Crimean–congo haemorrhagic fever virus, an emerging and re-emerging pathogen

Abstract

Crimean-Congo haemorrhagic fever (CCHF) is a tick-borne viral zoonosis distributed in Africa, Asia, eastern Europe and the Balkans. The broad geographic range correlates with that of the principal vector of the virus, ticks belonging to the genus Hyalomma. Humans acquire infection through tick-bite or exposure to infected blood or tissues of animals or humans. Human infection is characterized by febrile illness with headache, myalgia and petechial rash, frequently followed by a hemorrhagic state and in some cases a fatal outcome. The importance of the tick-vertebrate-tick cycle in maintaining virus transmission is well established. Small mammals are considered important amplifying hosts of the virus. Domestic livestock show mild or no clinical signs of illness but develop a short period of viremia, during which the virus can be transmitted to humans, hence there is an occupational risk associated with employment in the livestock industry among farmers, farm workers, abattoir workers and veterinarians. The emergence of CCHF from 2002 in several countries in the Balkans raises concerns that this virus could expand its current geographic distribution and establish new endemic foci. Monitoring and control of the spread will require increased diagnostic capacity as well as surveillance and novel approaches to development of vaccines and drugs and vector control.