Identification and validation of internal reference genes for real-time quantitative polymerase chain reaction-based studies in Hyalomma anatolicum ticks.

Crimean-Congo hemorrhagic fever (CCHF) is an emerging tick-borne viral disease caused by the orthonairovirus CCHF virus (CCHFV). Ticks of the genus Hyalomma are the viral reservoir and they represent the main vector transmitting the virus to their hosts during blood feeding. However, how CCHFV replicates in its natural arthropod host cells and the nature of virus/host interactions are still largely unknown. With the aim of developing tools for use in this field, we identified and validated expression of four candidate endogenous control tick genes in a Hyalomma anatolicum-derived cell line. These genes will be useful for normalization of viral/cellular transcripts in infection/expression studies or as internal controls in molecular epidemiology surveys of pathogens transmitted by Hyalomma ticks.