemorrhagic fever virus (CCHFV) is an orthonairovirus that can be found in Hyalomma spp. ticks. It can cause fatal disease in humans, with the potential for person-to-person transmission in clinical settings. To further characterize CCHFV within Mongolia, small (S), medium (M), and large (L) segments of viral genome were amplified. Adult unfed Hyalomma asiaticum were hand collected from the environment in Bayankhongor, Dornogovi, Dundgovi, Govi-Altai, and Umnugovi aimags (provinces) located in southern Mongolia. Seven of 184 pools tested positive for CCHFV using conventional PCR targeting the S segment. Through next-generation sequencing, a full genome from a single tick pool (n = 5 ticks) collected from Dornogovi in 2022 was detected, with phylogenetic analysis of all three segments indicating the genome fell within the Asian genotype IV. The closest identity (>98%) of all three sequences were to CCHFV viral genomes identified from H. asiaticum collected within China in 2015 and 2016. Given that the Dornogovi aimag directly borders the Inner Mongolia region of China, the sequence similarity is likely attributable to the geographic proximity. Continued surveillance and genetic characterization of CCHFV within Mongolia is vital for disease surveillance as the growing threat of CCHFV in this region is compounded by the expansion of trade and risk of cross-border transmission.