Crimean-Congo hemorrhagic fever virus in ticks in Turkey: A broad range tick surveillance study

In Turkey, Crimean-Congo hemorrhagic fever (CCHF) outbreaks started in northern regions in 2002. Human cases still continue to increase and the disease spreads in many other provinces of Turkey. The ecological role of the vector tick species occurring in Turkey is not certain exactly. Therefore, we planned a broad range tick study in three different ecological and geographical areas extending from the West Black Sea regions down to the Central Anatolia. The aim of this study was to determine and characterize CCHFV molecularly in feeding-ticks collected from various wild and domestic animals and from humans as well as in questing and unfed ticks. In this study, 4283 tick samples derived from 21 tick species were collected from 76 villages and 10 central districts in total. All tick pools were screened for the presence of CCHFV RNA by two nested RT-PCRs. PCR assays were positive for 27 (3.6%) of 736 pools. CCHFV was detected in Hyalomma marginatum, Dermacentor marginatus, Rhipicephalus bursa, Rhipicephalus turanicus, Hyalomma excavatum and Haemaphysalis parva pools. As a result of the phylogenetic analysis, it was determined that the obtained CCHFV sequences are clustered into Europe 1 clade. CCHFV was detected among ticks obtained from cattle, goats, wild boar, hare, and the ground. The presence of CCHFV in ticks obtained from various domestic and wild hosts and the nature, and thereby the distribution patterns of the virus in different ecological areas were presented in this study. Furthermore, CCHFV was also detected in unusual tick species. Consequently, these results indicate that tick surveillance studies in large-scale and wide varieties contribute to the ecology and epidemiology of CCHF in that region, and can be used as an early-warning system.