Detection of Crimean-Congo hemorrhagic fever virus (CCHFV) in Hyalomma ticks collected from Mauritanian livestock  : [Preprint]

Background: Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to the Nairovididae family in the Orthonairovirus genus and is an emerging tick-borne virus. It is endemic in most parts of Africa, Asia, as well as southern Europe, and can cause severe hemorrhagic symptoms in humans with high fatality rates (5-30 %). Methods: Hyalomma ticks were collected from four different livestock herds (cattle and camel) from Mauritania in 2018. The tick species was determined morphologically and confirmed on a molecular level by using cytochrome oxidase 1 gene marker (CO1). For the detection of CCHFV, ticks were tested individually with a one-step multiplex real-time RT-qPCR. Subsequently, the S-segment of all positive samples were sequenced to determine the CCHFV genotype. Results: Overall, 39 of 1,523 ticks (2.56 %) collected from 63 cattle and 28 camels were tested positive for CCHFV. Three Hyalomma (H.) species were identified. The highest prevalence of CCHFV was found in Hyalomma rufipes (5.67 %; 16/282), followed by H. dromedarii (1.89 %; 23/1,214) and H. impeltatum (0 %; 0/21). Positive ticks were found on only 6 out of 91 host animals. Sequence analysis of the positive samples revealed the presence of two different CCHFV lineages (Africa I and Africa III). Conclusions: This study reveals a CCHFV prevalence of 2.56 % in Hyalomma ticks collected from camels and cattle in Mauritania. The true prevalence of unfed ticks may however be lower since a considerable number of ticks may have been passively infected during the ingestion of the blood meal by co-feeding or viremia of the host. The study shows that tick control measures should be implemented, especially in the examined areas.