Crimean-congo haemorrhagic fever virus in ticks and small ruminants in western Iran: epidemiological insights and genotyping

BACKGROUND: Crimean-Congo haemorrhagic fever (CCHF) is an emerging zoonotic disease of significant public health concern caused by Crimean-Congo haemorrhagic fever virus (CCHFV), primarily transmitted by tick vectors. Its spread is further compounded by global warming, tick range expansion, and traditional farming practices. This study aimed to assess the prevalence of CCHFV in ticks parasitizing livestock in Kermanshah Province, Iran, which borders Iraq, a country that has experienced major CCHF outbreaks in recent years. METHODS: Serum and tick samples were collected from 302 small ruminants (SRs) in six districts, considering previous CCHF cases and regional differences. Following RNA extraction from both ticks and sera, a homemade real-time RT-PCR was used to detect CCHFV infection. RESULTS: All sera tested negative, while 0.67% (4/604) of ticks were infected with CCHFV (Hyalomma asiaticum and Rhipicephalus sanguineus were positive). This study confirms the circulation of CCHFV in the western region of Iran and, more importantly, reports the detection of an Aigai virus (formerly CCHFV genotype VI or AP-92-like strain) in tick populations for the first time in Iran. CONCLUSIONS: These findings emphasize the need for continued molecular surveillance, vector control, and cross-border cooperation to mitigate the risk of CCHF transmission in humans.