Current situation of Crimean Congo hemorrhagic fever (CCHF) in Anatolia and Balkan Peninsula

Abstract

Crimean-Congo hemorrhagic fever (CCHF) is a viral disease transmitted to humans mainly by bite of Ixodid ticks, mainly those of the Hyalomma genus. CCHFV belongs to the genus Nairovirus in the family Bunyaviridae. CCHF virus is a segmented, single stranded, negative sense and RNA viruses. The onset of the disease is very sudden, with symptoms such as fever, rigors, intense headache, chills, and backache or leg pains, myalgia, nausea, and vomiting. CCHF originally identified in the former Soviet Union and the Congo, has rapidly spread across large sections of Europe, Asia, and Africa, and has been reported in more than 30 countries. The climatic changes may affect the life cycle of ticks and the routes of migratory birds, leading to tick abundance and virus distribution in CCHF-free areas. Extended use of land for agriculture and farming and changes in hunting activities play also a role in CCHF incidence, while livestock trade and movement may influence host-tick-virus dynamics resulting in transfer of CCHFV-infected ticks in non-endemic areas. Recent years, the epidemiology of CCHF is changing in Balkans and Turkey. Balkan Peninsula is a known endemic CCHF area, and sporadic cases and even outbreaks are being reported every year. The annual number of human CCHF cases is increasing in Balkans and Turkey. While Bulgaria, Kosovo and Albania were known endemic regions in Balkans, the disease emerged only recently in Turkey (in 2002, and since then, many cases every year) and in Greece (in 2008, one fatal case). Seven main clades are distinguishable in the phylogenetic tree based on S segment sequences of CCHFV. Up to now all strains from Balkans belong into the Europe 1 clade, while in Greece, and, recently in Turkey, AP92 and AP92-like strains are also present. A detailed study on Turkish strains showed that they are grouped into two main clusters, each one further divided into two subclusters. In this article, we were aimed to review of the current status of CCHF disease in the Balkans and Anatolia peninsula.