An Emerging Biothreat: Crimean-Congo Hemorrhagic Fever Virus in Southern and Western Asia

Abstract

Tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV) is endemic in numerous countries, but the epidemiology and epizoology of Crimean-Congo hemorrhagic fever (CCHF) remain to be defined for most regions of the world. Using a broad database search approach, we reviewed the literature on CCHF and CCHFV in Southern and Western Asia to better define the disease burden in these areas. We used a One Health approach, moving beyond a focus solely on human disease burden to more comprehensively define this burden by reviewing CCHF case reports, human and animal CCHFV seroprevalence studies, and human and animal CCHFV isolations. In addition, we used published literature to estimate the distribution of Hyalomma ticks and infection of these ticks by CCHFV. Using these data, we propose a new classification scheme for organizing the evaluated countries into five categories by level of evidence for CCHF endemicity. Twelve countries have reported CCHF cases, five from Southern Asia and seven from Western Asia. These were assigned to level 1 or 2. Eleven countries that have evidence of vector circulation but did not report confirmed CCHF cases were assigned to level 3 or 4. This classification scheme was developed to inform policy toward strengthening CCHF disease surveillance in the Southern and Western Asia regions. In particular, the goal of this review was to inform international organizations, local governments, and health-care professionals about current shortcomings in CCHFV surveillance in these two high-prevalence regions.

Figure 1.

Burden of CCHF in Southern and Western Asia using a One Health approach. Data support CCHFV circulation in lower Level (1 and 2) countries, whereas further study and surveillance of CCHFV circulation is recommended in countries of higher Levels (3, 4, and 5). Classification at the country level was performed for policy implications. Country boundaries do not necessarily reflect the geographic area at risk. Map was created using ArcGIS Release 10.61. Source: Database of Global Administrative Areas (GADM). This figure appears in color at www.ajtmh.org.¹