Changes in the epidemiology of Crimean-Congo hemorrhagic fever: Impact of travel and a One Health approach in the European region

Abstract

Background: The World Health Organization has identified Crimean-Congo hemorrhagic fever (CCHF) as a priority disease for research and development in emergency contexts. The epidemiology of CCHF is evolving and this review highlights travel-associated cases and focuses on the need for a One Health approach in Europe.

Methods: For this narrative review, two searches were performed in PubMed and Google Scholar for the period 1980-October 2024. The first search identified travel-associated CCHF cases globally, additional cases were identified in the ProMED mail database and through healthmap.org. The second search, with a focus on the European region, aimed to analyse reports of CCHF virus (CCHFV) detected in ticks, CCHF seroprevalence studies in animals and/or humans, and autochthonous CCHF cases.

Results: Seventeen cases of imported CCHF, the majority acquired in Africa, were identified. Importation to European countries accounted for eight of the cases. Most patients presented with fever and hemorrhagic manifestations and the estimated case fatality rate was 35 %. In the WHO European region, at least 13 countries have reported ticks infected with different genotypes of CCHFV; 17 countries were found to have animals/humans with positive CCHF serology. Finally, 16 countries in the WHO European region have notified human cases of CCHF. The Russian Federation, Turkey, and several former USSR countries are considered highly endemic, followed by the Balkanic region, with sporadic cases emerging in Bulgaria, Greece, Spain, and recently Portugal.

Conclusions: Travel-associated CCHF is infrequent. However, given the recently reported increased geographical distribution in ticks and animals in the European region, additional human cases may be anticipated in the near future. Europe receives over half of all international tourist arrivals annually, so healthcare professionals should be aware of risk factors and current protocols for the management of suspected and confirmed cases.

Keywords: Arbovirus; Crimean-Congo hemorrhagic fever virus; Hyalomma spp; Tick-borne diseases; Traveler.