Molecular epidemiology of Crimean–Congo hemorrhagic fever virus in ticks collected from western Iran

Background: Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease that is endemic in Africa, southeastern Europe, and Asia. Ticks are both the reservoir and the vector of the CCHF virus (CCHFV). Determining the virus infection rate of the tick population in different geographical regions is necessary todesign public health policies to prevent CCHF outbreaks. Objectives: To determine the prevalence, seasonal activity, and the frequency of CCHFV infection of the tick population in Hamadan province of west Iran. Methods: This cross-sectional study was conducted in 3 counties of Hamadan Province from June 2013 to May 2014. The study areas included both lowland (plains) and highland (mountains) and covered 5% of the villages where 10 herds per village of sheep and goats were randomly selected for hard tick collection. Results: We examined 983 sheep and goats, and 881 ticks were collected and identified before being preserved for molecular tests. The collected ticks belonged to 3 genera including, Rhipicephalus (95.6%, n = 842), Hyalomma (4.1%, n = 36) and Haemaphysalis (0.4%, n = 4). After species identification, 100 randomly selected ticks were analyzed using reverse transcriptase-polymerase chain reaction (RT-PCR) to detect viral infection. CCHFV infection was observed in 7 collected ticks, of which 4 belonged to R. sanguineus, 2 belonged to R. bursa, and one Hy. asiaticum. Conclusions: Hyalomma and Rhipicephalus ticks are the main vectors of CCHFV in Hamadan province where CCHF is focal and endemic. Keywords: Crimean-Congo hemorrhagic fever, Hamadan, Iran, molecular epidemiology, tick-borne diseases, zoonotic viral disease