Human epidemiological data of Crimean-Congo haemorrhagic fever, 2014-2023: scoping review over one decade

Crimean-Congo haemorrhagic fever (CCHF), a severe emerging viral tick-borne disease, poses a global threat. The virus, endemic to Africa, the Middle East, Asia, and the Balkans, is being detected in new regions. This study aimed to summarise available human CCHF epidemiological data and determine whether scientific literature, surveillance system reports, and public health authorities' disease notifications offer uniform and sufficiently useful data to timely detect changes in epidemiological trends. We conducted a systematic PubMed search (2017-2023) using relevant CCHF MeSH and entry terms (e.g. CCHF and epidemiology). We reviewed ProMED reports and publicly available public health authorities' notifications on CCHF (2014-2023). We extracted case characteristics, reporting date, and transmission routes from these reports. The review includes 88 PubMed articles, 309 ProMED reports, and 44 public health authorities' notifications, reporting on 7073, 4169, and 3749 confirmed cases respectively, mostly from endemic regions. The number of ProMED reported cases did not increase significantly over one decade (p = .281). The case-fatality rate was significantly higher in the African and Southeast Asian Regions compared to the European and Eastern Mediterranean Regions. The risk appeared elevated in people working with animals and in healthcare workers. Tick exposure was the most frequently reported transmission route. None of the three data sources provided a complete overview of CCHF epidemiology. A more accurate CCHF monitoring system is needed to detect epidemiological changes timely. Addressing current gaps, such as inconsistencies in reporting frequency, requires coordinated, standardised data collection and sharing using standardised reporting frameworks to strengthen global preparedness and response.