WILD UNGULATES AS SENTINELS OF CRIMEAN-CONGO HEMORRHAGIC FEVER VIRUS CIRCULATION IN SPAIN

Introduction:
Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging tick-borne pathogen in southwestern Europe, maintained in enzootic cycles involving Hyalomma spp. ticks and vertebrate hosts. In Spain, evidence of viral circulation highlights the need for effective surveillance systems. Wild ungulates, particularly red deer, may serve as useful sentinels for monitoring CCHFV transmission and assessing zoonotic risk. This study aimed to determine the seroprevalence against CCHFV in wild ungulates and to evaluate their role as reservoirs of the virus in natural ecosystems.

Methods:
Between 2024 and 2026, a total of 184 wild ungulates from central and southern Spain were sampled during hunting activities. The study included red deer (Cervus elaphus), wild boar (Sus scrofa), and fallow deer (Dama dama). Serum samples were analyzed for antibodies against CCHFV using a commercial double-antigen ELISA (ID Screen CCHF Multispecies, IDvet), following the manufacturer’s instructions.

Results:
Antibodies against CCHFV were detected in 107 of 184 animals (58.15%). By species, 87 (70.16%, 95% CI 62.1%–78.2%) of the 124 red deer, 12 (24.49%, 95% CI 12.4%–36.5%) of the 49 wild boar, and 8 (72.73%, 95% CI 46.4%–99.1%) of the 11 fallow deer analyzed were seropositive. Evidence of CCHFV exposure was found across all sampling sites.

Conclusions:
The high seroprevalence observed supports widespread exposure to CCHFV among wild ungulates in Spain. These findings are consistent with previous findings that support the important role of cervids in the epidemiological cycle maintenance, while wild boar may have a more limited contribution. Additionally, as ungulates are major hosts for Hyalomma spp. ticks, the main vectors of CCHFV in the Iberian Peninsula, they may contribute to viral persistence in natural ecosystems and highlight their value as useful sentinels for CCHFV surveillance, reinforcing the importance of active monitoring programs in high-risk areas within a One Health framework.