Development and evaluation of a real-time RT-qPCR for detection of Crimean-Congo hemorrhagic fever virus representing different genotypes.

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic disease caused by a nairovirus belonging to family Bunyaviridae. The CCHF virus (CCHFV) can be transmitted to humans by Hyalomma ticks as well as by direct contact with infected body fluids or tissues from viremic livestock or humans. Our aim was to set up a fast RT-qPCR for detection of the different CCHFV genotypes in clinical samples, including an inactivation step to make the sample handling possible in lower biosafety levels (BSL) than BSL-4. This method was evaluated against commercial reference assays and international External Quality Assessment (EQA) samples. The analytical limit of detection for the developed CCHFV-S RT-qPCR was 11 CCHFV genomes per reaction. After exclusion of four dubious samples, we studied 38 CCHFV-positive samples (using reference tests) of which 38 were found positive by CCHFV-S RT-qPCR, suggesting a sensitivity of 100%. CCHFV-S RT q-PCR detected all eight different CCHFV strains representing five different CCHFV genotypes. In conclusion, the CCHFV-S RT-qPCR described in this study was evaluated using various sources of CCHFV samples and shown to be an accurate tool to detect human CCHFV infection caused by different genotypes of the virus.