Wagner et al.
First indications of Omsk haemorrhagic fever virus beyond Russia
Viruses. 2022;14(4):754. doi: 10.3390/v14040754

Omsk hemorrhagic fever virus (OHFV) belongs to the tick-borne encephalitis complex in the family of Flaviviridae. This virus has a highly similar genome sequence and similar morphology and replication mode of virions to the TBE virus. OHFV can cause a variety of clinical symptoms. In humans, it can cause hemorrhagic fever with a case fatality rate of 0.5% to 3.0%.

First outbreaks of OHFV have been reported between 1945 and 1958 in Siberia. Currently, OHFV infections are only reported in Russia. The Republic of Kazakhstan is adjacent to Western Siberia (Russia). In Kazakhstan, there are many cases of fever with unknown origin and many endemic viruses lead to disease with similar non-specific symptoms. Therefore, a German/Kazakh team has analyzed if OHFV may be present in Kazakhstan.

In 2/130 human CSF specimens of patients treated with symptoms like headache and meningitis, OHFV-specific RNA could be detected.

In 4993 ticks collected in three different regions, OHFV could be detected in Dermacentor marginatus, D. reticulatus, and Ixodes persulcatus.

In lungs of the rodents Clethrionoyms glareolus and Mus musculus (Muridae), OHFV-specific RNA could be detected. In conclusion, OHFV was, for the first time, detected in human patients, ticks and rodents outside of Russia in the Republic of Kazakhstan.

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