Crimean-Congo hemorrhagic fever virus in Central, Eastern, and South-eastern Asia

Abstract

Crimean-Congo hemorrhagic fever (CCHF), caused by Crimean-Congo hemorrhagic fever virus (CCHFV), is endemic in Africa, Asia, and Europe, but CCHF epidemiology and epizootiology is only rudimentarily defined for most regions. Here we summarize what is known about CCHF in Central, Eastern, and South-eastern Asia. Searching multiple international and country-specific databases using a One Health approach, we defined disease risk and burden through identification of CCHF cases, anti-CCHFV antibody prevalence, and CCHFV isolation from vector ticks. We identified 2313 CCHF cases that occurred in 1944-2021 in the three examined regions. Central Asian countries reported the majority of cases (2,026). In Eastern Asia, China was the only country that reported CCHF cases (287). In South-eastern Asia, no cases were reported. Next, we leveraged our previously established classification scheme to assign countries to five CCHF evidence levels. Six countries (China, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan) were assigned to level 1 or level 2 based on CCHF case reports and the maturity of the countries' surveillance systems. Two countries (Mongolia and Myanmar) were assigned to level 3 due to evidence of CCHFV circulation in the absence of reported CCHF cases. Thirteen countries in Eastern and South-eastern Asia were categorized in levels 4 and 5 based on prevalence of CCHFV vector ticks. Collectively, this paper describes the past and present status of CCHF reporting to inform international and local public-health agencies to strengthen or establish CCHFV surveillance systems and address shortcomings.

Keywords: Asia; Crimean-Congo hemorrhagic fever; Crimean-Congo hemorrhagic fever virus; Hyalomma; Tick.

Fig. 1

One Health approach to understanding the burden of CCHF in Central, Eastern, and South-eastern Asia. CCHFV circulation is confirmed in countries of lower levels (1 and 2), but it is recommended that further investigation and surveillance need to be conducted in countries of higher levels (3, 4, and 5). This classification is based on potential policy implications for individual countries. A highlighted country's boundaries are unlikely to reflect the exact ecological distribution of CCHFV within the country. However, even a single focus of CCHFV activity within a country will require the entire country to respond to it. (There is no guarantee that depicted country boundaries accurately reflect the geographical area at risk, nor are they necessarily endorsed by the authors).