Worldwide epidemiology of Crimean-Congo Hemorrhagic Fever Virus in humans, ticks and other animal species, a systematic review and meta-analysis

Abstract

There are uncertainties about the global epidemiological data of infections due to Crimean-Congo hemorrhagic fever virus (CCHFV). We estimated the global case fatality rate (CFR) of CCHFV infections and the prevalence of CCHFV in humans, ticks and other animal species. We also explored the socio-demographic and clinical factors that influence these parameters. In this systematic review with meta–analyses we searched publications from database inception to 03rd February 2020 in Pubmed, Scopus, and Global Index Medicus. Studies included in this review provided cross-sectional data on the CFR and/or prevalence of one or more targets used for the detection of CCHFV. Two independent investigators selected studies to be included. Data extraction and risk of bias assessment were conducted independently by all authors. Data collected were analysed using a random effect meta-analysis. In all, 2345 records were found and a total of 312 articles (802 prevalence and/or CFR data) that met the inclusion criteria were retained. The overall CFR was 11.7% (95% CI = 9.1–14.5), 8.0% (95% CI = 1.0–18.9), and 4.7% (95% CI = 0.0–37.6) in humans with acute, recent, and past CCHFV infections respectively. The overall CCHFV acute infections prevalence was 22.5% (95% CI = 15.7–30.1) in humans, 2.1% (95% CI = 1.3–2.9) in ticks, and 4.5% (95% CI = 1.9–7.9) in other animal species. The overall CCHFV recent infections seroprevalence was 11.6% (95% CI = 7.9–16.4) in humans and 0.4% (95% CI = 0.0–2.9) in other animal species. The overall CCHFV past infections seroprevalence was 4.3% (95% CI = 3.3–5.4) in humans and 12.0% (95% CI = 9.9–14.3) in other animal species. CFR was higher in low-income countries, countries in the WHO African, South-East Asia and Eastern Mediterranean regions, in adult and ambulatory patients. CCHFV detection rate in humans were higher in CCHFV suspected cases, healthcare workers, adult and hospitalized patients, ticks of the genus Ornithodoros and Amblyomma and in animals of the orders Perissodactyla and Bucerotiformes. This review highlights a significant disease burden due to CCHFV with a strong disparity according to country income levels, geographic regions, various human categories and tick and other animal species. Preventive measures in the light of these findings are expected.

Seroepidemiology of Crimean-Congo Hemorrhagic Fever Virus (CCHFV) in Cattle across Three Livestock Pastoral Regions in Kenya

“…Cattle and other domestic animals may serve as reservoirs for CCHFV, which pose a threat to humans [23,33]. In Kenya, evidence of CCHFV exposure in humans and diverse tick species has been documented [19][20][21][22].…”

Seroepidemiology of Crimean-Congo Haemorrhagic Fever among cattle in Cameroon: Implications from a One Health perspective

“…Less frequently, patients develop a severe and often fatal haemorrhagic disease after a brief incubation period (~ 1 week) characterized by high-fever, fatigue, myalgia, vomiting and diarrhoea that progress to a haemorrhagic period with reports of petechiae, hematomas, generalized bleeding and multi-organ insufficiency [ 1 , 9 ]. The overall case fatality rate (CFR) ranges from 4.7% to 11.7%, an estimate reflecting variation related to the infectious status (ongoing, recent or past infection) [ 10 ]. Primary infection occurs after an infected tick bite, by accidental crushing of infected ticks or through direct contact with tissues, fluids or blood of viraemic hosts (domestic or wildlife animals and humans)[ 1 , 2 ].…”

“…The disease exists in a silent enzootic cycle, whose balance relies in a complex ‘animal-tick-environment’ interplay, ultimately involving humans as accidental hosts [ 8 ]. CCHFV has been detected in a wide range of Ixodidae (hard ticks) and some Argasidae ticks (soft ticks) [ 10 , 12 , 13 ]. Gargili et al .…”

Ticks on the Run: A Mathematical Model of Crimean-Congo Haemorrhagic Fever (CCHF)—Key Factors for Transmission

“…CCHF is endemic in many regions that include Africa, Asia, Eastern and Southern Europe, Middle East but the course of transmission is not homogenous around these places [32]. Given the heterogeneity of socio-economic conditions and cultural divergences amongst these zones, potential reasons of sporadic cases of CCHF can not be explained by a single mechanism [33]. Therefore, we strive to construct reasonably simple mathematical models to determine current knowledge gaps blocking the effective control measures while taking account of different transmission routes.…”